CN106206639B - Phase change memory storage and its manufacturing method with needle-shaped junction - Google Patents

Abstract

The present invention relates to phase change memory storages and its manufacturing method with needle-shaped junction.The device includes at least one memory unit of the substrate and setting of access circuit on the substrate, wherein the memory unit includes the hearth electrode for being electrically connected and being set in the first dielectric layer with the access circuit, the first barrier layer being set between the hearth electrode and first dielectric layer and the access circuit, it extends from the hearth electrode and there is the heater for protruding from first dielectric layer, the protruding portion being set in the second dielectric layer, wherein the sectional area of the protruding portion is gradually reduced from lower to upper, and the top surface of the protruding portion is exposed to second dielectric layer.The method limits the projecting height of conductive material using sacrificial layer, refines conductive material outstanding by etching technique to form acicular heater, and then reduce the junction between heater and phase-transition material.The present invention can change the crystalline state of small range phase-transition material with lesser electric current, therefore can reduce power consumption and avoid generating cavity.

Description

Phase change memory storage and its manufacturing method with needle-shaped junction

Technical field

The present invention is related a kind of memory storage and its manufacturing method, especially a kind of phase change note with needle-shaped junctionRecall device and its manufacturing method.

The prior art

Phase change memory storage is a kind of Nonvolatile Random Access memory.Phase-transition material in phase change memory storageIt can pass through and apply electric current appropriate and converted between crystalline state and non-crystalline.Phase-transition material different conditions (such asIt is crystallization, hypocrystalline, noncrystalline) represent different resistance values.In general, non-crystalline person is compared to crystalline state person with higherResistance value, therefore, transit dose measuring resistance value can access data.

In order to change the crystalline state of phase-transition material, phase-transition material must be heated with heater.A kind of known phase transformationThere is biggish junction between the heater and phase-transition material of change memory storage, so can get preferable conductive characteristic.SoAnd so that the phase-transition material of larger junction is converted crystalline state and need biggish power consumption, in addition, converting the knot of phase-transition material repeatedlyCrystalline state is easy to produce empty (void), and the reliability of product is caused to reduce.Another known phase change memory storage be thenPhase-transition material is filled in tapered groove, so that the junction between heater and phase-transition material reduces.However, above structureWhen filling phase-transition material, since bottom portion of groove is smaller, it is easy to form cavity because filling not exclusively, also results in productionThe reliability of product is reduced or is directly scrapped.

In view of this, how to manufacture the smaller and of good reliability phase change note of junction between heater and phase-transition materialRecalling device is the target that current pole need to make great efforts.

Summary of the invention

The present invention provides a kind of phase change memory storage and its manufacturing method with needle-shaped junction, is by conductive materialRefinement reduces the junction between heater and phase-transition material to obtain acicular heater.According to this structure, with lesserElectric current can change the crystalline state of small range phase-transition material, and in other words, the present invention can not only reduce power consumption, and can avoid producingRaw cavity.

One embodiment of the invention provides a kind of manufacturing method of phase change memory storage with needle-shaped junction, this methodInclude: substrate is provided, it includes access circuits, and wherein access circuit includes at least one conductive junction point；In forming on substrateOne dielectric layer；In forming sacrificial layer on the first dielectric layer；At least one through-hole for running through the first dielectric layer and sacrificial layer is formed,Keep the conductive junction point of access circuit exposed；The first barrier layer is formed in the side wall of through-hole and bottom；Conductive material is filledIt is electrically connected into through-hole, and with the conductive junction point of access circuit；Sacrificial layer is removed, the first barrier layer of part and conductive material are madeProminent first dielectric layer；Remove the first barrier layer of prominent first dielectric layer；Part removes the conduction material of prominent first dielectric layerMaterial, to refine conductive material；The second dielectric layer is formed in the first dielectric layer, and covers conductive material；And the second dielectric of thinningLayer, keeps conductive material exposed.

Another embodiment of the present invention provide have needle-shaped junction phase change memory storage, the device include substrate andAt least one memory unit.Substrate includes access circuit.Memory unit is set on substrate.Memory unit includes hearth electrode, theOne barrier layer and heater.Hearth electrode is electrically connected with access circuit, and wherein hearth electrode is set in the first dielectric layer.First screenBarrier layer is set between hearth electrode and the first dielectric layer and access circuit.Heater extends from hearth electrode, and has one to protrudePortion protrudes from the first dielectric layer, and protruding portion is set in the second dielectric layer, and wherein the sectional area of protruding portion gradually contracts from lower to upperIt is small, and a top surface of protruding portion is exposed to the second dielectric layer.

