A double polishing wafer cleaning equipment and cleaning method without film sticking

Abstract

The application discloses a kind of not to be pasted film double-throw wafer cleaning equipment and cleaning method, it is related to wafer cleaning field.Cleaning equipment includes cleaning tank, retractable member is set in cleaning tank and can be extended or inducted into cleaning tank, retractable member is provided with rotatable PIN disc, PIN disc is provided with a plurality of clamping parts that can be clamped or loosened to double-throw wafer.The cleaning method of the application sequentially uses alcohol solution, isopropanol solution, alkaline solution and water to clean double-throw wafer, and the cleaning equipment can ensure consistent speed during the cleaning process, strictly control cleaning time and cleaning temperature, improve the yield of double-throw wafer cleaning while improving cleaning effect and cleaning efficiency, avoid the situation that wafer whitens appears in cleaning product, reduce the surface roughness and particle count of double-throw wafer, and the wafer surface is uniform.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wafer cleaning, in particular to a double-polished wafer cleaning device and method without film. BACKGROUND

[0002] In recent years, more and more electronic manufacturers choose double-polished GaAs wafers as substrate materials for manufacturing chips such as LEDs, lasers, and solar cells, because double-polished wafers have excellent flatness and are easy to obtain super-smooth processing surfaces. However, double-polished substrate wafers have higher requirements for surface impurities due to the harsh application field, and the cleaning degree of double-polished wafers is higher.

[0003] Currently, substrate manufacturers mainly rely on manual cleaning methods to clean double-polished wafers without film and of different sizes. The wafers are fixed on a special cleaning clamp, and then an employee holds the clamp to stir the wafers in the chemical solution and rinse them with water, as shown in FIG. 1. Figure 1 This method has high instability due to manual operation, and the cleaning effect of the product is highly dependent on the operation of the personnel. Therefore, the surface impurities are not cleaned, and the yield is low. SUMMARY

[0004] The present application provides a double-polished wafer cleaning device and method without film, which can improve the cleaning effect and yield of the double-polished wafer after cleaning, and the wafer surface has low uniform roughness and few particles.

[0005] To solve the above technical problems, one of the purposes of the present application provides a double-polished wafer cleaning device without film, which comprises a cleaning tank, a retractable member arranged in the cleaning tank, a rotatable PIN disc arranged in the retractable member, and a plurality of clamping parts arranged in the PIN disc for clamping or releasing the double-polished wafer.

[0006] By using the above scheme, when cleaning the double-polished wafer, the double-polished wafer is fixed on the PIN disc by the clamping part. After rotating to a certain speed, the retractable member controls the PIN disc to immerse in the solution in the cleaning tank. The wafer is cleaned during rotation. After cleaning is completed, the retractable member can be used to extend out of the cleaning tank, and the wafer can be spun dry to reduce the corrosion of the wafer surface caused by the residual cleaning solution when the wafer is exposed to the air.

[0007] As a preferred scheme, the cleaning tank is provided with a temperature control device for adjusting or maintaining the temperature of the solution in the cleaning tank.

[0008] To solve the above technical problems, the second purpose of the present application provides a double-polished wafer cleaning method without film, which uses a double-polished wafer cleaning device without film, and comprises the following steps:

[0009] (1) adding alcohol solution into the ultrasonic tank, and placing the double-polished wafer to be cleaned in the ultrasonic tank for ultrasonic cleaning;

[0010] (2) adding water solution containing 11.5vt%-13vt% isopropyl alcohol into the cleaning tank, and sending the double-polished wafer after ultrasonic cleaning to the cleaning tank for cleaning, maintaining the solution cleaning temperature at 18℃-23℃, and cleaning for 15s-25s;

[0011] (3) placing the double-polished wafer in the rinsing tank, and spraying deionized water on the front and back surfaces of the wafer to rinse the front and back surfaces of the wafer, and then drying;

[0012] (4) adding alkaline liquid into another cleaning tank, the alkaline liquid is mixed and configured by ammonia, hydroxide and water according to the mass ratio of 1:1:(7-9), maintaining the temperature of the solution at 18℃-25℃, and sending the double-polished wafer to the cleaning tank for cleaning, and cleaning for 15s-25s;

[0013] (5) placing the double-polished wafer in the rinsing tank, and spraying deionized water on the front and back surfaces of the wafer to rinse the front and back surfaces of the wafer, and then drying;

[0014] (6) adding water into another cleaning tank, and sending the double-polished wafer to the cleaning tank for cleaning, and then drying after cleaning.

