Wax-free grinding and polishing method for cadmium zinc telluride

Abstract

The invention belongs to the technical field of grinding and polishing, and particularly relates to a tellurium-zinc-cadmium wax-free grinding and polishing method which comprises the following steps: adhering one side of a pyrolytic film to a carrying disc, adhering the other side of the pyrolytic film to a tellurium-zinc-cadmium sample, grinding and polishing the adhered tellurium-zinc-cadmium sample, placing the carrying disc on a heating table for heating, and sampling the heated cadmium zinc telluride sample. The pyrolysis film is peptized at high temperature, so that the effect of no glue residue is achieved, the flatness of the sample can be effectively improved, the problems of non-uniform wax layer and wax residue are avoided, and wax pollution is prevented. And the pyrolysis film has relatively strong adhesion, so that the problem that the sample falls off is avoided, and the yield is improved to a relatively large extent. In addition, the process is simple in step and easy to operate, and the working efficiency can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of grinding and polishing, and in particular relates to a wax-free grinding and polishing method for cadmium zinc telluride. Background Art

[0002] Cadmium zinc telluride crystal materials have attracted widespread attention due to their excellent optoelectronic properties. This material is not only the most ideal epitaxial substrate for growing infrared detection material mercury cadmium telluride, but also plays an important role in the preparation of high-performance X-ray or gamma-ray detectors, optoelectronic modulators, solar cells and laser windows. Since the surface quality will directly affect the performance of the device, its surface quality must meet high standards whether it is used as a detector or an epitaxial substrate.

[0003] There are currently two methods for grinding and polishing cadmium zinc telluride. One is to use paraffin to adhere the sample to a carrier for grinding and polishing. This method may cause paraffin residue on the sample surface, and the paraffin layer is difficult to accurately control. The other method uses a vacuum adsorption pad to place the sample on the adsorption pad, and applies pressure to form a vacuum between the sample and the adsorption pad to adsorb the sample. However, the adsorption force of this method is limited. During the grinding and polishing process, the abrasive may penetrate and cause the sample to fall off. Samples with rough surfaces are difficult to firmly adsorb on the adsorption pad, limiting the scope of application of the operation. In addition, the adsorption pad material is relatively soft and the supporting force is insufficient, resulting in poor flatness of the sample after grinding and polishing. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a wax-free grinding and polishing method for cadmium zinc telluride, aiming to avoid the problem of sample falling off due to insufficient adhesion, solve the problems of uneven wax layer and wax residue after grinding and polishing, effectively improve surface flatness, and increase the yield rate.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a wax-free grinding and polishing method for cadmium zinc telluride. A pyrolytic film with a cadmium zinc telluride sample adhered thereto is adhered to a carrier plate. After the adhered cadmium zinc telluride sample is ground and polished, the carrier plate is heated to obtain a cadmium zinc telluride sample with a flat polished surface and no impurities remaining.

[0006] Further, the polishing method comprises the following steps:

[0007] Step 1: Take the pyrolytic film as the adhesive material, tear off a protective film of the pyrolytic film, and stick the sticky side on the carrier plate;

[0008] Step 2, tear off another layer of protective film of the pyrolysis film, and adhere the cadmium zinc telluride sample to the pyrolysis film;

[0009] Step 3, grinding and polishing the adhered cadmium zinc telluride sample;

[0010] Step 4: After grinding and polishing, the carrier plate is heated;

[0011] Step 5: Take out the heated cadmium zinc telluride sample.

[0012] Furthermore, after heating in step 4, the pyrolysis film is debonded and loses its viscosity.

[0013] Furthermore, in step 1, the size of the pyrolysis film is larger than the size of the sample, and the sample is completely adhered to the pyrolysis film.

[0014] Furthermore, in step 4, the carrier plate is placed on a heating table for heating.

[0015] Furthermore, the heating temperature in step 4 is 80-100° C., and the heating time is 1-3 minutes.

[0016] Furthermore, in step 1, the adhesion surface between the CdZnTe sample and the pyrolysis film is smooth or rough.

[0017] Furthermore, the CdZnTe samples adhered to the pyrolysis film are distributed circumferentially on the carrier plate.

[0018] Further, four CdZnTe samples are distributed on the carrier at an interval of 90° from each other, or eight CdZnTe samples are distributed on the carrier at an interval of 45° from each other.

