CN115197705B - Etching solution and thinning method of tellurium-cadmium-mercury infrared focal plane hybrid chip - Google Patents
Etching solution and thinning method of tellurium-cadmium-mercury infrared focal plane hybrid chip Download PDFInfo
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- CN115197705B CN115197705B CN202210601938.3A CN202210601938A CN115197705B CN 115197705 B CN115197705 B CN 115197705B CN 202210601938 A CN202210601938 A CN 202210601938A CN 115197705 B CN115197705 B CN 115197705B
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- 238000005530 etching Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 48
- 239000000758 substrate Substances 0.000 claims abstract description 61
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 35
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims abstract description 32
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 29
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000004310 lactic acid Substances 0.000 claims abstract description 16
- 235000014655 lactic acid Nutrition 0.000 claims abstract description 16
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 16
- 229920002120 photoresistant polymer Polymers 0.000 claims description 20
- 239000008367 deionised water Substances 0.000 claims description 14
- 229910021641 deionized water Inorganic materials 0.000 claims description 14
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 10
- 239000003292 glue Substances 0.000 claims description 10
- BMYNFMYTOJXKLE-UHFFFAOYSA-N 3-azaniumyl-2-hydroxypropanoate Chemical compound NCC(O)C(O)=O BMYNFMYTOJXKLE-UHFFFAOYSA-N 0.000 claims description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 8
- 238000001259 photo etching Methods 0.000 claims description 8
- 238000004140 cleaning Methods 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims description 7
- 238000000576 coating method Methods 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 claims description 6
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims description 6
- 229910052794 bromium Inorganic materials 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 5
- 238000002791 soaking Methods 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 239000000243 solution Substances 0.000 abstract description 40
- 230000008569 process Effects 0.000 abstract description 23
- 238000005260 corrosion Methods 0.000 abstract description 19
- 230000007797 corrosion Effects 0.000 abstract description 19
- YWIBETYWGSNTAE-UHFFFAOYSA-N [Br].Br Chemical compound [Br].Br YWIBETYWGSNTAE-UHFFFAOYSA-N 0.000 abstract description 2
- 239000007864 aqueous solution Substances 0.000 abstract description 2
- 230000007704 transition Effects 0.000 abstract description 2
- 238000001039 wet etching Methods 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 16
- 238000000227 grinding Methods 0.000 description 10
- 238000005498 polishing Methods 0.000 description 10
- 239000000306 component Substances 0.000 description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000007516 diamond turning Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000007514 turning Methods 0.000 description 3
- 229910000661 Mercury cadmium telluride Inorganic materials 0.000 description 2
- -1 Nitric acid Hydrochloric acid Lactic acid Chemical compound 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000004026 adhesive bonding Methods 0.000 description 2
- QWUZMTJBRUASOW-UHFFFAOYSA-N cadmium tellanylidenezinc Chemical compound [Zn].[Cd].[Te] QWUZMTJBRUASOW-UHFFFAOYSA-N 0.000 description 2
- MCMSPRNYOJJPIZ-UHFFFAOYSA-N cadmium;mercury;tellurium Chemical compound [Cd]=[Te]=[Hg] MCMSPRNYOJJPIZ-UHFFFAOYSA-N 0.000 description 2
- 238000007667 floating Methods 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000004528 spin coating Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- DVASVKJMGDPRDE-UHFFFAOYSA-N F.[N+](=O)(O)[O-].C(C(O)C)(=O)O Chemical compound F.[N+](=O)(O)[O-].C(C(O)C)(=O)O DVASVKJMGDPRDE-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000002318 adhesion promoter Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- DGJPPCSCQOIWCP-UHFFFAOYSA-N cadmium mercury Chemical compound [Cd].[Hg] DGJPPCSCQOIWCP-UHFFFAOYSA-N 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 239000002173 cutting fluid Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 235000019441 ethanol Nutrition 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K13/00—Etching, surface-brightening or pickling compositions
- C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
- C09K13/08—Etching, surface-brightening or pickling compositions containing an inorganic acid containing a fluorine compound
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/1892—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof methods involving the use of temporary, removable substrates
- H01L31/1896—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof methods involving the use of temporary, removable substrates for thin-film semiconductors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Condensed Matter Physics & Semiconductors (AREA)
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- Weting (AREA)
Abstract
The application provides an etching solution, which comprises nitric acid, hydrofluoric acid, lactic acid and water; the method can quickly remove the tellurium-zinc-cadmium substrate by a wet etching method, the corrosion rate of the tellurium-zinc-cadmium substrate can reach more than 500 micrometers/min, the etching solution can completely etch the tellurium-zinc-cadmium substrate within 2 min, a termination layer is formed on the tellurium-cadmium-mercury transition layer, the termination layer is only tens of nanometers, and the termination layer is removed by the corrosion of a bromine hydrobromic acid aqueous solution for about 10 seconds, so that the bright and fresh tellurium-cadmium-mercury surface is finally obtained. The method can rapidly remove the substrate with the original thickness of 900-1000 microns, effectively eliminates the damage caused by the physical thinning process of the substrate, and keeps the photoelectric performance of the tellurium-cadmium-mercury infrared detector free from the influence of the substrate thinning process.
