Thickness measuring pad and wafer cutting channel
By designing a thickness measurement pad and laser cutting line at a 45-degree angle, the problems of edge collapse, debris and low cutting efficiency during wafer cutting are solved, achieving a more efficient cutting process and higher yield.
Patent Information
- Application Number
- CN202421272816.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-05
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-06-05
AI Technical Summary
During the manufacturing process of semiconductor devices, edge collapse, debris splash and low cutting efficiency are prone to problems during wafer cutting.
A thickness measurement pad is designed, with a rectangular edge forming a 45-degree angle with the edge of the cutting path, located in the cutting path of the wafer to shorten the length of the laser cutting line, and a laser cutting line is provided in the cutting path to match the wheel knife cutting.
It improves the cutting efficiency and yield rate during wafer scribing, and increases the process window for laser cutting and wheel cutting, avoiding edge collapse and debris contamination.
Smart Images
Figure CN222600916U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor processing, in particular to a thickness measuring pad and a wafer cutting path. Background Art
[0002] In the semiconductor device manufacturing process, a wafer is provided with many chips arranged in an array, and each chip is separated by a dicing path, on which a number of thickness measurement pads are provided for monitoring the film thickness.
[0003] In the wafer cutting process, since wafers use more Low-k materials in advanced processes, this material is very brittle due to its structural characteristics. If a wheel cutter is used directly for cutting, it is easy to cause edge collapse and damage the chip, and the debris generated by the wheel cutter will splash onto the chip, causing pollution or defects to the chip; while laser cutting first vaporizes the Low-k material on the surface of the cutting path at high temperature for a short time, which will not cause abnormal defects such as edge collapse. Therefore, the cutting path is usually cut in the form of a combination of laser cutting and wheel cutter: first, the surface low-k material of the cutting path and the thickness measurement pad is cut by laser cutting, and then the wheel cutter is used to cut the substrate part, and finally the chip and the wafer are separated. In this way, the chip can be protected from edge collapse and costs can be saved.
[0004] Since the wafers used to make chips usually include layers of different materials such as metal and brittle materials, during laser cutting, on the one hand, metal conducts heat faster, so the laser needs more energy or longer focusing time; on the other hand, brittle materials such as low-k need laser cutting to avoid edge collapse. At present, in order to save costs, a combination of laser pre-cutting and wheel cutting is usually used for wafer dicing.
[0005] When dicing such a wafer, that is, dicing the cutting lanes in the wafer, it is occasionally easy to damage chips outside the cutting lanes during dicing, or the cutting time needs to be increased, the cutting efficiency is low, or there is a risk of broken chips or fragments being encountered during cutting, or hidden cracks on the cutting edges. Utility Model Content
[0006] In order to solve the problems mentioned in the above background technology and improve the cutting efficiency and yield rate when wafer dicing, an embodiment of the utility model provides a thickness measuring pad, which is located in the cutting path of the wafer. Generally, the thickness measuring pad is used to monitor the film thickness of the thin film process in the semiconductor process. The plane shape of the thickness measuring pad on the surface where the wafer is located is a rectangle, and the angle between the rectangular side of the thickness measuring pad and the edge of the cutting path is greater than 0 degrees and less than 90 degrees.
[0007] Optionally, the angle between the rectangular side of the thickness measuring pad and the edge of the cutting path is 45 degrees.
[0008] Another embodiment of the present invention provides a thickness measuring pad, which is located in the sawing path of a wafer. Generally, the thickness measuring pad is used to monitor the film thickness of a thin film process in a semiconductor process, and the plane shape of the thickness measuring pad on the surface where the wafer is located is circular.
[0009] The third embodiment of the utility model provides a thickness measuring pad, which is located in the cutting path of the wafer. Generally, the thickness measuring pad is used to monitor the film thickness of the thin film process in the semiconductor process, and the plane shape of the thickness measuring pad on the surface where the wafer is located is a rectangle, the rectangular side of the thickness measuring pad is parallel to the edge of the cutting path, and the four corners of the thickness measuring pad are chamfered.
[0010] A fourth embodiment of the utility model provides a wafer cutting path, wherein a plurality of thickness measuring pads as described in any of the above embodiments are arranged in the cutting path, wherein two parallel laser cutting lines are arranged in the cutting path, wherein the laser cutting lines pass through a plurality of the thickness measuring pads, wherein the distance between the laser cutting lines is slightly greater than the thickness of the wheel cutter used to cut the wafer; and wherein the distance between the laser cutting lines passing through the thickness measuring pads is less than the side length of the thickness measuring pads.
[0011] Optionally, the angle between the rectangular side of the thickness measuring pad and the edge of the cutting path is 45 degrees.
