Method for separating semiconductor wafers
By scribing lines on the surface of semiconductor wafers to form separation channels and then using laser ablation, the problems of edge chipping and cracking caused by mechanical cutting have been solved, resulting in higher product yield and smaller edge chipping size.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SAE TECH DELEVOPMENT DONGGUAN
- Filing Date
- 2024-12-26
- Publication Date
- 2026-06-30
AI Technical Summary
In existing technologies, mechanical cutting methods for semiconductor wafers are prone to edge chipping and cracking, and traditional methods are difficult to effectively solve this problem, affecting product yield.
A scribing tool is used to form separation channels on the wafer surface, and separation is carried out along the separation channels through a laser ablation step. By combining a diamond scribing wheel and controlling laser parameters such as pneumatic pressure, tilt angle, laser power and spot diameter, stress and deformation are reduced.
It reduces the risk of deformation, chipping, and cracking during semiconductor wafer separation, and improves product yield, especially by reducing chipping size to below 2-5 micrometers and reducing the chipping rate to 0.001-0.002%.
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a method for separating semiconductor wafers. Background Technology
[0002] Currently, the requirements for semiconductor manufacturing and processing are becoming increasingly stringent. Separating semiconductor wafers into the required units is an essential step, and the traditional method for separating semiconductor wafers is generally through mechanical cutting. However, during the cutting process, the cutting blade can easily cause chipping on the semiconductor surface. The usual solution is to adjust the blade amplitude and optimize the blade speed, but the results are not ideal.
[0003] Therefore, there is an urgent need to provide an improved method for separating semiconductor wafers to overcome the above-mentioned defects. Summary of the Invention
[0004] The purpose of this invention is to provide an improved method for separating semiconductor wafers, reducing deformation during semiconductor separation, lowering the risk of edge chipping and cracking in semiconductors, and improving product yield.
[0005] To achieve the above objectives, the present invention provides a method for separating semiconductor wafers, comprising the following steps:
[0006] The scribing process involves using a scribing tool to scribble lines on the surface of a semiconductor wafer to form separation channels; and
[0007] Laser ablation step: Control the laser beam to irradiate the separation channel and move along the separation channel until the semiconductor wafer is separated along the separation channel.
[0008] Compared to existing technologies, this invention first uses a scribing tool to create separation channels, rather than directly cutting and separating the semiconductor wafer. This mechanical scribing method reduces stress and prevents excessive deformation of the semiconductor wafer. Then, a laser ablation step is performed, using a laser beam to irradiate the separation channels, thereby separating the semiconductor wafer. This process further reduces stress in the separation channels, minimizing wafer chipping and cracking. The sidewalls of the separation channels are also smoothed to some extent, thus smoothing or eliminating cracks. Therefore, this invention, through its separation method, reduces deformation during semiconductor separation, lowers the risk of chipping and cracking, and improves product yield.
[0009] Preferably, in the scribing step, the separation path is controlled to be a non-crack propagation type crack line.
[0010] Preferably, in the scribing step, the pneumatic pressure of the scribing tool is controlled to be 900-1000 MPa.
[0011] Preferably, the scribing tool is inclined at a 40-55° angle to the surface of the semiconductor wafer when scribing.
[0012] Preferably, the scribing tool is a diamond scribing wheel.
[0013] Preferably, in the laser ablation step, the laser beam has a power of 6-9 kW, a spot diameter of 0.01-0.05 mm, and a defocusing amount of 5-8 mm.
[0014] Preferably, in the laser ablation step, the moving speed of the laser beam is 10-12 mm / s.
[0015] Preferably, in the laser ablation step, helium is used as the protective gas, and the flow rate of helium is 40-45 L / min. Detailed Implementation
[0016] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific implementation methods of this application are described in detail below with reference to some embodiments. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0017] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0018] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0019] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0020] The semiconductor wafer separation method of the present invention will be further described below with reference to embodiments, but this does not limit the present invention. The method of the present invention aims to provide an improved semiconductor wafer separation method, reducing deformation during semiconductor separation, lowering the risk of semiconductor chipping and cracking, and improving product yield.
[0021] In one embodiment of the semiconductor wafer separation method of the present invention, the following steps are included:
[0022] The scribing process involves using a scribing tool to scribble lines on the surface of a semiconductor wafer to form separation channels; and
[0023] Laser ablation step: Control the laser beam to irradiate the separation channel and move along the separation channel until the semiconductor wafer is separated along the separation channel.
