Wafer cutting method and wafer

Abstract

The invention discloses a wafer cutting method and a wafer, the wafer comprises a silicon wafer layer and a glass layer, and the silicon wafer layer and the glass layer are in bonding connection; the cutting method comprises the following steps: cutting the silicon wafer layer from one side, far away from the glass layer, of the silicon wafer layer, and performing laser cutting on the glass layer from one side, far away from the silicon wafer layer, of the glass layer; wherein the cutting depth reaches the bonding surface of the silicon wafer layer and the glass layer; the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer; and carrying out splitting treatment on the wafer. According to the invention, the cutting groove width and the actual cutting mark width between crystal grains on the front silicon wafer layer of the wafer can be greatly reduced, more chip crystal grains can be arranged on the front silicon wafer layer of the wafer, and the utilization rate of the wafer is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a wafer cutting method and a wafer. Background Art

[0002] For semiconductor wafers with double-layer structures bonded by different materials, the traditional cutting process is: first use a fine-grained diamond grinding wheel knife to cut the silicon wafer layer, and use a dedicated wafer grinding wheel cutting machine under deionized water cooling to step-cut the silicon wafer layer along the cutting grooves designed between the grains. The cutting depth of each knife is about to the bonding surface of the silicon wafer layer and the glass layer. Then rotate the wafer horizontally 90° and step-cut in another direction. The width of the cut must be greater than the width of the cut of the large-grained glass cutting diamond grinding wheel blade used in the next step. Finally, use a large-grained diamond grinding wheel knife with a blade width of about or equal to 100um, along the cutting groove cut by the silicon wafer layer, repeat the same cutting steps to cut the glass layer, and cut through the glass layer with each knife to obtain each grain unit. When cutting glass, the actual blade selection is related to the thickness of the glass to be cut. Generally, the thicker the glass, the thicker the blade thickness, and the larger the corresponding cut width. Correspondingly, the cuts made by the fine-grained diamond grinding wheel in the first step when cutting the silicon wafer layer must be larger than the cuts made when cutting glass to ensure that there are no fragments on the surface of the grain after cutting.

[0003] In the traditional cutting process, a large-grained diamond grinding wheel with a blade width of about 100um or more is required to cut the glass layer. In order to prevent the cutting grooves between the grains from being too narrow, which will cause the diamond grinding wheel to cut through the glass and cause the surface of the silicon wafer layer to break and fragment, the width of the cutting grooves between the grains of the silicon wafer layer needs to be designed to be about 200-400um, and the actual cut width is about 200-400um. However, the cutting groove area between the grains cannot be made into finished chips and is an invalid area. Therefore, the setting of a wider cutting groove greatly reduces the wafer utilization rate. For example, for a 6-inch wafer, the grain size is 1.8mm*1.8mm, and only about 3,500 chip grains can be cut in the end. Summary of the invention

[0004] The invention provides a wafer cutting method and a wafer, so as to solve the problem that the width of the cutting groove between the crystal grains is currently set too wide, thereby reducing the utilization rate of the wafer.

[0005] In a first aspect, the present invention provides a method for cutting a wafer, wherein the wafer comprises a silicon wafer layer and a glass layer, and the silicon wafer layer and the glass layer are bonded to each other; the cutting method comprises:

[0006] The silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer, and the glass layer is laser cut from a side of the glass layer away from the silicon wafer layer; wherein the cutting depth reaches the bonding surface of the silicon wafer layer and the glass layer; and the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer;

[0007] The wafer is split.

[0008] Optionally, cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer, include:

[0009] Cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer;

[0010] The wafer is flipped over and the glass layer is laser cut from the side of the glass layer away from the silicon layer.

[0011] Optionally, cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer, include:

[0012] Laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer;

[0013] The wafer is turned over and the silicon layer is cut from the side away from the glass layer.

[0014] Optionally, cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer, include:

[0015] The silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer, and at the same time, the glass layer is laser cut from a side of the glass layer away from the silicon wafer layer.

[0016] Optionally, the wafer includes a plurality of crystal grains, and a first cutting groove and a second cutting groove are provided between the crystal grains; and the silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer, comprising:

[0017] Using a diamond grinding wheel cutter with fine grain and thin thickness, the silicon wafer layer is step-cut from the side of the silicon wafer layer away from the glass layer along the first cutting groove between the grains, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer;

[0018] The wafer is rotated 90°, and a diamond grinding wheel with fine grain and thin thickness is used to step-cut the silicon wafer layer from the side of the silicon wafer layer away from the glass layer along the second cutting groove between the grains. The cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

[0019] Optionally, the wafer includes a plurality of crystal grains, and a first cutting groove and a second cutting groove are provided between the crystal grains; and the silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer, comprising:

[0020] Using a silicon material laser, the silicon wafer layer is step-cut along the first cutting groove between the crystal grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer;

[0021] The wafer is rotated 90° and a silicon laser is used to step-cut the silicon wafer layer along the second cutting groove between the grains from the side of the silicon wafer layer away from the glass layer. The cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer. The first cutting groove and the second cutting groove are perpendicular to each other.