[0012] Optionally, a plurality of thickness measuring pads are arranged in the cutting path at equal intervals from each other.
[0013] Optionally, the lengths of the laser cutting lines drawn on a plurality of the thickness measuring pads are substantially equal.
[0014] Optionally, the surface of the cutting path is a protective layer of a low dielectric constant material.
[0015] Compared with the prior art, the technical solution of the embodiment of the utility model has the following beneficial effects:
[0016] The thickness measuring pad in the wafer cutting lane provided by the utility model can improve the cutting efficiency by shortening the length of the cutting line of the thickness measuring pad during dicing, and can also increase the process window of laser cutting and subsequent wheel cutting. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0018] Figure 1 It is a schematic diagram of the structure in which the thickness measuring pad is located in the cutting path in the prior art;
[0019] Figure 2 It is a schematic diagram of the structure of a laser cutting line passing through a thickness measuring pad in the prior art;
[0020] Figure 3 It is a schematic diagram of the structure in which the thickness measuring pad is located in the cutting path in one embodiment of the utility model;
[0021] Figure 4 It is a schematic diagram of the structure of a laser cutting line passing through a thickness measuring pad in one embodiment of the utility model;
[0022] Figure 5 It is a schematic diagram of the structure in which the thickness measuring pad is located in the cutting path in another embodiment of the utility model;
[0023] Figure 6 It is a schematic diagram of the structure in which the thickness measuring pad is located in the cutting path in the third embodiment of the utility model;
[0024] Figure 7 This is a schematic diagram of the structure of the cutting path in the fourth embodiment of the utility model.
[0025] Description of reference numerals:
[0026] 10—cutting path;
[0027] 20—thickness measuring pad;
[0028] 20'—Thickness measuring pad;
[0029] 20”—Thickness measuring pad;
[0030] 20”’—Thickness measuring pad;
[0031] 30—Laser cutting line. DETAILED DESCRIPTION
[0032] As described in the background technology, in order to improve the cutting efficiency and yield rate during wafer dicing, the technicians of the present invention have found that when using laser cutting, the thickness measuring pad in the cutting path of the wafer will affect the efficiency of laser cutting. In addition to the thickness measuring pad, other electrical test structures and other types of test structures are also placed in the cutting path of the wafer. However, since there is a relatively dense metal film layer on the thickness measuring pad and the brittle low dielectric constant material on the metal film layer, it brings certain difficulties to laser cutting, resulting in a long time required for laser cutting and the risk of some damage or hidden cracks on the edge of the dicing.
[0033] The invention of the utility model will be described in detail below with reference to the accompanying drawings.
[0034] Please refer to Figure 1 and Figure 2 The thickness measuring pad 20 is currently located in the cutting path 10, and its plane shape on the surface where the wafer is located is rectangular. The thickness measuring pad 20 is placed flat in the cutting path 10, that is, the rectangular side of the rectangular thickness measuring pad 20 is arranged parallel to the edge of the cutting path 10. Two parallel laser cutting lines 30 are symmetrically arranged in the cutting path 10. Both of these laser cutting lines 30 pass through the thickness measuring pad 20. The distance between these two laser cutting lines 30 is slightly larger than the thickness of the wheel knife used to cut the wafer. The length l of the laser cutting line 30 passing through the thickness measuring pad 20 1 It is equal to the side length of the thickness measuring pad 20, that is, the cutting line length of the thickness measuring pad 20 is longer, which increases the cutting time and reduces the cutting efficiency.
[0035] To solve the above problems, please refer to Figure 3 and Figure 4 An embodiment of the utility model provides a thickness measuring pad 20', which is located in the cutting path 10 of the wafer and is used to monitor the film thickness of the thin film process in the semiconductor process. The plane shape of the thickness measuring pad 20' on the surface where the wafer is located is a rectangle, and the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10 is greater than 0 degree and less than 90 degrees.
[0036] In this embodiment, the current rectangular thickness measuring pad 20 is placed in a tilted manner instead of being placed flat, and is rotated at any acute angle to form a new thickness measuring pad 20' in the cutting path 10. Then, the length l of the laser cutting line 30 passing through the thickness measuring pad 20' is 2 Therefore, in the dicing process, when laser pre-cutting is performed, the cutting line length of the thickness measuring pad 20' required to be cut during laser cutting can be shortened.
