Small-size gallium arsenide substrate flushing device and cleaning method

Abstract

The invention discloses a small-size gallium arsenide substrate flushing device and a cleaning method, and belongs to the technical field of semiconductor material processing. The device mainly comprises a flushing tank, a spraying system and a dynamic flower basket driving mechanism. The spraying system is arranged on the inner wall of the flushing tank, and the dynamic flower basket driving mechanism drives a screw rod through a servo motor and drives a base connected with a flower basket clamping seat to do precise reciprocating rectilinear motion along a guide shaft; and meanwhile, the flower basket can generate controllable torsion angle deviation in the horizontal moving process by utilizing the matching of the round corners of the flower basket clamping seat and the fixed inclined blocks on the base plate. The composite motion can significantly optimize the flow field distribution of the cleaning fluid on the surface of the substrate, and avoids a cleaning dead zone. Manual operation is replaced by mechanical automation, the cleaning efficiency and inter-wafer uniformity of the 1-2-inch small-size gallium arsenide substrate are greatly improved, chemical consumption and surface oxides are effectively reduced, and the method is suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gallium arsenide substrate cleaning, and particularly relates to a small-size gallium arsenide substrate flushing device and a cleaning method. BACKGROUND

[0002] As a representative of the second generation of semiconductor materials, gallium arsenide is widely used in the production of LED, radio frequency devices, lasers and other device products due to its high power density, low energy consumption, high temperature resistance, high luminous efficiency, radiation resistance, high breakdown voltage and other characteristics. Clean gallium arsenide substrate is the basis for making gallium arsenide devices. The cleanliness of the surface plays a role in determining the working performance, service life and reliability of the device, even more than the body material itself. If there are defects such as dirt, particles and cleaning solution residues on the surface of the substrate, they will extend along the epitaxial layer during epitaxial growth, thereby affecting the uniformity and integrity of the epitaxial layer, and ultimately affecting the performance of the device or even causing it to be scrapped.

[0003] Cleaning is the last process in the substrate processing process and is also the key to obtaining a high-quality surface. The purpose is to remove various residual substances from the previous process to obtain a fresh and clean surface to provide a basis for subsequent production. At present, the industry still mainly uses single-wet cleaning for small-size gallium arsenide substrates. Typical processes include RCA standard cleaning, ultrasonic-assisted chemical treatment or acid solution etching, etc. However, the single-piece mode uses independent tanks or mechanical arms to operate piece by piece, which can achieve high process control accuracy, but the efficiency is low. The single-piece processing results in low unit capacity, which is difficult to meet the needs of large-scale production. SUMMARY

[0004] In order to solve the above technical problems, the application designs a small-size gallium arsenide substrate flushing device and a cleaning method to effectively improve the cleaning efficiency, improve the consistency and uniformity of the cleaning pieces, and meet the needs of large-scale production.

[0005] The small-size gallium arsenide substrate flushing device of the application comprises a flushing tank, a spray pipe is installed on the inner wall of the flushing tank, and a plurality of spray heads are arranged on the spray pipe; A substrate holder is arranged at the bottom of the flushing tank, and two symmetrical base plates are installed on the substrate holder. A lead screw is installed on one of the base plates through a support, and a guide shaft is installed on the other base plate through a support, and the guide shaft and the lead screw are parallel to each other; The lead screw and the guide shaft are respectively connected to the two sides of the base, a spring sleeve connecting a basket holder is arranged at the center of the base, and a matching basket is installed on the basket holder; The matching basket is inserted into the substrate piece; One end of the lead screw is connected to the output shaft of a servo motor.

[0006] The matching basket is connected to the basket holder through the cooperation of the clamping block fixedly connected to the bottom and the clamping groove on the basket holder.

[0007] The flower basket holder is also equipped with a limit plate to clamp the matching flower basket.

[0008] The flower basket holder has an inclined support plate at its center to support the substrate pieces inserted into the matching flower basket, so that all substrate pieces are tilted at an angle of 5-10°.

[0009] A fixed inclined block is provided at a diagonal position on the substrate; when the flower basket holder moves back and forth under the drive of the lead screw, its rounded corner contacts the fixed inclined block, causing the flower basket holder to twist.