Description
Technical Field
The application relates to the technical field of etching, in particular to an etching solution and a thinning method of a tellurium-cadmium-mercury infrared focal plane hybrid chip.
Background
The tellurium-cadmium-mercury infrared focal plane hybrid chip is a core component of the tellurium-cadmium-mercury infrared focal plane detector assembly, and the hybrid chip set is prepared by reversely connecting a tellurium-cadmium-mercury infrared focal plane array chip and a silicon readout circuit through an indium column. The tellurium-cadmium-mercury infrared focal plane array chip is prepared from infrared photosensitive materials based on the tellurium-zinc-cadmium substrate epitaxy technology through a series of semiconductor process flows of surface treatment, passivation, photoetching, injection, etching, electrode forming and the like, wherein the thickness of the substrate is about 900-1000 microns, as shown in figure 1. The tellurium-zinc-cadmium substrate thinning and removing of the tellurium-cadmium-mercury infrared focal plane detector mixed chip can effectively reduce the internal stress generated by the temperature impact of the chip photosensitive element, improve the infrared radiation transmittance and improve the working stability and reliability of the detector component.
The main technical route of the prior substrate thinning and removing process is that firstly, the substrate thinning is carried out by a physical (including grinding and polishing, single-point diamond turning and the like) method, so that the tellurium-zinc-cadmium substrate is kept about 10 microns; the residual cadmium zinc telluride substrate of about 10 microns is completely removed by chemical etching. The grinding and polishing process is to reversely buckle the mixed chip set on a grinding and polishing disc or a grinding and polishing pad of the grinding and polishing equipment, dropwise add grinding and polishing liquid by applying pressure, and realize the grinding and polishing effect of the substrate and the grinding and polishing liquid by the rotation and revolution of the grinding and polishing disc, the grinding and polishing pad and the chip set, thereby achieving the purpose of thinning the substrate. The single-point diamond turning adopts a fly cutter milling method, a mixed chip set is fixed on a workpiece table, and a substrate is turned under the combined action of the transverse feeding of a fly cutter and the longitudinal feeding of the workpiece table, so that the thinning purpose of the tellurium-zinc-cadmium substrate is achieved. The physical method for thinning and removing the substrate requires related equipment and auxiliary materials, and the equipment and the auxiliary materials are high in price, so that the cost for thinning and removing the substrate is high. In the process of thinning the substrate by using the polishing method, scratches appear on the surface with a certain probability, and the occurrence of the scratches can influence the performance of pixels at corresponding positions on the detector, so that the image quality is influenced; in addition, micro cracks, broken edges and the like are easy to form around the focal plane array chip under the action of stress, and the photoelectric performance of the detector is affected.
In the process of thinning the substrate by using the single-point diamond turning method, cutting fluid is sprayed to cool the detector chip, turning residues can cover the surface, scratches are easy to generate in subsequent turning, and in addition, edge breakage phenomenon and turning stress can occur at the cutter outlet edge of the detector chip with high probability, so that the photoelectric performance of the detector can be influenced. In addition, the technical scheme has the advantages of complex process, long period and low efficiency.