[0037] This embodiment does not impose any specific restrictions on the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10, as long as it is an acute angle. In order to further shorten the cutting line length of the thickness measuring pad 20', this embodiment preferably sets the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10 to 45 degrees, because when the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10 is 45 degrees, the length l of the laser cutting line 30 passing through the thickness measuring pad 20' is 2 The minimum, that is, the cutting line length of the thickness measuring pad 20' is the shortest. This shape of the thickness measuring pad does not affect its normal function as a thickness measuring pad in the semiconductor process, and at the same time, it can effectively shorten the length of the laser cutting thickness measuring pad during scribing, especially in the laser and wheel knife combined scribing process, improve the cutting efficiency, and increase the process window of laser cutting and subsequent wheel knife cutting.
[0038] To solve the problems mentioned in the background technology, please refer to Figure 5 The utility model provides another embodiment. In this embodiment, the thickness measuring pad 20" is located in the cutting path 10 of the wafer, and is used to monitor the film thickness of the thin film process in the semiconductor process. The plane shape of the thickness measuring pad 20" on the surface where the wafer is located is a rectangle, and the rectangular side of the thickness measuring pad 20" is parallel to the edge of the cutting path 10, and the four corners of the thickness measuring pad 20" are chamfered.
[0039] This embodiment does not limit the chamfer shapes of the four corners of the thickness measuring pad 20 ″. The four corners of the thickness measuring pad 20 ″ can be chamfered in an inclined plane or in an arc shape. Figure 3 The four corners of the thickness measuring pad 20" are shown as arc-shaped chamfers.
[0040] In this embodiment, the four corners of the current rectangular thickness measuring pad 20" are chamfered so that the four corners become arc chamfers or bevel chamfers. The laser cutting line 30 passes through the chamfer of the thickness measuring pad 20", and the length l of the laser cutting line 30 passing through the thickness measuring pad 20" is 3 If the thickness of the thickness measuring pad 20" is smaller than the side length of the thickness measuring pad 20", the embodiment can also shorten the cutting line length of the thickness measuring pad 20", thereby reducing the cutting time and increasing the cutting efficiency.
[0041] To solve the above problems, please refer to Figure 6 The third embodiment of the utility model further provides a thickness measuring pad 20'', which is located in the cutting path 10 of the wafer and is used to monitor the film thickness of the thin film process in the semiconductor process. The plane shape of the thickness measuring pad 20'' on the surface where the wafer is located is circular.
[0042] In this embodiment, the current rectangular thickness measuring pad 20 is replaced with a circular thickness measuring pad 20"', so the length l of the laser cutting line 30 passing through the thickness measuring pad 20"' is 4 The diameter of the thickness measuring pad 20"' is smaller than that of the thickness measuring pad 20"'. This embodiment can also shorten the cutting line length of the thickness measuring pad 20"'.
[0043] To solve the above problems, please refer to Figure 7 The fourth embodiment of the utility model further provides a wafer cutting street 10, in which a plurality of thickness measuring pads in any one or several embodiments of the utility model are arranged, and two parallel laser cutting lines 30 are arranged in the cutting street 10, and the laser cutting lines 30 pass through a plurality of thickness measuring pads; the distance that the laser cutting lines 30 pass through the thickness measuring pads is less than the side length or diameter of the thickness measuring pads.
[0044] In this embodiment, since the middle of the two laser cutting lines 30 is the position of the wheel cutting, and the wheel cutting tool has a certain thickness, the distance l between the laser cutting lines 30 is 5 Slightly larger than the thickness of the wheel used to cut the wafer, in order to leave a larger wheel cutting window.
[0045] Since the surface of the wafer's cutting path 10 is a protective layer of low-dielectric constant material, if a wheel cutter is used directly for cutting, it is easy to cause edge collapse and damage the chip, and the debris generated by the wheel cutter will splash onto the chip, causing contamination or defects to the chip. Therefore, in this embodiment, the protective layer of low-dielectric constant material such as low-k material on the cutting path 10 and the surface of the thickness measurement pad is cut by laser cutting to form two parallel laser cutting lines 30; then a wheel cutter is used to cut the substrate part between the two laser cutting lines 30. In this way, the chip can be protected from edge collapse and cost can be saved when wafer dicing is performed.
[0046] Please refer to Figure 3 and Figure 4 When the thickness measuring pad 20' is rotated at any acute angle and tilted to be placed in the cutting path 10, and the plane shape of the wafer surface is rectangular, the wheel cutting area on the thickness measuring pad 20' is located in the connecting area of two diagonal corners of the thickness measuring pad 20', and the two laser cutting lines are located on both sides of the connecting area and are close to a pair of corners of the thickness measuring pad 20', respectively. Therefore, the length l of the laser cutting line 30 passing through the thickness measuring pad 20' 2 Smaller than the side length of the thickness measuring pad 20'.