[0010] This invention also provides a method for cleaning small-sized gallium arsenide substrates, comprising the following steps: S1. After polishing, insert the substrate into the matching basket and place it in an alcohol bath for cleaning. S2. Install the matching flower basket into the rinsing tank of the rinsing device for rinsing; S3. After rinsing, place the matching flower basket in a weak alkaline cleaning solution with a megahertz effect for further cleaning. S4. Reinstall in the rinsing tank of the rinsing device for rinsing; S5. The substrate of the entire matching flower basket is spun dry for inspection.

[0011] In S1, the substrate sheets are inserted into the matching flower basket in a closely arranged or spaced manner, and the main cleaning surface faces the end with the tilt angle raised.

[0012] The S3 has a megaphonic range of 1 MHz to 1.5 MHz, and the cleaning solution is composed of ammonium hydroxide, hydrogen peroxide and deionized water in a volume ratio of 1~6:1~3:15~25.

[0013] The beneficial effects of this invention are: 1. Using matching flower baskets for batch cleaning improves cleaning efficiency. Compared with conventional manual single-piece cleaning, it improves the consistency and uniformity between pieces and allows for centralized application of medicine, thereby reducing the amount of chemical reagents used.

[0014] 2. When the spray head sprays and rinses the substrate in the matching basket, the base will drive the basket holder to move back and forth in a straight line, which in turn causes the substrate in the matching basket to move back and forth in a straight line as well. This significantly improves the uniformity of cleaning by dynamically disturbing the flow field and optimizing the liquid distribution.

[0015] 3. As the matching flower basket moves back and forth in a straight line, it will also undergo a slight angular shift due to the contact between the flower basket holder and the fixed inclined block, thereby increasing the cleaning range. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0017] Figure 1 It is a schematic diagram of the overall appearance of the flushing device in the embodiment.

[0018] Figure 2 It is a schematic diagram of the internal structure of the flushing device in the embodiment.

[0019] Figure 3 It is a schematic diagram of the substrate bracket structure of the flushing device in the embodiment.

[0020] Figure 4 It is a schematic diagram of the base connection structure of the flushing device in the embodiment.

[0021] Figure 5 It is a front view sectional view of the base of the flushing device in the embodiment.

[0022] Figure 6 It is a schematic diagram of the flower basket card seat structure of the flushing device in the embodiment.

[0023] Figure 7 It is a schematic diagram of the supporting flower basket structure of the flushing device in the embodiment.

[0024] Figure 8 It is a microscope image of Example 1 and Comparative Example 1 under 20x magnification.

[0025] Figure 9 It is a comparison chart of the efficiency of Example 1 and Comparative Example 1.

[0026] Figure 10 It is a comparison chart of the detection of gallium oxide and arsenic oxide in Example 1 and Comparative Example 1.

[0027] In the drawings, the structural names represented by each reference numeral are as follows: 1 - flushing tank, 101 - bracket, 2 - jet pipe, 3 - spray head, 4 - water supply pipe, 5 - substrate bracket, 6 - substrate, 7 - support, 8 - screw rod, 801 - servo motor, 9 - guide shaft, 10 - base, 11 - spring sleeve, 12 - flower basket card seat, 13 - supporting flower basket, 14 - substrate sheet, 15 - card slot, 16 - limiting plate, 17 - clamping block, 18 - inclined support plate, 19 - fixed inclined plate. Specific Embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0029] Example 1 Refer to Figures 1 to 7As shown, this embodiment provides a small-sized gallium arsenide substrate rinsing device, including a rinsing tank 1, which is fixed by a bracket 101. A spray pipe 2 is installed on the inner wall of the rinsing tank 1, and multiple spray heads 3 are provided on the spray pipe 2. The spray pipe 2 is connected to a water supply pipe 4.

[0030] A substrate holder 5 is provided at the bottom of the rinsing tank 1, and two symmetrical substrates 6 are mounted on the substrate holder 5. A lead screw 8 is mounted on one substrate 6 via a support 7, and one end of the lead screw 8 is connected to the output shaft of the servo motor 801; a guide shaft 9 is mounted on the other substrate 6 via a support 7, and the guide shaft 9 is arranged parallel to the lead screw 8.

