Wafer laser processing system

Abstract

The utility model discloses a wafer laser processing system. In the grooving equipment, after a wafer is coated with laser cutting protection glue, an ultraviolet laser is matched with a machining platform, a metal layer on the front face of the wafer is cut and grooved, and the grooved wafer is cleaned and put back to be clamped; in the hidden cutting equipment, a wafer is inversely buckled on a working platform deck, an infrared laser is matched with the working platform deck, infrared light penetrates through a through cutting film to carry out hidden cutting on the wafer, and cracks are formed in the wafer on the path through which laser passes; in the film expanding machine, the through cutting film expands to decompose the wafer into crystal grains along cracks in the wafer. According to the utility model, the front slotting, the back hidden cutting and the film expanding technology are matched to complete the cutting and separation of the wafer at one time, so that the production efficiency and the cutting quality are greatly improved. Through cooperation of the working platform deck and the ultrasonic cleaning device, the front face of the wafer is protected, and the front face of the wafer is prevented from being damaged during implicit cutting.

Description

Technical Field:

[0001] The utility model belongs to the technical field of semiconductor wafer production, and particularly relates to a wafer laser processing system. Background Art:

[0002] In the semiconductor chip manufacturing process, wafer cutting is one of the important processes in the packaging and testing section. In a common chip structure, there is usually a metal layer on the chip surface of a silicon-based substrate. To facilitate cutting, the metal layer is usually removed before cutting. When using traditional cutting methods (such as dicing with a dicing wheel) to remove the metal layer, the dicing wheel cutting speed is slow, and at the same time, phenomena such as film detachment, breakage, and chipping are likely to occur. The metal layer causes great damage to the dicing wheel, increasing the consumption of the dicing wheel. Laser has the characteristics of good consistency, concentrated energy, high automation, and convenience for large-scale production. In the field of wafer cutting, the laser cutting method has a trend of gradually replacing the traditional cutting method.

[0003] The laser cutting method is mainly divided into two types: surface ablation cutting and stealth cutting. The laser for surface ablation cutting generally uses ultraviolet light, with less penetrability. The depth that can be processed by surface ablation cutting at one time is relatively small, only about 10 μm at a time. Due to the certain thickness of the wafer, the processing time of surface ablation cutting is relatively long, and the processing efficiency is low. The laser for stealth cutting generally uses infrared light. Although the penetrability is good, it requires a flat processing surface. After the metal layer is removed from the wafer surface, the surface is rough, and stealth cutting cannot be processed.

[0004] The information disclosed in this background art section is only intended to enhance the overall understanding of the present utility model and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Utility Model:

[0005] The purpose of the present utility model is to provide a wafer laser processing system, which organically combines front-side grooving, back-side membrane-penetrating stealth cutting, and membrane expansion, thereby overcoming the defects in the above-mentioned prior art.

[0006] To achieve the above object, the utility model provides a wafer laser processing system, which includes a grooving device, a scribing device, and a film expanding machine; the grooving device includes a loading station, a coating station, a cleaning station, a handling robot, an ultraviolet laser, and a processing platform. The coating station and the cleaning station are sequentially arranged on one side of the loading station. The handling robot and the processing platform are both provided with power mechanisms. Through the corresponding power mechanisms, the handling robot and the processing platform move in the X-axis direction and the Y-axis direction. The movement trajectory of the handling robot in the X-axis direction passes through the loading station, the cleaning station, and the coating station, and the movement trajectory of the handling robot in the Y-axis direction passes through the cleaning station, the coating station, and the processing platform; the ultraviolet laser is located above the processing platform, and the processing platform cooperates with the ultraviolet laser; the scribing device includes a loading workbench, a loading and unloading robot, an infrared laser, a working stage, an ultrasonic cleaning device, and a linear motion mechanism. An loading and unloading robot is arranged between the loading workbench and the working stage. The infrared laser and the ultrasonic cleaning device are located above the working stage. The working stage is arranged on the linear motion mechanism, and the linear motion mechanism drives the working stage to move in the X-axis direction and the Y-axis direction. The working stage cooperates with the infrared laser; the film expanding machine includes a lifting plate, an upper pressing plate, a lifting mechanism, and a tabletop. The lifting plate is arranged on the tabletop, the upper pressing plate is openably arranged on the tabletop, the upper pressing plate is located above the lifting plate, and the lifting mechanism is arranged below the tabletop. The lifting mechanism is connected to the lifting plate. The size of the lifting plate matches the size of the wafer, and the size of the upper pressing plate matches the size of the steel ring of the wafer.

