Liquid film accompanying protection metal stripping process for reducing crushing and scratching of wafer
Through the metal peeling process with liquid film protection, high-pressure and atmospheric pressure nozzles are used to spray liquid liquid and deionized water, the problems of wafer crushing and scratching in traditional processes are solved, the conductivity and yield are improved, and the improvement is achieved. Efficient cleaning and drying.
Patent Information
- Application Number
- CN202310769888.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-28
- Publication Date
- 2024-12-31
AI Technical Summary
In the metal peeling process of LED optoelectronic devices, traditional methods can easily lead to wafer crushing and scratching, affecting conductivity and yield.
The metal peeling process with liquid film accompanied by protection is adopted, and the liquid liquid is sprayed together through high-pressure and normal pressure nozzles to form a lubricating liquid film, reducing friction, and using deionized water and nitrogen during the cleaning and drying process to ensure full cleaning and drying.
It effectively avoids debris scratches during the peeling process, improves the product's conductivity and yield, and increases the cleaning effect and production capacity.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of LED and optical communication, and in particular to a metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching. Background Art
[0002] In the field of LED optoelectronic devices, the stripping process for preparing the electrode leads of the light-emitting diode is as follows: bury the substrate of the PN junction, expose the bottom electrode of the wafer through the coating and development process, and then make a conductive metal layer (such as Al layer) through the evaporation process. After the evaporation process is completed, the photoresist and the evaporated metal above the photoresist need to be stripped off. The traditional stripping process is to adhere the blue film tape to the front of the wafer, and firmly suck the back of the wafer with a vacuum suction cup. The adhesion of the blue film tape is used to tear off part of the photoresist and the metal to be stripped by external force. If there is electrostatic breakdown or repeated pressure injury during the tearing process, it will affect the conductivity and yield of the final product.
[0003] Another stripping process is a single-wafer high-pressure stripping process, in which the wafer is fixed on a rotating suction cup and the metal electrode is stripped under the pressure of the high-speed rotation of the wafer and the high-pressure jet. This method will cause the residual stripped metal that is not thrown off in time to rub against each other, resulting in a certain amount of electrode scratches. Summary of the invention
[0004] In order to solve the above-mentioned deficiencies existing in the prior art, the purpose of the present invention is to provide a metal stripping process with liquid film protection that reduces wafer crushing and scratching, which can prevent the stripped debris from scratching the wafer, thereby avoiding adverse effects on the conductive properties of the product.
[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:
[0006] A metal stripping process with liquid film accompanying protection to reduce wafer crushing and scratching, the process performs metal stripping treatment on a wafer coated with photoresist and exposed, developed and evaporated with a metal film layer, the metal stripping treatment is to first place the wafer in a stripping unit for metal stripping, and then place it in a cleaning unit for cleaning and drying; the process specifically includes the following steps:
[0007] (1) placing a wafer on a wafer stage of a stripping unit, wherein the stripping unit includes a high-pressure degumming nozzle and a normal-pressure nozzle; using the high-pressure degumming nozzle to spray a high-pressure chemical solution onto the wafer, and the normal-pressure nozzle follows the high-pressure nozzle to scan the edge of the wafer;
[0008] (2) The wafer keeps rotating and the atmospheric pressure liquid is sprayed using an atmospheric pressure nozzle at a flow rate of 200-1000 mL / min to fully dissolve the residual photoresist on the wafer;
[0009] (3) Adjust the wafer rotation speed to 1000-2000 r / min and rotate for 5-20 seconds to reduce the residual solution on the wafer surface;
[0010] (4) Wafer washing: Place the wafer on the wafer stage of the cleaning unit, and use the nozzle to swing from one edge of the wafer to the other edge and spray deionized water to achieve a more complete cleaning effect;
[0011] (5) Wafer drying: Place the wafer on the wafer stage of the cleaning unit, use a nozzle to swing from one edge of the wafer to the other edge and spray nitrogen, and use high speed and long-term rotation to dry the wafer.
[0012] Furthermore, the evaporated metal film layer of the present invention is one or more of aluminum, gold, nickel, silver and chromium, and has a thickness of 1-8 μm.
[0013] The stripping unit includes a debonding chamber, in which a rotatable wafer stage and a high-pressure debonding nozzle and a normal-pressure nozzle installed on the same swing arm are provided; wherein: the spraying direction of the normal-pressure nozzle is perpendicular to the wafer surface, and the spraying direction of the high-pressure debonding nozzle has an angle of 10-30° with the vertical direction of the wafer.
[0014] The high-pressure degumming nozzle is a needle-shaped nozzle, and the diameter of the end of the needle-shaped nozzle is 0.1-0.2 mm; the normal-pressure nozzle is a columnar nozzle.
[0015] In the above step (1), the high-pressure degumming nozzle is used to spray the liquid medicine, and the spraying method is to scan back and forth from the edge to the center of the wafer, the wafer rotation speed is 300-1000rpm, the high-pressure liquid medicine spraying time is 0.1-5s, and the pressure of the high-pressure liquid medicine is 5-15MPa.
