WO2018150830A1 - Liquid discharge head substrate, method of manufacturing the same, liquid discharge head, and liquid discharge apparatus - Google Patents

Abstract

A method of manufacturing a liquid discharge head substrate is provided. The method includes forming a first substrate that includes a semiconductor element and a first wiring structure; forming a second substrate that includes a liquid discharge element and a second wiring structure; and bonding the first wiring structure and the second wiring structure such that the semiconductor element and the liquid discharge element are electrically connected to each other after the forming the first substrate and the second substrate.

Description

LIQUID DISCHARGE HEAD SUBSTRATE, METHOD OF MANUFACTURING THE SAME, LIQUID DISCHARGE HEAD, AND LIQUID DISCHARGE APPARATUS

The present invention relates to a liquid discharge head substrate, a method of manufacturing the same, a liquid discharge head, and a liquid discharge apparatus.

A liquid discharge head is widely used as a part of a printing apparatus that prints information such as characters or images on a sheet-shaped printing medium such as a sheet or a film. Japanese Patent Laid-Open No. 2016-137705 describes a method of forming a wiring structure on a semiconductor substrate where a circuit element is formed, and forming a heat generation element on the wiring structure, thereby forming a liquid discharge head substrate. The wiring structure includes a plurality of wiring layers, and its upper surface is planarized every time each wiring layer is formed.

Japanese Patent Laid-Open No. 2016-137705

In a liquid discharge head substrate, the liquid discharge characteristic of a heat generation element is determined by the thickness of an insulating layer between the heat generation element and a conductive member immediately below it. Heat dissipation from the heat generation element to the conductive member decreases if the thickness of this insulating layer is larger than a design value, making a liquid discharge amount larger than the design value. On the other hand, heat dissipation from the heat generation element to the conductive member increases if the thickness of this insulating layer is smaller than the design value, making the liquid discharge amount smaller than the design value. In a manufacturing method described in Japanese Patent Laid-Open No. 2016-137705, the heat generation element is formed on the uppermost wiring layer. An upper surface is planarized each time a wiring layer is formed, and thus an upper wiring layer has lower flatness. It is therefore difficult to form the liquid discharge head substrate such that the thickness of the insulating layer between the heat generation element and the conductive member immediately below it conforms to the design value over an entire wafer, making it impossible to improve performance of the liquid discharge head substrate sufficiently. An aspect of the present invention provides a technique for improving the performance of the liquid discharge head substrate.

According to some embodiments, a method of manufacturing a liquid discharge head substrate is provided. The method includes forming a first substrate that includes a semiconductor element and a first wiring structure; forming a second substrate that includes a liquid discharge element and a second wiring structure; and bonding the first wiring structure and the second wiring structure such that the semiconductor element and the liquid discharge element are electrically connected to each other after the forming the first substrate and the second substrate.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

Fig. 1A is a view for explaining an example of the arrangement of a liquid discharge head substrate according to the first embodiment.Fig. 1B is a view for explaining an example of the arrangement of a liquid discharge head substrate according to the first embodiment.

Fig. 2A is a view for explaining an example of a method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 2B is a view for explaining an example of a method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 2C is a view for explaining an example of a method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 2D is a view for explaining an example of a method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 2E is a view for explaining an example of a method of manufacturing the liquid discharge head substrate according to the first embodiment.

Fig. 3A is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 3B is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 3C is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 3D is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 3E is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.

Fig. 4A is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.Fig. 4B is a view for explaining an example of the method of manufacturing the liquid discharge head substrate according to the first embodiment.

Fig. 5A is a view for explaining a liquid discharge head substrate according to the second embodiment.Fig. 5B is a view for explaining a liquid discharge head substrate according to the second embodiment.

Fig. 6 is a view for explaining a liquid discharge head substrate according to the third embodiment.

Fig. 7A is a view for explaining a liquid discharge head substrate according to the fourth embodiment.Fig. 7B is a view for explaining a liquid discharge head substrate according to the fourth embodiment.Fig. 7C is a view for explaining a liquid discharge head substrate according to the fourth embodiment.Fig. 7D is a view for explaining a liquid discharge head substrate according to the fourth embodiment.Fig. 7E is a view for explaining a liquid discharge head substrate according to the fourth embodiment.

Fig. 8A is a view for explaining a liquid discharge head substrate according to the fifth embodiment.Fig. 8B is a view for explaining a liquid discharge head substrate according to the fifth embodiment.

Fig. 9A is a view for explaining a liquid discharge head substrate according to the sixth embodiment.Fig. 9B is a view for explaining a liquid discharge head substrate according to the sixth embodiment.

Fig. 10A is a view for explaining still another embodiment.Fig. 10B is a view for explaining still another embodiment.Fig. 10C is a view for explaining still another embodiment.Fig. 10D is a view for explaining still another embodiment.

Fig. 11A is a view for explaining a liquid discharge head substrate according to the seventh embodiment.Fig. 11B is a view for explaining a liquid discharge head substrate according to the seventh embodiment.Fig. 11C is a view for explaining a liquid discharge head substrate according to the seventh embodiment.Fig. 11D is a view for explaining a liquid discharge head substrate according to the seventh embodiment.

Fig. 12 is a view for explaining the liquid discharge head substrate according to the seventh embodiment.

Fig. 13A is a view for explaining a liquid discharge head substrate according to the eighth embodiment.Fig. 13B is a view for explaining a liquid discharge head substrate according to the eighth embodiment.

