Wafer separation processing method
Through the combination of secondary ion etching and diamond-like carbon layer protective film, the wafer edge collapse problem caused by mechanical cutting is solved, the product yield rate is improved and production costs are reduced.
Patent Information
- Application Number
- CN202410099729.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-24
- Publication Date
- 2025-07-25
AI Technical Summary
In the prior art, edge cracking and debris fall off easily when cutting wafers mechanically, resulting in low product yield and high cost.
The etching channel is formed by secondary ion etching method, and a protective film of diamond-like carbon layer is formed on the sides of the etching channel to avoid stress caused by mechanical cutting and prevent side debris from falling off.
It significantly reduces the wafer edge collapse rate, improves product yield, and reduces production costs.
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor manufacturing, and particularly to a method for separating and processing wafers. Background Art
[0002] With the rapid progress of semiconductor technology, the requirements for semiconductor manufacturing and processing are getting higher and higher. Separating wafers into required units is an essential process in wafer processing. A common method for wafer separation is mechanical separation using a rotating tool. However, during mechanical separation, the cutting wheel cuts along the scribe line of the semiconductor, and the area near the scribe line of the semiconductor will bear a large stress, which is likely to cause edge chipping or even wafer breakage.
[0003] Therefore, there is an urgent need to provide an improved method for separating and processing wafers to overcome the above defects. Summary of the Invention
[0004] The object of the present invention is to provide an improved method for separating and processing wafers, which has low cost, simple operation, can avoid excessive stress caused by mechanical cutting, reduce the occurrence of wafer edge chipping, and prevent side debris from falling off, thereby improving the yield rate of products.
[0005] To achieve the above object, the method for separating and processing wafers of the present invention includes the following steps:
[0006] Perform a first ion etching on the separation area of the wafer to form an etching channel;
[0007] Perform a second ion etching on the etching channel to separate the wafer along the etching channel; and
[0008] Perform sputtering on the side of the etching channel to form a diamond-like carbon layer.
[0009] Compared with the prior art, the present invention uses secondary ion etching to separate wafers. First, a first ion etching is performed to form an etching channel, and then a second ion etching is performed on the etching channel to separate the wafer. This separation method can greatly reduce the stress generated by the wafer compared with traditional cutting wheel cutting, thereby greatly reducing the edge chipping rate of the wafer. And, after separation, a protective film layer of diamond-like carbon is formed by sputtering on the side of the etching channel to prevent side debris from falling off, further reducing the edge chipping rate, thereby improving the yield rate of products and reducing production costs.
[0010] Preferably, the step of the first ion etching includes: introducing SF6 and C4F8 into the chamber, controlling the pressure of the chamber to be 50 - 70 mtorr, the source power to be 2200 - 2500 W, and the bias power to be 40 - 45 W.
[0011] Preferably, the gas flow rate of SF6 is 1200 - 1250 sccm, and the gas flow rate of C4F8 is 800 - 900 sccm.
[0012] Preferably, the steps of the second ion etching include: introducing CF4, CHF3, and O2 into the chamber, controlling the pressure of the chamber to be 50 - 70 mtorr, the source power to be 2500 - 2800 W, and the bias power to be 60 - 65 W.
[0013] Preferably, the flow rates of CF4, CHF3, and O2 are 1500 - 1800 sccm.
[0014] Preferably, after the first ion etching, the depth of the etching channel accounts for 1 / 6 to 1 / 3 of the total separation depth.
[0015] Preferably, the sputtering includes: sputtering to form a transition layer on the side surface of the etching channel and sputtering to form the diamond-like carbon layer on the transition layer.
[0016] Preferably, the steps of forming the transition layer include: adjusting the air pressure of the chamber to be 2×10 -4 Pa to 2.2×10 - 4 Pa, introducing argon and nitrogen into the chamber to make the air pressure of the chamber 5×10 -1 Pa to 5.2×10 -1 Pa, using a silicon target, and controlling the power of the magnetron sputtering source to be 1500 - 1800 W.