The attached drawing elaborate appended by specific embodiment cooperation below, when purpose, the skill for being easier to understand the present inventionArt content, feature and its it is reached the effect of.

Detailed description of the invention

Fig. 1 a to Fig. 1 j is a schematic diagram, shows the phase change memory dress with needle-shaped junction of first embodiment of the inventionThe manufacturing method set.

Fig. 2 a to Fig. 2 c is a schematic diagram, shows the phase change memory dress with needle-shaped junction of second embodiment of the inventionThe manufacturing method set.

Fig. 3 a and Fig. 3 b are a schematic diagram, show the phase change memory with needle-shaped junction of third embodiment of the inventionThe manufacturing method of device.

Fig. 4 a and Fig. 4 b are a schematic diagram, show the phase change memory with needle-shaped junction of fourth embodiment of the inventionThe manufacturing method of device.

Fig. 5 is a schematic diagram, shows the system of the phase change memory storage with needle-shaped junction of fifth embodiment of the inventionMake method.

Fig. 6 is a schematic diagram, shows the knot of the phase change memory storage with needle-shaped junction of sixth embodiment of the inventionStructure.

Fig. 7 is a schematic diagram, shows the knot of the phase change memory storage with needle-shaped junction of seventh embodiment of the inventionStructure.

Specific embodiment

It will be described various embodiments of the present invention below, and cooperate attached drawing as illustration.Other than these are described in detail, thisInvention also can be widely performed in other embodiments, and substitution easily, modification, the equivalence changes of any embodiment are all wrappedContaining within the scope of the present invention, and it is subject to claim.In the description of specification, in order to make reader to the present invention have compared withIt is complete to understand, provide many specific details；However, the present invention may be in clipped or the premise of whole specific detailsUnder, it is still implementable.Moreover, it is well known that the step of or component be not described in details, to avoid to the present invention formed need notThe limitation wanted.Same or similar component will be indicated in attached drawing with same or like symbol.It is specifically intended that attached drawing is onlySchematically, not the size or quantity of proxy component reality, some details may not drawn completely, succinct in the hope of attached drawing.

Fig. 1 a to Fig. 1 j is please referred to, to illustrate the phase change memory storage with needle-shaped junction of one embodiment of the inventionManufacturing method.Firstly, providing substrate 10, it includes access circuits 11, and wherein access circuit 11 includes at least one conductive junction point(not shown).For example, substrate 10 can be silicon substrate, but not limited to this, other suitable material can also be used as substrate 10, exampleSuch as ceramic material, organic material or glass material.Access circuit 11 may include switch block, such as MOS fieldIt imitates transistor (Metal Oxide Semiconductor Field Effect Transistor, MOSFET), such as institute in Fig. 1 aThe gate 12 of the MOSFET shown.Gate voltage by control MOSFET is that can control the read-write of each memory unit.It can manageSolution, the conductive junction point of access circuit 11 can be planar conductive region or be post-like conductive plug.Then, on substrate 10The first dielectric layer 20 is formed, in forming a sacrificial layer 20a on the first dielectric layer 20, re-forms at least one through the first dielectric layerThe through-hole 21 of 20 and sacrificial layer 20a, so that the conductive junction point of access circuit 11 is exposed via through-hole 21.For example, sharpCorresponding multiple through-holes 21 can be formed via micro image etching procedure with photoresist layer 100, as shown in Figure 1a.In an embodimentIn, the material of the first dielectric layer 20 can be oxide or nitride, such as silica, silicon oxynitride, silicon nitride or other JieElectric material；The material of sacrificial layer can be polysilicon (Polysilicon).

Then, the first barrier layer 22 is formed in the side wall of multiple through-holes 21 and bottom, as shown in Figure 1 b.In an embodimentIn, the material of the first barrier layer 22 can be titanium, titanium nitride, tantalum nitride or tantalum.For example, the first barrier layer 22 can utilize physicsBe vapor-deposited (physical vapor deposition, PVD), chemical vapor deposition (chemical vaporDeposition, CVD) or the technologies such as atomic layer deposition (atomic layer deposition, ALD) formed.

Then, conductive material 23 is filled in Yu Tongkong 21, and is electrically connected with multiple conductive junction points of access circuit 11, is such as schemedShown in 1c.Likewise, conductive material 23 can be formed with technologies such as PVD, CVD, ALD.In an embodiment, conductive material can beTungsten, titanium, titanium nitride, TiAlN or titanium silicon nitride.Then, thinning sacrificial layer 20a, and keep the top surface of sacrificial layer 20a flatChange, as shown in Figure 1 d.For example, thinning sacrificial layer 20a can be with chemical mechanical grinding (chemical-mechanicalPolish, CMP) mode realized.For example, the thickness of the sacrificial layer 20a after thinning is about 2nm to 20nm.