Embodiments of the present invention will now be described with reference to the accompanying drawings. The same reference numerals denote the same elements throughout various embodiments, and a repetitive description thereof will be omitted. The embodiments can appropriately be changed or combined. A liquid discharge head substrate will simply be referred to as a discharge substrate hereinafter. The discharge substrate is used for a liquid discharge apparatus such as a copying machine, a facsimile apparatus, or a word processor. In the embodiments below, a heat generation element is treated as an example of a liquid discharge element of a discharge substrate. The liquid discharge element may be an element such as a piezoelectric element or the like capable of applying energy to a liquid.

＜First Embodiment＞
An example of the arrangement of adischarge substrate 100 according to the first embodiment will be described with reference to Figs. 1A and 1B. Fig. 1A is a sectional view that focuses on a part of thedischarge substrate 100. Fig. 1B is an enlarged view of aregion 100a in Fig. 1A.

Thedischarge substrate 100 includes abase 110, awiring structure 120, aheat generation element 130, aprotective film 140, ananti-cavitation film 150, and anozzle structure 160. Thebase 110 is, for example, a semiconductor layer of silicon or the like. Asemiconductor element 111 such as a transistor and anelement isolation region 112 such as LOCOS or STI are formed in thebase 110.

Thewiring structure 120 is positioned on thebase 110. Using aflat bonding surface 121 as a boundary, thewiring structure 120 is divided into awiring structure 120a below thebonding surface 121 and awiring structure 120b above thebonding surface 121. Thewiring structure 120a includes an insulatingmember 122 andconductive members 123 to 125 of a plurality of layers inside the insulatingmember 122. Theconductive members 123 to 125 of the plurality of layers are stacked. Theconductive member 123 of a layer closest to thebase 110 is connected, by plugs, to thesemiconductor element 111 and the like formed in thebase 110. The conductive members positioned in adjacent layers of the plurality of layers are connected to each other by plugs.

Thewiring structure 120b includes an insulatingmember 126, andconductive members 127 and 128 of a plurality of layers inside the insulatingmember 126. Theconductive members 127 and 128 of the plurality of layers are stacked. Theconductive member 128 of a layer farthest from thebase 110 is connected to theheat generation element 130 by a plug. Theconductive member 127 and theconductive member 128 are connected to each other by a plug.

Each of theconductive members 123 to 125, 127, and 128 may partially include a dummy pattern. The dummy pattern is a conductive pattern which is not electrically connected to thesemiconductor element 111 and does not contribute to signal transfer or power supply. Each of theconductive members 123 to 125, 127, and 128 may be formed by a barrier metal layer and a metal layer. The barrier metal layer is formed by, for example, tantalum, a tantalum compound, titanium, or a titanium compound and suppresses diffusion or interaction of a material included in the metal layer. The metal layer is formed by copper or an aluminum compound and is lower than the barrier metal layer in resistance.

As shown in Fig. 1B, theconductive member 125 is formed by ametal layer 125a and abarrier metal layer 125b. Thebarrier metal layer 125b is arranged between themetal layer 125a and the insulatingmember 122. Theconductive member 127 is formed by ametal layer 127a and abarrier metal layer 127b. Thebarrier metal layer 127b is arranged between themetal layer 127a and the insulatingmember 126. Themetal layer 125a and themetal layer 127a, thebarrier metal layer 125a and thebarrier metal layer 125b, and the insulatingmember 122 and the insulatingmember 126 are bonded to each other on thebonding surface 121. Since thebonding surface 121 is flat, the upper surface of theconductive member 125 and the upper surface of the insulatingmember 122 are flush with each other, and the lower surface of theconductive member 127 and the lower surface of the insulatingmember 126 are flush with each other. As will be described later, thedischarge substrate 100 is manufactured by bonding two substrates. Consequently, a part of themetal layer 125a may be bonded to a part of thebarrier metal layer 127b, or a part of themetal layer 127a may be bonded to a part of thebarrier metal layer 125b depending on an alignment accuracy or processing accuracy at the time of bonding. The thickness of thebarrier metal layer 125b may be adjusted so as not to bond themetal layer 125a and the insulatingmember 126 to each other even if the alignment accuracy or the processing accuracy varies. The same also applies to bonding between themetal layer 127a and the insulatingmember 122.

Theheat generation element 130 is positioned in the upper part of thewiring structure 120. The side surfaces of theheat generation element 130 contact the insulatingmember 126. The upper surface of theheat generation element 130 is on the same plane as the upper surface of thewiring structure 120, that is, the upper surface of the insulatingmember 126. Thesemiconductor element 111 and theheat generation element 130 are electrically connected to each other by the wiring structure 120 (more specifically, by the conductive members included in the wiring structure 120). Theheat generation element 130 is formed by, for example, tantalum or a tantalum compound. Instead of this, theheat generation element 130 may be formed by polysilicon or tungsten silicide.

Theconductive member 128 of a layer closest to theheat generation element 130 out of theconductive members 123 to 125, 127, and 128 of the plurality of layers includes a conductive portion immediately below theheat generation element 130. The liquid discharge characteristic of theheat generation element 130 is determined by the thickness of aregion 126a of the insulatingmember 126 between this conductive portion and theheat generation element 130. Heat dissipation from theheat generation element 130 to the conductive members decreases if the thickness of this insulating layer is larger than a design value, making a liquid discharge amount larger than the design value. On the other hand, heat dissipation from theheat generation element 130 to the conductive members increases if the thickness of this insulating layer is smaller than the design value, making the liquid discharge amount smaller than the design value. Theregion 126a can also be referred to as a heat accumulation region.

