The content of the invention
The present invention solve the problem of be existing layer gold etching easily go out cash residual, and multiple golden pattern blocks undercuttingMeasure uniformity not high.
To solve the above problems, the present invention provides a kind of preparation method of semiconductor devices, including：
There is provided to have in Semiconductor substrate, the Semiconductor substrate and there is patterned mask layer in layer gold, the layer gold；
Using the patterned mask layer layer gold is patterned as mask, the layer gold is patterned into wet methodCorrosion, the solution used is comprising KI and I2The aqueous solution, the wet etching carries out several times, the time of each wet etchingLess than 2 minutes, deionized water rinsing is used after each wet etching is complete.
Alternatively, the time of each wet etching is less than 1 minute.
Alternatively, the number of times of the wet etching is more than 4 times.
Alternatively, the time of each deionized water rinsing is more than 2 minutes.
Alternatively, the time range of each deionized water rinsing is：2 minutes~5 minutes.
Alternatively, in the aqueous solution that wet etching is used, I2Mass percent be less than 2%, KI mass percent it is smallIn 5%, the mass percent of deionized water is more than 93%.
Alternatively, in the aqueous solution that wet etching is used, I2Mass percent be for 1.3%, KI mass percent4%, the mass percent of deionized water is 94.7%.
Alternatively, the thickness of the layer gold is 300 nanometers, and the undercutting amount of each golden pattern block graphically formed is less than 3Micron.
Alternatively, the Semiconductor substrate material is silicon, and the mask layer material is photoresist.
Alternatively, after the layer gold is graphical, dried up using low-pressure air current.
Alternatively, the semiconductor devices is MEMS, and the patterned layer gold is used for wafer bonding.
Alternatively, the semiconductor devices is MEMS, and the MEMS has movable sensitive film and fixed electricityPole, the patterned layer gold is used to form the extraction movable sensitive film electrode of the contact with fixed electrode electric signal.
Compared with prior art, technical scheme has advantages below：1) using multiple wet etching to layer goldIt is patterned, wet etching solution is to include KI and I2The aqueous solution, time of each wet etching is less than 2 minutes, every timeDeionized water rinsing is used after wet etching is complete, in this way, the accessory substance that corrosion is produced every time can be able to peel off in time, it is to avoid oneThe etch by-products that secondary long-time corrosion layer gold is produced coat the layer gold and cause the further corrosion rate of the layer gold to slow down, simultaneouslyThere is undercutting amount uniformity in the multiple golden pattern blocks for avoiding the different zones corrosion rate difference gold residual caused and being formedNot high problem.
2) in alternative, the time of each wet etching is less than 1 minute, and research shows, above-mentioned time-triggered protocol formationThe undercutting amount uniformity of multiple golden pattern blocks is higher.
3) in alternative, the time range of each deionized water rinsing is：2 minutes~5 minutes, research showed, above-mentionedThe deionized water rinsing of time range can remove etch by-products completely, and total processing time is short, and treatment effeciency is high.
Embodiment
As described in the background art, there are problems that in the existing etching process to layer gold, one, easily go out cash it is residualStay；2nd, undercutting (Undercut) amount uniformity is not high, i.e., the amount of laterally removing of the multiple golden pattern blocks formed with a collection of etching is notDeng what is had is more, and what is had lacks.In view of the above-mentioned problems, present inventor has performed analysis, the reason for finding generation problem is：If to goldLayer carries out long-time corrosion, for example with including KI and I2The aqueous solution corroded, above-mentioned corrosion be isotropic etch, thenIt can find：Elapse over time, the increasing etch by-products of layer gold surface aggregation, because layer gold is etched accessory substance bagCover, thus influence the further corrosion rate of layer gold, how much different the etch by-products amount of different zones cladding is, subregionLayer gold possibly can not be contacted with etchant solution, thus on the one hand, in the vertical, be likely to result in golden residual, on the other hand, in transverse directionOn, the undercutting amount of different gold pattern blocks is different.Based on above-mentioned analysis, the present invention is proposed：It once will for a long time corrode and be changed to repeatedlyWet etching is patterned to layer gold, and the time of each wet etching is less than 2 minutes, is used and is gone after each wet etching is completeIonized water is rinsed, in this way, the accessory substance that corrosion is produced every time can be able to peel off in time, the further corrosion speed of layer gold is not influenceedRate, thus can solve simultaneously gold residual with undercutting amount it is uneven the problem of.
It is understandable to enable the above objects, features and advantages of the present invention to become apparent, below in conjunction with the accompanying drawings to the present inventionSpecific embodiment be described in detail.For the principle of the clear explanation present invention, chart not in scale below.
Fig. 1 to Fig. 4 is structural representation of the semiconductor devices in each production phase of one embodiment of the invention offer.BelowWith reference to Fig. 1 to Fig. 4, preparation method is described in detail.
Have as shown in Figure 1 there is provided Semiconductor substrate 1, in the Semiconductor substrate 1 in layer gold 11, the layer gold 11 and haveThere is patterned mask layer 12.