[0047] Since the thickness measuring pad 20' is rotated at an arbitrary acute angle and then tilted and placed in the cutting path 10, the plane shape of the wafer surface is a rectangle, so the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10 is greater than 0 degrees and less than 90 degrees. This embodiment does not impose any specific restrictions on the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10, as long as it is an acute angle. In this embodiment, it is preferred that the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10 is 45 degrees. Because when the angle between the rectangular side of the thickness measuring pad 20' and the edge of the cutting path 10 is 45 degrees, the length of the laser cutting line 30 passing through the thickness measuring pad 20' is the shortest, that is, the length of the thickness measuring pad 20' cut by the laser is the shortest.
[0048] Please refer to Figure 5 When the plane shape of the thickness measuring pad 20" on the surface where the wafer is located is a rectangle with four chamfered corners, the laser cutting line 30 passes through two adjacent chamfers of the thickness measuring pad 20", so the length l of the laser cutting line 30 passing through the thickness measuring pad 20" 3 Smaller than the side length of the thickness measuring pad 20".
[0049] Please refer to Figure 6 When the plane shape of the thickness measuring pad 20"' on the surface of the wafer is a circle, the wheel cutting area on the thickness measuring pad 20"' passes through the center of the circle, and the laser cutting line 30 does not pass through the center of the circle. Therefore, the length l of the laser cutting line 30 passing through the thickness measuring pad 20"' 4 It is smaller than the diameter of the thickness measuring pad 20'.
[0050] This embodiment can also shorten the distance that the laser cutting line 30 passes through the thickness measuring pad, that is, the cutting line length of the thickness measuring pad 20 .
[0051] The present embodiment does not impose any specific restrictions on the arrangement of the plurality of thickness measuring pads in the cutting street 10. The plurality of thickness measuring pads can be arranged in the cutting street 10 at equal intervals or at unequal intervals, which can be set according to actual application requirements. In the present embodiment, it is preferred that the plurality of thickness measuring pads can be arranged in the cutting street 10 at equal intervals.
[0052] The present embodiment does not impose any specific restrictions on the lengths of the laser cutting lines 30 drawn on the thickness measuring pads. The lengths of the laser cutting lines 30 may be equal or unequal, and may be set according to actual application requirements. The present embodiment preferably sets the lengths of the laser cutting lines 30 drawn on the thickness measuring pads to be approximately equal.
[0053] In summary, the thickness measuring pad in the wafer cutting lane provided by the present invention can improve the cutting efficiency by shortening the length of the cutting line of the thickness measuring pad during dicing, and can also increase the process window of laser cutting and subsequent wheel cutting.
[0054] Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the scope defined by the claims.
Claims
1. A thickness measurement pad, located in a dicing path of a wafer, for monitoring the film thickness of a thin film process in a semiconductor process, characterized in that: The plane shape of the thickness measuring pad on the surface where the wafer is located is a rectangle, and the angle between the rectangular side of the thickness measuring pad and the edge of the cutting road is greater than 0 degree and less than 90 degrees.
2. The thickness measuring pad according to claim 1, characterized in that: The angle between the rectangular side of the thickness measuring pad and the edge of the scribe line is 45 degrees.
3. A thickness measurement pad, located in a dicing path of a wafer, for monitoring the film thickness of a thin film process in a semiconductor process, characterized in that: The plane shape of the thickness measuring pad on the surface where the wafer is located is circular.
4. A thickness measurement pad, located in a dicing path of a wafer, for monitoring the film thickness of a thin film process in a semiconductor process, characterized in that: The plane shape of the thickness measuring pad on the surface where the wafer is located is a rectangle, the rectangular side of the thickness measuring pad is parallel to the edge of the cutting road, and the four corners of the thickness measuring pad are chamfered.
5. A wafer dicing road, characterized in that: A plurality of thickness measuring pads as described in any one of claims 1 to 4 are arranged in the cutting path, and two parallel laser cutting lines are arranged in the cutting path, and the laser cutting lines pass through a plurality of the thickness measuring pads, and the distance between the laser cutting lines is slightly larger than the thickness of the wheel knife used to cut the wafer; and the distance between the laser cutting lines passing through the thickness measuring pads is smaller than the side length of the thickness measuring pads.
6. The wafer dicing road according to claim 5, characterized in that: The angle between the rectangular side of the thickness measuring pad and the edge of the scribe line is 45 degrees.
7. The wafer dicing road according to claim 5, characterized in that: A plurality of thickness measuring pads are arranged in the cutting path at equal intervals from each other.
8. The wafer dicing road according to claim 5, characterized in that: The lengths of the laser cutting lines drawn on a plurality of the thickness measuring pads are substantially equal.
9. The wafer dicing road according to claim 5, characterized in that: The surface of the cutting path is a protective layer of a low dielectric constant material.