Corrosive liquid for polishing indium phosphide chip, polishing method of indium phosphide chip and indium phosphide chip

Abstract

The invention belongs to the technical field of indium phosphide chip treatment, and discloses an indium phosphide chip polishing corrosive liquid, an indium phosphide chip polishing method and an indium phosphide chip, the indium phosphide chip polishing corrosive liquid comprises hydrochloric acid and nitric acid, the mass concentration of the hydrochloric acid in the corrosive liquid is 0.16-0.38%, and the mass concentration of the nitric acid in the corrosive liquid is 0.16-0.35%. The invention discloses a corrosive liquid for polishing an indium phosphide chip, which is prepared by compounding hydrochloric acid and nitric acid with specific concentration, can effectively control the corrosion condition of the indium phosphide chip in the corrosion process, can effectively control the surface roughness of the indium phosphide chip, and improves the yield of products.

Description

Technical Field

[0001] The invention belongs to the technical field of indium phosphide chip processing, and more specifically, relates to an etching solution for polishing an indium phosphide chip, an indium phosphide chip polishing method and an indium phosphide chip. Background Art

[0002] Indium phosphide (InP) is an important III-V compound semiconductor material. Indium phosphide has a direct transition band structure and a wide bandgap. Indium phosphide crystal material has the advantages of high electric field drift velocity, good thermal conductivity and strong radiation resistance. It is suitable for manufacturing high-frequency, high-speed and low-power microwave devices and circuits. In the field of optical fiber communication, indium phosphide is also the preferred communication material. When used in solar cells, it has a higher conversion rate and its radiation resistance is better than semiconductor materials such as Si and GaAs. It also has a high operating temperature (675-725K), making it very suitable for use as a solar cell material for artificial satellites.

[0003] In addition, indium phosphide has a high electron migration rate and good optical properties, and can be used as a substrate material to make optoelectronic devices and optoelectronic integrated circuits.

[0004] As a semiconductor substrate, indium phosphide needs to go through processes such as single crystal growth, slicing, chamfering, grinding, polishing and cleaning. Due to its low hardness and soft and brittle texture, surface / subsurface damage layers are easily generated on the wafer surface during sawing and grinding processes, and the final polishing process is required to remove surface / subsurface damage, reduce dislocation density and reduce surface roughness. Polishing is the last step in wafer surface processing, and its purpose is to reduce surface roughness and obtain a smooth surface without damage.

[0005] Common polishing methods include mechanical polishing, chemical mechanical polishing (CMP), magnetorheological polishing, elastic emission polishing, dynamic pressure floating polishing, float polishing, low-temperature polishing, etc. For indium phosphide materials, the CMP method is currently mainly used for polishing.

[0006] For example, prior art 1: Chinese patent application 202210164144.5 discloses an indium phosphide wafer and a preparation method thereof, and the indium phosphide wafer preparation method includes the following operating steps: S1. Coat a layer of protective liquid on the surface of the indium phosphide crystal, cut it into indium phosphide wafers, and remove the protective liquid after cutting; S2. Roughly grind and finely grind the indium phosphide wafer treated in step S1 in sequence; S3. Thin the ground indium phosphide wafer; S4. Use a polishing liquid to chemically mechanically polish the thinned indium phosphide wafer, the polishing liquid includes an oxidant and an abrasive, and the chemical mechanical polishing includes rough polishing and fine polishing in sequence; S5. Clean the indium phosphide wafer after chemical mechanical polishing to obtain a finished indium phosphide wafer.

[0007] Prior art 1 utilizes a chemical polishing method to polish an indium phosphide chip. The method of prior art 1 is used to prepare an indium phosphide wafer, which can reduce the surface roughness of the indium phosphide wafer. However, after the indium phosphide chip is polished by prior art 1, the chemical polishing causes damage to the indium phosphide chip and residual stress, and the residual substances left during the grinding and polishing process need to be cleaned, which affects the quality of the indium phosphide chip and needs to be fully cleaned.