[0015] By adopting the above scheme, the concentration, temperature and cleaning time of isopropyl alcohol in the cleaning tank and the concentration, cleaning time and cleaning temperature of the alkaline liquid are strictly controlled, the cleaning method ensures to improve the cleaning effect and cleaning efficiency, improves the yield of double-polished wafers, effectively avoids the whitening of wafers during cleaning, reduces the surface roughness and particle number of double-polished wafers, the wafer surface is uniform, and the yield of cleaned products is significantly improved.

[0016] The temperature of the isopropyl alcohol solution during the cleaning process is too low, which affects the cleaning effect of the double-polished wafer, may cause the organic matter to be not completely removed in time, and affects the subsequent cleaning steps, and the temperature is too high, which may cause the isopropyl alcohol to be easily volatilized, the concentration of the isopropyl alcohol solution is too high, the corresponding viscosity is improved, the flowability is poor, and the cleaning efficiency of the double-polished wafer is reduced, and the concentration is too low, which affects the cleaning effect.

[0017] As a preferred scheme, in step (1), the alcohol solution contains 45vt%-50vt% alcohol, the solution cleaning temperature is maintained at 13℃-20℃, and the cleaning time is 15s-20s.

[0018] As a preferred scheme, in step (1), the solution cleaning temperature is maintained at 15℃-18℃.

[0019] By using the above scheme, when the alcohol solution is used for ultrasonic cleaning, if the temperature is too low, the solution impact sound pressure is not uniform, resulting in poor cleaning effect of the double-polished wafer; if the temperature is too high, the alcohol volatilizes, affecting the cleaning effect.

[0020] As a preferred scheme, in steps (3) and (5), the rinsing time is 20-30s, and the spin-drying time after rinsing is 20-40s, and the spin-drying speed is 3000-4000r / min.

[0021] As a preferred scheme, in step (4), the hydroxyl compound is ammonium hydroxide.

[0022] As a preferred scheme, in step (6), the cleaning time is 30-40s.

[0023] As a preferred scheme, in steps (2), (4) and (6), the step of sending the double-polished wafer to the cleaning tank for cleaning is as follows: the double-polished wafer is placed on the PIN disc, and is rotated to reach a speed of 2000-2500r / min, and then the double-polished wafer is deepened into the solution in the cleaning tank by using the telescopic member, and the speed is uniformly increased to 3000-3500r / min for cleaning.

[0024] As a preferred scheme, in step (4), the alkaline solution is mixed and configured by ammonia, a hydroxyl compound and water in a mass ratio of 1:1:8.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] In the present application, the double-polished wafer is sequentially cleaned by using alcohol solution, isopropyl alcohol solution, alkaline solution and water, the cleaning equipment can ensure consistent speed during the cleaning process, and the cleaning time and temperature are strictly controlled, so that the cleaning effect and efficiency are improved, the yield of the double-polished wafer is improved, the wafer whitening phenomenon is avoided, the surface roughness and particle count of the double-polished wafer are reduced, the wafer surface is uniform, and the yield of the cleaned product is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 : is the equipment used for cleaning the double-polished wafer mentioned in the background art;

[0028] Figure 2 : is a structure diagram of a double-polished wafer cleaning equipment without film in the embodiment of the present application;

[0029] Figure 3 : is a step diagram of a double-polished wafer cleaning method without film in the embodiment of the present application;

[0030] In the description, the drawings Figure 2The reference signs in the drawings are as follows: 1, cleaning tank; 2, PIN disc; 3, telescopic part; 4, double-throw wafer. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0032] Embodiment one