[0007] Preferably, in the technical solution, the ultraviolet laser includes a limiting laser and a grooving laser. The limiting laser cooperates with the processing platform to form limiting grooves on both sides of the edge of the metal layer on the front side of the wafer, and the grooving laser cooperates with the processing platform to form a cutting groove on the metal layer on the front side of the wafer. The cutting groove is located between the two limiting grooves.

[0008] Preferably, in the technical solution, the wavelength of the ultraviolet light emitted by the ultraviolet laser is 355 nm.

[0009] Preferably, in the technical solution, the wavelength of the infrared light emitted by the infrared laser is 900 - 1100 nm.

[0010] Preferably, in the technical solution, an antireflection film is attached to the surface of the scribing film. The scribing film is made of a composite material of PVC and PO, and the antireflection film is made of PO material.

[0011] Preferably, in the technical solution, the working stage includes a metal base, an anti-adhesion coating, a ceramic suction cup, and a porous adsorption film. The anti-adhesion coating is arranged on the surface of the metal base. The ceramic suction cup is arranged on the metal base to form an adsorption area, and the porous adsorption film covers the surface of the adsorption area. The porous adsorption film is made of a polyethylene polymer porous film; the front side of the wafer is protected from damage through the porous adsorption film.

[0012] Preferably, in the technical solution, the ultrasonic cleaning device includes a positive pressure chamber, an ultrasonic nozzle, and a negative pressure chamber. The positive pressure chamber is connected to a positive pressure interface, and the positive pressure interface is connected to an external positive pressure air duct. An ultrasonic nozzle is provided at the outlet of the positive pressure chamber. The negative pressure chamber is connected to a negative pressure interface, and the negative pressure interface is connected to a negative pressure generator. The negative pressure chamber is located on both sides of the ultrasonic nozzle, and the ultrasonic nozzle and the inlet of the negative pressure chamber are arranged facing the surface of the working stage. By blowing positive pressure gas through the positive pressure chamber, ultrasonic waves are formed, and the ultrasonic waves are transmitted to the surface of the working stage by the ultrasonic nozzle.

[0013] Preferably, in the technical solution, the positive pressure chamber includes a chamber and a cavity. The chambers are connected by cavities to form a continuous air flow channel. The volume of the chamber is larger than the volume of the cavity. The previous chamber and the next cavity form an amplification excitation unit. Multiple continuous amplification excitation units are formed in the air flow channel. An ultrasonic nozzle is provided at the outlet of the air flow channel. When the positive pressure gas passes through the amplification excitation unit, due to the sharp change in volume, the flow rate increases sharply, and ultrasonic waves are generated by excitation of the positive pressure gas. The ultrasonic waves are amplified by one level every time they pass through an amplification excitation unit. After being amplified by multiple levels, the ultrasonic waves are ejected from the ultrasonic nozzle.

[0014] Preferably, in the technical solution, the frequency of the ultrasonic wave is 20 kHz - 80 kHz.

