CN103021817B - Cleaning method after wet etching - Google Patents
Cleaning method after wet etching Download PDFInfo
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- CN103021817B CN103021817B CN201210579772.6A CN201210579772A CN103021817B CN 103021817 B CN103021817 B CN 103021817B CN 201210579772 A CN201210579772 A CN 201210579772A CN 103021817 B CN103021817 B CN 103021817B
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Abstract
The invention discloses the cleaning method after a kind of wet etching, to ensure that silicon chip surface meets quality inspection requirement after wet etching.The cleaning method is included after completing metallic aluminium wet-etching technology, carries out first time wet method and removes silicon dust residue；Photoresist is formed on the metallic aluminium after wet etching by photoetching process；Carry out photoresist drying；Carry out photoresist dry ashing；And carry out second of wet method and remove silicon dust residue.
Description
Technical field
The invention belongs to semiconductor integrated circuit manufacturing process area, the cleaning side being related to after a kind of metallic aluminium wet etching
Method.
Background technology
With the continuous growth of integrated circuit integrated level, device feature size constantly reduces in integrated circuit, integrated circuit
The fine degree of production and processing is also continuing to increase.And the quarter of device final size is determined in integrated circuit manufactures link
Etching technique just highlights important all the more.Under the requirement that integrated circuit constantly develops to small size, dry etch process is because tool
There are good side wall control ability, good characteristic size control ability, minimum photoresist to come off with sticking problem, well
Uniformity and good process stabilizing and controllability are widely used.And wet-etching technology is because be isotropism
Chemical attack, all produce corrosion to horizontal and vertical in etching process, characteristic size control ability is poor.In high integration, small
In the super large-scale integration of characteristic size, almost no longer use.
But metal wet-etching technology but have the advantages that cost is low, production capacity is big, without charge accumulated, without physical damnification.
This causes wet processing to be used widely in some specialities manufacturing fields.As power device product, high reliability are produced
Product, Aero-Space Flouride-resistani acid phesphatase product, MEMS (Micro-electro Mechanical Systems, microelectromechanical systems)
Deng.
Now widely used metallic aluminium wet-etching technology is usually to etch metal with aluminium corrosive liquid, however, because wet
The isotropism of method etching, corrosive liquid also corrode the thin oxide layer of aluminium lower floor while metallic aluminium is etched.When thin oxide layer is thick
Spend the distance s that h is less than between aluminum strip, then when metallic aluminium is etched clean completely, thin oxide layer has been corroded totally,
Backing material silicon is also corroded, and forms silicon bits and separates out, as shown in Figure 1.Therefore, it is necessary to caused silicon after metallic aluminium wet etching
Bits are cleaned.Caused silicon bits after generally use dry or wet technique etching.Fig. 2 is refer to, it show existing
Metallic aluminium wet etching and silicon is gone to consider processing step to be worth doing in technology, including metallic aluminium photoetching, photoresist drying, photoresist ashing is wet
Method etches metallic aluminium, goes photoresist and dry or wet to go silicon to consider to be worth doing.Wherein, dry method goes silicon bits will using the method for Ions Bombardment
Removing residues after etching, process costs are low, the process time is short, simple to operate, flux is big, are suitable for typical products in mass production life
Production.But plasma damage and charge accumulated can be introduced using dry process, reliability and the radioresistance for reducing product are horizontal.
Wet method goes silicon bits then to remove the residue after etching using the method for chemical attack, does not produce damage and charge accumulated to substrate,
Avoid the influence that plasma damage and charge accumulated are horizontal to product reliability and Flouride-resistani acid phesphatase.But wet processing goes the ability that silicon is considered to be worth doing
It is weak compared to dry process, silicon bits, the problem of silicon dust residue can be produced can not be removed completely.In subsequent technique, the silicon of residual
Bits can fly away the various pieces of silicon chip, form macroscopic stain, so as to meet that Cargo Inspection is examined and gone out to On-line Product
Test requirement.If silicon bits are stayed on metal connecting line or encapsulation welding tray, integrity problem and encapsulation problem can be caused.
The content of the invention
It is a primary object of the present invention to provide the cleaning method after a kind of wet etching, to ensure silicon chip after wet etching
Surface meets quality inspection requirement.To reach above-mentioned purpose, the cleaning method after wet etching of the present invention comprises the following steps：
After completing metallic aluminium wet-etching technology, carry out first time wet method and remove silicon dust residue；
Photoresist is formed on the metallic aluminium after wet etching by photoetching process；
Carry out photoresist drying；
Carry out photoresist dry ashing；
Carry out second of wet method and remove silicon dust residue.