Theprotective film 140 is positioned on thewiring structure 120 and theheat generation element 130. Theprotective film 140 covers at least the upper surface of theheat generation element 130 and also covers the upper surface of thewiring structure 120 in this embodiment. Theprotective film 140 is made of, for example, SiO, SiON, SiOC, SiC, or SiN and protects theheat generation element 130 from liquid erosion. In this embodiment, the both surfaces of theprotective film 140, that is, the surface on the side of theheat generation element 130 and the surface opposite to it are flat. It is therefore possible to sufficiently ensure the coverage of theheat generation element 130 even if theprotective film 140 is thin, as compared with a case in which the protective film has a step. Energy transfer efficiency to a liquid improves by thinning theprotective film 140, making it possible to implement both a reduction in power consumption and an improvement in image quality by stabilizing foaming.

Theanti-cavitation film 150 is positioned on theprotective film 140. Theanti-cavitation film 150 covers theheat generation element 130 across theprotective film 140. Theanti-cavitation film 150 is formed by, for example, tantalum, and protects theheat generation element 130 and theprotective film 140 from a physical shock at the time of liquid discharge.

Thenozzle structure 160 is positioned on theprotective film 140 and theanti-cavitation film 150. Thenozzle structure 160 includes anadherence layer 161, anozzle member 162, and a water-repellent material 163. Achannel 164 and anorifice 165 of a discharged liquid are formed in thenozzle structure 160.

Then, a method of manufacturing thedischarge substrate 100 will be described with reference to Figs. 2A to 4B. First, as shown in Fig. 2E, asubstrate 200 that includes thesemiconductor element 111 is formed. A method of forming thesubstrate 200 will be described below in detail. As shown in Fig. 2A, thesemiconductor element 111 and theelement isolation region 112 are formed in thebase 110 of a semiconductor material. Thesemiconductor element 111 may be, for example, a switch element such as a transistor. Theelement isolation region 112 may be formed by the LOCOS method or the STI method.

Subsequently, a structure shown in Fig. 2B is formed. More specifically, an insulatinglayer 201 is formed on thebase 110, holes are formed in the insulatinglayer 201, and aplug 202 is formed in each hole. Theplug 202 is formed by, for example, forming a metal film on the insulatinglayer 201 and removing a portion other than a portion of this metal film that enters the hole of the insulatinglayer 201 by etchback or CMP. The insulatinglayer 201 is formed by, for example, SiO, SiN, SiC, SiON, SiOC, or SiCN. The upper surface of the insulatinglayer 201 may be planarized.

Subsequently, a structure shown in Fig. 2C is formed. More specifically, an insulatinglayer 203 is formed on the insulatinglayer 201, and openings are formed in the insulatinglayer 203. A barrier metal layer is formed on the insulatinglayer 203, and a metal layer is formed thereon. Theconductive member 123 is formed by removing a portion other than portions of the barrier metal layer and metal film that enter the openings of the insulatinglayer 203 by etchback or CMP. The barrier metal layer is formed by, for example, tantalum, a tantalum compound, titanium, or a titanium compound. Theconductive member 123 is formed by, for example, copper, aluminum, or tungsten. The upper surfaces of the insulatinglayer 203 and theconductive member 123 may be planarized.

Subsequently, a structure shown in Fig. 2D is formed. More specifically, an insulatinglayer 204 is formed on the insulatinglayer 203, and openings are formed in the insulatinglayer 204. Theconductive member 124 is formed in the same manner as theconductive member 123. The upper surfaces of the insulatinglayer 204 and theconductive member 124 may be planarized.

Subsequently, a structure shown in Fig. 2E is formed. More specifically, an insulatinglayer 205 is formed on the insulatinglayer 204, and openings are formed in the insulatinglayer 205. Theconductive member 125 is formed in the same manner as theconductive member 124. The upper surfaces of the insulatinglayer 205 and theconductive member 125 may be planarized.

Thesubstrate 200 is formed as described above. In this embodiment, thesubstrate 200 includes theconductive members 123 to 125 of three layers. However, the number of layers of the conductive members is not limited to this, and it may be one, two, or four or more. In addition, each conductive member may have a single damascene structure or a dual damascene structure. The wiring structure of thesubstrate 200 becomes thewiring structure 120a of thedischarge substrate 100. The insulatingmember 122 of thewiring structure 120a is formed by the insulatinglayers 201, 203, 204, and 205. The upper surface of the substrate 200 (a surface on the side opposite to the base 110) is flat.

The upper limit value of a temperature at which metal materials of theplug 202, theconductive members 123, 124, and 125, and the like included in thewiring structure 120a are not influenced by melting or the like will be referred to as a critical temperature. The critical temperature can change depending on the type of metal material and may be, for example, 400℃, 450℃, or 500℃. Thesubstrate 200 is formed such that the highest temperature in thermal histories received by the metal materials included in thewiring structure 120a during the manufacture of thesubstrate 200 becomes lower than the critical temperature (for example, lower than 400℃, lower than 450℃, or lower than 500℃).