Then, sacrificial layer 20a is removed, the first barrier layer of part 22 and conductive material 23 is made to protrude from the first dielectric layer20, as shown in fig. le.In an embodiment, after the height of the first barrier layer 22 and conductive material 23 outstanding is approximately equal to thinningThe thickness of sacrificial layer 20a.The method for removing sacrificial layer 20a can utilize the prior art, and details are not described herein.Then, it removes and protrudesFirst barrier layer 22 of the first dielectric layer 20 makes prominent first dielectric layer 20 of the conductive material 23 of uncoated first barrier layer 22,As shown in Figure 1 f.For example, the first barrier layer 22 can be removed using etchants such as CR14.CR-14 is institute, Cyantek companyThe commercially available wet etchant of production, composition is by (NH₄)₂Ce(NO₃)₆, HAc and H₂O is formed by proper proportion, canThe first barrier layer 22 is removed, but very slow to the etching speed of the first dielectric layer 20.It is understood that the present invention is not limited to useCR-14 etchant, the technical field of the invention technical staff can be according to 20 materials of 22 material of the first barrier layer and the first dielectric layerThe difference of material selects etchant appropriate, it is required that for the selection of etching the first barrier layer 22 and 20 Shi Yougao of the first dielectric layerThan more specifically, the etchant that selection the first barrier layer 22 of etching is faster than the first dielectric layer 20 of etching.

Then, part removes the partially electronically conductive material 23 of prominent first dielectric layer 20, to refine conductive material 23 outstanding,As shown in Figure 1 g.It is understood that the conductive material 23 not refined can be used as a hearth electrode 23a, and it is refined into acicular leadElectric material 23 can be used as a heater 23b.For example, conductive material 23 can be tungsten, then the side of part removing conductive material 23Method can be selected hydrogen peroxide and etch conductive material 23, but not limited to this, other wet etchings or dry etching technique be also reachableTo identical effect.Likewise, the difference according to conductive material, may be selected engraving method appropriate, it is required that conductive for etchingThe selection ratio of 20 Shi Yougao of material 23 and the first dielectric layer, more specifically, selection etching conductive material 23 is situated between than etching firstThe fast etchant of electric layer 20.

Then, in forming the second dielectric layer 30 on the first dielectric layer 20, and conductive material is covered, i.e., exposed heatingDevice 23b, as shown in figure 1h.For example, the material of the second dielectric layer 30 can be oxide or nitride, such as silica,Silicon oxynitride, silicon nitride or other dielectric materials.Then, the second dielectric layer of thinning 30 planarizes the second dielectric layer 30 and exposesExpose conductive material, the i.e. top surface of heater 23b, as shown in figure 1i.

Finally, in forming patterned phase-transition material 40 on the second dielectric layer 30, and with conductive material (i.e. heaterIt 23b) is electrically connected, as shown in fig. ij.For example, it can be recycled micro- prior to forming phase-change material layer on the second dielectric layer 30Shadow etching technique patterns phase-transition material, is formed in patterned phase-transition material on corresponding heater 23b.CitingFor, the material of phase-transition material 40 can be to include germanium, antimony and at least one of chalcogen compound of tellurium(chalcogenide) or alloy.Chalcogen compound includes the compound with more positive electricity element or foundation.Chalcogen compoundAlloy includes combining chalcogen compound and other materials such as transition metal etc..In addition, following alloy can also be used as phase change materialMaterial, such as gallium/antimony, germanium/antimony, indium/antimony, antimony/tellurium, germanium/tellurium, germanium/antimony/tellurium, indium/antimony/tellurium, gallium/selenium/tellurium, tin/antimony/tellurium, indium/Antimony/germanium, silver/indium/antimony/tellurium, germanium/tin/antimony/tellurium, germanium/antimony/selenium/tellurium and tellurium/germanium/antimony/sulphur etc., wherein preferably be germanium/antimony/Tellurium alloy family.

In an embodiment, the manufacturing method of the present invention, which is also contained on phase-transition material 40, forms a top electrode 50.ShapeIt can be real using existing technology in the detailed manufacturing process on corresponding heater 23b at phase-transition material 40 and top electrode 50Existing, details are not described herein.