The substrate 10 of above-mentioned Semiconductor substrate 1 for example, silicon substrate, germanium substrate, silicon-on-insulator etc., the present embodiment makesDuring the semiconductor devices of formation is, for example, MEMS, one embodiment, above-mentioned MEMS includes being bonded together to shapeInto the substrate and cap rock of cavity, the substrate 10 of above-mentioned Semiconductor substrate 1 can be in the substrate of MEMS, i.e., above-mentioned substrate 10Various active, passive devices are formed with, layer gold 11 is formed on active, passive device or formed electric with active, passive deviceOn the metal interconnection structure of connection, the substrate 10 of above-mentioned Semiconductor substrate 1 can also be the cap rock of MEMS, i.e., above-mentioned substrateFormed on 10 without other devices, layer gold 11 is formed directly on silicon or SOI.
The thickness of layer gold 11 is, for example, 300 nanometers.In other embodiments, layer gold 11 can also select other thickness as neededDegree.
In the present embodiment, patterned mask layer 12 is the photoresist of patterning, is formed using exposure, developing technique.ItsIn its embodiment, the patterned mask layer 12 can also be other materials, such as silicon nitride.
Then, as shown in Figure 2 and Figure 3, it is that mask carries out figure to the layer gold 11 with the patterned mask layer 12Change, the layer gold 11 is patterned into wet etching, and the solution used is comprising KI and I2The aqueous solution, the wet etching pointRepeatedly carry out, the time of each wet etching is less than 2 minutes, and deionized water rinsing is used after each wet etching is complete.
First, shown in reference picture 2, first Semiconductor substrate 1 (shown in reference picture 1) is placed in comprising KI and I2The aqueous solution 2In.I2With strong oxidizing property, oxidation generation etch by-products 111 can be carried out to gold, above-mentioned accessory substance 111 can be dissolved in KI solution,To weaken the cladding of accessory substance 111, realize that preferably accessory substance 111 produces/removed ratio, it is preferable that layer gold 11 is corrodedThe aqueous solution 2 in, I2Mass percent be less than 2%, KI mass percent be less than 5%, the mass percent of deionized waterMore than 93%.It is highly preferred that I2Mass percent be 1.3%, KI mass percent be 4%, the quality hundred of deionized waterDivide than being 94.7%.
Although considering the removal of accessory substance 111 in the selection of the corrosive liquid aqueous solution 2, however, to realize faster gold11 corrosion rate of layer, KI mass percent selection causes to still suffer from the residual of accessory substance 111 in above-mentioned corrosion process.
In view of the residual quantity of above-mentioned accessory substance 111, the processing time of this step is less than 2 minutes, preferably smaller than 1 minute.
To be removed to the remaining bi-products 111 still suffered from above-mentioned corrosion process, to avoid it from coating the shadow of layer gold 11The further corrosion of layer gold is rung, as shown in figure 3, also rinsing above-mentioned Semiconductor substrate 1 using deionized water 3.
The time that above-mentioned deionized water 3 is rinsed is more than 2 minutes, it is preferable that the time range that deionized water 3 is rinsed is：2 pointsClock~5 minute, the deionized water 3 of above-mentioned time range is rinsed and can remove etch by-products 111 completely, and total processing timeShort, treatment effeciency is high.
The step of above-mentioned Fig. 2 to Fig. 3, can circulate progress repeatedly, to realize layer gold 11 in the vertical (i.e. on thickness direction)Removal amount demand, in the present embodiment, it is contemplated that batch processing, preferably more than 4 times., can also be according to reality in other embodimentsNeed to use other number of times.
Finally, the golden pattern block 11 ' formed after the layer gold 11 is graphical, is dried up, for example nitrogen using inactive gas,Preferred lower pressure air-flow.
As can be seen that in the present embodiment, because each wet etching time is shorter, being carried out afterwards to etch by-products 111Timely removal, the above-mentioned burn into deionized water 3 of the corrosive liquid aqueous solution 2, which is rinsed, repeatedly to be carried out thus removes after mask layer 12, such asShown in Fig. 4, the golden pattern block 11 ' formed：In the vertical, no gold residual, in the horizontal, the undercutting amount of golden pattern block 11 ' is smallIn 3 microns, and the undercutting amount of different golden pattern blocks 11 ' is roughly equal.
In the present embodiment, the material of mask layer 12 is photoresist, is removed for example with ashing method.In other embodiments, exampleSuch as the mask layer 12 that material is silicon nitride, removed for example with hot phosphoric acid.
In the present embodiment, MEMS includes being bonded together to form the substrate of cavity and cap rock, it is graphical afterGolden pattern block 11 ' is used for the projection for forming two wafer eutectic bondings, such as positioned at cavity both sides.It is above-mentioned in other embodimentsThe cavity of MEMS can also be by the sacrifice layer in the substrate 10 or substrate 10 of corrosion resistant semiconductor substrate 1 directly in semiconductorFormed on substrate 1, in such cases, movable sensitive film and fixed electrode be also formed with Semiconductor substrate 1, it is graphical afterGolden pattern block 11 ' can be used for forming the extraction movable sensitive film electrode of the contact with fixed electrode electric signal.Certainly, for thisHave in the MEMS that use cap rock in implementation is bonded together to form with substrate, the substrate of the MEMS movable sensitive film andDuring fixed electrode, it is graphical after golden pattern block 11 ' can be used for forming extraction movable sensitive film and fixed electrode telecommunicationsNumber contact electrode.For in other embodiments, it is above-mentioned the patterned method of layer gold can be used for forming other materials beThe part of gold.
Although present disclosure is as above, the present invention is not limited to this.Any those skilled in the art, are not departing from thisIn the spirit and scope of invention, it can make various changes or modifications, therefore protection scope of the present invention should be with claim instituteThe scope of restriction is defined.