The thermal history about a certain portion of a semiconductor device means a temperature transition of the portion in a manufacturing step of the semiconductor device including a time when the portion is formed. For example, a certain member is formed at a substrate temperature of 400℃, and then a substrate including the portion is processed at a substrate temperature of 350℃. In this case, the portion has a thermal history of 400℃ and 350℃.

Then, as shown in Fig. 3E, asubstrate 300 that includes theheat generation element 130 is formed. Either thesubstrate 200 or thesubstrate 300 may be formed first. A method of forming thesubstrate 300 will be described below in detail. As shown in Fig. 3A, theprotective film 140 is formed on abase 301, and theheat generation element 130 is formed on theprotective film 140. The base 301 may be formed by a semiconductor material such as silicon or an insulator material such as glass.

Theprotective film 140 is formed by, for example, a silicon insulator of silicon dioxide, silicon nitride, silicon carbide, or the like. Theprotective film 140 may be annealed at a high temperature in order to improve the humidity resistance of theprotective film 140. In general, the insulator improves in humidity resistance as a temperature used for annealing is high. A wiring structure has not been formed yet at this point, and thus it is possible to anneal theprotective film 140 at a temperature equal to or higher than the critical temperature (for example, 400℃ or higher, 450℃ or higher, or 500℃ or higher, and more specifically, 650℃). Before theheat generation element 130 is formed, the upper surface of theprotective film 140 may be planarized by the CMP method or the like. Instead of annealing, plasma processing may be performed on theheat generation element 130. In this embodiment, the humidity resistance of theprotective film 140 is high, increasing the life of thedischarge substrate 100.

Theheat generation element 130 is formed by, for example, tantalum or a tantalum compound. Theheat generation element 130 may be annealed at the temperature equal to or higher than the critical temperature (for example, 400℃ or higher, 450℃ or higher, or 500℃ or higher, and more specifically, 650℃). This makes it possible to improve the resistance value of theheat generation element 130 and save power of thedischarge substrate 100. Theheat generation element 130 crystalizes by annealing theheat generation element 130 at the temperature equal to or higher than the critical temperature, making it possible to stabilize the initial characteristic of theheat generation element 130. Theheat generation element 130 may be formed by polysilicon higher than tantalum or the tantalum compound in resistance. A high-temperature process is needed in order to form theheat generation element 130 by polysilicon. It is possible, however, to form theheat generation element 130 at the temperature equal to or higher than the critical temperature as described above. In addition, it is possible to select a material that cannot be used at a temperature lower than the critical temperature as a material of theheat generation element 130.

A wiring conductive member may be formed in the same layer as theheat generation element 130. In this case, theheat generation element 130 may not be annealed at the temperature equal to or higher than the critical temperature. Theprotective film 140 and theheat generation element 130 may be annealed separately or simultaneously. At least one of theprotective film 140 and theheat generation element 130 is annealed at the temperature equal to or higher than the critical temperature.

Subsequently, a structure shown in Fig. 3B is formed. More specifically, an insulatinglayer 302 is formed on theprotective film 140 and theheat generation element 130, holes are formed in the insulatinglayer 302, and aplug 303 is formed in each hole. Theplug 303 is formed by, for example, forming a metal film of copper or tungsten on the insulatinglayer 302 and removing a portion other than a portion of this metal film that enters the hole of the insulatinglayer 302 by etchback or CMP. The insulatinglayer 302 is formed by, for example, SiO, SiN, SiC, SiON, SiOC, or SiCN. The thickness of the insulatinglayer 302 may be adjusted by further planarizing the upper surface of the insulatinglayer 302.

Subsequently, as shown in Fig. 3C, theconductive member 128 is formed on the insulatinglayer 302. Theconductive member 128 is formed by copper or aluminum. Subsequently, as shown in Fig. 3D, an insulatinglayer 304 is formed on the insulatinglayer 302 and theconductive member 128, and aplug 305 is formed in the insulatinglayer 304. Theplug 305 includes a barrier metal layer and a metal layer. The barrier metal layer is formed by, for example, titanium, or a titanium compound. The metal layer is, for example, a tungsten layer.

Subsequently, as shown in Fig. 3E, an insulatinglayer 306 and theconductive member 127 are formed on the insulatinglayer 304. Theconductive member 127 includes a barrier metal layer and a metal layer. The barrier metal layer is formed by, for example, tantalum, a tantalum compound, titanium, or a titanium compound. The metal layer is formed by, for example, copper or aluminum.

Thesubstrate 300 is formed as described above. In this embodiment, thesubstrate 300 includes the conductive members of two layers. However, the number of layers of the conductive members is not limited to this, and it may be one, or three or more. In addition, each conductive member may have a single damascene structure or a dual damascene structure. The wiring structure of thesubstrate 300 becomes thewiring structure 120b of thedischarge substrate 100. The insulatingmember 126 of thewiring structure 120b is formed by the insulatinglayers 302, 304, and 306. The upper surface of the substrate 300 (a surface on the side opposite to the base 301) is flat.

Thesubstrate 300 is formed such that the highest temperature in a thermal history received by theheat generation element 130 or theprotective film 140 becomes equal to or higher than the critical temperature, and the highest temperature in thermal histories received by metal materials included in thewiring structure 120b during the manufacture of thesubstrate 300 becomes lower than the critical temperature. The metal materials included in thewiring structure 120b are, for example, theplugs 303 and 305, and theconductive members 127 and 128.