Therefore, the substrate thinning and removing process is a key process technology for influencing the performance and the reliability of the tellurium-cadmium-mercury infrared focal plane detector component.
Disclosure of Invention
In order to solve the problems in the prior art, the application provides an etching solution and a thinning method of a tellurium-cadmium-mercury infrared focal plane hybrid chip.
In a first aspect, the present application provides an etching solution comprising nitric acid, hydrofluoric acid, lactic acid and water.
As a specific embodiment of the application, the etching solution preparation method comprises the step of mixing nitric acid, hydrofluoric acid, lactic acid and water.
As a specific embodiment of the present application, the molar ratio of nitric acid, hydrofluoric acid, lactic acid and water is 12:1:6: (6-50).
Specifically, the pH value of the etching solution is changed by adjusting the proportion of water, so that the corrosion rate is adjusted; when the water is 6 moles, the corrosion rate is fastest, and when the water exceeds 50 moles, the corrosion rate is remarkably reduced, the effect of rapid corrosion is not achieved, and the corrosion uniformity is deteriorated.
In a second aspect, the application provides application of the etching solution in the field of tellurium-zinc-cadmium materials.
In a third aspect, the application provides a thinning method of a tellurium-cadmium-mercury infrared focal plane hybrid chip, which adopts the etching solution to etch and remove a tellurium-zinc-cadmium substrate of the tellurium-cadmium-mercury infrared focal plane hybrid chip.
As a specific embodiment of the present application, the thinning method includes the steps of:
s1: coating photoresist around the tellurium-cadmium-mercury infrared focal plane hybrid chip, baking, exposing, developing, photoetching and forming a film;
s2: placing the chip obtained in the step 1 after the glue coating and film forming in the etching solution of claim 1 or 2, and cleaning after removing the tellurium-zinc-cadmium substrate;
s3: placing the chip with the tellurium-zinc-cadmium substrate removed obtained in the step S2 in a stop layer etching solution for etching, and removing the stop layer;
s4: and (3) cleaning and drying the chip with the termination layer removed, which is obtained in the step (S3), to obtain the tellurium-cadmium-mercury infrared focal plane hybrid chip with the thinned substrate.
As a specific embodiment of the present application, in the step S1, the photoresist is a positive photoresist; the positive photoresist preferably comprises AZ6130, kowa BP218; specifically, taking AZ6130 as an example, a spin coating mode can be selected as a glue coating mode, and the spin coating rotating speed is 2000-3000 rpm.
The photoresist has a glue coating thickness of 4-10 mu m; when the glue is actually applied, the thickness of the photoresist is 4-10 mu m, the thickness of the flat area is 4 mu m, but the phenomenon of photoresist accumulation at the corners of the mixed chip occurs, and the thickness of the photoresist is about 6-10 mu m;
the baking temperature is 80-100 ℃; the baking time is 1-10 min;
the exposure mode is contact exposure; the exposure time is 10-20 s;
the development time is 30-90 s; specifically, immersing the chip in the developing solution for 30-90 s to complete development;
the film forming temperature is 50-80 ℃; the film forming time is 1-3 h; specifically, the film forming method is preferably oven baking.
As a specific implementation mode of the application, the whole surface is coated with the glue, and then the needed pattern is selected through the photoetching technology; the process flow of the photoetching technology comprises gluing, pre-baking, exposure, development, hardening and other technologies; positive photoresist is sufficient, but a certain photoresist thickness is ensured, and the unnecessary photoresist can be removed by development after exposure. The size of the photoetching plate is 5 micrometers larger than that of the tellurium-zinc-cadmium substrate of the mixed chip in each direction; the method is to ensure that the tellurium-zinc-cadmium substrate can be completely exposed and can be removed by corrosion in the subsequent corrosion process; the size is 5 micrometers larger, firstly for photoetching alignment, and secondly for completely exposing the tellurium-zinc-cadmium substrate, so that preparation is made for subsequent corrosion.
In the specific embodiment of the present application, in the step S2, the etching solution includes nitric acid, hydrofluoric acid, lactic acid and water, wherein the molar ratio of nitric acid, hydrofluoric acid, lactic acid and water is 12:1:6: (6-50); the etching time is 1-3 min.