[0033] A double-throw wafer cleaning device without film, as shown in Figure 2 , comprises a cleaning tank 1, the cleaning tank 1 is used for loading a solution for cleaning the double-throw wafer 4, and the cleaning tank 1 is also provided with a temperature control device, which can adjust or maintain the temperature of the solution in the cleaning tank 1. A telescopic part 3 controlled by a program to go up and down is installed at the bottom of the cleaning tank 1, the telescopic part 3 is vertically arranged, and a PIN disc 2 controlled by a program to rotate is fixedly installed at the end of the telescopic part 3 away from the bottom of the cleaning tank 1, the PIN disc 2 is provided with a plurality of clamping parts, the clamping parts can be controlled by a program to clamp or release the double-throw wafer 4, and when the double-throw wafer 4 is fixed on the PIN disc 2, the double-throw surface of the double-throw wafer 4 can be exposed to contact with the solution in the cleaning tank 1. During cleaning, the PIN disc 2 is extended out of the cleaning tank 1 by the telescopic part 3, the double-throw wafer 4 is placed on the PIN disc 2 by a mechanical hand, a rotating switch is turned on, the PIN disc 2 drives the double-throw wafer 4 to rotate, after a certain rotating speed is reached, the telescopic part 3 controls the PIN disc 2 to be deeply immersed in the cleaning tank 1 to start cleaning. After cleaning is completed, the PIN disc 2 can be extended out of the cleaning tank 1 by the telescopic part 3 to perform spin-drying, so as to reduce the corrosion of the wafer surface caused by the residual chemical liquid when the double-throw wafer 4 is exposed to air, and avoid affecting the roughness difference of the wafer surface.

[0034] A double-throw wafer cleaning method without film, using the above-mentioned double-throw wafer cleaning device without film, as shown in Figure 3 , comprises the following steps:

[0035] (1) A water solution containing 45% alcohol is added to an ultrasonic tank, the temperature of the solution is maintained at 15°C, the double-throw wafer to be cleaned is placed in the ultrasonic tank for ultrasonic treatment, the ultrasonic rate is 45KHZ, and the ultrasonic time is 15s;

[0036] (2) in the cleaning tank A, add 11.5% isopropyl alcohol aqueous solution, maintain the temperature of the solution at 23℃, put the double polished wafer after ultrasonic treatment on the PIN tray of the cleaning tank A by the mechanical hand, rotate to make the double polished wafer reach 2500r / min, then make the double polished wafer go deep into the cleaning solution of the cleaning tank by the telescopic part, and the rotation speed is uniformly increased to 3500r / min for cleaning, and the cleaning time is 15s;

[0037] (3) after the isopropyl alcohol solution cleaning, put the double polished wafer into the rinsing tank by the mechanical hand, and spray deionized water on the front and back surfaces of the wafer to rinse the front and back surfaces of the wafer, the rinsing time is 15s, and the spin-drying time is 30s at 3500r / min;

[0038] (4) in the cleaning tank B, add alkaline solution, the alkaline solution is prepared by mixing ammonia, ammonium hydroxide and deionized water according to the mass ratio of 1:1:8, maintain the temperature of the solution at 25℃, put the double polished wafer into the PIN tray of the cleaning tank B by the mechanical hand, and the cleaning operation is the same as step (2);

[0039] (5) after the alkaline solution cleaning, put the double polished wafer into the rinsing tank by the mechanical hand, and the rinsing operation is the same as step (3), except that the rinsing time is 30s;

[0040] (6) in the cleaning tank C, add deionized water, put the double polished wafer into the PIN tray of the cleaning tank C by the mechanical hand, and the cleaning operation is the same as step (2), except that the cleaning time is 40s, and the double polished wafer is spin-dried after cleaning.

[0041] Example two

[0042] A double polished wafer cleaning method without film, using the above-mentioned double polished wafer cleaning equipment without film, using the double polished wafer cleaning equipment without film in example one, as shown in FIG. 1, comprising the following steps: Figure 3

[0043] (1) in the ultrasonic tank, add 50% alcohol aqueous solution, maintain the temperature of the solution at 18℃, and put the double polished wafer to be cleaned in the ultrasonic tank for ultrasonic treatment, the ultrasonic rate is 50KHZ, and the ultrasonic time is 20s;

[0044] (2) in the cleaning tank A, add 11.5% isopropyl alcohol aqueous solution, maintain the temperature of the solution at 18℃, put the double polished wafer after ultrasonic treatment on the PIN tray of the cleaning tank A by the mechanical hand, rotate to make the double polished wafer reach 2000r / min, then make the double polished wafer go deep into the cleaning solution of the cleaning tank by the telescopic part, and the rotation speed is uniformly increased to 3000r / min for cleaning, and the cleaning time is 20s;