[0019] It can be seen from the above technical solution that the present invention has the following beneficial effects:

[0020] The wax-free grinding and polishing method of cadmium zinc telluride of the present invention can effectively improve the flatness of the sample, avoid the problems of uneven wax layer and wax residue, and prevent wax pollution. And because the pyrolysis film has strong adhesion, the problem of sample falling off is avoided, and the yield rate is greatly improved. In addition, the process steps of the present invention are simple and easy to operate, which can effectively improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of grinding and polishing of the cadmium zinc telluride adhesive pyrolysis film in Example 1;

[0022] Figure 2 This is a physical picture of the grinding and polishing of the cadmium zinc telluride adhesive pyrolysis film in Example 1;

[0023] Figure 3 Schematic diagram of thickness measurement points of the cadmium zinc telluride sample in Example 1;

[0024] Figure 4 , Figure 5 , Figure 6 They are respectively the surface microscopic images of three cadmium zinc telluride samples after grinding and polishing with pyrolysis films adhered thereto in Example 1;

[0025] Figure 7This is a physical picture of the cadmium zinc telluride adhered to paraffin wax grinding and polishing in Comparative Example 1;

[0026] Figure 8 This is a real picture of cadmium zinc telluride after being adhered to paraffin wax polishing in comparative example 1. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0028] like Figure 1 As shown, the pyrolytic film is cut into a size slightly larger than the sample. After tearing off a layer of the protective film of the pyrolytic film, the sticky side is adhered to the carrier plate, and then the other layer of the protective film of the pyrolytic film is torn off, so that the CdZnTe sample is adhered to the pyrolytic film. The adhered CdZnTe sample is ground and polished. After the grinding and polishing is completed, the carrier plate is placed on a heating table for heating, wherein the heating temperature is 80-100°C and the heating time is 1-3 minutes. After heating, the pyrolytic film is debonded and loses its stickiness. Finally, the heated CdZnTe sample is taken out for thickness measurement.

[0029] Example 1

[0030] like Figure 2 As shown in the figure, there are eight CdZnTe samples in the same batch for the experiment. The pyrolytic film is cut into a size slightly larger than the sample so that the CdZnTe sample can be attached to the pyrolytic film as a whole. After tearing off a layer of protective film of the pyrolytic film, the sticky side is attached to the carrier plate, and then the other layer of protective film of the pyrolytic film is torn off to allow the CdZnTe sample to adhere to the pyrolytic film. The attached CdZnTe sample is ground and polished. After the grinding and polishing is completed, the carrier plate is placed on a heating table for heating, wherein the heating temperature is 90°C and the heating time is 2 minutes. After heating, the pyrolytic film is debonded and loses its viscosity. Finally, the heated CdZnTe sample is taken out for thickness measurement.

[0031] Four samples were randomly selected according to Figure 3 The test points shown in the figure, 16 thickness measurement points are selected on each CdZnTe sample, and they are evenly arranged in four rows and four columns. The thickness of the CdZnTe sample is measured before the pyrolytic film is adhered. The thickness is measured again at the same points after the sample is adhered, polished, and heated, and the TTV value is calculated and recorded in Tables 1 to 4. TTV (Total Thickness Variation) refers to the difference between the maximum thickness and the minimum thickness of the measured wafer in the thickness measurement of a series of points. This parameter is used to measure the thickness uniformity of silicon wafers or wafers.

[0032] From Table 1, we can see that the TTV value of sample 5-3 before mucoadhesion is 14um, and the TTV value after mucoadhesion after grinding, polishing and heating is 15um; from Table 2, we can see that the TTV value of sample 6-4 before mucoadhesion is 14um, and the TTV value after mucoadhesion after grinding, polishing and heating is 12um; from Table 3, we can see that the TTV value of sample 4-2 before mucoadhesion is 11um, and the TTV value after mucoadhesion after grinding, polishing and heating is 12um; from Table 4, we can see that the TTV value of sample 9-1 before mucoadhesion is 29um, and the TTV value after mucoadhesion after grinding, polishing and heating is 29um. From the above data, we can see that the thickness deviation before and after mucoadhesion is very small, indicating that there is no glue residue on the surface of the cadmium zinc telluride sample after heating.

[0033] Table 1

[0034]

[0035] Table 2

[0036]

[0037] Table 3

[0038]

[0039]

[0040] Table 4

[0041]

[0042] from Figure 2 Three of the eight polished CdZnTe samples from the same batch were randomly selected for microscopic observation, and the results were Figures 4 to 6 From the three microscopic examination images, it was observed that there was no obvious glue residue on the surface of the CdZnTe sample, indicating that by peeling off the CdZnTe sample after the glue lost its viscosity under the heating conditions of the pyrolysis film, there could be no residual glue on the sample surface, thus ensuring the purity of the sample surface.

[0043] Comparative Example 1

[0044] First, the sample coated with paraffin is pasted on the carrier. Then, the sample is ground and polished. After grinding and polishing, the carrier is placed on a heating table, and the heating temperature is set at 90 degrees Celsius for 2 minutes. After the heating step, the sample is sampled and its thickness is measured.

[0045] To ensure the consistency and comparability of the experimental data, this batch of experiments prepared Figure 7The four CdZnTe samples shown are marked as 6-2, 6-3, 6-4, and 6-5. Sixteen thickness measurement points were selected on each sample. Before waxing, the thickness of these points was measured and the total thickness change TTV value was calculated. After waxing, grinding, polishing, and heating, the thickness of the same points was measured again and a new TTV value was obtained. The results before and after waxing are shown in Tables 5 to 8.