[0008] Based on this, it is necessary to perform stress elimination, damage maintenance and impurity cleaning on the indium phosphide chip after chemical polishing to ensure the quality of the indium phosphide chip. Generally, in order to clean the impurities of the indium phosphide chip after chemical polishing, highly corrosive chemical reagents such as hydrogen peroxide, concentrated sulfuric acid, and citric acid are used for cleaning. Although such corrosive liquid can effectively clean the impurities, it will cause problems such as excessive corrosion and rough surface. If general weak acid is used, the impurities will not be cleaned up, which also affects the quality of the finished product of the indium phosphide chip and reduces the yield rate. Summary of the invention

[0009] The main purpose of the present invention is to provide an etching solution for polishing an indium phosphide chip, which can effectively clean the impurities on the surface of the indium phosphide chip after chemical polishing, and can also effectively avoid the problem of excessive corrosion caused by strong etching solution and increased surface roughness of the indium phosphide chip.

[0010] Another object of the present invention is to provide an indium phosphide chip polishing method. The indium phosphide chip prepared by the indium phosphide chip polishing method has high finished quality and high yield, and effectively reduces production costs.

[0011] The present invention also provides an indium phosphide chip, which is prepared by the indium phosphide chip polishing method and has excellent finished product quality.

[0012] In order to achieve the above object, the present invention discloses an etching solution for polishing indium phosphide chips, comprising hydrochloric acid and nitric acid, wherein the mass concentration of the hydrochloric acid in the etching solution is 0.16-0.38%, and the mass concentration of the nitric acid is 0.16-0.35%.

[0013] Since the indium phosphide chip is a finished product, it not only contains indium phosphide, but also includes an outer layer and a substrate layer. As a photosensitive material, the indium phosphide chip needs to achieve relatively excellent optical properties after corrosion, so the corrosion of the outer layer and the substrate layer will make the surface roughness of the indium phosphide chip difficult to control; and the etching liquid for polishing the indium phosphide chip of the present invention can effectively control the corrosion degree of the indium phosphide chip, so that the surface roughness of the indium phosphide chip after corrosion is low.

[0014] Preferably, the etching solution is obtained by mixing hydrochloric acid solution, nitric acid solution and pure water; the volume ratio of the hydrochloric acid solution, nitric acid solution and pure water is 1-2:1:400-420.

[0015] More preferably, the mass concentration of hydrochloric acid in the hydrochloric acid solution is 36-38%, and the mass concentration of nitric acid in the nitric acid solution is 68-70%.

[0016] The present invention also discloses a method for polishing an indium phosphide chip, comprising the following steps:

[0017] Step 1: Grinding the indium phosphide chip;

[0018] Step 2: Polishing the ground indium phosphide chip;

[0019] Step 3: Use the above-mentioned etching solution for polishing the indium phosphide chip to etch the indium phosphide chip that has been polished.

[0020] Further, the specific operation of step 1 is: 150-200g / cm 2 The indium phosphide chip is ground at a grinding pressure of 25-30 RPM and a grinding speed of 10-15 ml / min until the thickness of the indium phosphide chip is 540±2 μm.

[0021] Furthermore, the grinding liquid includes abrasive and pure water, the volume ratio of the abrasive to pure water is 2-5:8-12, and the abrasive is one of zirconium oxide and diamond and has a particle size of 3-5 μm.

[0022] Further, the specific operation of step 2 is: 50-80g / cm 2 The ground indium phosphide chip was polished for 30-40 minutes at a polishing pressure of 30-40 RPM and a polishing speed of 8-10 ml / min.

[0023] Furthermore, the polishing liquid is a sodium hypochlorite polishing liquid containing aluminum oxide, and the particle size of the aluminum oxide is 0.1-0.3 μm.

[0024] Further preferably, the polishing liquid is 0CON-141 sodium hypochlorite polishing liquid provided by Logitech.

[0025] Furthermore, the corrosion treatment time in step 3 is 10-20s.

[0026] The invention also discloses an indium phosphide chip, which is prepared by adopting the indium phosphide chip polishing method.

[0027] Beneficial Effects

[0028] Compared with the prior art, the present invention has at least the following advantages:

[0029] (1) The present invention discloses an etching solution for polishing an indium phosphide chip, which uses a compound of hydrochloric acid and nitric acid to perform etching treatment on the indium phosphide chip after polishing, and can effectively remove impurities remaining on the surface of the indium phosphide chip due to the grinding and polishing process, and has a high removal rate, thereby effectively improving the quality of the indium phosphide chip;

[0030] (2) The present invention discloses an etching solution for polishing an indium phosphide chip, which is compounded with hydrochloric acid and nitric acid of a specific concentration, can effectively control the corrosion of the indium phosphide chip during the etching process, can effectively control the surface roughness of the indium phosphide chip, and improve the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0032] Figure 1 is a 3D contour diagram of Example 1 of the present invention;