[0031] The lead screw 8 and guide shaft 9 are respectively connected to the two sides of the base 10. A spring sleeve 11 is provided at the center of the base 10, and the upper end of the spring sleeve 11 is connected to the basket holder 12. The basket holder 12 is used to install the matching basket 13, and multiple substrate sheets 14 can be inserted into the matching basket 13. A locking block 17 is fixedly connected to the bottom of the matching basket 13. The locking block 17 cooperates with the locking groove 15 provided on the basket holder 12 to achieve quick positioning and installation. A limiting plate 16 is also provided on the basket holder 12 to clamp the matching basket 13 from the side. An inclined support plate 18 is also provided at the center of the basket holder 12. When the matching basket 13 is installed in place, the inclined support plate 18 supports all the substrate sheets 14, so that the height of each substrate sheet 14 increases from one end to the other, forming an inclined angle of 5-10°, ensuring that the main cleaning surface is fully exposed and rinsed.

[0032] The four corners of the basket holder 12 are rounded. Fixed wedges 19 are provided at opposite corners of the two substrates 6. When the servo motor 801 drives the lead screw 8 to rotate, causing the base 10 and the basket holder 12 to reciprocate linearly along the guide shaft 9, the rounded corners of the basket holder 12 will contact the fixed wedges 19, causing the basket holder 12 to twist slightly along the spring sleeve 11 while moving horizontally, resulting in an angular offset, further increasing the cleaning range of the substrate 14 and optimizing the flow field distribution.

[0033] This embodiment also provides a method for cleaning small-sized gallium arsenide substrates using the above-described rinsing apparatus, including the following steps: S1. Twenty-five gallium arsenide substrates 14, after being polished and dried, are sequentially inserted into the matching basket 13 in each slot, ensuring that the processing main surface of all substrates 14 faces the same end with the tilt angle raised. S2. Place the matching flower basket 13 containing the substrate into a cleaning tank filled with alcohol, manually hold the flower basket with clamps and shake it left and right for 20 seconds to clean it. S3. Install the matching flower basket 13, which has been cleaned with alcohol, onto the flower basket holder 12 of the rinsing device, and start the device. The servo motor 801 drives the flower basket to move back and forth, while the spray head 3 is turned on, operating in the "spray + fast drain" mode to thoroughly rinse the substrate 14; S4. Place the rinsed flower basket 13 into a weakly alkaline cleaning tank with megasonite frequency of 1 MHz. The cleaning solution is composed of ammonium hydroxide, hydrogen peroxide, and deionized water in a volume ratio of 4:3:15. The cleaning method involves manually holding the flower basket and shaking it from side to side for 12 seconds. S5. After being cleaned by the hysteresis cleaner, the matching flower basket 13 is reinstalled into the rinsing device, and the rinsing steps of S3 are repeated. S6. Finally, put the entire matching flower basket 13 together with the substrate 14 into the spin dryer for 10 minutes, and then take it out for inspection.

[0034] The standard for determining whether a cleaning is clean is to check for the absence of drug marks, drug particles, or other dirt residue under strong light. The results are shown in Table 1 below.

[0035] Table 1 Testing revealed that none of the 25 substrate wafers in this batch had any chemical residue or particulate contamination on their surfaces. Only 3 wafers had scratches due to defects in the wafers themselves. Microscopic examination showed that the surfaces were uniform. Figure 8 As shown. The average cleaning time per wafer is approximately 0.4 minutes. XPS analysis of randomly selected wafers showed that the surface composition of Ga2O3 was 4.39% and the composition of As2O3 was 6.59%.

[0036] Comparative Example 1 Traditional manual single-wafer cleaning was used. The cleaning solution ratio was the same as in Example 1. 25 substrate wafers were cleaned one by one: alcohol cleaning for 20 seconds → water spray rinsing for 30 seconds → alkaline cleaning solution cleaning for 15 seconds → water spray rinsing for 60 seconds → spin-drying for 70 seconds. The cleaning results are shown in Table 2 below.

[0037] Table 2 The results showed that out of 25 samples, 1 had particulate contamination, 1 had chemical residue, and 2 had scratches. The average cleaning time per sample was approximately 3.4 minutes. XPS analysis of randomly selected samples indicated that the surface composition of Ga2O3 was 5.54%, and the composition of As2O3 was 9.41%.