[0024] This invention first uses a scribing tool to create separation channels, rather than directly cutting and separating the semiconductor wafer. This mechanical scribing method reduces stress and prevents excessive deformation of the semiconductor wafer. Then, a laser ablation step is performed, using a laser beam to irradiate the separation channels, thereby separating the semiconductor wafer. This process further reduces stress in the separation channels, minimizing wafer chipping and cracking. The sidewalls of the separation channels are also smoothed to some extent, thus smoothing or eliminating cracks. Therefore, this invention, through its separation method, reduces deformation during semiconductor separation, lowers the risk of chipping and cracking, and improves product yield.
[0025] Specifically, this invention employs a diamond scribing wheel for the scribing process, for example, a diamond scribing wheel with a diameter of 2 mm. Preferably, the scribing tool is tilted at a 40-55° angle to the surface of the semiconductor wafer during scribing to achieve better scribing results. Simultaneously, to prevent wafer breakage, the pneumatic pressure of the scribing tool is preferably controlled at 900-1000 MPa. To reduce wafer edge chipping, the depth of the separation channel is preferably controlled to be 1 / 5 to 1 / 3 of the wafer thickness.
[0026] Specifically, in the laser ablation step, the laser power of the laser beam is controlled at 6-9 kW, the spot diameter at 0.01-0.05 mm, and the defocusing distance at 5-8 mm. The laser beam irradiates the separation channel at a specific distance, thereby deepening the separation channel until the wafer is separated. As a preferred embodiment, the laser beam moves along the separation channel at a uniform speed, for example, a laser beam movement speed of 10-12 mm / s. More preferably, helium is used as the protective gas during the laser ablation process, with a helium flow rate of 40-45 L / min. Through the laser ablation step, the depth of the separation channel can be increased, thereby separating the wafer. Moreover, compared with mechanical cutting, laser cutting can significantly reduce the number and size of wafer chipping, thus achieving higher processing quality. Wafers separated using this method can have chipped edges reduced to below 2-5 micrometers, with a chipping rate of 0.001-0.002%.
[0027] In summary, this invention uses a scribing tool to create separation channels, rather than directly cutting and separating the semiconductor wafer. This mechanical scribing method reduces stress and prevents excessive deformation of the semiconductor wafer. Subsequently, a laser ablation step uses a laser beam to irradiate the separation channels, thereby separating the semiconductor wafer. This process further reduces stress in the separation channels, minimizing wafer chipping and cracking. The sidewalls of the separation channels are also smoothed to some extent, thus smoothing or eliminating cracks. Therefore, this invention, through its separation method, reduces deformation during semiconductor separation, lowers the risk of chipping and cracking, and improves product yield.
[0028] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.
Claims
1. A method for separating semiconductor wafers, characterized in that, Includes the following steps: Scribing step: Using a scribing tool, scribing lines are made on the surface of the semiconductor wafer to form separation channels; as well as Laser ablation step: Control the laser beam to irradiate the separation channel and move along the separation channel until the semiconductor wafer is separated along the separation channel.
2. The semiconductor wafer separation method as described in claim 1, characterized in that, In the scribing step, the separation channel is controlled to be a non-crack propagation type crack line.
3. The semiconductor wafer separation method as described in claim 1, characterized in that, In the scribing step, the pneumatic pressure of the scribing tool is controlled to be 900-1000 MPa.
4. The semiconductor wafer separation method as described in claim 1, characterized in that, The scribing tool is inclined at a 40-55° angle to the surface of the semiconductor wafer when scribing.
5. The semiconductor wafer separation method as described in claim 1, characterized in that, The scribing tool is a diamond scribing wheel.
6. The semiconductor wafer separation method as described in claim 1, characterized in that, In the laser ablation step, the laser beam has a power of 6-9kW, a spot diameter of 0.01-0.05mm, and a defocusing amount of 5-8mm.
7. The semiconductor wafer separation method as described in claim 1, characterized in that, In the laser ablation step, the moving speed of the laser beam is 10-12 mm / s.
8. The semiconductor wafer separation method as described in claim 1, characterized in that, In the laser ablation step, helium is used as the protective gas, and the flow rate of helium is 40-45 L / min.