Preferably, the metallic aluminium wet-etching technology includes：Figure is formed on the metallic aluminium by photoetching process
The photoresist of change；Carry out photoresist drying；Carry out photoresist dry ashing；Using photoresist as mask, metal described in wet etching
For aluminium to form groove, thin oxide layer of the groove below the metallic aluminium simultaneously extends to substrate, produces the substrate
The silicon dust residue；Remove the photoresist.
Preferably, the thickness of the thin oxide layer is less than the width of the groove.
Preferably, the photoetching process includes coating photoresist layer, exposed and developed, wherein the thickness of the photoresist layer
For 2 to 2.5 microns.
Preferably, the temperature for carrying out photoresist drying is 100 to 120 DEG C, and the time is 10 to 30 minutes.
Preferably, the podzolic gas for carrying out photoresist dry ashing is carbon tetrafluoride and oxygen, and ashing time is 10 to 30
Second.
Preferably, by metallic aluminium described in aluminium corrosive liquid wet etching, wherein the aluminium corrosive liquid composition includes 80% phosphorus
Acid, 5% nitric acid, 5% acetic acid and 10% water；Technological temperature is 35 to 45 DEG C.
Preferably, the process gas for removing the photoresist is oxygen, and the time is 30 to 90 minutes.
Preferably, silicon dust residue is removed by going silicon to consider liquid wet method to be worth doing, wherein the composition for removing silicon bits liquid includes 60% ~ 70%
Phosphoric acid, 5% ~ 10% nitric acid, 10% ~ 20% acetic acid and 10% ~ 20% water；Technological temperature is 23 to 25 DEG C, and the time is 1 to 10 minute.
It is an advantage of the current invention that by adding the steps such as secondary photoetching metallic aluminium, it is residual to remove silicon bits in increase wet method
Protect metallic aluminium unaffected while staying the process time, can not only effectively reduce silicon dust residue and remove the white residue of residual,
Also charge accumulated and plasma damage will not be produced, the reliability and anti-radiation performance of device and products can be ensured, is met
Requirement of the specialities to high reliability and highly anti-radiation performance.
Brief description of the drawings
Fig. 1 show schematic diagram after the metallic aluminium wet etching with thin oxide layer structure.
Fig. 2 be in the prior art metallic aluminium wet etching and go silicon bits technique flow chart.
Fig. 3 is the flow chart of the cleaning method after one embodiment of the invention wet etching.
Embodiment
To make present disclosure more clear understandable, below in conjunction with Figure of description, present disclosure is made into one
Walk explanation.Certainly the invention is not limited in the specific embodiment, the general replacement known to those skilled in the art
Cover within the scope of the present invention.
A preferred embodiment below with reference to Fig. 3 descriptions according to the cleaning method after wet etching of the invention.
It refer to Fig. 3, the cleaning method after wet etching of the invention comprises the following steps：
Step 301：After metallic aluminium wet-etching technology is completed, carry out first time wet method and remove silicon dust residue.
Wherein, metallic aluminium wet-etching technology is to carry out wet etching to the metallic aluminium on thin oxide layer, it is necessary to pay attention to
It is that thin oxide layer is very thin, its thickness is less than the spacing between the metal aluminum strip after etching, so when wet etching is completed
Wait, oxide layer has been corroded totally, and silicon substrate is also corroded, and forms silicon bits and separates out and remain.
The step of wet etching, specifically includes：First, by coating photoresist layer, expose, the first time photoetching work such as development
Skill forms patterned photoresist on metallic aluminium, and the thickness of photoresist layer can be 2 ~ 2.5 microns, and its type and thickness can bases
The thickness of metallic aluminium and optimal etching condition determine.
Then, photoresist drying is carried out, drying temperature is 100 DEG C ~ 120 DEG C, and drying time is 10 ~ 30 minutes；It is laggard
Row photoresist dry ashing, podzolic gas are carbon tetrafluoride and oxygen, and ashing time is 10 ~ 30 seconds.By photoresist drying and
Dry ashing, make photoresist that there is more preferable adhesiveness and decay resistance, and can be effectively improved photoresist surface configuration and
Hydrophobic character, so as to reduce the surface tension of the wet etching decoction used in etching metallic aluminium；Additionally become photoresist corner
Must be mellow and full, be advantageous to etch product disengaging, so that wet etching decoction reaches uniform quarter more fully with Al Contact
Erosion, the purpose for reducing metal residual.
Then, wet etching is carried out to metallic aluminium using aluminium corrosive liquid using photoresist as mask, aluminium corrosive liquid into subpackage
Include：80% phosphoric acid, 5% nitric acid, 5% acetic acid and 10% water；Technological temperature is 35 to 45 DEG C, and etch period can be according to the thickness of metallic aluminium
Calculated with the etch rate of aluminium corrosive liquid.Afterwards, photoresist is removed, for the process gas used for oxygen, the time is 30 ~ 90 points
Clock.