As a specific embodiment of the present application, in the step S3, the composition of the etching solution for the termination layer includes bromine, hydrobromic acid and water; the volume ratio of bromine, hydrobromic acid and water in the components of the etching solution of the stop layer is 0.1:10:90; the hydrobromic acid concentration is 50%; the etching time is 5-15 s.
As a specific embodiment of the present application, in the step S4, the cleaning includes three steps of deionized water rinsing, acetone soaking, and absolute ethanol rinsing.
As a specific embodiment of the application, the deionized water flushing time is 3-8 min; the acetone soaking time is 3-5 min; washing with ethanol for 3-5 times; and the drying is performed by adopting nitrogen.
The above-mentioned raw materials in the present application are all self-made or commercially available, and the present application is not particularly limited thereto.
Compared with the prior art, the application has the beneficial effects that:
1. the etching solution can quickly remove the tellurium-zinc-cadmium substrate by a wet etching method, the etching rate of the tellurium-zinc-cadmium substrate can reach more than 500 micrometers/min, the etching solution can completely etch the tellurium-zinc-cadmium substrate within 2 minutes, a termination layer is formed on a tellurium-cadmium-mercury transition layer, the termination layer is only tens of nanometers, the termination layer is removed by etching with a bromine hydrobromic acid aqueous solution, the etching time is about 10 seconds, and finally the bright and fresh tellurium-cadmium-mercury surface is obtained. The method can rapidly remove the substrate with the original thickness of 900-1000 microns, effectively eliminates the damage caused by the physical thinning process of the substrate, and keeps the photoelectric performance of the tellurium-cadmium-mercury infrared detector free from the influence of the substrate thinning process.
2. The embodiment of the application shows that the etching liquid obviously improves the efficiency of the thinning and removing process of the tellurium-zinc-cadmium substrate, saves the cost of equipment, manpower, materials and the like, eliminates the stress damage caused by the substrate thinning by a physical mode, ensures that the performance of the infrared detector is not influenced by the substrate thinning and removing process, and improves the yield of the substrate thinning process.
3. The etching solution has low cost and high substrate removal efficiency, and is particularly suitable for thinning and removing the substrate of the small-spacing tellurium-zinc-cadmium-tellurium-cadmium-mercury infrared detector mixed chip.
Drawings
FIG. 1 is a schematic diagram of a tellurium-cadmium-mercury infrared focal plane hybrid chip in an embodiment of the application;
FIG. 2 is a schematic diagram of a chip formed by mixing the tellurium-cadmium-mercury infrared focal plane after the glue is applied in the step S1;
FIG. 3 is a schematic diagram of an exposure process performed on a coated tellurium-cadmium-mercury infrared focal plane hybrid chip obtained in step S1 in an embodiment of the present application;
FIG. 4 is a schematic diagram of a Cd-Hg infrared focal plane hybrid chip after developing in step S1 to completely reveal a CdZn-Cd substrate in an embodiment of the application;
FIG. 5 is a schematic diagram of a tellurium-cadmium-mercury infrared focal plane hybrid chip with a tellurium-zinc-cadmium-removed substrate obtained in step S2 in an embodiment of the application;
fig. 6 is a schematic diagram of a thinned mercury cadmium telluride infrared focal plane hybrid chip with a termination layer removed in step S3 according to an embodiment of the present application.
Wherein, the substrate of 1-tellurium zinc cadmium, 2-tellurium cadmium mercury epitaxial film, 3-interconnection indium column; 4-readout circuit chip.
Detailed Description
The application is further illustrated below in connection with specific examples, which are not to be construed as limiting the application in any way.
The information on the reagents used in the examples of the present application are as follows:
nitric acid, tianjin Fengshan TSVL grade, concentration 98%, density about 1.52g/ml, molecular weight 63;
hydrofluoric acid, tianjin Fengsha TSVL grade, concentration 40%, density about 1.12g/ml, molecular weight 20;
lactic acid, tianjin Fengshan TSVL grade, density about 1.2g/ml, molecular weight 90;
water, deionized water, resistivity 18 mohm, molecular weight 18;
bromine, tianjin Fengshui, purity 5N;
hydrobromic acid, tianjin Fengshan TSVL grade, concentration 50%.