[0016] In the above step (1), when a normal pressure nozzle is used to scan behind the high pressure degumming nozzle, the normal pressure nozzle sprays the liquid medicine under normal pressure, and the liquid medicine flow rate is 200-1000ml / min.
[0017] In the above step (2), the wafer rotation speed is 50-300 rpm.
[0018] The cleaning unit comprises a cleaning chamber, in which a rotatable wafer stage and two columnar nozzles respectively mounted on two swing arms are arranged; wherein: one columnar nozzle is used for spraying deionized water, and the other columnar nozzle is used for spraying nitrogen, and the spraying directions of the two columnar nozzles are perpendicular to the wafer surface.
[0019] During the deionized water spraying process in the above step (4), the wafer rotation speed is 300r / min-1000r / min, the spraying time is 10-60s, and the deionized water flow rate is 500-1000ml / min.
[0020] During the wafer drying process in the above step (5), nitrogen is sprayed on the front side of the wafer. The wafer rotation speed is 1000-3000 r / min, the front side nitrogen spraying flow rate is 20-50 L / min, and the time is 20-80 s.
[0021] The advantages and beneficial effects of the present invention are as follows:
[0022] 1. The present invention uses a high-pressure nozzle to spray the degumming liquid, and at the same time, sprays a large flow of normal-pressure degumming liquid behind the high-pressure nozzle to form a protective lubricating liquid film, so that when the peeled metal falls back on the wafer, the friction is reduced, the contact time between the liquid and the photoresist is increased to a greater extent, and a better cleaning effect is achieved per unit time.
[0023] 2. The present invention can prevent the peeled debris from scratching the wafer, thereby avoiding adverse effects on the conductive properties of the product.
[0024] 3. The present invention increases the contact time between the liquid and the wafer per unit time, thereby increasing the cleaning effect and improving the production capacity; BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a schematic diagram of the structure of the degumming chamber of the present invention.
[0026] Figure 2 This is a schematic diagram of the cleaning chamber structure of the present invention.
[0027] Figure 3 Schematic diagram before metal stripping in Example 1. AU-NI, evaporated metal; PR photoresist.
[0028] Figure 4 Schematic diagram of the metal stripping process in Example 1 (the nozzle is tilted at 20°, and the high-pressure jet scans back and forth from E→O, while the normal-pressure jet is turned on to form a thin liquid film protection). DETAILED DESCRIPTION
[0029] 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.
[0030] The present invention provides a liquid film accompanying protection metal stripping process (Liquid Film Accompanying Protection Liftoff-(LFAP)) for reducing wafer crushing and scratching. The process performs metal stripping treatment on a wafer coated with photoresist and exposed, developed and evaporated with a metal film layer. The metal stripping treatment is to first place the wafer in a stripping unit for metal stripping, and then place the wafer in a cleaning unit for cleaning and drying.
[0031] like Figure 1As shown, the stripping unit includes a degumming chamber, in which a rotatable wafer stage and a high-pressure degumming nozzle and a normal-pressure nozzle mounted on the same swing arm are provided; wherein: the spraying direction of the normal-pressure nozzle is perpendicular to the wafer surface, and the angle between the spraying direction of the high-pressure degumming nozzle and the vertical direction of the wafer is 10-30°. The high-pressure degumming nozzle is a needle-shaped nozzle with a nozzle tip diameter of 0.1-0.2 mm; the normal-pressure degumming nozzle is a columnar nozzle.
[0032] like Figure 2 As shown, the cleaning unit includes a cleaning chamber, in which a rotatable wafer stage and two columnar nozzles respectively installed on two swing arms are provided; wherein: the columnar nozzle installed on the DIW cleaning swing arm is used to spray deionized water, and the columnar nozzle installed on the nitrogen drying swing arm is used to spray nitrogen, and the spraying directions of the two columnar nozzles are perpendicular to the wafer surface.
[0033] Embodiment 1:
[0034] Step 1: Place the wafer coated with photoresist, exposed, developed and evaporated with a 2.8μm metal film layer (Au-Ni composite film layer, first Ni and then Au) on the stripping unit wafer stage. Figure 3 The figure is a schematic diagram of the cross section of the wafer to be peeled. A high-pressure degumming nozzle is used to spray high-pressure liquid onto the wafer. The high-pressure degumming nozzle uses a needle nozzle with a tip diameter of 0.1mm. The angle between the high-pressure liquid spray direction and the vertical direction of the wafer is 25°. The wafer rotation speed is 800r / min, the high-pressure liquid pressure is 13MPa, and the high-pressure liquid spraying method is to scan back and forth from the edge of the wafer to the center. At the same time, the normal pressure nozzle is turned on to spray the normal pressure liquid following the high-pressure degumming nozzle. The normal pressure liquid flow rate is 600ml / min, so that a thin liquid film is covered on the wafer. As the high-pressure scanning is completed, the metal peeling ( Figure 4 ).
[0035] Step 2: Use the atmospheric pressure degumming nozzle in the stripping unit to spray atmospheric pressure liquid, keep the wafer rotating at 300r / min, the flow rate of atmospheric pressure liquid is 600mL / min, and spray for 30s to make the residual PR on the wafer more fully dissolved.