[0017] Preferably, the steps of forming the diamond-like carbon layer include: adjusting the air pressure of the chamber to be 2×10 -1 Pa to 2.2×10 -1 Pa, using a graphite target, and controlling the power of the magnetron sputtering source to be 800 - 1000 W. Detailed implementation manners
[0018] To make the above objects, features, and advantages of the present application more obvious and understandable, the following describes the detailed implementation manners of the present application in combination with some embodiments. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.
[0019] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.
[0020] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.
[0021] In the present application, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.
[0022] In the present application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.
[0023] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation manners.
[0024] The following further describes the method for separating and processing wafers of the present invention in conjunction with embodiments, but does not limit the present invention thereby. The method of the present invention aims to provide an improved method for separating and processing wafers, which method has low cost, simple operation, and can avoid excessive stress caused by mechanical cutting, reduce the occurrence of wafer chipping, and thus improve the yield rate of products.
[0025] In an embodiment of the method for separating and processing wafers of the present invention, the following steps are included:
[0026] Perform a first ion etching on the separation area of the wafer to form an etching channel;
[0027] Perform a second ion etching on the etching channel to separate the wafer along the etching channel; and
[0028] Perform sputtering on the side surface of the etching channel to form a diamond-like carbon layer.
[0029] The present invention uses secondary ion etching to separate wafers. First, a first ion etching is performed to form an etching channel, and then a second ion etching is performed on the etching channel, so that the wafers are separated. This separation method can greatly reduce the stress generated by the wafers compared with traditional dicing wheel cutting, thereby greatly reducing the chipping rate of the wafers; and, after separation, a protective film layer of a diamond-like carbon layer is formed by sputtering on the side surface of the etching channel to prevent side debris from falling off, further reducing the chipping rate, thereby improving the yield rate of products and reducing production costs.
[0030] As a specific embodiment, first, a mask is made by using photoresist through exposure and development. The mask covers the wafer, leaving a cutting position feed path, that is, the separation area. In the first ion etching, first, SF6 and C4F8 are introduced into the chamber. The two gases can be introduced separately or in the form of a mixed gas. For example, the gas flow rate of SF6 is 1200 - 1250 sccm, and the gas flow rate of C4F8 is 800 - 900 sccm. They are respectively introduced into the chamber, and the pressure of the chamber is adjusted to 75 - 100 mtorr. In order to obtain a better ion etching effect, the temperature of the chamber is controlled at 35 - 50 °C. At this time, the source power is adjusted to 2200 - 2500 W, and the bias power is adjusted to 40 - 45 W. A first ion etching is performed on the separation area of the wafer. The etching time is 10 - 30 minutes. Preferably, after the first ion etching, the depth of the separation channel accounts for 1 / 6 to 1 / 3 of the total separation depth.
[0031] Next, a second ion etching is performed. Specifically, CF4, CHF3, and O2 are introduced into the chamber. These three gases can be introduced separately or in the form of a mixed gas. For example, the total flow rate of the mixed gas of the three is 1500 - 1800 sccm and is introduced into the chamber. At this time, the pressure of the chamber is adjusted to 50 - 70 mtorr. To obtain a better ion etching effect, the temperature of the chamber is controlled at 35 - 50 °C. The source power is adjusted to 2500 - 2800 W, and the bias power is 60 - 65 W. Preferably, the etching time is 30 - 60 minutes. After two ion etchings, the wafer can be separated. Since ion etching is different from mechanical cutting, the chipping situation generated on the edge of the wafer is significantly improved compared to mechanical cutting, and the chipping rate is about 0.05% - 0.1%.