[0022] Optionally, using a diamond grinding wheel with fine grain and thin thickness to step-cut the silicon wafer layer from the side of the silicon wafer layer away from the glass layer along the first cutting groove between the grains, and rotating the wafer 90°, using a diamond grinding wheel with fine grain and thin thickness to step-cut the silicon wafer layer from the side of the silicon wafer layer away from the glass layer along the second cutting groove between the grains, including:

[0023] Using a diamond grinding wheel with fine grain and a blade thickness of 25 μm, the silicon wafer layer is step-cut along the first cutting groove between the grains from the side of the silicon wafer layer away from the glass layer;

[0024] The wafer is rotated 90°, and a diamond grinding wheel cutter with fine grain and a blade thickness of 25 μm is used to step-cut the silicon wafer layer from the side of the silicon wafer layer away from the glass layer along the second cutting groove between the grains.

[0025] Optionally, the wafer includes a plurality of crystal grains, and a first cutting groove and a second cutting groove are provided between the crystal grains; and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer includes:

[0026] Using a glass material laser, the glass layer is step-cut from the side of the glass layer away from the silicon wafer layer corresponding to the first cutting groove between the grains, and the cutting depth is from the side of the glass layer away from the silicon wafer layer to the bonding surface of the silicon wafer layer and the glass layer;

[0027] The wafer is rotated 90° and a glass material laser is used to step-cut the glass layer from the side of the glass layer away from the silicon wafer layer corresponding to the second cutting groove between the grains. The cutting depth is from the side of the glass layer away from the silicon wafer layer to the bonding surface between the silicon wafer layer and the glass layer. The first cutting groove and the second cutting groove are perpendicular to each other.

[0028] In a second aspect, the present invention provides a wafer, wherein the wafer includes a silicon wafer layer and a glass layer, and the silicon wafer layer and the glass layer are bonded to each other; a plurality of crystal grains are made on the wafer, and a first cutting groove and a second cutting groove are arranged between the crystal grains; the wafer is cut using the wafer cutting method provided in the first aspect above.

[0029] The technical solution of the embodiment of the present invention performs double-sided cutting on the front and back sides of a double-layer wafer, that is, performs double-sided cutting on the silicon wafer layer and the glass layer. The glass layer is laser cut from the side of the glass layer away from the silicon wafer layer, and there is no need to use a large-grained diamond grinding wheel knife with a blade width of about greater than or equal to 100um to cut the glass layer. The width of the cut in the glass layer by laser cutting is usually less than 5um, which is much smaller than the width of the cut made by the diamond grinding wheel cutting knife. When designing the cutting grooves between the grains on the front side of the wafer, there is no need to consider the blade thickness of the diamond grinding wheel knife for cutting the glass material. Therefore, the width of the cutting grooves between the grains on the silicon wafer layer on the front side of the wafer and the actual width of the cut can be greatly reduced, and more chip grains can be arranged on the silicon wafer layer on the front side of the wafer, effectively improving the wafer utilization rate.

[0030] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 is a flow chart of a wafer cutting method provided by an embodiment of the present invention;

[0033] Figure 2 is a top view of a wafer provided by an embodiment of the present invention;

[0034] Figure 3 is a cross-sectional view of a crystal grain provided by an embodiment of the present invention;

[0035] Figure 4 is a flow chart of another wafer cutting method provided by an embodiment of the present invention;

[0036] Figure 5 is a flow chart of another wafer cutting method provided by an embodiment of the present invention;

[0037] Figure 6is a flow chart of another wafer cutting method provided by an embodiment of the present invention;

[0038] Figure 7 is a flow chart of another wafer cutting method provided by an embodiment of the present invention;

[0039] Figure 8 is a flow chart of another wafer cutting method provided by an embodiment of the present invention;

[0040] Fig. 9 is a flow chart of another wafer cutting method provided by an embodiment of the present invention;

[0041] Fig.10 It is a flow chart of another wafer cutting method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] Figure 1 is a flow chart of a wafer cutting method provided by an embodiment of the present invention. Figure 2 is a top view of a wafer provided by an embodiment of the present invention, Figure 3 is a cross-sectional view of a crystal grain provided by an embodiment of the present invention, Figure 3 Can be Figure 2 The cross-sectional view obtained after cutting along the dotted line AB is as follows: Figure 2 and Figure 3 As shown, the wafer includes a silicon layer 1 and a glass layer 2, and the silicon layer 1 and the glass layer 2 are bonded together.