[0015] Compared with the prior art, the present utility model has the following beneficial effects:

[0016] The front-side grooving process is used to remove the metal layer on the surface of the wafer, the back-side scribing process is used to scribe the back side of the wafer, cracks are formed inside the wafer, and the expansion film process is used to separate the wafer to form chips. The front-side grooving, back-side scribing, and expansion film are coordinated to complete the cutting and separation of the wafer in one processing, greatly improving the production efficiency and cutting quality. By cooperating the working stage and the ultrasonic cleaning device, the front side of the wafer is protected to prevent damage to the front side of the wafer during scribing. Description of the drawings:

[0017] Figure 1 It is a flowchart of the wafer laser processing method of the present utility model; 1a is a diagram of the initial state of the wafer, 1b is a diagram of the front-side grooving state of the wafer, 1c is a diagram of the back-side scribing state of the wafer, 1d is a diagram of the state before the wafer expansion film, and 1e is a diagram of the state after the wafer expansion film;

[0018] Figure 2 It is a schematic structural diagram of the grooving device of the present utility model;

[0019] Figure 3 It is a schematic structural diagram of the scribing device of the present utility model;

[0020] Figure 4 It is a schematic structural diagram of the working stage of the present utility model;

[0021] Figure 5Cross-sectional view of the ultrasonic cleaning device of the present utility model in the horizontal direction;

[0022] Figure 6 Longitudinal sectional view of the ultrasonic cleaning device of the present utility model;

[0023] Figure 7 Schematic structural diagram of the film expanding machine of the present utility model;

[0024] Figure 8 Schematic diagram of the opened state of the film expanding machine of the present utility model;

[0025] Figure 9 Diagram showing the change of the wafer film expanding state of the present utility model. Specific implementation manner:

[0026] The following will describe in detail the specific implementation manner of the present utility model, but it should be understood that the protection scope of the present utility model is not limited by the specific implementation manner.

[0027] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0028] As Figure 1 shown, a wafer laser processing method includes the following steps: (1) In a grooving device, a manipulator takes out a wafer from a clamp at a loading station. As Figure 1 shown in a, the manipulator moves along the X-axis direction to send the wafer to a coating station, where the wafer is coated with a laser cutting protective glue at the coating station to form a protective film on the wafer surface;

[0029] (2) The manipulator moves along the Y-axis direction to send the wafer to a processing platform. The processing platform moves in the X-axis direction and the Y-axis direction to align the edge of the metal layer in the wafer circuit layer on the front side of the wafer with a quasi-limiting laser. The quasi-limiting laser is started to emit ultraviolet light with a wavelength of 355 nm. With the coordinated movement of the processing platform, the quasi-limiting laser cuts to form a limiting groove at one edge of the metal layer, and then cuts to form a second limiting groove at the other edge of the metal layer. With the coordinated movement of the processing platform, the grooving laser is aligned with the metal layer. The grooving laser is started to emit ultraviolet light with a wavelength of 355 nm to cut the metal layer on the front side of the wafer to remove the metal layer and form a cutting groove at the metal layer part. The depth of the cutting groove reaches the silicon substrate below the wafer circuit layer. As Figure 1 shown in b; after grooving, the manipulator takes the wafer off the processing platform and transports it to a cleaning station to clean the laser cutting protective glue and the dust remaining from grooving on the wafer surface, and then puts the wafer back into the clamp;

[0030] (3) In the dicing equipment, the manipulator places the wafer with a front-side groove upside down on the working stage. The front side of the wafer is adsorbed on the porous adsorption film. The wafer film connecting the wafer and the steel ring is a transmissive cutting film that can transmit infrared rays. The working stage moves in the X-axis direction and the Y-axis direction to align the infrared laser with the back side of the wafer. The infrared laser is activated to output infrared light with a wavelength of 1064 nm. With the cooperation of the working stage, the infrared light cuts the back side of the wafer in the X-axis direction and the Y-axis direction. The infrared light sequentially penetrates the antireflection film and the transmissive cutting film and enters the wafer silicon substrate. Under the action of the infrared light, cracks are formed in the path where the infrared light passes inside the silicon substrate, as Figure 1 shown in Fig. c;

