Developing process for reducing smudginess of developed low-viscosity glue

Abstract

The invention discloses a developing process for reducing smudginess of developed low-viscosity glue, and belongs to the technical field of manufacturing of displays and semiconductor devices. According to the process, a wafer spin-coated with low-viscosity photoresist is exposed and then is subjected to a developing process; comprising the following steps: (1) placing a wafer on a wafer bearing table of a developing unit, swinging from the edge of the wafer to the center of the wafer by using a nozzle and spraying a developing solution, and controlling the rotating speed of the wafer in the process of spraying the developing solution; (2) a nozzle is used for swinging from the edge of the wafer to the center of the wafer and spraying deionized water, the rotating speed of the wafer is firstly low, then high and then low, the developing solution and part of photoresist reacting with the developing solution are thrown out of the wafer in time through variable-speed rotation of the wafer, and after-tack is avoided; (3) repeating the steps (1)-(2) for 0-5 times; and (4) spin-drying the wafer by rotating at a high rotating speed. The process effectively improves the condition that a large amount of dirt remains on the surface of the wafer after development.

Description

Technical Field

[0001] The invention relates to the technical field of integrated circuit, display and semiconductor device manufacturing, and in particular to a development process for reducing dirt after low-viscosity glue development. Background Art

[0002] In the field of integrated circuit, display and semiconductor device manufacturing, a layer of low-viscosity photoresist is first spin-coated as an anti-etching agent, and then exposed through a photolithography machine to cause part of the photoresist to react and denature. After the exposure is completed, the effective pattern needs to be retained through a development process while the ineffective part is washed away. In this process, there will be dirt residues caused by the nature of the photoresist itself, especially when using a photoresist composed of fine particles. If the amount of dirt residue is large, it will have an adverse effect on subsequent etching or stripping processes, and will ultimately affect product performance and reliability.

[0003] The commonly used developing method at present is to accelerate the wafer to a certain rotation speed through a fixed acceleration when spraying the developer, and then directly puddle. When developing some low-viscosity photoresists, this method cannot promptly throw the photoresist that reacts with the developer out of the wafer. In the subsequent puddle process, this part of the photoresist will adhere to the surface of the existing structure again, and once this part of the photoresist sticks back, it is difficult to remove it after the wafer is dried, which ultimately affects the graphic structure of the product. Summary of the invention

[0004] The purpose of the present invention is to provide a development process for reducing dirt after low-viscosity glue development. The process is used to improve the situation in which a large amount of dirt remains on the wafer surface after development when spin coating low-viscosity (500cp and below) photoresist on a silicon wafer for photolithography.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A developing process for reducing dirt after developing a low-viscosity glue, the process is for a wafer spin-coated with a low-viscosity photoresist, after which the wafer is exposed and subjected to a developing process so that effective patterns are retained and ineffective parts are washed away at the same time; the developing process comprises the following steps:

[0007] (1) Place a 12-inch wafer on the wafer stage of the developing unit, use a nozzle to swing from the edge of the wafer to the center of the wafer and spray the developer, and control the wafer rotation speed during the spraying process;

[0008] (2) Use a nozzle to swing from the edge of the wafer to the center of the wafer and spray deionized water or fixer. The wafer speed is first low, then high, and then low. By rotating the wafer at a variable speed, the developer and part of the photoresist that reacts with the developer are thrown out of the wafer in time to avoid re-sticking;

[0009] (3) Repeat steps (1)-(2) 0-5 times;

[0010] (4) Use high speed rotation to spin dry the wafer.

[0011] Preferably, the viscosity of the low-viscosity photoresist is below 500 cp.

[0012] During the spraying of the developer in step (1) above, the wafer is first accelerated in a stepwise manner, then decelerated in a stepwise manner, and finally the developer nozzle is closed and left to stand for a period of time.

[0013] In the above step (1), during the stepwise acceleration of the wafer, the rotation speed dwell time in each stage should be short, which can effectively avoid the photolithography machine from sticking back without increasing the overall acceleration time.

[0014] Preferably, during the step (1) of spraying the developer, the total time for stepwise acceleration of the wafer is 4-8s, the acceleration stage is 4-5 sections, and the speed dwell time in each stage is 0.3-3s; the total time for stepwise deceleration is 2-4s, the deceleration stage is 2 sections, and the speed dwell time in each stage is 1-2s; and the standing time is 2-4s.

[0015] Preferably, during the step (1) of spraying the developer, the wafer rotation speed is gradually accelerated from 200-400 rpm to 2300-2800 rpm during the wafer stepwise acceleration process; and the total flow rate of the developer during the spraying of the developer is 800-1200 ml / min.

[0016] In the above step (2), the wafer is first rotated at 80-200 rpm for 2-4 seconds, then at 2200-2800 rpm for 1-3 seconds, and finally at 60-80 rpm for 1-3 seconds.

[0017] In the above step (4), the wafer rotation speed is 2200-2800 rpm, and the rotation time is 20-40 s.

[0018] The design mechanism of the present invention is as follows:

[0019] In the process of spraying the developer, the present invention maintains the developer to be continuously and stably discharged while covering the entire wafer with the developer at the fastest speed; in addition, during the development process, the wafer is accelerated in a step-by-step manner, but the time used for each acceleration is short and the acceleration is large, so that the photoresist reacting with the developer is thrown out of the wafer in time to prevent this part of the photoresist from adhering to the surface of the existing structure again. The above development process can increase the number of developments according to the actual development effect, and the developer on the surface of the wafer needs to be rinsed with deionized water in time between each development. Finally, while ensuring the development effect, the occurrence of abnormal phenomena such as dirt falling back is avoided to the greatest extent.