Example 1
The embodiment provides an etching solution, which comprises the following specific component information:
50ml of nitric acid, 5ml of hydrofluoric acid, 45ml of lactic acid and 10ml of deionized water;
mixing the nitric acid, the hydrofluoric acid, the lactic acid and the water in the proportion, and stirring the mixture on a magnetic stirrer for 3 minutes in a rotating way to obtain the etching solution which is uniformly mixed.
The etching solution obtained in example 1 had a pH of 0.
Examples 2 to 5
The etching solutions provided in examples 2 to 5 were prepared in the same manner as in example 1, except that the water ratios were different, and specific details are shown in table 1:
table 1 examples 1 to 5 provide etching solution components and ratio information
| Nitric acid | Hydrofluoric acid | Lactic acid | Deionized water | pH value of | Corrosion rate (microns/min) | |
| Example 1 | 50ml | 5ml | 45ml | 10ml | 0 | ≥620 |
| Example 2 | 50ml | 5ml | 45ml | 50ml | 0 | ≥550 |
| Example 3 | 50ml | 5ml | 45ml | 90ml | 0 | ≥520 |
| Example 4 | 50ml | 5ml | 45ml | 100ml | 0 | ≤150 |
| Example 5 | 50ml | 5ml | 45ml | 150ml | 0 | ≤50 |
Comparative example 1
The comparative example provides an etching solution, and the specific component proportion information is as follows:
50ml of nitric acid, 5ml of hydrochloric acid (concentration is 37%), 45ml of lactic acid and 10ml of deionized water;
nitric acid, hydrochloric acid (concentration is 37%), lactic acid and water in the above proportions are mixed, and the mixture is stirred for 3 minutes by rotating on a magnetic stirrer, so as to obtain an etching solution which is uniformly mixed.
The etching solution obtained in comparative example 1 had a pH of 0 and a corrosion rate of about 10 μm/min.
Comparative examples 2 to 5
The etching solutions provided in comparative examples 2 to 5 were prepared in the same manner as in example 1, and the composition and ratio information are shown in table 2:
table 2 comparative examples 1 to 5 provide etching solution components and ratio information
| Nitric acid | Hydrochloric acid | Lactic acid | Deionized water | pH value of | Corrosion rate (microns/min) | |
| Comparative example 1 | 50ml | 5ml | 45ml | 10ml | 0 | About 10 |
| Comparative example 2 | 50ml | 15ml | 45ml | 10ml | 0 | About 15 |
| Comparative example 3 | 20ml | 20ml | 45ml | 10ml | 0 | About 8 |
| Comparative example 4 | 20ml | 20ml | 10ml | 10ml | 0 | About 10 |
| Comparative example 5 | 15ml | 45ml | 45ml | 10ml | 0 | About 5 |
TABLE 3 other etchant composition and formulation information
| Nitric acid | Hydrochloric acid | Potassium dichromate | Deionized water | pH value of | Corrosion rate (microns/min) | |
| Comparative example 6 | 30ml | 20ml | 20g | 50ml | 0 | About 8 |
The chemical reaction of wet corrosion belongs to the reaction of liquid phase and solid phase, and is a process controlled by diffusion effect. The corrosion rates of comparative examples 1 to 6 were too slow, and the corrosion rates were further decreased and the uniformity of corrosion was poor with the lapse of time. In addition, the photoresist is not enough to provide effective protection because the photoresist is soaked in the etching solution for a long time, and the phenomenon of floating glue can occur after 10-15 minutes, so that the etching solution erodes the bonding pad of the reading circuit, and the circuit is disabled. Even if the adhesion promoter is applied before the adhesion, the phenomenon of floating glue can occur after 20-25 minutes of corrosion, and the excessively slow speed can not be applied to the nondestructive thinning and removal of the substrate.