Due to the isotropism of wet etching, and in the present embodiment thin oxide layer metal aluminum strip after being less than wet etching
Spacing, that is to say the width of the groove formed during wet etching metallic aluminium, groove will pass through thin oxide layer and extend to substrate,
So that substrate produces silicon bits and separates out and remain.Therefore, according to the cleaning method of the present invention, metallic aluminium wet etching work is completed
After skill, the silicon dust residue on silicon bits liquid progress first time wet method removal substrate is first passed through.Go silicon bits liquid composition include 60% ~
70% phosphoric acid, 5% ~ 10% nitric acid, 10% ~ 20% acetic acid and 10% ~ 20% water；It is 23 ~ 25 DEG C that wet method, which removes the technological temperature of silicon bits technique,
Time is 1 ~ 10 minute, and etch rate can remain/ minute.After metallic aluminium wet etching, some quarters can be also produced
The accessory substance of erosion, first time wet method removes silicon dust residue can play a part of cleaning accessory substance in the lump.In addition, after photoresist removes
The photoetching material of metallic aluminum surface residual can also go silicon bits fully erased by wet method, so as to ensure the metallic aluminium in follow-up photoetching
Surface can have surface nature when being similar to first time photoetching, and the line width of metal aluminum strip will not also produce change.However, by
The process window deficiency of silicon bits technique is gone in wet method, silicon bits or white residue residual are still suffered from after a wet method goes silicon to consider to be worth doing.
Step 302, photoresist is formed on metallic aluminium after wet etching by second of photoetching process.
The condition of second of photoetching process is identical with first time, and it also includes photoresist gluing, exposure, the technique step of development
Suddenly, the thickness of photoresist can be 2 ~ 2.5 microns.This layer of photoresist removes masking layer during silicon bits technique as subsequent wet.
Step 303, photoresist drying is carried out, so that photoresist has more preferable adhesiveness and decay resistance.
Drying condition is identical when can be with wet etching metallic aluminium, drying temperature be 100 DEG C ~ 120 DEG C, drying time be 10 ~
30 minutes.
Step 304, photoresist dry ashing is carried out.
It is follow-up wet so as to reduce to be effectively improved the surface configuration of photoresist and hydrophobic character by photoresist partial etching
Method goes in silicon bits technique to go the surface tension of silicon bits liquid.
Step 305, carry out second of wet method and remove silicon dust residue.
Its process conditions is identical when can be with first time wet method removal silicon dust residue, specifically, is entered by going silicon to consider liquid to be worth doing
Second of wet method of row goes silicon to consider to be worth doing, removes the composition of silicon bits liquid and includes 60% ~ 70% phosphoric acid, 5% ~ 10% nitric acid, and 10% ~ 20% acetic acid and 10% ~
20% water；Technological temperature is 23 ~ 25 DEG C；Etch rate can remain/ minute；Time is 1 ~ 10 minute, with specific reference to white residue
Residual degree determines.Because photoresist as masking layer is covered in metallic aluminum surface, play a protective role, therefore carrying out second
When secondary wet method removes silicon dust residue, metallic aluminum surface can't be corroded.
In order to prove the technique effect of the present invention, it have chosen 3 kinds of technical schemes and tested, experimental result such as following table
1：
Table 1
The result of experiment 1 shows that the time of increase metallic aluminium wet-etching technology can not solve the problems, such as silicon dust residue, real
Although the result for testing 2 shows that increasing wet method goes the time of silicon bits technique to expand process window, reduces the quantity of silicon dust residue,
But in the case where unglazed photoresist is sheltered, metallic aluminum surface can be caused damage.And according to the cleaning method of the present invention, carry out
Wet method goes silicon bits technique to expand wet method and removes silicon bits process window twice, effectively reduces silicon dust residue, and pass through light
Carving technology protects metallic aluminium, and metallic aluminum surface property can be kept constant.
From the invention described above preferred embodiment, silicon dust residue after removal metallic aluminium wet-etching technology of the invention
Cleaning method adds the steps such as photolithographic aluminium compared with traditional cleaning method, using photoresist as masking layer, is expanding
Wet method goes silicon to protect metallic aluminium unaffected while considering process window to be worth doing, so as to which charge accumulated and plasma damage will not be produced,
The reliability and anti-radiation performance of device and products can be ensured, to meet specialities to high reliability and highly anti-radiation
The requirement of performance.In addition, the present invention is applicable not only to common product, the product for the thin oxide layer structure that is particularly suitable for use in.
Although the present invention is disclosed as above with preferred embodiment, right many embodiments are illustrated only for the purposes of explanation
, the present invention is not limited to, those skilled in the art can make without departing from the spirit and scope of the present invention
Some changes and retouching, the protection domain that the present invention is advocated should be to be defined described in claims.