[0031] (4) After the laser dicing is completed, the manipulator places the wafer back into the chuck, and the ultrasonic cleaning device on the dicing equipment is activated to clean the working stage. The positive-pressure gas passes through multiple consecutive amplification and vibration units in the positive-pressure cavity. The positive-pressure gas generates ultrasonic waves due to vibration. After being amplified in multiple stages, the ultrasonic waves are sprayed onto the working stage by the ultrasonic nozzle. The ultrasonic waves clean the residual micron-sized particulate dust on the working stage. The ultrasonic waves separate these dusts from the surface of the working stage. At the same time, the negative-pressure cavity of the ultrasonic cleaning device generates negative pressure to suck the dust into the negative-pressure cavity and discharge it. After the working stage is cleaned, the dicing of the next wafer is carried out;

[0032] (5) In the film expanding machine, the wafer that has been grooved on the front side and diced on the back side is placed on the lifting plate, as Figure 1 shown in Fig. d. The upper pressing plate covers the wafer and presses the steel ring. The lifting plate rises to lift the wafer upward. The outer edge of the transmissive cutting film is pressed by the steel ring. During the process of the whole transmissive cutting film being lifted upward by the lifting plate along with the wafer, the whole transmissive cutting film begins to expand outward from the center. During the outward expansion of the transmissive cutting film, the tension generated by the transmissive cutting film drives the wafer to expand. When the wafer expands from the original boundary 46 to the new boundary 47, the wafer circuit layer and the silicon substrate in the wafer decompose along the cracks inside the wafer to form individual grains 48, as Figure 1 shown in Fig. e. The lifting plate resets, the upper pressing plate is opened, and the expanded wafer is taken out to complete the cutting of the wafer.

[0033] A wafer laser processing system includes a grooving device 1, a dicing device 2, and a film expanding machine 3; as Figure 2As shown in the figure, the grooving device 1 includes a loading station 10, a coating station 11, a cleaning station 12, a handling robot 13, a limit laser 14, a grooving laser 15, and a processing platform 16. The coating station 11 and the cleaning station 12 are sequentially arranged on one side of the loading station 10. The handling robot 13 and the processing platform 16 are both provided with power mechanisms. Through the corresponding power mechanisms, the handling robot 13 and the processing platform 16 move in the X-axis direction and the Y-axis direction. The movement trajectory of the handling robot 13 in the X-axis direction passes through the loading station 10, the cleaning station 12, and the coating station 11. The movement trajectory of the handling robot 13 in the Y-axis direction is located between the cleaning station 12 or the coating station 11 and the processing platform 16. The limit laser 14 and the grooving laser 15 are located above the processing platform 16, and the processing platform 16 cooperates with the limit laser 14 and the grooving laser 15. The ultraviolet light emitted by the limit laser 14 and the grooving laser 15 has a wavelength of 355 nm. The limit laser 14 cooperates with the processing platform 16 to form limit grooves on both side edges of the metal layer 41 in the front wafer circuit layer 40 of the wafer 4. The grooving laser 15 cooperates with the processing platform 16 to form a cutting groove 42 at the metal layer 41. The cutting groove 42 is located between the two limit grooves.

[0034] As Figure 3 shown in the figure, the hidden cutting device 2 includes a loading workbench 20, a loading and unloading robot 21, an infrared laser 22, a working stage 23, an ultrasonic cleaning device 24, and a linear motion mechanism 25. A loading and unloading robot 21 is arranged between the loading workbench 20 and the working stage 23. The infrared laser 22 and the ultrasonic cleaning device 24 are located above the working stage 23. The working stage 23 is arranged on the linear motion mechanism 25. The linear motion mechanism 25 drives the working stage 23 to move in the X-axis direction and the Y-axis direction. The working stage 23 cooperates with the infrared laser 22. The infrared light emitted by the infrared laser 22 has a wavelength of 900 - 1100 nm. As Figure 1 shown in c, an antireflection film is attached to the surface of the through-cut film 44. The through-cut film 44 is made of a composite material of PVC and PO, and the antireflection film is made of PO material. As Figure 4 shown in the figure, the working stage 23 includes a metal base 230, an anti-adhesion coating 231, a ceramic suction cup 232, and a porous adsorption film 233. The anti-adhesion coating 231 is provided on the surface of the metal base 230. The ceramic suction cup 232 is arranged on the metal base 230 to form an adsorption area. The surface of the adsorption area is covered with the porous adsorption film 233. The porous adsorption film 233 is made of a polyethylene polymer porous film. The front side of the wafer 4 is protected from damage through the porous adsorption film 233.