[0046] As shown in Tables 5 to 8, the TTV values ​​of the wax layer thickness of the CdZnTe sample 6-2 before and after waxing are 31um and 10um respectively; the TTV values ​​of the wax layer thickness of the CdZnTe sample 6-3 before and after waxing are 6um and 10um respectively; the TTV values ​​of the wax layer thickness of the CdZnTe sample 6-4 before and after waxing are 15um and 17um respectively; the TTV values ​​of the wax layer thickness of the CdZnTe sample 6-5 before and after waxing are 27um and 10um respectively.

[0047] Table 5

[0048]

[0049] Table 6

[0050]

[0051]

[0052] Table 7

[0053]

[0054] Table 8

[0055]

[0056] Comparing the TTV values ​​before and after the mucosa, it can be seen that the TTV value of CdZnTe sample 6-2 changed from 31um to 10um, a decrease of 21um; the TTV value of CdZnTe sample 6-3 changed from 6um to 10um, an increase of 4um; the TTV value of CdZnTe sample 6-4 changed from 15um to 17um, an increase of 2um; the TTV value of CdZnTe sample 6-5 changed from 27um to 10um, a decrease of 17um. The results show that the use of paraffin wax to adhere the sample for grinding and polishing will produce wax residue and affect the surface flatness of the sample.

[0057] After waxing, grinding, polishing and heating, the samples were taken out for observation. Figure 8 for Figure 7 The microscopic photograph of sample A shows that there is obvious wax residue in area B and the surface of the sample is uneven and flat.

[0058] Comparative Example 2

[0059] First, the adsorption pad is attached to the carrier plate, and then the sample is attached to the adsorption pad. Subsequently, the sample is ground and polished. During the grinding and polishing process, part of the CdZnTe sample fell off. In addition, since the adsorption pad is made of a soft material and cannot provide good support, the surface of the sample obtained by grinding and polishing is uneven.

[0060] In summary, compared with paraffin and adsorption pad, the use of pyrolytic film can grind and polish the surface of CdZnTe samples to form a flat surface, significantly improving the surface flatness of the samples, and without obvious residue, which is conducive to improving the yield rate. In addition, the strong adhesion of the pyrolytic film can effectively prevent the sample from falling off, and it can adhere to samples of different roughness and size, and has strong adaptability.

[0061] The above embodiments are only used to illustrate the present invention and do not constitute a limitation on the scope of the claims. Other alternative means that can be thought of by those skilled in the art are all within the scope of the claims of the present invention.

Claims

1. A wax-free grinding and polishing method for cadmium zinc telluride, characterized in that: The pyrolysis film with the CdZnTe sample adhered thereto is adhered to a carrier plate, the adhered CdZnTe sample is ground and polished, and then the carrier plate is heated to obtain a CdZnTe sample with a smooth polished surface and no impurities remaining.

2. The wax-free grinding and polishing method of CdZnTe according to claim 1, characterized in that: The polishing method comprises the following steps: Step 1: Take the pyrolytic film as the adhesive material, tear off a protective film of the pyrolytic film, and stick the sticky side on the carrier plate; Step 2, tear off another layer of protective film of the pyrolysis film, and adhere the cadmium zinc telluride sample to the pyrolysis film; Step 3, grinding and polishing the adhered cadmium zinc telluride sample; Step 4: After grinding and polishing, the carrier plate is heated; Step 5: Take out the heated cadmium zinc telluride sample.

3. The wax-free grinding and polishing method of CdZnTe according to claim 2, characterized in that: After heating in step 4, the pyrolysis film is debonded and loses its viscosity.

4. The wax-free grinding and polishing method of CdZnTe according to claim 2, characterized in that: In the step 1, the size of the pyrolysis film is larger than the size of the sample, and the sample is completely adhered to the pyrolysis film.

5. The wax-free grinding and polishing method of CdZnTe according to claim 2, characterized in that: In the step 4, the carrier plate is placed on a heating platform for heating.

6. The wax-free grinding and polishing method of CdZnTe according to claim 2, characterized in that: The heating temperature in step 4 is 80-100° C., and the heating time is 1-3 minutes.

7. The wax-free grinding and polishing method of CdZnTe according to claim 2, characterized in that: In the step 1, the adhesion surface between the cadmium zinc telluride sample and the pyrolysis film is smooth or rough.

8. The wax-free grinding and polishing method of CdZnTe according to claim 2, characterized in that: The cadmium zinc telluride sample adhered to the pyrolysis film is distributed circumferentially on the carrier plate.

9. The wax-free grinding and polishing method of CdZnTe according to claim 8, characterized in that: Four CdZnTe samples are distributed on the carrier at 90° intervals from each other, or eight CdZnTe samples are distributed on the carrier at 45° intervals from each other.

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