In a manufacturing method of forming a wiring structure on a base that includes a semiconductor element and forming a heat generation element thereon, the heat generation element is formed on the uppermost wiring layer. An upper surface is planarized each time a wiring layer is formed, and thus an upper wiring layer has lower flatness. In contrast, in the above-described method of manufacturing thesubstrate 300, the insulatinglayer 302 in which the insulatingmember 126 is closest to theprotective film 140 and theheat generation element 130 is formed prior to other insulating layers of thewiring structure 120, and thus the flatness of this insulatinglayer 302 is high. As a result, it becomes easier to form thesubstrate 300 such that the thickness of theregion 126a in the insulatinglayer 302 conforms to a design value over an entire wafer, improving discharge performance of theheat generation element 130.

Then, as shown in Fig. 4A, the wiring structure of thesubstrate 200 and the wiring structure of thesubstrate 300 are bonded to each other such that thesemiconductor element 111 and theheat generation element 130 are electrically connected to each other. More specifically, theconductive member 125 and theconductive member 127 are bonded to each other, and the insulatingmember 122 and the insulatingmember 126 are bonded to each other. Thesubstrate 200 and thesubstrate 300 may be bonded to each other by heating them in an overlaid state or by using a catalyst such as argon.

Subsequently, theentire base 301 is removed as shown in Fig. 4B. Subsequently, thedischarge substrate 100 is manufactured by forming theanti-cavitation film 150 and thenozzle structure 160. Steps in Figs. 4A and 4B may be performed at the temperature lower than the critical temperature. Therefore, the highest temperature of the thermal history received by theheat generation element 130 or theprotective film 140 during the manufacture of thedischarge substrate 100 is higher than the highest temperature in thermal histories received by the conductive members included in thewiring structure 120 during the manufacture of thedischarge substrate 100.

The respective steps of the above-described manufacturing method may be performed by a single manufacturer or a plurality of manufacturers. Thesubstrate 200 and thesubstrate 300 may be bonded to each other after, for example, one manufacturer forms thesubstrate 200 and thesubstrate 300, and another manufacturer prepares thesubstrate 200 and thesubstrate 300 by purchasing them. Instead of this, one manufacturer may form thesubstrate 200 and thesubstrate 300, and then this manufacturer may instruct another manufacturer to bond them.

＜Second Embodiment＞
An example of the arrangement of adischarge substrate 500 and a manufacturing method thereof according to the second embodiment will be described with reference to Figs. 5A and 5B. A description of the same part as in the first embodiment will be omitted. The method of manufacturing thedischarge substrate 500 may be the same as a method of manufacturing adischarge substrate 100 until steps shown in Fig. 4A. Subsequently, as shown in Fig. 5A, a portion of a base 301 that overlaps aheat generation element 130 is removed instead of removing theentire base 301. Consequently, anopening 501 is formed in a remaining portion of thebase 301. Thisopening 501 is positioned above theheat generation element 130.

Subsequently, as shown in Fig. 5B, anozzle member 162 and a water-repellent material 163 are formed on thebase 301. Anorifice 165 is formed by thenozzle member 162 and the water-repellent material 163. Theopening 501 of the base 301 forms a part of achannel 164 of a discharged liquid. Thedischarge substrate 500 is thus manufactured.

Thedischarge substrate 500 shown in Fig. 5B does not include an anti-cavitation film. However, an anti-cavitation film that covers theheat generation element 130 across aprotective film 140 may be formed after a part of thebase 301 is removed. An adherence layer for improving adhesion may further be formed between the base 301 and thenozzle member 162. According to this embodiment, the part of the base 301 can also be used as a nozzle structure.

＜Third Embodiment＞
An example of the arrangement of adischarge substrate 600 according to the third embodiment will be described with reference to Fig. 6. A description of the same part as in the first embodiment will be omitted. Thedischarge substrate 600 is different from adischarge substrate 100 in shape of aconductive member 128. In thedischarge substrate 600, theconductive member 128 of a layer closest to aheat generation element 130 out of conductive members of a plurality of layers does not include a conductive portion immediately below theheat generation element 130, and aconductive member 127 of a second closest layer includes this conductive portion. Therefore, aregion 126b between theheat generation element 130 and theconductive member 127 becomes a heat accumulation region. According to this embodiment, the heat accumulation region can be wider than in the first embodiment. The size of the heat accumulation region is not limited to this. For example, the heat accumulation region may extend across abonding surface 121.

＜Fourth Embodiment＞
An example of the arrangement of adischarge substrate 700 and a manufacturing method thereof according to the fourth embodiment will be described with reference to Figs. 7A to 7E. A description of the same part as in the first embodiment will be omitted. A method of manufacturing thedischarge substrate 700 is different from a method of manufacturing adischarge substrate 100 in method of manufacturing asubstrate 300.

As in the first embodiment, as shown in Fig. 7A, aprotective film 140 and aheat generation element 130 are formed on abase 301. When theheat generation element 130 is formed thin, for example, when it is formed with a film thickness of several to several tens of nm, a contact failure may occur between theheat generation element 130 and a plug. In order to avoid such a contact failure, a conductive member is arranged between theheat generation element 130 and aplug 303. This conductive member may be referred to as a connection auxiliary member.