[0035] As Figures 5 - 6As shown, the ultrasonic cleaning device 24 includes a positive pressure chamber 240, an ultrasonic nozzle 241, and a negative pressure chamber 242. The positive pressure chamber 240 is connected to a positive pressure interface 243, and the positive pressure interface 243 is connected to an external positive pressure air duct. An ultrasonic nozzle 241 is provided at the outlet of the positive pressure chamber 240. The negative pressure chamber 242 is connected to a negative pressure interface 244, and the negative pressure interface 244 is connected to a negative pressure generator. The negative pressure chamber 242 is located on both sides of the ultrasonic nozzle 241, and the ultrasonic nozzle 241 and the inlet of the negative pressure chamber 242 are arranged facing the surface of the work stage 23. The positive pressure chamber 240 includes a chamber 245 and a chamber passage 246. The chambers 245 are connected through the chamber passage 246 to form a continuous air flow passage. The volume of the chamber 245 is larger than that of the chamber passage 246. The previous chamber 245 and the subsequent chamber passage 246 form an amplification excitation unit. Multiple continuous amplification excitation units are formed in the air flow passage. An ultrasonic nozzle 241 is provided at the outlet of the air flow passage. The positive pressure gas passes through the amplification excitation unit. Due to the sharp change in volume, the flow rate increases sharply. The positive pressure gas generates ultrasonic waves due to excitation. The ultrasonic waves are amplified by one level every time they pass through an amplification excitation unit. After being amplified by multiple levels, the ultrasonic waves are ejected from the ultrasonic nozzle 241. The ultrasonic frequency is 20 kHz - 80 kHz. Through the cooperation of the work stage 23 and the ultrasonic cleaning device 24, the front surface of the wafer 4 is protected to prevent damage to the front surface of the wafer 4 during dicing.

[0036] As Figures 7 - 8 shown, the film expanding machine 3 includes a lifting plate 30, an upper pressing plate 31, a lifting mechanism 32, and a table 33. The lifting plate 30 is arranged on the table 33. The upper pressing plate 31 is movably arranged on the table 33 through a cylinder 34 arranged on the table 33. The upper pressing plate 31 is located above the lifting plate 30. A lifting mechanism 32 is arranged below the table 33. The lifting mechanism 32 is connected to the lifting plate 30. The size of the lifting plate 30 is matched with the size of the wafer 4, and the size of the upper pressing plate 31 is matched with the size of the steel ring 45 of the wafer 4. As Figure 9 shown, when the lifting mechanism 32 is activated to drive the lifting plate 30 to rise, the outer edge of the dicing film 44 is pressed by the steel ring 45. During the process of the dicing film 44 being lifted upward by the lifting plate 30 together with the wafer 4 as a whole, the dicing film 44 begins to expand as a whole. The tension generated by the dicing film 44 drives the wafer 4 to expand. During the expansion process of the wafer 4, the wafer 4 is decomposed along the cracks inside the wafer to form individual grains 48.

[0037] The front grooving, back dicing, and film expanding are coordinated to complete the cutting and separation of the wafer in one processing, greatly improving the production efficiency and cutting quality.

[0038] The foregoing description of the specific exemplary embodiments of the present utility model is for purposes of illustration and exemplification. These descriptions are not intended to limit the present utility model to the precise forms disclosed, and it is apparent that many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present utility model and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the present utility model, as well as various different selections and changes. The scope of the present utility model is intended to be defined by the claims and their equivalents.