Example 6
The embodiment provides a thinning method of a tellurium-cadmium-mercury infrared focal plane hybrid chip, which comprises the following specific details:
s1: the tellurium-cadmium-mercury infrared focal plane hybrid chip (hereinafter referred to as a chip) is coated with positive photoresist in a spin mode, the type of the photoresist is AZ6130, the spin speed is 2500 rpm, and the thickness of the photoresist is 4-10 mu m;
pre-baking the chip coated with the glue on a hot plate at 95 ℃ for 3 minutes; then exposing for 15 seconds by adopting a contact exposure mode; the size of the photoetching plate is 5 micrometers larger than that of the tellurium-zinc-cadmium substrate of the mixed chip in each direction;
immersing the exposed chip into AZ300MIF (2.38%) developing solution, keeping the temperature at 23 ℃ and developing for 60 seconds; washing with deionized water for 30 seconds after development is finished, and then placing the solution in an oven at 60 ℃ to dry and harden the film for 2 hours;
s2: placing the chip subjected to the gluing film formation obtained in the step 1 into the etching solution prepared in the embodiment 1, corroding for 2 minutes, and cleaning with deionized water for 5 minutes after removing the tellurium-zinc-cadmium substrate;
s3: bromine, hydrobromic acid with the concentration of 50 percent and deionized water are mixed according to the volume ratio of 0.1:10:90, and rotating and stirring for 3 minutes on a magnetic stirrer to obtain a stop layer etching solution; placing the chip with the tellurium-zinc-cadmium substrate removed obtained in the step S2 in a stop layer etching solution for etching for 10 seconds, and removing the stop layer;
s4: and (3) washing the chip with the termination layer removed, which is obtained in the step (S3), with deionized water for 5 minutes, soaking in acetone for 3 minutes, washing with absolute ethyl alcohol for 3 times, and drying with nitrogen to obtain the final substrate-thinned tellurium-cadmium-mercury infrared focal plane hybrid chip.
The tellurium-cadmium-mercury infrared focal plane hybrid chip obtained in the example 6 is observed by an optical microscope, and the substrate clearance rate reaches 100%.
Examples 7 to 15
Examples 7 to 15 employed the etching solutions provided in examples 2 to 5 and comparative examples 1 to 5, and the thickness of the cadmium zinc telluride substrate was 920 to 930 μm. The chip thinning treatment was performed by using the thinning method provided in example 6, and the specific effects obtained are shown in table 3:
TABLE 3 effects of etching solutions of examples 1 to 5 and comparative examples 1 to 5 on chip thinning treatment
The comparison of the comparative example and the example shows that the reaction rate is only 15 microns/min at the fastest speed after hydrochloric acid replaces hydrofluoric acid, and the mercury cadmium telluride film has stronger corrosiveness; sulfuric acid is too oxidizing and reacts with lactic acid.
In conclusion, the etching solution formula for rapidly etching and removing the tellurium-zinc-cadmium substrate is effectively applied to the thinning and removing process of the chip substrate mixed by the tellurium-zinc-cadmium-based tellurium-cadmium-mercury infrared focal plane detector. The application of the etching solution obviously improves the efficiency of the thinning and removing process of the tellurium-zinc-cadmium substrate, saves the cost of equipment, manpower, materials and the like, eliminates the stress damage caused by the substrate thinning by a physical mode, ensures that the performance of the infrared detector is not influenced by the substrate thinning and removing process, and improves the yield of the substrate thinning process.
Any numerical value recited in this disclosure includes all values incremented by one unit from the lowest value to the highest value if there is only a two unit interval between any lowest value and any highest value. For example, if the amount of one component, or the value of a process variable such as temperature, pressure, time, etc., is stated to be 50-90, it is meant in this specification that values such as 51-89, 52-88 … …, and 69-71, and 70-71 are specifically recited. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 units may be considered as appropriate. This is only a few examples of the specific designations. In a similar manner, all possible combinations of values between the lowest value and the highest value enumerated are to be considered to be disclosed.
It should be noted that the above-described embodiments are only for explaining the present application and do not constitute any limitation of the present application. The application has been described with reference to exemplary embodiments, but it is understood that the words which have been used are words of description and illustration, rather than words of limitation. Modifications may be made to the application as defined in the appended claims, and the application may be modified without departing from the scope and spirit of the application. Although the application is described herein with reference to particular means, materials and embodiments, the application is not intended to be limited to the particulars disclosed herein, as the application extends to all other means and applications which perform the same function.