In an embodiment, the process conditions of processing time or the suitable point of adjustment can be extended when removing the first barrier layer 22,So that the top surface of the first barrier layer 22 is lower than the top surface of the first dielectric layer 20, as shown in Figure 2 a.Subsequent refinement conductive materialWhen 23, longer needle-shaped heater 23b can be formed, as shown in Figure 2 b.Later, it is walked according to the manufacture of earlier figures 1h to Fig. 1 jSuddenly, structure as shown in Figure 2 c can be formed.

In an embodiment, it can also extend the process conditions of processing time or the suitable point of adjustment when refining conductive material, withMake the conductive material (i.e. hearth electrode 23a) not refined top surface be lower than the first barrier layer 22 top surface, so can get compared withLong needle-shaped heater 23b, as shown in Figure 3a.Later, it according to the manufacturing step of earlier figures 1h to Fig. 1 j, can be formed such as Fig. 3 bShown in structure.It is understood that more elongated needle-shaped heater 23b can get higher current density, in other words, havePreferable heating effect.In addition, also having because of more elongated heater 23b between hearth electrode 23a and phase-transition material 40 longerDistance.Therefore, thermal energy of the heater 23b at 40 end of phase-transition material less influences whether hearth electrode 23a, and phase-transition material40 also less likely diffusion pollution to hearth electrode 23a.

In an embodiment, after forming needle-shaped heater 23b shown in Fig. 1 g, the manufacturing method of the present invention also includesIt in forming the second barrier layer 22a on the first dielectric layer 22, covers conductive material (i.e. heater 23b), and the second screen of patterningBarrier layer 22a, as shown in fig. 4 a.Later, according to the manufacturing step of earlier figures 1h to Fig. 1 j, knot as shown in Figure 4 b can be formedStructure.It is understood that the second barrier layer 22a can prevent phase change material during phase-transition material 40 is repeated heatingPollution caused by 40 diffusion of material.

In an embodiment, in the processing procedure for patterning the second barrier layer 22a, using relatively thin photoresist, it can not cover completelyLid the second barrier layer 22a, even if also exposed corresponding to the protruding portion of heater 23b.In this way, removing the second barrier in partWhen layer 22a is to pattern the second barrier layer 22a, the top of conductive material (i.e. heater 23b) can be made exposed, such as Fig. 5Shown in structure.Later, according to the manufacturing step of earlier figures 1h to Fig. 1 j, structure as shown in Figure 4 b can also be formed.

In an embodiment, after completing structure shown in Fig. 2 b and Fig. 3 a, according to earlier figures 4a and Fig. 1 h to Fig. 1 jManufacturing step, can be respectively formed such as Fig. 6 and structure shown in Fig. 7.Detailed manufacturing process, structure and technology effect areAs previously mentioned, details are not described herein.

Fig. 1 j is please referred to, to illustrate the phase change memory storage with needle-shaped junction of one embodiment of the invention.The present inventionPhase change memory storage include substrate 10 and at least one memory unit (memory cell).Substrate 10 includes access electricityRoad 11.Memory unit is set to substrate 10.Memory unit is electrically connected with access circuit 11.Each memory unit includes hearth electrode23a, the first barrier layer 22 and heater 23b.Hearth electrode 23a is electrically connected with access circuit 11, and hearth electrode 23a is set toIn one dielectric layer 20.First barrier layer 22 is set between hearth electrode 23a and the first dielectric layer 20 and access circuit 11.HeatingDevice 23b extends from hearth electrode 23a, and there is a protruding portion to protrude from the first dielectric layer 20, and protruding portion is set to the second dielectric layerIn 30, wherein the sectional area of protruding portion is gradually reduced from lower to upper, that is, heater 23b is one needle-shaped, and one of protruding portionTop surface is exposed to the second dielectric layer 30.In an embodiment, phase change memory storage of the invention also includes phase-transition material 40And top electrode 50.Phase-transition material 40 and top electrode 50 are sequentially arranged on heater 23b.Memory unit it is other in detailAs described above, details are not described herein for structure.

In summary, of the invention phase change memory storage and its manufacturing method with needle-shaped junction is by conductive materialRefinement can so reduce the junction between heater and phase-transition material to obtain acicular heater.According to this structure, with smallerElectric current can change the crystalline state of small range phase-transition material, therefore power consumption can be reduced.Also, phase-transition material of the inventionPhase change range it is smaller, the issuable cavity of heating institute repeatedly when can avoid phase-transition material operation.In addition, sediment phase changeChange material when needle-shaped heater, the exposed top surface of heater institute is therefore a flattened condition will not be generated because of phase transformationThe problem of filling of change material not exclusively forms cavity blemish.