Claims (7)
1. the cleaning method after a kind of wet etching, it is characterised in that comprise the following steps：
Patterned photoresist is formed on metallic aluminium by first time photoetching process；
Carry out photoresist drying；
Carry out photoresist dry ashing；
Using the patterned photoresist as mask, with metallic aluminium described in isotropism wet etching to form groove, the ditch
Thin oxide layer of the groove below the metallic aluminium simultaneously extends to substrate, the substrate is produced silicon bits；Wherein described thin oxidation
The thickness of layer is less than the width of the groove；
Remove the photoresist；
Carry out first time wet method and remove silicon dust residue；
By second of photoetching process of process conditions identical with the first time photoetching process in the gold after wet etching
Patterned photoresist is formed on category aluminium；
Carry out photoresist drying；
Carry out photoresist dry ashing；
Second of the wet method of process conditions identical for removed with the first time wet method silicon dust residue removes silicon dust residue.
2. the cleaning method after wet etching according to claim 1, it is characterised in that the photoetching process includes coating
Photoresist layer, it is exposed and developed, wherein the thickness of the photoresist layer is 2 to 2.5 microns.
3. the cleaning method after wet etching according to claim 1, it is characterised in that carry out the temperature of photoresist drying
For 100 to 120 DEG C, the time is 10 to 30 minutes.
4. the cleaning method after wet etching according to claim 1, it is characterised in that carry out photoresist dry ashing
Podzolic gas is carbon tetrafluoride and oxygen, and ashing time is 10 to 30 seconds.
5. the cleaning method after wet etching according to claim 1, it is characterised in that pass through aluminium corrosive liquid wet etching
The metallic aluminium, wherein the aluminium corrosive liquid composition includes 80% phosphoric acid, 5% nitric acid, 5% acetic acid and 10% water；Technological temperature
For 35 to 45 DEG C.
6. the cleaning method after wet etching according to claim 1, it is characterised in that the technique for removing the photoresist
Gas is oxygen, and the time is 30 to 90 minutes.
7. the cleaning method after wet etching according to claim 1, it is characterised in that removed by going silicon to consider liquid wet method to be worth doing
Silicon dust residue, wherein the composition for removing silicon bits liquid includes 60%~70% phosphoric acid, 5%~10% nitric acid, 10%~20% second
Acid and 10%~20% water；Technological temperature is 23 to 25 DEG C, and the time is 1 to 10 minute.
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| CN201210579772.6A CN103021817B (en) | 2012-12-27 | 2012-12-27 | Cleaning method after wet etching |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104810279B (en) * | 2014-01-23 | 2018-07-10 | 北大方正集团有限公司 | A kind of aluminium lithographic method and device |
| CN107342217B (en) * | 2017-07-18 | 2019-11-12 | 成都海威华芯科技有限公司 | A kind of processing method based on secondary wet process etching |
| CN110438504A (en) * | 2019-08-19 | 2019-11-12 | 江阴江化微电子材料股份有限公司 | A kind of alum gate Ke Kai area's silicon slag removes composition and silicon slag sweep-out method |
| CN110970313B (en) * | 2019-11-14 | 2021-05-07 | 长江存储科技有限责任公司 | Welding pad structure and preparation method of semiconductor structure |
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| US6054393A (en) * | 1997-01-09 | 2000-04-25 | Texas Instruments Incorporated | Method for improving the wet process chemical sequence |
| CN101043007A (en) * | 2006-12-21 | 2007-09-26 | 上海集成电路研发中心有限公司 | Preparing technique for metallic oxide silicon field-effect transistor |
| CN102446701A (en) * | 2010-10-12 | 2012-05-09 | 上海华虹Nec电子有限公司 | Method for improving defect of silicon spikes of edge of silicon wafer with etched deep groove |
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| CN102403216B (en) * | 2010-09-09 | 2013-06-12 | 上海华虹Nec电子有限公司 | Wet etching method for preparation of super-junction device |
| CN102420168A (en) * | 2011-04-29 | 2012-04-18 | 上海华力微电子有限公司 | Method of carrying out wet process cleaning on plasma etching residues |
| CN102800576B (en) * | 2011-05-26 | 2015-09-02 | 中芯国际集成电路制造(上海)有限公司 | The method of graphic diaphragm layer, the method for grid, MOS transistor of being formed |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6054393A (en) * | 1997-01-09 | 2000-04-25 | Texas Instruments Incorporated | Method for improving the wet process chemical sequence |
| CN101043007A (en) * | 2006-12-21 | 2007-09-26 | 上海集成电路研发中心有限公司 | Preparing technique for metallic oxide silicon field-effect transistor |
| CN102446701A (en) * | 2010-10-12 | 2012-05-09 | 上海华虹Nec电子有限公司 | Method for improving defect of silicon spikes of edge of silicon wafer with etched deep groove |
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