Substrate clamp for liquid phase epitaxial growth of wafer

Abstract

The utility model discloses a substrate clamp for a liquid phase epitaxial growth wafer. The substrate clamp comprises at least four supporting columns which are symmetrically distributed on a main body framework, the main body framework is an annular component, and a fixed bracket is arranged above the main body framework; the fixed bracket is connected with a connecting rod and is connected with liquid phase epitaxy equipment through the connecting rod; and an included angle of 2-10 degrees is formed between the extension line of the central axis of the supporting column and the longitudinal central axis of the clamp. According to the utility model, the lower part of the wafer is not contacted with the clamp, so that the stress of the clamp on the wafer in the growth process and the cracking caused by solution residue in the cooling process are eliminated, and the yield of the wafer is improved.

Description

Technical Field

[0001] The utility model relates to the field of artificial crystal growth equipment, in particular to a substrate clamp used for liquid phase epitaxial growth of wafers, especially used in the growth process of rare earth iron garnet single crystals. Background Art

[0002] Liquid phase epitaxial growth technology can be used to grow various thin films on various substrates. In the process of liquid phase epitaxial growth of rare earth iron garnet wafers, a clamp is needed to fix the wafer, and the shape and material of the clamp have a great influence on the quality of the wafer. Previous technologies often use a gripping method to fix the wafer, and inevitably introduce corresponding grooves or lifting support components in the clamping position, such as the platinum column bottom support disclosed in publication number CN113073383A. The clamp that fixes the wafer in a lifting and gripping manner in the prior art will cause the Faraday rotator at the corresponding position to be unable to be used normally. And in the process of cooling, the residual raw materials bond the wafer to the clamp, generating huge stress, which eventually leads to severe cracking of the four corners of the wafer or even the inside, reducing the yield rate. In order to overcome the above shortcomings, a new clamp is invented, which eliminates the influence of the clamp on the wafer while meeting the normal growth of the wafer. Utility Model Content

[0003] In view of the above-mentioned deficiencies in the prior art, the purpose of the utility model is to design a substrate clamp so that there is no contact between the bottom of the wafer and the clamp, thereby eliminating the stress of the clamp on the wafer during the growth process and the cracking caused by solution residue during the cooling process, thereby improving the yield rate of the wafer.

[0004] In order to achieve the above-mentioned purpose, the technical solution provided by the utility model is: a substrate clamp for liquid phase epitaxial growth of wafers, comprising at least 4 support columns symmetrically distributed on a main frame; the main frame is an annular component, and a fixed bracket is arranged on the top; the fixed bracket is connected to a connecting rod, and is connected to the liquid phase epitaxial equipment through the connecting rod; the extended line of the central axis of the support column has an angle with the longitudinal center axis of the clamp; wherein the angle ranges of the extended lines of the central axes of at least 2 support columns and the longitudinal center axis of the clamp are different but the same.

[0005] Preferably, the angle has a value range of 2 to 10 degrees, and more preferably has a value range of 2 to 5 degrees.

[0006] Preferably, the angle ranges between the extended lines of the central axes of the three adjacent support columns and the longitudinal center axis of the clamp are different, and the angles differ by 1 to 5 degrees.

[0007] Furthermore, an inclined groove is provided at the end of the support column. Preferably, the inclined angle of the inclined groove is at least 45 degrees.

[0008] Preferably, the support column includes a first support column, a second support column, a third support column, and a fourth support column, which are distributed in order from small to large inclination degree, and the angles between the extension line of the axis and the longitudinal center axis of the clamp are 2 degrees, 2 degrees, 4 degrees, 5 degrees or 3 degrees, 3 degrees, 5 degrees, 6 degrees or 6 degrees, 6 degrees, 8 degrees, and 10 degrees respectively.

[0009] Preferably, the angles between the extended lines of the central axes of the first support column, the second support column, the third support column and the fourth support column and the longitudinal center axis of the fixture are 2 degrees, 4 degrees, 2 degrees, 5 degrees or 3 degrees, 5 degrees, 3 degrees, 6 degrees or 6 degrees, 8 degrees, 6 degrees, and 10 degrees, respectively.

[0010] The main features of the structure of the utility model are: 1. The support column of the clamp is at a certain angle to the vertical direction, and at least three support columns have different angles, which prevents the wafer from falling off, thereby replacing the gripping and fixing method, eliminating the stress introduced to the wafer by the difference in thermal expansion between the protrusion of the existing clamp and the wafer. On the other hand, no additional lifting and supporting components are required, which improves the wafer collection rate.