More specifically, as shown in Fig. 7B, aconductive film 701 is formed on theheat generation element 130. Theconductive film 701 is formed by, for example, an aluminum alloy. Subsequently, as shown in Fig. 7C, aconductive member 702 is formed by removing a part of theconductive film 701 by dry etching or wet etching. Theconductive member 702 contacts only the both sides of theheat generation element 130 and does not contact the central portion of theheat generation element 130. Subsequently, as shown in Fig. 7D, an insulatinglayer 302 and theplug 303 are formed. Subsequently, thedischarge substrate 700 shown in Fig. 7E is manufactured as in steps from Fig. 3C.

＜Fifth Embodiment＞
An example of the arrangement of adischarge substrate 800 and a manufacturing method thereof according to the fifth embodiment will be described with reference to Figs. 8A and 8B. A description of the same part as in the first embodiment will be omitted. A method of manufacturing thedischarge substrate 800 is different from a method of manufacturing adischarge substrate 100 in method of manufacturing asubstrate 300.

As shown in Fig. 8A, after aprotective film 140 and aheat generation element 130 are formed on a base 301 as in the first embodiment, an insulatinglayer 802 is formed on theprotective film 140 and theheat generation element 130, and atemperature sensor 801 is formed thereon. The insulatinglayer 802 may be formed by the same material as an insulatinglayer 302. Subsequently, thedischarge substrate 800 shown in Fig. 8B is manufactured as in steps from Fig. 3B.

Thetemperature sensor 801 is used to measure the temperature of theheat generation element 130 and detect whether ink is discharged correctly. Thetemperature sensor 801 is formed by a conductive material such as titanium or a titanium compound whose heat resistance change ratio is not high. The temperature sensor is positioned closer to theheat generation element 130 than aconductive member 128 of a layer closest to theheat generation element 130 out of a plurality of conductive members in awiring structure 120.

Before thetemperature sensor 801 is formed, the upper surface of the insulatinglayer 802 is planarized by CMP or the like. Heat of theheat generation element 130 is transferred to thetemperature sensor 801 via the insulatinglayer 802. It is therefore possible to improve the accuracy of thetemperature sensor 801 by forming the thickness of the insulatinglayer 802 accurately. Another underlayer does not exist between the insulatinglayer 802 and theheat generation element 130, making it possible to form the insulatinglayer 802 having a uniform thickness accurately in a wafer surface. Thetemperature sensor 801 is formed before the conductive members in the wiring structure are formed, and thus thetemperature sensor 801 may be annealed at a temperature equal to or higher than a critical temperature (for example, 400℃ or higher, 450℃ or higher, or 500℃ or higher).

＜Sixth Embodiment＞
An example of the arrangement of adischarge substrate 900 and a manufacturing method thereof according to the sixth embodiment will be described with reference to Figs. 9A and 9B. A description of the same part as in the first embodiment will be omitted. A method of manufacturing thedischarge substrate 900 is different from a method of manufacturing adischarge substrate 100 in method of manufacturing asubstrate 300.

As shown in Fig. 9A, after aprotective film 140 and aheat generation element 130 are formed on a base 301 as in the first embodiment, aprotective film 901 is further formed on theprotective film 140 and theheat generation element 130. Theprotective film 901 may be formed by the same material as theprotective film 140 and may be annealed at a temperature equal to or higher than the critical temperature (for example, 400℃ or higher, 450℃ or higher, or 500℃ or higher, and more specifically, 650℃) as in theprotective film 140. Subsequently, thedischarge substrate 900 shown in Fig. 9B is manufactured as in steps from Fig. 3B.

Thedischarge substrate 900 also includes theprotective film 901 between theheat generation element 130 and awiring structure 120, making it possible to suppress oxygen contained in thewiring structure 120 and a base 110 from being supplied to theheat generation element 130. This further suppresses oxidation of theheat generation element 130, implementing the long life of thedischarge substrate 900.

＜Seventh Embodiment＞
An example of the arrangement of adischarge substrate 1200 and a manufacturing method thereof according to the seventh embodiment will be described with reference to Figs. 11A to 12. Thedischarge substrate 1200 is different from adischarge substrate 100 in that it uses a substrate 1100 (Fig. 11C) instead of asubstrate 300. In a description below, the same part as in the first embodiment will be omitted.

A method of manufacturing thedischarge substrate 1200 will be described. As shown in Fig. 11A, a sacrificinglayer 166 is formed on abase 301. Subsequently, as shown in Fig. 11B, aprotective film 140 is formed on thebase 301, and then aheat generation element 130 is formed on theprotective film 140. Theprotective film 140 covers the entire surface of the sacrificinglayer 166. Theheat generation element 130 is arranged at a position overlapping a portion of the sacrificinglayer 166. Subsequently, thesubstrate 1100 shown in Fig. 11C is formed as in Figs. 3B to 3E of the first embodiment.

Then, as shown in Fig. 11D, the wiring structure of asubstrate 200 and the wiring structure of thesubstrate 1100 are bonded to each other as in the first embodiment. Subsequently, as shown in Fig. 12, a water-repellent material 163 is formed on thebase 301, anorifice 165 is formed, and the sacrificinglayer 166 is removed via thisorifice 165. Thedischarge substrate 1200 is manufactured as described above. The base 301 after the sacrificinglayer 166 is removed forms a part of achannel 164 of a discharged liquid. According to this embodiment, anadherence layer 161 can be omitted as compared with the first embodiment, making it possible to omit a nozzle generation step.

＜Eighth Embodiment＞
An example of the arrangement of adischarge substrate 1300 and a manufacturing method thereof according to the eighth embodiment will be described with reference to Figs. 13A and 13B. Thedischarge substrate 1300 is different from adischarge substrate 1200 in structure of achannel 164. A description of the same part as in the seventh embodiment will be omitted.