[0033] Figure 2 is a 3D contour diagram of Example 2 of the present invention;

[0034] Figure 3 is a 3D contour diagram of Example 3 of the present invention;

[0035] Figure 4 is a 3D contour diagram of Example 4 of the present invention;

[0036] Figure 5 is a 3D profile diagram of Comparative Example 1 of the present invention;

[0037] Figure 6 is a 3D profile diagram of Comparative Example 2 of the present invention;

[0038] Figure 7 is a 3D profile diagram of Comparative Example 3 of the present invention;

[0039] Figure 8 is a 3D profile diagram of Comparative Example 4 of the present invention;

[0040] Fig. 9 It is the 3D profile diagram of comparative example 5 of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0042] In order to explain the technical content of the present invention in detail, further description is given below in conjunction with the implementation modes.

[0043] The indium phosphide chips used in the following examples and comparative examples were ground and polished by the following steps:

[0044] Step 1: Use a non-grooved ceramic disc as the grinding disc, with a grinding speed of 200 g / cm 2 The indium phosphide chip is ground at a grinding pressure of 25 RPM and a grinding speed of 25 RPM until the thickness of the indium phosphide chip is 540±2 μm, and the grinding liquid flow rate is 12 ml / min; the grinding liquid includes abrasive and pure water, the volume ratio of the abrasive to the pure water is 3:10, and the abrasive is zirconium oxide with a particle size between 3-5 μm;

[0045] Step 2: Use an automatic polishing machine with a polishing cloth at 60g / cm 2 The ground indium phosphide chip was polished for 40 minutes at a polishing pressure of 35 RPM and a polishing speed of 35 RPM, and the polishing liquid flow rate was 8 ml / min; the polishing liquid was the 0CON-141 sodium hypochlorite polishing liquid provided by Logitech.

[0046] Example 1

[0047] The invention discloses an etching liquid for polishing an indium phosphide chip, comprising hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.08%, and the mass concentration of the nitric acid is 0.17%.

[0048] Example 2

[0049] The invention discloses an etching liquid for polishing an indium phosphide chip, comprising hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.19%, and the mass concentration of the nitric acid is 0.18%.

[0050] Example 3

[0051] The invention discloses an etching liquid for polishing an indium phosphide chip, the components of which include hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.092%, and the mass concentration of the nitric acid is 0.167%.

[0052] Example 4

[0053] The invention discloses an etching liquid for polishing an indium phosphide chip, comprising hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.179%, and the mass concentration of the nitric acid is 0.167%.

[0054] Comparative Example 1

[0055] The invention discloses an etching liquid for polishing an indium phosphide chip, the components of which include hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.179%, and the mass concentration of the nitric acid is 0.342%.

[0056] Comparative Example 2

[0057] The invention discloses an etching liquid for polishing an indium phosphide chip, the components of which include hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.072%, and the mass concentration of the nitric acid is 0.167%.

[0058] Comparative Example 3

[0059] The invention discloses an etching liquid for polishing an indium phosphide chip, the components of which include hydrochloric acid, nitric acid and water. The mass concentration of the hydrochloric acid in the etching liquid is 0.275%, and the mass concentration of the nitric acid is 0.167%.

[0060] Comparative Example 4

[0061] An etching solution for polishing indium phosphide chips, comprising nitric acid, citric acid and water, wherein the mass concentration of nitric acid in the etching solution is 0.167%, and the mass concentration of citric acid is 0.179%.

[0062] Comparative Example 5

[0063] A etching solution for polishing indium phosphide chips, comprising lactic acid, oxalic acid and water, wherein the mass concentration of lactic acid in the etching solution is 0.320%, and the mass concentration of oxalic acid is 0.260%.

[0064] The polished indium phosphide chips were chemically etched for 20 seconds using the etching solutions of Examples 1-4 and Comparative Examples 1-5, and then tested. The surface roughness of the indium phosphide chips was then detected by a 3D profilometer. The results are shown in Tables 1 and Figure 1-9 As shown;

[0065] Table 1 Surface roughness results of indium phosphide chips after etching by etching solution of Examples 1-4 and Comparative Examples 1-5

[0066]

[0067]

[0068] According to Table 1 and Figure 1-9 It can be seen that:

[0069] According to the data of Examples 1-4, after the polished indium phosphide chip is chemically etched by the etching solution of the present invention, the surface roughness of the indium phosphide chip is limited to below 0.6 nm. At the same time, according to Examples 1-4, it can be seen that the usage ratio of hydrochloric acid and nitric acid in the etching solution actually has some influence on the surface roughness of the indium phosphide chip.