[0045] like Figure 1 As shown, the wafer cutting method includes:

[0046] S100: cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer; wherein the cutting depth reaches the bonding surface of the silicon wafer layer and the glass layer; and the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0047] Specifically, Figure 2 and Figure 3 As shown, the wafer includes a silicon wafer layer 1 and a glass layer 2. The wafer is a double-layer structure. The silicon wafer layer 1 can be the front side of the wafer, the surface of the silicon wafer layer 1 is the circuit functional surface, and the glass layer 2 can be the back side of the wafer. A plurality of crystal grains 11 are made on the wafer, and a first cutting groove 12 and a second cutting groove 13 can be pre-set between the crystal grains 11. The silicon wafer layer 1 is cut from the side of the silicon wafer layer 1 away from the glass layer 2. For example, a diamond grinding wheel cutter with fine grain size and thin thickness can be used to cut the silicon wafer layer 1 from the side of the silicon wafer layer 1 away from the glass layer 2 along the first cutting groove 12 and the second cutting groove 13 respectively.

[0048] It is also necessary to laser cut the glass layer 2 from the side of the glass layer 2 away from the silicon wafer layer 1. A laser made of glass material can be used to laser cut the glass layer 2 from the side of the glass layer 2 away from the silicon wafer layer 1 corresponding to the first cutting groove 12 and the second cutting groove 13. The width of the laser cutting is relatively small. For example, the width of the laser cutting is about 5um. The cutting depths of the silicon wafer layer 1 and the glass layer 2 are both about to the bonding surface of the silicon wafer layer 1 and the glass layer 2.

[0049] Exemplarily, a diamond grinding wheel with a blade thickness of about 25um can be used to cut the silicon wafer layer 1 from the side of the silicon wafer layer 1 away from the glass layer 2 along the first cutting groove 12 and the second cutting groove 13, respectively, and the glass layer 2 can be laser cut from the side of the glass layer 2 away from the silicon wafer layer 1. At this time, the width of the cutting groove between the grains on the front of the wafer is only set to about 30um-80um. It has been tested and verified that for a 6-inch wafer, the grain size is 1.8mm*1.8mm, and about 5000 chip grains can be cut in the end. Compared with the traditional cutting process, when the grain size of a 6-inch wafer is 1.8mm*1.8mm, only about 3500 chip grains can be cut in the end. The technical solution of the embodiment of the present invention increases the number of chip grains finally cut from 3500 to 5000 when the grain size of a 6-inch wafer is 1.8mm*1.8mm, effectively improving the wafer utilization rate. The blade thickness of the diamond grinding wheel knife used to cut the silicon wafer layer 1 can be set according to actual needs and is not specifically limited here. Reducing the blade thickness while ensuring that the silicon wafer layer 1 can be cut well can further improve the utilization rate of the wafer.

[0050] S110: performing a wafer splitting process.

[0051] Specifically, the cut wafer is split to obtain individual chip grains.

[0052] The technical solution of the embodiment of the present invention performs double-sided cutting on the front and back sides of a double-layer wafer, that is, performs double-sided cutting on the silicon wafer layer and the glass layer. The glass layer is laser cut from the side of the glass layer away from the silicon wafer layer, and there is no need to use a large-grained diamond grinding wheel knife with a blade width of about greater than or equal to 100um to cut the glass layer. The width of the cut in the glass layer by laser cutting is usually less than 5um, which is much smaller than the width of the cut by the grinding wheel knife. When designing the cutting grooves between the grains on the front side of the wafer, there is no need to consider the blade thickness of the diamond grinding wheel knife for cutting the glass material. Therefore, the width of the cutting grooves between the grains on the front side of the wafer and the actual width of the cut can be greatly reduced, and more chip grains can be arranged on the front side of the wafer, effectively improving the wafer utilization rate.

[0053] Optionally, based on the above embodiments, Figure 4 is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Figure 4 As shown, the wafer cutting method includes:

[0054] S200: cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer; the cutting depth reaches the bonding surface between the silicon wafer layer and the glass layer.