A method of manufacturing thedischarge substrate 1300 will be described below. As shown in Fig. 11D, the method is the same as in the seventh embodiment until a step of bonding the wiring structure of asubstrate 200 and the wiring structure of asubstrate 1100 to each other. Subsequently, as shown in Fig. 13A, abase 301 is thinned so as to expose the upper surface of a sacrificinglayer 166. This thinning may be performed by, for example, polishing.

Subsequently, as shown in Fig. 13B, the sacrificinglayer 166 is removed, anozzle member 162 is formed, a water-repellent material 163 is formed, and anorifice 165 is formed. Thedischarge substrate 1300 is manufactured as described above. A base 301 after the sacrificinglayer 166 is removed forms a part of achannel 164 of a discharged liquid. According to this embodiment, anadherence layer 161 can be omitted as compared with the first embodiment, making it possible to omit a nozzle generation step.

＜Still Another Embodiment＞
Fig. 10A exemplifies the internal arrangement of aliquid discharge apparatus 1600 typified by an inkjet printer, a facsimile apparatus, a copy machine, or the like. In this example, the liquid discharge apparatus may be referred to as a printing apparatus. Theliquid discharge apparatus 1600 includes aliquid discharge head 1510 that discharges a liquid (ink or a printing material in this example) to a predetermined medium P (a printing medium such as paper in this example). In this example, the liquid discharge head may be referred to as a printhead. Theliquid discharge head 1510 is mounted on acarriage 1620, and thecarriage 1620 can be attached to alead screw 1621 having ahelical groove 1604. Thelead screw 1621 can rotate in synchronism with rotation of a drivingmotor 1601 via driving force transfer gears 1602 and 1603. Along with this, theliquid discharge head 1510 can move in a direction indicated by an arrowa or b along aguide 1619 together with thecarriage 1620.

The medium P is pressed by apaper press plate 1605 in the carriage moving direction and is fixed to aplaten 1606. Theliquid discharge apparatus 1600 reciprocates theliquid discharge head 1510 and performs liquid discharge (printing in this example) on the medium P conveyed on theplaten 1606 by a conveyance unit (not shown).

Theliquid discharge apparatus 1600 confirms the position of alever 1609 provided on thecarriage 1620 viaphotocouplers 1607 and 1608, and switches the rotational direction of the drivingmotor 1601. Asupport member 1610 supports acap member 1611 for covering the nozzles (liquid orifices or simply orifices) of theliquid discharge head 1510. Asuction unit 1612 performs recovery processing of theliquid discharge head 1510 by sucking the interior of thecap member 1611 via anintra-cap opening 1613. Alever 1617 is provided to start recovery processing by suction, and moves along with movement of acam 1618 engaged with thecarriage 1620. A driving force from the drivingmotor 1601 is controlled by a well-known transfer mechanism such as clutch switching.

A mainbody support plate 1616 supports a movingmember 1615 and acleaning blade 1614. The movingmember 1615 moves thecleaning blade 1614, and performs recovery processing of theliquid discharge head 1510 by wiping. A control unit (not shown) is also provided in theliquid discharge apparatus 1600, and controls driving of each mechanism described above.

Fig. 10B exemplifies the outer appearance of theliquid discharge head 1510. Theliquid discharge head 1510 can include ahead unit 1511 including a plurality ofnozzles 1500, and a tank (liquid containing unit) 1512 that holds a liquid to be supplied to thehead unit 1511. Thetank 1512 and thehead unit 1511 can be isolated at, for example, a broken line K, and thetank 1512 can be changed. Theliquid discharge head 1510 includes an electrical contact (not shown) for receiving an electrical signal from thecarriage 1620, and discharges a liquid in accordance with the electrical signal. Thetank 1512 includes, for example, a fibrous or porous liquid holding member (not shown), and can hold a liquid by the liquid holding member.

Fig. 10C exemplifies the internal arrangement of theliquid discharge head 1510. Theliquid discharge head 1510 includes abase 1508,channel wall members 1501 that are arranged on thebase 1508 andform channels 1505, and atop plate 1502 having aliquid supply path 1503. As discharge elements or liquid discharge elements, heaters 1506 (electrothermal transducers) are arrayed on the substrate (liquid discharge head substrate) of theliquid discharge head 1510 in correspondence with therespective nozzles 1500. When a driving element (switching element such as a transistor) provided in correspondence with eachheater 1506 is turned on, theheater 1506 is driven to generate heat.

A liquid from theliquid supply path 1503 is stored in acommon liquid chamber 1504, and supplied to eachnozzle 1500 through the correspondingchannel 1505. The liquid supplied to eachnozzle 1500 is discharged from thenozzle 1500 in response to driving of theheater 1506 corresponding to thenozzle 1500.

Fig. 10D exemplifies the system arrangement of theliquid discharge apparatus 1600. Theliquid discharge apparatus 1600 includes aninterface 1700, anMPU 1701, aROM 1702, aRAM 1703, and a gate array (G.A.) 1704. Theinterface 1700 receives an external signal for performing liquid discharge from the outside. TheROM 1702 stores a control program to be executed by theMPU 1701. TheRAM 1703 saves various signals and data such as the above-mentioned liquid discharge external signal and data supplied to aliquid discharge head 1708. Thegate array 1704 performs supply control of data to theliquid discharge head 1708, and controls data transfer between theinterface 1700, theMPU 1701, and theRAM 1703.