[0045] ​(3) After the isopropyl alcohol solution cleaning is finished, the double-polished wafer is placed in the rinsing tank by the mechanical hand, deionized water is sprayed on the front and back surfaces of the wafer to rinse the front and back surfaces of the wafer, the rinsing time is 20 s, and the wafer is spun dry for 30 s at a rotation speed of 3500 r / min after the rinsing is completed;

[0046] (4) The alkaline liquid is added into the cleaning tank B, the alkaline liquid is mixed and configured according to a mass ratio of 1:1:8 of ammonia water, ammonium hydroxide and deionized water, the temperature of the solution is maintained at 18℃, the double-polished wafer is sent to the PIN disc of the cleaning tank B by the mechanical hand, and the cleaning operation is the same as that in step (2);

[0047] (5) After the alkaline solution cleaning is finished, the double-polished wafer is placed in the rinsing tank by the mechanical hand, the rinsing operation is the same as that in step (3), and the difference lies in that the rinsing time is 30 s;

[0048] (6) The deionized water is added into the cleaning tank C, the double-polished wafer is sent to the PIN disc of the cleaning tank C by the mechanical hand, the cleaning operation is the same as that in step (2), and the difference lies in that the cleaning time is 30 s, and the double-polished wafer is spun dry after the cleaning is completed.

[0049] Example Three

[0050] A double-polished wafer cleaning method without film pasting, each step and the reagents and process parameters used in each step are the same as those in Example One, and the difference lies in that, in step (1), the temperature of the solution is maintained at 13℃.

[0051] Example Four

[0052] A double-polished wafer cleaning method without film pasting, each step and the reagents and process parameters used in each step are the same as those in Example One, and the difference lies in that, in step (2), the cleaning time is 25 s; in step (4), the cleaning time is 25 s; and in step (6), the cleaning time is 30 s.

[0053] Example Five

[0054] A double-polished wafer cleaning method without film pasting, each step and the reagents and process parameters used in each step are the same as those in Example One, and the difference lies in that, in step (2), the cleaning liquid of the cleaning tank A is a water solution containing 13 vt% isopropyl alcohol.

[0055] Comparative Example One

[0056] A double-polished wafer cleaning method without film pasting, each step and the reagents and process parameters used in each step are the same as those in Example One, and the difference lies in that, in step (2), the cleaning liquid of the cleaning tank A is a water solution containing 15 vt% isopropyl alcohol.

[0057] Comparative Example Two

[0058] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that in step (4), the alkaline solution is mixed and configured by ammonia, ammonium hydroxide and deionized water according to the mass ratio of 1:1:6.

[0059] Comparative example three

[0060] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that in step (2), the temperature of the solution is maintained at 15℃.

[0061] Comparative example four

[0062] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that in step (2), the cleaning solution of cleaning tank A is an aqueous solution containing 12.5vt% acetone.

[0063] Comparative example five

[0064] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that in step (2), the cleaning solution of cleaning tank A is an aqueous solution containing 10vt% isopropanol.

[0065] Comparative example six

[0066] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that in step (4), the temperature of the solution is maintained at 28℃.

[0067] Comparative example seven

[0068] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that the cleaning step of step (1) is not performed, and the double polished wafer to be cleaned is directly subjected to the cleaning steps of steps (2)-(6).

[0069] Comparative example eight

[0070] A cleaning method for double polished wafer without film, each step and reagent used in each step and process parameters are the same as example one, the difference is that the cleaning process of cleaning tanks A, B and C is performed by workers holding the device as shown in Figure 1 .

[0071] Performance detection test

[0072] 1. Product detection: The LED wafer inspection standard under normal pressure was adopted, and the double-polished wafers after cleaning in the examples and the comparative examples were detected according to the standard of GBT 30856-2014 "Gallium Arsenide Substrate for LED Epitaxial Chip", 50 samples were detected in each test, and the detection items and detection results are shown in Table 1, wherein the roughness of the main surface is the roughness of 5 points, and the average value is taken, and Ra≤0.3 is calculated as a qualified product; the surface particle number is the surface particle number of the wafer tested during the cleaning process, and the qualified distinction is made according to different needs in the actual production process, and the surface particle number below 65 particles @03um is qualified in the application.