[0032] Subsequently, in order to further improve the chipping rate and repair the etching channel, the present invention also sputter coats the side surface of the etching channel. Specifically, a transition layer is first sputtered on the side surface of the etching channel, and then a diamond-like carbon layer is sputtered on the transition layer. Specifically, the transition layer is a transparent silicon nitride layer. This sputtering step includes: adjusting the pressure of the chamber to 2×10 -4 Pa to 2.2×10 -4 Pa, introducing argon and nitrogen into the chamber to make the pressure of the chamber 5×10 -1 Pa to 5.2×10 -1 Pa, using a silicon target, and controlling the power of the magnetron sputtering source to be 1500 - 1800 W. Preferably, the temperature of the chamber is controlled at 80 - 100 °C to facilitate sputtering. Thus, a transition layer with a thickness of 20 - 50 nanometers is formed. Then, argon is introduced into the chamber, and a diamond-like carbon layer is sputtered on the silicon nitride layer using a pure graphite target. Specifically, the pressure of the chamber is adjusted to 2×10- 1 Pa to 2.2×10- 1 Pa, controlling the power of the magnetron sputtering source to be 800 - 1000 W, and the temperature of the chamber is 80 - 100 °C. Under these conditions, a diamond-like carbon layer with a thickness of 1 - 3 nanometers is formed. By coating and trimming the side surface of the etching channel, the separated edge of the wafer can be repaired, the size of the chipping can be reduced, and thus the chipping rate can be further reduced. After the wafer is processed through this step, the chipping size can be reduced to less than 2 micrometers, and the chipping rate is 0.01 - 0.02%.
[0033] In summary, the present invention uses secondary ion etching to separate wafers. First, the first ion etching is performed to form an etching channel, and then the second ion etching is carried out on the etching channel, so that the wafers are separated. Compared with the traditional dicing wheel cutting, this separation method can greatly reduce the stress generated by the wafers, thus greatly reducing the chipping rate of the wafers. Moreover, after separation, a protective film layer of diamond-like carbon is formed by sputtering on the side surface of the etching channel to prevent the side debris from falling off, further reducing the chipping rate, thereby improving the yield of the product, reducing the production cost, and being suitable for industrial promotion and use.
[0034] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.
Claims
1. A method for separating and processing a wafer, characterized in that, The steps include: Performing a first ion etching on the separation area of the wafer to form an etching channel; Performing a second ion etching on the etching channel to separate the wafer along the etching channel; and Sputtering the side surface of the etching channel to form a diamond-like carbon layer.
2. The method for separating and processing a wafer according to claim 1, characterized in that, The step of the first ion etching includes: introducing SF6 and C4F8 into the chamber, controlling the pressure of the chamber to be 50 - 70 mtorr, the source power to be 2200 - 2500 W, and the bias power to be 40 - 45 W.
3. The method for separating and processing a wafer according to claim 2, wherein, The gas flow rate of the SF6 is 1200 - 1250 sccm, and the gas flow rate of the C4F8 is 800 - 900 sccm.
4. The method for separating and processing a wafer according to claim 1, characterized in that: The step of the second ion etching includes: introducing CF4, CHF3 and O2 into the chamber, controlling the pressure of the chamber to be 50 - 70 mtorr, the source power to be 2500 - 2800 W, and the bias power to be 60 - 65 W.
5. The method for separating and processing a wafer according to claim 1, wherein The flow rates of the CF4, CHF3 and O2 are 1500 - 1800 sccm.
6. The method for separating and processing a wafer according to claim 1, wherein, After the first ion etching, the depth of the etching channel accounts for 1 / 6 to 1 / 3 of the total separation depth.
7. The method for separating and processing a wafer according to claim 1, characterized in that, The sputtering includes: sputtering to form a transition layer on the side surface of the etching channel and sputtering to form the diamond-like carbon layer on the transition layer.
8. The separation processing method of the wafer according to claim 7, wherein, The steps of forming the transition layer include: adjusting the air pressure in the chamber to 2×10 -4 Pa to 2.2×10 -4 Pa, introducing argon and nitrogen into the chamber to make the air pressure in the chamber 5×10 -1 Pa to 5.2×10 -1 Pa, using a silicon target, and controlling the power of the magnetron sputtering source to be 1500 - 1800 W.
9. The method for separating and processing a wafer according to claim 7, wherein, The steps of forming the diamond-like carbon layer include: adjusting the air pressure in the chamber to 2×10 -1 Pa to 2.2×10 -1 Pa, using a graphite target, and controlling the power of the magnetron sputtering source to be 800 - 1000W.
10. The method for separating and processing a wafer according to claim 7, characterized in that, The temperature of the sputtering is 80 - 100 °C.