[0011] 2. The design of the inclined groove under the fixture support column makes it easier for the droplets remaining at the connection between the wafer and the fixture after the growth is completed to drip off, eliminating the cracking caused by the platinum bonding between the wafer and the support column during the cooling process. At the same time, it eliminates the force of the solidified melt residue on the side of the wafer, reduces the possibility of wafer cracking, and improves the yield.

[0012] 3. Reduces radial stress during wafer growth and cooling, and improves wafer growth yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a three-dimensional structural schematic diagram of the utility model.

[0014] Figure 2 It is the front view of the utility model.

[0015] Figure 3 yes Figure 2 Enlarged schematic diagram of part A.

[0016] Figure 4 It is the use state of the utility model Figure 1 .

[0017] Figure 5 It is the use state of the utility model Figure 2 .

[0018] Figure 6 It is a schematic diagram of substrate cutting edge.

[0019] Figure numerals: 1, substrate clamp; 2, first support column; 3, second support column; 4, third support column; 5, fourth support column; 6, main frame; 7, fixed bracket; 8, connecting rod; 9, inclined groove; 10, substrate; 11, cutting edge. DETAILED DESCRIPTION

[0020] In order to better understand the technical solution of the utility model, the embodiments of the utility model are described in detail below in conjunction with specific embodiments. It should be clear that the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms unless the context clearly indicates other meanings. The test materials used in the present invention are all common commercial products and can be purchased on the market.

[0022] Taking the growth of rare earth iron garnet single crystal by liquid phase epitaxy as an example, refer to Figures 1 to 6 , Figure 1 This is a schematic diagram of the three-dimensional structure of the utility model, which is illustrated by 4 support columns. The substrate clamp 1 used includes a first support column 2, a second support column 3, a third support column 4, and a fourth support column 5, and the four support columns are symmetrically distributed on the main frame 6; the main frame 6 is an annular component, and a fixed bracket 7 is arranged on the top; the fixed bracket 7 is connected to a connecting rod 8, and is connected to the liquid phase epitaxy equipment through the connecting rod 8; the extended lines of the central axes of the first support column 2, the second support column 3, the third support column 4, and the fourth support column 5 have an angle with the longitudinal center axis of the substrate clamp 1 (not shown in the figure), and the angle range is 2 to 10 degrees. The more preferred angle value range is 2 to 5 degrees.

[0023] In one example, the angle ranges between the extended lines of the central axes of at least two support columns and the longitudinal center axis of the fixture are different but the same, that is, the support columns have different degrees of inclination with respect to the vertical direction; further, the support columns with different degrees of inclination can be distributed at intervals or adjacently, which are associated with the positions of the cut edges 11 of the substrate 10. When the substrate 10 has two cut edges 11, such as Figure 6 (a) or Figure 6 (c) shows that one case is that the cutting edge 11 is Figure 6 (a) is in adjacent positions, then the angles between the extended lines of the central axes of the first support column 2, the second support column 3, the third support column 4, and the fourth support column 5 and the longitudinal center axis of the fixture are 2 degrees, 2 degrees, 4 degrees, and 5 degrees, respectively. Figure 6 (c) is in a relative position, the angle values ​​of the second support column 3 and the third support column 4 are interchanged, that is, the angles between the extended lines of the central axis of the first support column 2, the second support column 3, the third support column 4, and the fourth support column 5 and the longitudinal center axis of the fixture are 2 degrees, 4 degrees, 2 degrees, and 5 degrees, respectively. In general, the support column with the largest degree of inclination from the vertical direction corresponds to the side with the most cut edges 11 of the substrate 10, that is, Figure 4 or Figure 5 The fourth support column 5 in the substrate 10. The support column with the smallest inclination from the vertical direction corresponds to the side of the substrate 10 without cutting edges. The support column with a slightly larger inclination from the vertical direction corresponds to the side of the substrate 10 with slightly more cutting edges 11. When the substrate 10 has only one cutting edge 11, such as Figure 6 (b) Two angles are sufficient, wherein a support column with a larger angle corresponds to the cut edge 11 of the substrate 10, and the extended lines of the central axes of the other support columns have the same angle with the longitudinal central axis of the fixture.

[0024] In an example, the angle between the extended lines of the central axes of the first support column 2, the second support column 3, the third support column 4, and the fourth support column 5 and the longitudinal center axis of the fixture can also be 3 degrees, 3 degrees, 5 degrees, 6 degrees or 6 degrees, 6 degrees, 8 degrees, 10 degrees. The specific angle depends on the size of the circular ring of the main frame 6 in the substrate fixture 1 and the size of the substrate 10. The difference between different angles can be 1 to 5 degrees.