Claims

1. A wafer laser processing system, characterized in that: It includes a grooving device, a hidden cutting device, and a film expanding machine; the grooving device includes a loading station, a coating station, a cleaning station, a handling robot, an ultraviolet laser, and a processing platform. The coating station and the cleaning station are sequentially arranged on one side of the loading station. The handling robot and the processing platform are both provided with power mechanisms. Through the corresponding power mechanisms, the handling robot and the processing platform move in the X-axis direction and the Y-axis direction. The movement trajectory of the handling robot in the X-axis direction passes through the loading station, the cleaning station, and the coating station. The movement trajectory of the handling robot in the Y-axis direction passes through the cleaning station, the coating station, and the processing platform; the ultraviolet laser is located above the processing platform, and the processing platform cooperates with the ultraviolet laser; the hidden cutting device includes a loading workbench, a loading and unloading robot, an infrared laser, a working stage, an ultrasonic cleaning device, and a linear motion mechanism. A loading and unloading robot is arranged between the loading workbench and the working stage. The infrared laser and the ultrasonic cleaning device are located above the working stage. The working stage is arranged on the linear motion mechanism, and the linear motion mechanism drives the working stage to move in the X-axis direction and the Y-axis direction. The working stage cooperates with the infrared laser; the film expanding machine includes a lifting disk, an upper pressing plate, a lifting mechanism, and a tabletop. The lifting disk is arranged on the tabletop, the upper pressing plate is openably arranged on the tabletop, the upper pressing plate is located above the lifting disk, and the lifting mechanism is arranged below the tabletop. The lifting mechanism is connected to the lifting disk. The size of the lifting disk matches the size of the wafer, and the size of the upper pressing plate matches the size of the steel ring of the wafer.

2. The wafer laser processing system according to claim 1, wherein: The ultraviolet laser includes a limiting laser and a grooving laser. The limiting laser cooperates with the processing platform to form limiting grooves on both sides of the edge of the metal layer on the front side of the wafer. The grooving laser cooperates with the processing platform to form cutting grooves in the metal layer on the front side of the wafer. The cutting grooves are located between the two limiting grooves.

3. The wafer laser processing system according to claim 1, wherein: The wavelength of the ultraviolet light emitted by the ultraviolet laser is 355 nm.

4. The wafer laser processing system according to claim 1, wherein: The wavelength of the infrared light emitted by the infrared laser is 900 - 1100 nm.

5. The wafer laser processing system according to claim 1, wherein: The working stage includes a metal base, an anti-sticking coating, a ceramic suction cup, and a porous adsorption film. The anti-sticking coating is arranged on the surface of the metal base. The ceramic suction cup is arranged on the metal base to form an adsorption area. The surface of the adsorption area is covered with a porous adsorption film, and the porous adsorption film is made of a polyethylene polymer porous film.

6. The wafer laser processing system according to claim 1, wherein: The ultrasonic cleaning device includes a positive pressure chamber, an ultrasonic nozzle, and a negative pressure chamber. The positive pressure chamber is connected to a positive pressure interface, and the positive pressure interface is connected to an external positive pressure air duct. The ultrasonic nozzle is arranged at the outlet of the positive pressure chamber. The negative pressure chamber is connected to a negative pressure interface, and the negative pressure interface is connected to a negative pressure generator. The negative pressure chamber is located on both sides of the ultrasonic nozzle. The ultrasonic nozzle and the inlet of the negative pressure chamber are arranged facing the surface of the working stage.

7. The wafer laser processing system according to claim 6, wherein: The positive pressure chamber includes chambers and channels. The chambers are connected through the channels to form a continuous air flow channel. The volume of the chambers is larger than the volume of the channels. The previous chamber and the next channel form an amplification excitation unit. Multiple continuous amplification excitation units are formed in the air flow channel. The ultrasonic nozzle is arranged at the outlet of the air flow channel; the positive pressure gas passes through the amplification excitation unit. Due to the sharp change in volume, the flow rate increases sharply. The positive pressure gas generates ultrasonic waves due to excitation. The ultrasonic waves are amplified by one level every time they pass through an amplification excitation unit. After being amplified by multiple levels, the ultrasonic waves are ejected from the ultrasonic nozzle.

8. The wafer laser processing system according to claim 7, wherein: The ultrasonic frequency is 20 kHz - 80 kHz.

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