[0036] Step 3: Stop spraying the solution, adjust the wafer rotation speed to 1000r / min, and rotate for 18s so that the least amount of solution remains on the surface of the wafer.
[0037] Step 4: Transfer the wafer into the cleaning chamber and spray deionized water at the center point. The wafer speed is 300r / min, the deionized water flow rate is 800mL / min, and the spraying time is 50s.
[0038] Step 5: In the cleaning unit, the wafer is rotated at a high speed for a long time, and nitrogen is sprayed on the front of the wafer to dry it. The wafer rotation speed is 3000r / min, the front nitrogen spray flow rate is 30L / min, and the time is 30s.
[0039] After the above-mentioned stripping process is completed, the AOI microscope is used to observe the size and scratch / pressure damage of the pad, and the undercut angle and the residual metal amount at the edge are determined.
[0040] After stripping, scratch comparison was performed through AOI and OM, and the data showed that there was no loss in stripping yield through the process of the present invention, proving that the process of the present invention effectively avoids scratches / pressure damage / static breakdown caused by metal stripping, thereby avoiding adverse effects on the conductive properties of the product.
Claims
1. A metal stripping process with liquid film protection to reduce wafer crushing and scratching, characterized by: The process performs metal stripping on a wafer coated with photoresist and exposed, developed and evaporated with a metal film layer. The metal stripping process is to first place the wafer in a stripping unit for metal stripping, and then place it in a cleaning unit for cleaning and drying. The process specifically includes the following steps: (1) placing a wafer on a wafer stage of a stripping unit, wherein the stripping unit includes a high-pressure degumming nozzle and a normal-pressure nozzle; using the high-pressure degumming nozzle to spray a high-pressure chemical solution onto the wafer, and the normal-pressure nozzle follows the high-pressure nozzle to scan the edge of the wafer; (2) The wafer keeps rotating and the atmospheric pressure liquid is sprayed using an atmospheric pressure nozzle at a flow rate of 200-1000 mL / min to fully dissolve the residual photoresist on the wafer; (3) Adjust the wafer rotation speed to 1000-2000 r / min and rotate for 5-20 seconds to reduce the residual solution on the wafer surface; (4) Wafer washing: Place the wafer on the wafer stage of the cleaning unit, and use the nozzle to swing from one edge of the wafer to the other edge and spray deionized water to achieve a more complete cleaning effect; (5) Wafer drying: Place the wafer on the wafer stage of the cleaning unit, use a nozzle to swing from one edge of the wafer to the other edge and spray nitrogen, and use high speed and long-term rotation to dry the wafer.
2. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1 is characterized in that: The evaporated metal film layer is one or more of aluminum, gold, nickel, silver and chromium, and has a thickness of 1-8 μm.
3. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1 is characterized in that: The stripping unit includes a debonding chamber, in which a rotatable wafer stage and a high-pressure debonding nozzle and a normal-pressure nozzle installed on the same swing arm are provided; wherein: the spraying direction of the normal-pressure nozzle is perpendicular to the wafer surface, and the spraying direction of the high-pressure debonding nozzle has an angle of 10-30° with the vertical direction of the wafer.
4. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 3 is characterized in that: The high-pressure degumming nozzle is a needle-shaped nozzle, and the diameter of the end of the needle-shaped nozzle is 0.1-0.2 mm; the normal-pressure nozzle is a columnar nozzle.
5. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1 is characterized in that: In step (1), the high-pressure degumming nozzle is used to spray the liquid medicine. The spraying mode of the high-pressure degumming nozzle is to scan back and forth from the edge to the center of the wafer. The wafer rotation speed is 300-1000rpm, the high-pressure liquid medicine spraying time is 0.1-5s, and the pressure of the high-pressure liquid medicine is 5-15MPa.
6. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1 is characterized in that: In step (1), when a normal pressure nozzle is used to scan behind a high pressure degumming nozzle, the normal pressure nozzle sprays liquid medicine at normal pressure, and the liquid medicine flow rate is 200-1000 ml / min.
7. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1 is characterized in that: In step (2), the wafer rotation speed is 50-300 rpm.
8. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1 is characterized in that: The cleaning unit comprises a cleaning chamber, in which a rotatable wafer stage and two columnar nozzles respectively mounted on two swing arms are arranged; wherein: one columnar nozzle is used for spraying deionized water, and the other columnar nozzle is used for spraying nitrogen, and the spraying directions of the two columnar nozzles are perpendicular to the wafer surface.
9. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1, characterized in that: During the deionized water spraying process in step (4), the wafer rotation speed is 300r / min-1000r / min, the spraying time is 10-60s, and the deionized water flow rate is 500-1000ml / min.
10. The metal stripping process with liquid film accompanying protection for reducing wafer crushing and scratching according to claim 1, characterized in that: During the wafer drying process in step (5), nitrogen is sprayed on the front side of the wafer. The wafer rotation speed is 1000-3000 r / min, the front side nitrogen spraying flow rate is 20-50 L / min, and the time is 20-80 s.