[0025] During the test, it was found that when three support columns with different tilt angles were used, the stability of the substrate 10 was insufficient and there was a risk of falling off. If the tilt angles of the support columns were the same, that is, the values ​​of the angles between the extended lines of the central axes of all the support columns and the longitudinal central axis of the substrate fixture 1 were the same, the substrate 10 could not be stably fixed during the growth of rare earth iron garnet single crystals by liquid phase epitaxy.

[0026] In one example, the end of the support column is provided with an inclined slot, such as Figure 2 The first support column 2, the second support column 3, the third support column 4, and the fourth support column 5 are respectively provided with an inclined groove 9 at their ends. Figure 3 The diagram is an enlarged schematic view of the end A of the first support column 2, and the inclined angle of the inclined groove is at least 45 degrees.

[0027] After studying the wafer growth process, it is clear that the density of the substrate 10 material and the rare earth iron garnet thick film grown on it is lower than that of the high-temperature melt. That is, during the crystal epitaxial growth process, even if the wafer is not supported by the fixture, the wafer will not sink into the melt. Figure 6As shown, generally, one or both sides of the substrate 10 are deburred so that the fixture can fit the substrate 10. It should be noted that the vertical inclination angle of the support column corresponds to the cut edge and the uncut edge of the substrate 10, and the larger the inclination angle of the support column corresponds to the deeper cut edge of the substrate 10. Based on the above two points, the general bottom lifting method of the fixture is eliminated. The inclined groove solution eliminates the influence of the support point on the wafer collection rate in the prior art.

[0028] And if Figure 4 and Figure 5 As shown, the substrate 10 will move upwards (actually much smaller than the rising distance shown in the figure, for illustration purposes only) due to the influence of thermal expansion and contraction during the process of slowly entering the device. The support effect provided by the upper clamp can keep the wafer stable at a fixed height to complete crystal growth. This eliminates the radial stress exerted by the clamp on the wafer and improves the yield of the wafer.

[0029] Furthermore, during the cooling process, since there is no support at the bottom and the inclined slot design is adopted, the melt can easily drip from the fixture along the end of the support column, eliminating the effect of the melt bonding the wafer to the fixture. At the same time, the wafer cools and shrinks, and slides down again, reducing the radial stress exerted by the fixture on the wafer and improving the wafer yield rate.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A substrate fixture for liquid phase epitaxial growth of wafers, characterized in that: It comprises at least 4 support columns symmetrically distributed on the main frame; the main frame is an annular component with a fixed bracket arranged on the top; the fixed bracket is connected to a connecting rod, and is connected to the liquid phase epitaxial device through the connecting rod; the extended line of the central axis of the support column has an angle with the longitudinal center axis of the fixture; wherein the angle ranges of the extended line of the central axis of at least 2 support columns and the longitudinal center axis of the fixture are different but the same.

2. A substrate fixture for liquid phase epitaxial growth of wafers according to claim 1, characterized in that: The numerical range of the angle is 2 to 10 degrees.

3. A substrate fixture for liquid phase epitaxial growth of wafers according to claim 1, characterized in that: The numerical range of the angle is 2 to 5 degrees.

4. A substrate fixture for liquid phase epitaxial growth of wafers according to claim 1, characterized in that: The angle ranges between the extended lines of the central axes of the three adjacent support columns and the longitudinal central axis of the fixture are different, and differ by 1 to 5 degrees.

5. A substrate holder for liquid phase epitaxial growth of wafers according to any one of claims 1 to 4, characterized in that: An inclined groove is arranged at the end of the supporting column.

6. A substrate fixture for liquid phase epitaxial growth of wafers according to claim 5, characterized in that: The inclined surface angle of the inclined groove is at least 45 degrees.

7. The substrate fixture for liquid phase epitaxial growth of wafers according to claim 1, characterized in that: The support columns include a first support column, a second support column, a third support column, and a fourth support column, which are distributed in order from small to large according to the degree of inclination; the angles between the extension lines of the central axes of the first support column, the second support column, the third support column, and the fourth support column and the longitudinal center axis of the clamp are 2 degrees, 2 degrees, 4 degrees, 5 degrees or 3 degrees, 3 degrees, 5 degrees, 6 degrees or 6 degrees, 6 degrees, 8 degrees, and 10 degrees, respectively.

8. The substrate fixture for liquid phase epitaxial growth of wafers according to claim 1, characterized in that: The support columns include a first support column, a second support column, a third support column, and a fourth support column, which are distributed in sequence. The angles between the extension lines of each central axis and the longitudinal center axis of the fixture are 2 degrees, 4 degrees, 2 degrees, 5 degrees or 3 degrees, 5 degrees, 3 degrees, 6 degrees or 6 degrees, 8 degrees, 6 degrees, and 10 degrees, respectively.

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