[0020] The advantages and beneficial effects of the present invention are as follows:

[0021] 1. When spraying the developer, whether accelerating or decelerating, it is done in a gradient manner, so that the photoresist that reacts with the developer is thrown out of the wafer in time;

[0022] 2. During water washing, the wafer is rotated at a variable speed to improve the effect of water replacing the developer;

[0023] 3. The process of the present invention can effectively prevent the photoresist from sticking back;

[0024] 4. The process of the present invention can optimize the process performance only by adjusting the developing process parameters, without adding other process steps, without affecting the production capacity, and has been implemented; BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The AOI result after development in Example 1 is compared with the AOI result of the common development method. DETAILED DESCRIPTION

[0026] In order to further understand the present invention, the present invention is described below in conjunction with examples, but the examples are only for further elaboration of the features and advantages of the present invention, rather than for limiting the claims of the present invention.

[0027] Embodiment 1:

[0028] This embodiment uses a 12-inch silicon wafer, the viscosity of the spin-coated photoresist is 60cp, and the thickness of the photoresist film is about 500nm. After photolithography, a development process is performed, and the development process is as follows:

[0029] Step 1: Place the wafer on the wafer stage of the developing unit, use a cylindrical nozzle to swing from the edge of the wafer to the center of the wafer and spray the developer, and gradually accelerate the wafer speed from 300rpm to 2500rpm, including: 300rpm for 1s, 600rpm for 0.3s, 900rpm for 0.3s, and 2500rpm for 3s; then gradually decelerate to 0rpm, including: first 900rpm for 2s, then 400rpm for 1s; decelerate to 0rpm and let it stand for 3s; the total flow rate of the developer in this process is 1000ml / min.

[0030] Step 2: Use a cylindrical nozzle to swing and spray deionized water from the edge of the wafer to the center of the wafer. The wafer rotation speed is 100rpm, the deionized water flow rate is 1000mL / min, and the spraying is 3s.

[0031] Step 3: Use a cylindrical nozzle to swing and spray deionized water from the edge of the wafer to the center of the wafer. The wafer rotation speed is 2500rpm, the deionized water flow rate is 1000mL / min, and the spraying time is 1s.

[0032] Step 4: Use a cylindrical nozzle to swing and spray deionized water from the edge of the wafer to the center of the wafer. The wafer rotation speed is 70rpm, the deionized water flow rate is 1000mL / min, and the spraying is 2s.

[0033] Step 5: Use a cylindrical nozzle to swing and spray deionized water from the edge of the wafer to the center of the wafer. The wafer rotation speed is 30rpm, the deionized water flow rate is 1000mL / min, and the spraying time is 1s.

[0034] Repeat steps 1 to 5.

[0035] Finally, the wafer is dried by rotating at high speed for a long time. The wafer rotation speed is 2500r / min and the time is 30s.

[0036] After the development process is completed, AOI is used to detect the amount of dirt.

[0037] After the development of this process method, the AOI results show that the number of abnormal particles is within 10, which is different from the AOI results of the ordinary development method (a large amount of sticky residues cannot be calculated accurately, see Figure 1 ) by comparison, it can be clearly observed that the dirt is effectively removed.

Claims

1. A developing process for reducing dirt after developing low-viscosity adhesives, characterized in that: The process is for a wafer spin-coated with a low-viscosity photoresist, and after exposing it, a development process is performed to retain the effective pattern and wash away the ineffective part at the same time; the development process includes the following steps: (1) Place a 12-inch wafer on the wafer stage of the developing unit, and use a nozzle to swing from the edge of the wafer to the center of the wafer and spray the developer. Control the wafer rotation speed during the spraying process; (2) Use a nozzle to swing from the edge of the wafer to the center of the wafer and spray deionized water or fixer. The wafer speed is first low, then high, and then low. By rotating the wafer at a variable speed, the developer and part of the photoresist that reacts with the developer are thrown out of the wafer in time to avoid re-sticking; (3) Repeat steps (1)-(2) 0-5 times; (4) Use high speed rotation to spin dry the wafer.

2. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 1, characterized in that: The viscosity of the low-viscosity photoresist is below 500 cp.

3. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 1, characterized in that: During the step (1) of spraying the developer, the wafer is first accelerated in a stepwise manner, then decelerated in a stepwise manner, and finally the developer nozzle is closed and left to stand for a period of time.

4. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 3, characterized in that: In step (1), during the stepwise acceleration of the wafer, the rotation speed dwell time in each stage should be short, which can effectively avoid the photolithography machine from sticking back without increasing the overall acceleration time.

5. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 3 or 4, characterized in that: During the step (1) of spraying the developer, the total time for stepwise acceleration of the wafer is 4-8s, the acceleration stage is 4-5 sections, and the speed dwell time in each stage is 0.3-3s; the total time for stepwise deceleration is 2-4s, the deceleration stage is 2 sections, and the speed dwell time in each stage is 1-2s; the standing time is 2-4s.

6. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 5, characterized in that: During the step (1) of spraying the developer, the wafer rotation speed is gradually accelerated from 200-400 rpm to 2300-2800 rpm during the wafer stepwise acceleration process; and the total flow rate of the developer during spraying the developer is 800-1200 ml / min.

7. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 1, characterized in that: In step (2), the wafer is first rotated at 80-200 rpm for 2-4 seconds, then at 2200-2800 rpm for 1-3 seconds, and finally at 60-80 rpm for 1-3 seconds.

8. The developing process for reducing dirt after developing low-viscosity adhesive according to claim 1, characterized in that: In step (4), the wafer rotation speed is 2200-2800 rpm, and the rotation time is 20-40 s.

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