[0070] According to the data comparison between Example 4 and Comparative Examples 1 and 3, when the concentration of hydrochloric acid or nitric acid in the etching solution is too high, the ratio of hydrochloric acid and nitric acid will be unbalanced, which will make the etching process difficult to control, and the surface roughness of the indium phosphide chip finally obtained will be significantly improved.

[0071] According to the data comparison between Example 4 and Comparative Example 2, it can be seen that too little hydrochloric acid in the etching solution will also cause the surface roughness of the indium phosphide chip to be significantly improved, even higher than that of Comparative Example 1 and Comparative Example 3. The reason is that due to the low concentration of hydrochloric acid, the potential of the impurity metal is insufficiently reduced, resulting in many insoluble impurities not being completely corroded, which not only greatly improves the surface roughness of the indium phosphide chip, but also leaves impurities, seriously affecting the quality of the indium phosphide chip.

[0072] According to the data comparison between Example 4 and Comparative Examples 4 and 5, it can be seen that Comparative Examples 4 and 5 adopt other acid compounding technical solutions, which cannot effectively corrode the indium phosphide chip, and their ability to corrode impurities is significantly different from the technical solution of the present application, resulting in a significant improvement in the surface roughness of the indium phosphide chip finally obtained.

[0073] The embodiments presented herein are only embodiments selected according to the combination of all possible embodiments. The appended claims should not be limited by the embodiments describing the present invention. Some numerical ranges used in the claims include sub-ranges therein, and the changes in these ranges should also be covered by the appended claims.

Claims

1. An etching solution for polishing an indium phosphide chip, characterized in that: The etching solution comprises hydrochloric acid and nitric acid. The mass concentration of the hydrochloric acid in the etching solution is 0.08-0.19%, and the mass concentration of the nitric acid is 0.16-0.18%.

2. The etching solution for polishing an indium phosphide chip according to claim 1, characterized in that: The etching solution is obtained by mixing hydrochloric acid solution, nitric acid solution and pure water; the volume ratio of the hydrochloric acid solution, nitric acid solution and pure water is 1-2:1:400-420.

3. The etching solution for polishing an indium phosphide chip according to claim 2, characterized in that: The mass concentration of hydrochloric acid in the hydrochloric acid solution is 36-38%, and the mass concentration of nitric acid in the nitric acid solution is 68-70%.

4. A method for polishing an indium phosphide chip, characterized in that: The steps include: Step 1: Grinding the indium phosphide chip; Step 2: Polishing the ground indium phosphide chip; Step 3: using the indium phosphide chip polishing etching solution described in any one of claims 1 to 3 to corrode the indium phosphide chip that has been polished.

5. The indium phosphide chip polishing method according to claim 4, characterized in that: The specific operation of step 1 is: 2 The indium phosphide chip is ground at a grinding pressure of 25-30 rpm and a grinding speed of 25-30 rpm until the thickness of the indium phosphide chip is 540±2 μm, and the grinding liquid flow rate is 10-15 ml / min.

6. The indium phosphide chip polishing method according to claim 5, characterized in that: The grinding liquid comprises abrasive and pure water, the volume ratio of the abrasive to pure water is 2-5:8-12, the abrasive is one of zirconium oxide and diamond and the particle size is 3-5 μm.

7. The indium phosphide chip polishing method according to claim 4, characterized in that: The specific operation of step 2 is: 2 The ground indium phosphide chip was polished for 30-40 minutes at a polishing pressure of 30-40 RPM and a polishing speed of 8-10 ml / min.

8. The indium phosphide chip polishing method according to claim 7, characterized in that: The polishing liquid is a sodium hypochlorite polishing liquid containing aluminum oxide, and the particle size of the aluminum oxide is 0.1-0.3 μm.

9. The indium phosphide chip polishing method according to claim 4, characterized in that: The time of the corrosion treatment in step 3 is 10-20s.

10. An indium phosphide chip, characterized in that: The indium phosphide chip is prepared by the indium phosphide chip polishing method as described in any one of claims 4 to 9.

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