Claims (8)
1. The application of the etching solution in the field of tellurium-zinc-cadmium materials is characterized in that the etching solution comprises nitric acid, hydrofluoric acid, lactic acid and water;
the volume ratio of nitric acid to hydrofluoric acid to lactic acid to water is 10:1:9:2; or (b)
Nitric acid, hydrofluoric acid, lactic acid and water in a water volume ratio of 10:1:9:10; or (b)
Nitric acid, hydrofluoric acid, lactic acid and water in a ratio of 10:1:9:18;
wherein the nitric acid concentration is 98%; the hydrofluoric acid concentration was 40%.
2. A thinning method of a tellurium-cadmium-mercury infrared focal plane hybrid chip is characterized in that the etching solution of claim 1 is adopted to etch and remove a tellurium-zinc-cadmium substrate of the tellurium-cadmium-mercury infrared focal plane hybrid chip.
3. The thinning method according to claim 2, characterized by comprising the steps of:
s1: coating photoresist around the tellurium-cadmium-mercury infrared focal plane hybrid chip, baking, exposing, developing, photoetching and forming a film;
s2: placing the chip obtained in the step 1 after the glue coating and film forming in the etching solution of claim 1, and cleaning after removing the tellurium-zinc-cadmium substrate;
s3: placing the chip with the tellurium-zinc-cadmium substrate removed obtained in the step S2 in a stop layer etching solution for etching, and removing the stop layer;
s4: and (3) cleaning and drying the chip with the termination layer removed, which is obtained in the step (S3), to obtain the tellurium-cadmium-mercury infrared focal plane hybrid chip with the thinned substrate.
4. A thinning method according to claim 3 wherein in step S1, the photoresist is a positive photoresist; and/or the photoresist coating thickness is 4-10 mu m;
and/or the baking temperature is 80-100 ℃; the baking time is 1-10 min;
and/or, the exposure mode is contact exposure; the exposure time is 10-20 s;
and/or the development time is 40-90 s;
and/or the film forming temperature is 50-80 ℃; the film forming time is 1-3 h.
5. The thinning method according to claim 3, wherein in the step S2, the etching time is 1 to 3 minutes.
6. The method according to claim 3, wherein in the step S3, the stop layer etching liquid component includes bromine, hydrobromic acid and water; the volume ratio of bromine, hydrobromic acid and water in the components of the etching solution of the stop layer is 0.1:10:90; the hydrobromic acid concentration is 50-60%; and/or the etching time is 5-15 s.
7. A thinning method according to claim 3, wherein in step S4, the cleaning comprises three steps of deionized water rinsing and acetone soaking, and absolute ethanol rinsing.
8. The thinning method according to claim 7, wherein the deionized water rinse time is 3-8 min; and/or the acetone soaking time is 3-5 min; and/or washing the substrate with ethanol for 3-5 times; and/or, the drying is performed by adopting nitrogen.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2165089A (en) * | 1983-09-13 | 1986-04-03 | Marconi Co Ltd | I.R. photodetector incorporating epitaxial C.M.T. |
| CN104535578A (en) * | 2014-12-09 | 2015-04-22 | 中国科学院上海技术物理研究所 | Method for rapidly revealing various defects of tellurium-zinc-cadmium crystal |
| CN107907812A (en) * | 2017-10-13 | 2018-04-13 | 中国科学院上海技术物理研究所 | A kind of failure analysis method of HgCdTe infrared focal plane detector |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2165089A (en) * | 1983-09-13 | 1986-04-03 | Marconi Co Ltd | I.R. photodetector incorporating epitaxial C.M.T. |
| CN104535578A (en) * | 2014-12-09 | 2015-04-22 | 中国科学院上海技术物理研究所 | Method for rapidly revealing various defects of tellurium-zinc-cadmium crystal |
| CN107907812A (en) * | 2017-10-13 | 2018-04-13 | 中国科学院上海技术物理研究所 | A kind of failure analysis method of HgCdTe infrared focal plane detector |
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