[0073] Table 1 - Product detection results of double-polished wafers of examples and comparative examples of the application

[0074]

[0075]

[0076] It can be known from the comparison of the performance detection results of examples 1 and 5 and comparative examples 1, 3 and 5 in Table 1 that if the concentration of the isopropyl alcohol solution in step (2) is too high, the corresponding viscosity is increased, the fluidity is poor, the cleaning efficiency of the double-polished wafer is reduced, and if the concentration is too low, the cleaning effect is affected, and the yield is reduced; and the temperature in the cleaning process is too low, the cleaning effect of the double-polished wafer is affected, the organic matter cannot be completely removed in time, the subsequent cleaning step is affected, and the isopropyl alcohol is easily volatilized.

[0077] It can be known from the comparison of the performance detection results of examples 1 and comparative examples 2 and 6 in Table 1 that by controlling the Ph and concentration of the alkaline solution, the excessive corrosion of the wafer surface during cleaning is avoided, the pit or medicine black spot phenomenon on the wafer surface is avoided, or the surface whitening is avoided, and if the concentration is too low, the cleaning is not complete, and the dirt on the wafer surface is spread.

[0078] The above specific examples further illustrate the purpose, technical solutions and advantages of the application. It should be understood that the above description is only a specific embodiment of the application and is not used to limit the protection scope of the application. It is particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A method for cleaning wafers without applying a protective film using double-polished wafers, characterized in that, A non-coating double-polished wafer cleaning device is adopted. The cleaning device includes a cleaning tank (1). The cleaning tank (1) is provided with a telescopic component (3) that can extend or extend into the cleaning tank (1). The telescopic component (3) is provided with a rotatable PIN disk (2). The PIN disk (2) is provided with several clamping parts that can clamp or release the double-polished wafer (4). The non-coating double-polished wafer cleaning method includes the following steps: (1) Add alcohol solution to the ultrasonic tank, place the double-polished wafer to be cleaned in the ultrasonic tank for ultrasonic cleaning; (2) Add an aqueous solution containing 11.5 vol% isopropanol to the cleaning tank, and send the ultrasonically polished wafer to the cleaning tank for cleaning. Maintain the cleaning solution temperature at 18℃-23℃ and the cleaning time at 15s-25s. (3) Place the double-polished wafer in the rinsing tank, and rinse the front and back sides of the wafer with deionized water by spraying it. After rinsing, spin dry. (4) Add an alkaline solution to another cleaning tank. The alkaline solution is prepared by mixing ammonia, hydroxide and water in a mass ratio of 1:1:(7-9). Maintain the temperature of the solution at 18℃-25℃. Send the double-polished wafer to the cleaning tank for cleaning. The cleaning time is 15s-25s. (5) Place the double-polished wafer in the rinsing tank, and rinse the front and back sides of the wafer with deionized water by spraying it. After rinsing, spin dry. (6) Add water to another cleaning tank, send the double-polished wafers into the cleaning tank for cleaning, and spin dry after cleaning; In step (1), the alcohol solution contains 45%-50% alcohol, the solution cleaning temperature is maintained at 15℃-18℃, and the cleaning time is 15s-20s; In steps (2), (4), and (6), the step of sending the double-polished wafer to the cleaning tank for cleaning is as follows: the double-polished wafer is placed on the PIN disk and rotated to a speed of 2000r / min-2500r / min. Then, the double-polished wafer is inserted into the solution in the cleaning tank by using the telescopic component, and the speed is uniformly increased to 3000r / min-3500r / min for cleaning.

2. The non-coating double-polished wafer cleaning method as described in claim 1, characterized in that, The cleaning tank (1) is equipped with a temperature control device that can adjust or maintain the temperature of the solution inside the cleaning tank (1).

3. The non-coating double-polished wafer cleaning method as described in claim 1, characterized in that, In steps (3) and (5), the rinsing time is 20s-30s, and after rinsing, the spin-drying time is 20s-40s, with a spin-drying speed of 3000r / min-4000r / min.

4. The non-coating double-polished wafer cleaning method as described in claim 1, characterized in that, In step (4), the hydroxide compound is ammonium hydroxide.

5. The non-coating double-polished wafer cleaning method as described in claim 1, characterized in that, In step (6), the cleaning time is 30s-40s.

6. The non-coating double-polished wafer cleaning method as described in claim 1, characterized in that, In step (4), the alkaline solution is prepared by mixing ammonia, hydroxide compound and water in a mass ratio of 1:1:8.

Images