Embodiment described above is only technical idea and feature to illustrate the invention, and purpose makes to be familiar with this skillArtist scholar cans understand the content of the present invention and implement it accordingly, when the scope of the patents of the invention cannot be limited with it, i.e., generally according toEquivalent change made by disclosed spirit or modification should be covered in the scope of the patents of the invention.

Attached drawing and symbol description used above are as follows:

10 substrates

100 photoresist layers

11 access circuits

12 gates

20 first dielectric layers

20a sacrificial layer

21 through-holes

22 first barrier layers

The second barrier layer of 22a

23 conductive materials

23a hearth electrode

23b heater

30 second dielectric layers

40 phase-transition materials

50 top electrodes

Claims (8)

1. a kind of manufacturing method of the phase change memory storage with needle-shaped junction, characterized by comprising:

Substrate is provided, it includes access circuits, and wherein the access circuit includes at least one conductive junction point；

In forming the first dielectric layer on the substrate；

In forming sacrificial layer on first dielectric layer, and first dielectric layer is made of different materials with the sacrifice series of strata；

At least one is formed through first dielectric layer and the through-hole of the sacrificial layer, exposes the conductive junction point of the access circuitExpose；

The first barrier layer is formed in the side wall of the through-hole and bottom；

The through-hole is filled with conductive material, and is electrically connected with the conductive junction point of the access circuit；

The sacrificial layer is removed, part first barrier layer and the conductive material is made to protrude from first dielectric layer；

First barrier layer for protruding from first dielectric layer is removed, so that the top surface of first barrier layer is lower than first JieThe top surface of electric layer；

Part removes the conductive material for protruding from first dielectric layer, to refine the conductive material as a heater, should addThe height of hot device is defined by the thickness of the sacrificial layer；

In forming the second dielectric layer on first dielectric layer, and cover the conductive material；And

Thinning second dielectric layer, keeps the conductive material exposed.

2. the manufacturing method of the phase change memory storage with needle-shaped junction as described in claim 1, which is characterized in that in portionPoint remove the conductive material also include after refining the conductive material:

In forming the second barrier layer on first dielectric layer, and cover the conductive material；And

Pattern second barrier layer.

3. the manufacturing method of the phase change memory storage with needle-shaped junction as claimed in claim 1 or 2, which is characterized in thatIt also include the thinning sacrificial layer before removing the sacrificial layer.

4. the manufacturing method of the phase change memory storage with needle-shaped junction as claimed in claim 1 or 2, which is characterized in thatThe method further includes:

Patterned phase-transition material is formed in second dielectric layer, and is electrically connected with the conductive material；And

In forming top electrode on the phase-transition material.

5. the manufacturing method of the phase change memory storage with needle-shaped junction as claimed in claim 1 or 2, which is characterized in thatAfter part removes the conductive material, the top surface for the conductive material not refined is lower than the top surface of first barrier layer.

6. the manufacturing method of the phase change memory storage with needle-shaped junction as claimed in claim 4, which is characterized in that thisThe material of one dielectric layer includes silica, silicon nitride or silicon oxynitride；

The material of the sacrificial layer includes polysilicon；

The material of first barrier layer includes titanium, titanium nitride, tantalum nitride or tantalum；

The conductive material includes tungsten, titanium, titanium nitride, TiAlN or titanium silicon nitride；

The phase-transition material includes germanium, antimony and at least one of chalcogen compound of tellurium or alloy.

7. a kind of phase change memory storage with needle-shaped junction, characterized by comprising:

Substrate, it includes access circuits；And

At least one memory unit is set on the substrate, and wherein the memory unit includes:

Hearth electrode is electrically connected with the access circuit, and wherein the hearth electrode is set in the first dielectric layer；

First barrier layer is set between the hearth electrode and first dielectric layer and the access circuit, first barrier layerTop surface be lower than first dielectric layer top surface；Alternatively, the top surface of the hearth electrode is lower than the top table of first barrier layerFace；

Heater, extends from the hearth electrode, and there is a protruding portion to protrude from first dielectric layer, which is set to theIn two dielectric layers, wherein the sectional area of the protruding portion is gradually reduced from lower to upper, and the top surface of the protruding portion be exposed to this secondDielectric layer；And

Second barrier layer is set to around the protruding portion between second dielectric layer, and exposes the top of the protruding portionFace.

8. as claimed in claim 7 with the phase change memory storage of needle-shaped junction, which is characterized in that described device is also wrappedContain:

Phase-transition material is set on the top surface of the heater；And

Top electrode is set on the phase-transition material.