Chemical mechanical fine polishing composition for polishing gallium antimonide substrate

Abstract

The invention discloses a chemical mechanical fine polishing composition for polishing a gallium antimonide substrate, which comprises the following components in percentage by weight: 5 to 20 percent of silica sol abrasive, 0.1 to 1 percent of oxidant, 0.01 to 0.1 percent of surface protective agent and the balance of deionized water. The polishing solution provided by the invention is mainly applicable to gallium antimonide surface polishing in manufacturing of infrared detectors, sensors and optoelectronic devices, the polished gallium antimonide surface is good in state and free of surface defects such as scratches and orange peels, and meanwhile, the polishing solution can also be used for fine polishing of gallium arsenide and indium arsenide.

Description

Technical Field

[0001] The invention relates to the technical field of chemical mechanical polishing for ultra-precision machining, and in particular to a chemical mechanical polishing composition for polishing a gallium antimonide substrate. Background Art

[0002] Gallium antimonide (GaSb) is an important semiconductor material that can be used to make many useful narrowband optoelectronic devices. It has the characteristics of high electron mobility and low power consumption. In addition to having good application prospects in infrared detectors, lasers, optical communications, solar cells and other fields, it also has great potential application value in other fields, such as sensors for fire alarms and environmental pollution detection, sensors for monitoring the leakage of corrosive and toxic gases in factories, etc. At present, chemical mechanical polishing (CMP) is mainly used to polish gallium antimonide materials to improve their surface quality.

[0003] Gallium antimonide materials have low hardness, brittle texture, easy to scratch, and active surface properties, which are very easy to be oxidized, so the requirements for chemical mechanical polishing are also high. In the polishing process, in order to obtain good surface quality, the polishing liquid is required to be matched with finer and softer abrasive particles and suitable chemical corrosive agents to avoid a series of problems such as scratches, orange peel, fogging and surface roughness on the surface. In order to obtain gallium antimonide single crystal substrates with excellent surface, most of the current domestic research focuses on the optimization of process conditions, such as patents CN112077691A, CN113894623A, CN117733719A, etc. Most of the polishing liquids purchased on the market are acidic polishing liquids. Patent CN118126633A introduces an acidic silica sol polishing liquid with a surface Ra value of up to 0.191nm, but the service life of the polishing liquid is less than 8 hours. Patent CN112701037A provides an idea of ​​abrasive-free polishing liquid to solve the problem of instability of polishing liquid under acidic conditions. However, abrasive-free polishing liquid has not been actually used in industrial production and the technical means are immature.

[0004] The polishing liquid for GaSb substrates currently used is mostly purchased from outside, with unclear composition. The mismatch between chemical and mechanical effects during the polishing process causes surface scratches, damage, chemical residue, surface roughness and other defects, which cannot meet production needs. Therefore, we urgently need to develop a silica sol polishing liquid with good surface quality, low cost and good polishing liquid stability to meet the needs of GaSb electronic device manufacturing. Summary of the invention

[0005] The object of the present invention is to provide a chemical mechanical polishing composition for polishing gallium antimonide substrates to solve one or more of the above-mentioned prior art problems.

[0006] A chemical mechanical polishing composition for polishing a gallium antimonide substrate according to the present invention comprises, by weight percentage, 5-20wt% of silica sol abrasive, 0.1-1wt% of an oxidant, 0.01-0.1wt% of a surface protective agent and the balance being deionized water.

[0007] In some embodiments, the average particle size of the silica sol abrasive is 50-100 nm.

[0008] In some embodiments, the oxidizing agent is sodium hypochlorite.

[0009] In some embodiments, the surface protective agent is an azole compound.

[0010] In some embodiments, the azole compound is one of benzotriazole, methylbenzotriazole, 1,2,4-triazole, 1-methyl-1,2,4-triazole, 5-aminotetrazolyl, imidazole, methylimidazole and mercaptobenzothiazole.

[0011] Beneficial effects:

[0012] The polishing liquid provided by the present invention is mainly suitable for polishing the surface of gallium antimonide in the manufacture of infrared detectors, sensors and optoelectronic devices. The surface of gallium antimonide after polishing is in good condition without surface defects such as scratches and orange peel. At the same time, the polishing liquid can also be used for fine polishing of gallium arsenide and indium arsenide. DETAILED DESCRIPTION

[0013] The present invention is further described in detail below.

[0014] The detailed proportions of the polishing liquid components of Examples 1 to 6 are shown in Table 1.

[0015] Table 1. Detailed ratio of each component in the polishing liquid example

[0016]

[0017] The prepared polishing liquid is used for polishing gallium antimonide, and the polishing conditions are as follows:

[0018] Polishing machine: Shenyang Kejing 1200S single-sided polishing machine;

[0019] Polished wafer: 2-inch GaSb wafer;

[0020] Polishing pad: black damping pad;

[0021] Polishing pressure: 150 g / cm2;

[0022] Workpiece speed: 40 rpm;

[0023] Lower plate speed: 50 rpm;

[0024] Polishing liquid flow rate: 10 ml / min

[0025] Polishing time: 30 minutes

[0026] After polishing, the GaSb surface was washed and dried, and then the surface quality of the GaSb wafer was measured.

[0027] The surface states of GaSb after polishing with the polishing liquids of Examples 1 to 6 are shown in Table 2.

[0028] Table 2. Polishing effect of polishing liquid example

[0029]

[0030]

[0031] It can be seen from the polishing effect in Table 2 that, compared with the comparative example, the surface state of gallium antimonide in the silica sol polishing liquid of Examples 1 to 6 is better, with a smooth surface, no orange peel, scratches, and other surface defects.

[0032] The present invention studies the technical bottleneck of poor surface quality after polishing faced by gallium antimonide in the prior art, and invents a CMP polishing liquid for fine polishing of gallium antimonide. The present invention is an alkaline polishing liquid with high stability, which can be stably stored for one year, has simple composition and preparation process, has good wafer surface quality, and the surface Ra value is less than 0.15nm.

[0033] The polishing liquid of the present invention is used for ultra-fine surface polishing of gallium antimonide, which has the characteristics of stable polishing performance; the polished surface is flat, free of scratches, orange peel and other defects, and can be used in infrared detectors, lasers, detector light emitting diodes, optical communications, solar cells and other fields.

[0034] The above are only preferred embodiments of the present invention. It should be pointed out that a person skilled in the art can make several similar modifications and improvements without departing from the inventive concept of the present invention, and these should also be regarded as within the protection scope of the present invention.

Claims

1. A chemical mechanical polishing composition for polishing a gallium antimonide substrate, characterized in that: Calculated by weight percentage, the invention comprises: 5-20wt% of silica sol abrasive, 0.1-1wt% of oxidant, 0.01-0.1wt% of surface protective agent and the balance is deionized water.

2. The chemical mechanical polishing composition for polishing gallium antimonide substrate according to claim 1, characterized in that: The average particle size of the silica sol abrasive is 50-100 nm.

3. The chemical mechanical polishing composition for polishing gallium antimonide substrate according to claim 1, characterized in that: The oxidant is sodium hypochlorite.

4. The chemical mechanical polishing composition for polishing gallium antimonide substrate according to claim 1, characterized in that: The surface protective agent is an azole compound.

5. The chemical mechanical polishing composition for polishing gallium antimonide substrate according to claim 4, characterized in that: The azole compound is one of benzotriazole, methylbenzotriazole, 1,2,4-triazole, 1-methyl-1,2,4-triazole, 5-aminotetrazole, imidazole, methylimidazole and mercaptobenzothiazole.

Images