Theliquid discharge apparatus 1600 further includes ahead driver 1705,motor drivers 1706 and 1707, aconveyance motor 1709, and acarrier motor 1710. Thecarrier motor 1710 conveys theliquid discharge head 1708. Theconveyance motor 1709 conveys the medium P. Thehead driver 1705 drives theliquid discharge head 1708. Themotor drivers 1706 and 1707 drive theconveyance motor 1709 and thecarrier motor 1710, respectively.

When a driving signal is input to theinterface 1700, it can be converted into liquid discharge data between thegate array 1704 and theMPU 1701. Each mechanism performs a desired operation in accordance with this data, thus driving theliquid discharge head 1708.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Applications No. 2017-028421, filed February 17, 2017 and No. 2017-219330, filed November 14, 2017, which are hereby incorporated by reference herein in their entirety.

Claims (20)

1. A method of manufacturing a liquid discharge head substrate, the method comprising:
   forming a first substrate that includes a semiconductor element and a first wiring structure;
   forming a second substrate that includes a liquid discharge element and a second wiring structure; and
   bonding the first wiring structure and the second wiring structure such that the semiconductor element and the liquid discharge element are electrically connected to each other after the forming the first substrate and the second substrate.
2. The method according to claim 1, wherein the forming the second substrate includes forming the second wiring structure after forming the liquid discharge element.
3. The method according to claim 2, wherein the forming the second substrate includes
   forming a protective film above a base,
   forming the liquid discharge element above the protective film, and
   forming the second wiring structure above the liquid discharge element.
4. The method according to claim 3, wherein the forming the second substrate further includes annealing at least one of the liquid discharge element and the protective film at a temperature not lower than 400℃ before forming the second wiring structure.
5. The method according to claim 3 or 4, wherein the forming the second wiring structure includes
   forming an insulating layer above the liquid discharge element, and
   planarizing an upper surface of the insulating layer.
6. The method according to any one of claims 3 to 5, wherein the second wiring structure includes an insulating member and conductive members of a plurality of layers inside the insulating member, and
   a conductive member of a layer closest to the liquid discharge element out of the conductive members of the plurality of layers does not include a conductive portion immediately below the liquid discharge element.
7. The method according to claim 6, wherein the second wiring structure further includes a temperature sensor inside the insulating member, the temperature sensor being configured to measure a temperature of the liquid discharge element, and
   the temperature sensor is positioned closer to the liquid discharge element than the conductive member of the closest layer is.
8. The method according to claim 7, wherein the forming the second substrate further includes annealing the temperature sensor at the temperature not lower than 400℃ before forming the conductive members of the plurality of layers.
9. The method according to any one of claims 3 to 8, further comprising removing a portion of the base that overlaps the liquid discharge element after the bonding.
10. The method according to claim 9, wherein a remaining portion of the base forms a part of a channel of a discharged liquid.
11. The method according to claim 10, further comprising forming an anti-cavitation film that covers the liquid discharge element across the protective film after the removing the overlapping portion of the base.
12. The method according to any one of claims 3 to 8, wherein the forming the second substrate further includes forming a sacrificing layer in the base before forming the protective film above the base,
    the method further comprises removing the sacrificing layer before the bonding, and
    the base after the removing the sacrificing layer forms a part of a channel of a discharged liquid.
13. The method according to any one of claims 3 to 12, wherein the protective film is a first protective film, and
    the forming the second substrate further includes
    forming a second protective film that covers the liquid discharge element after forming the liquid discharge element, and
    annealing the second protective film at a temperature not lower than 400℃.
14. The method according to any one of claims 1 to 13, wherein the liquid discharge element is a heat generation element.
15. A method of manufacturing a liquid discharge head substrate, the method comprising:
    preparing a first substrate that includes a semiconductor element and a first wiring structure, and a second substrate that includes a liquid discharge element and a second wiring structure; and
    bonding the first wiring structure and the second wiring structure such that the semiconductor element and the liquid discharge element are electrically connected to each other after the preparing.
16. A method of manufacturing a liquid discharge head substrate, the method comprising:
    forming a first substrate that includes a semiconductor element and a first wiring structure;
    forming a second substrate that includes a liquid discharge element and a second wiring structure; and
    giving an instruction to bond the first wiring structure and the second wiring structure such that the semiconductor element and the liquid discharge element are electrically connected to each other after the forming the first substrate and the second substrate.
17. A liquid discharge head substrate comprising:
    a base where a semiconductor element is formed;
    a wiring structure positioned above the base;
    a liquid discharge element positioned above the wiring structure; and
    a protective film positioned above the liquid discharge element,
    wherein a surface of the protective film on a side of the liquid discharge element is flat.
18. The substrate according to claim 17, wherein the wiring structure has a first bonding surface between an insulating member and an insulating member, and a second bonding surface between a conductive member and a conductive member, and
    the first bonding surface and the second bonding surface are positioned on the same plane.
19. A liquid discharge head comprising:
    a liquid discharge head substrate defined in claim 17 or 18; and
    an orifice where discharge of a liquid is controlled by the liquid discharge head substrate.
20. A liquid discharge apparatus comprising:
    a liquid discharge head defined in claim 19; and
    a supply means configured to supply a driving signal for causing the liquid discharge head to discharge a liquid.

Images