[0038] Combining Example 1 and Comparative Example 1, see reference Figure 9 and Figure 10As shown, by using the rinsing device and cleaning method of the present invention, the cleaning efficiency is increased by more than 350%, and the surface oxide content is effectively reduced.

[0039] Example 2 The difference between this embodiment and Embodiment 1 lies in the ratio of the cleaning solution and the method of inserting the plates.

[0040] The cleaning solution is composed of ammonium hydroxide, hydrogen peroxide and deionized water in a volume ratio of 4:2:20.

[0041] Twelve 1-inch Si-doped gallium arsenide substrates 14 are inserted into the matching basket 13 at intervals of one slot each, with the main surface of the substrate 14 also facing the end with the tilt angle raised.

[0042] The cleaning steps are the same as in Example 1. The cleaning results are shown in Table 3 below.

[0043] Table 3 Testing revealed that none of the 12 substrate wafers in this batch had any chemical residue or particulate contamination on their surfaces, with only one wafer showing scratches due to its own defects. The average cleaning time per wafer was approximately 0.8 minutes.

[0044] In summary, the rinsing device and cleaning method provided by the present invention can significantly improve the cleaning efficiency and consistency of small-sized gallium arsenide substrates, effectively reduce the surface oxide content, and reduce chemical consumption.

[0045] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification.

Claims

1. A small size gallium arsenide substrate rinsing apparatus, characterized by, Including the flush groove (1), the flush groove (1) inner wall installs the jet pipe (2), the jet pipe (2) is provided with several spray heads (3); The flush groove (1) bottom is provided with a substrate bracket (5), the substrate bracket (5) is installed with two symmetrical base plates (6), one of the base plates (6) is installed with a lead screw (8) through a support (7), the other base plate (6) is installed with a guide shaft (9) through a support (7), the guide shaft (9) and the lead screw (8) are parallel to each other; The lead screw (8) and the guide shaft (9) are respectively connected to the two sides of the base (10), the spring sleeve (11) is arranged at the center of the base (10) to connect the flower basket holder (12), the matching flower basket (13) is installed on the flower basket holder (12). One end of the lead screw (8) is connected with the output shaft of the servo motor (801).

2. The apparatus for rinsing small size GaAs substrates according to claim 1, wherein The matching flower basket (13) is connected with the clamping groove (15) on the flower basket holder (12) through the clamping block (17) fixedly connected at the bottom.

3. The apparatus for rinsing small size GaAs substrates according to claim 2, wherein The flower basket holder (12) is further provided with a limiting plate (16) for clamping the matching flower basket (13).

4. The apparatus for rinsing small size GaAs substrates according to claim 3, wherein The center of the flower basket holder (12) is provided with an inclined support plate (18) for supporting the substrate sheet (14) inserted into the matching flower basket (13), so that all the substrate sheets (14) are inclined at an angle of 5-10°.

5. The apparatus for rinsing small size gallium arsenide substrates according to claim 4, wherein The diagonal position of the base plate (6) is provided with a fixed inclined block; when the flower basket holder (12) reciprocates under the drive of the lead screw (8), the circular corner contacts the fixed inclined block to make the flower basket holder (12) twist.

6. A method for cleaning a small-size GaAs substrate using the small-size GaAs substrate rinsing apparatus according to claim 1, characterized by, The method comprises the following steps: S1, after the substrate sheet (14) after polishing is inserted into the matching flower basket (13), it is placed in the alcohol tank for cleaning; S2, the matching flower basket (13) is installed in the flush groove (1) of the flush device for flushing; S3, the matching flower basket (13) after flushing is placed in the weak alkaline cleaning solution with megasonic for cleaning; S4, it is installed in the flush groove (1) of the flush device again for flushing; S5, the substrate sheet (14) of the whole matching flower basket (13) is dried and inspected.

7. The cleaning method of small-size gallium arsenide substrates according to claim 6, characterized in that, In S1, the substrate sheet (14) is inserted into the matching flower basket (13) in a close arrangement or interval arrangement, and the main cleaning surface is inclined to the same head of the inclined angle.

8. The cleaning method of small-size gallium arsenide substrates according to claim 7, characterized in that, In S3, the megasonic range is 1 MHz ~ 1.5 MHz, the cleaning solution is composed of ammonium hydroxide, hydrogen peroxide and deionized water, and the volume ratio is 1~6:1~3:15~25.

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