[0055] Specifically, Figure 2 and Figure 3As shown, the silicon wafer layer 1 can be cut from the side of the silicon wafer layer 1 away from the glass layer 2, and the cutting depth is about to the bonding surface of the silicon wafer layer 1 and the glass layer 2. Exemplarily, a diamond grinding wheel cutter with fine grain and thin thickness can be used to cut the silicon wafer layer 1 from the side of the silicon wafer layer 1 away from the glass layer 2 along the first cutting groove 12 and the second cutting groove 13 respectively.

[0056] S210: flipping the wafer, and laser cutting the glass layer from the side of the glass layer away from the silicon wafer layer; the cutting depth reaches the bonding surface between the silicon wafer layer and the glass layer; wherein the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0057] Specifically, Figure 2 and Figure 3 As shown, after the silicon wafer layer 1 is cut, the wafer is flipped 180°, with the glass layer 2 facing upward. The glass layer 2 is laser cut from the side of the glass layer 2 away from the silicon wafer layer 1, and the cutting depth is about to the bonding surface of the silicon wafer layer 1 and the glass layer 2. Exemplarily, a laser made of glass material can be used to laser cut the glass layer 2 from the side of the glass layer 2 away from the silicon wafer layer 1 corresponding to the first cutting groove 12 and the second cutting groove 13, respectively. The width of the laser cutting is relatively small, and for example, the width of the laser cutting is about 5um.

[0058] Optionally, after the silicon wafer layer 1 is cut, the glass layer 2 on the back side may be directly laser cut without turning the wafer over.

[0059] S220: performing a wafer splitting process.

[0060] Optionally, based on the above embodiments, Figure 5 is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Figure 5 As shown, the wafer cutting method includes:

[0061] S300: laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer; the cutting depth reaches the bonding surface between the silicon wafer layer and the glass layer.

[0062] Specifically, Figure 2 and Figure 3 As shown, the glass layer 2 can be first laser cut from the side of the glass layer 2 away from the silicon wafer layer 1, and the cutting depth is about to the bonding surface of the silicon wafer layer 1 and the glass layer 2. The back glass layer 2 facing downward can be laser cut, or the wafer can be flipped 180° first, so that the back glass layer 2 faces upward, and then the glass layer 2 is laser cut. Exemplarily, a laser made of glass material can be used to laser cut the glass layer 2 from the side of the glass layer 2 away from the silicon wafer layer 1 corresponding to the first cutting groove 12 and the second cutting groove 13 respectively. The width of the laser cutting is relatively small, and for example, the width of the laser cutting is about 5um.

[0063] S310: turning over the wafer, and cutting the silicon wafer layer from the side of the silicon wafer layer away from the glass layer; the cutting depth reaches the bonding surface of the silicon wafer layer and the glass layer; wherein the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0064] Specifically, Figure 2 and Figure 3 As shown, after the glass layer 2 is cut, if the front silicon wafer layer 1 is facing upward and the back glass layer 2 is facing downward, there is no need to flip the wafer. If the front silicon wafer layer 1 is facing downward and the back glass layer 2 is facing upward, the wafer needs to be flipped 180°. Then the silicon wafer layer 1 is cut from the side away from the glass layer 2, and the cutting depth is about to the bonding surface between the silicon wafer layer 1 and the glass layer 2. Exemplarily, a diamond grinding wheel cutter with fine grain and thin thickness can be used to cut the silicon wafer layer 1 from the side away from the glass layer 2 along the first cutting groove 12 and the second cutting groove 13 respectively.

[0065] S320: performing a wafer splitting process.

[0066] Optionally, based on the above embodiments, Figure 6 is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Figure 6 As shown, the wafer cutting method includes:

[0067] S400: cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and simultaneously laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer; wherein the cutting depth reaches the bonding surface of the silicon wafer layer and the glass layer; and the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0068] Specifically, Figure 2 and Figure 3 As shown, while the silicon wafer layer 1 is cut from the side away from the glass layer 2, the glass layer 2 is laser cut from the side away from the silicon wafer layer 1. Exemplarily, a diamond grinding wheel cutter with fine grain and thin thickness can be used to cut the silicon wafer layer 1 from the side away from the glass layer 2 along the first cutting groove 12 and the second cutting groove 13. A laser made of glass material can be used to laser cut the glass layer 2 from the side away from the silicon wafer layer 1 corresponding to the first cutting groove 12 and the second cutting groove 13. This arrangement can effectively improve the cutting efficiency of the wafer and reduce the time cost.

[0069] S410: performing a wafer splitting process.

[0070] Optionally, based on the above embodiments, Figure 7is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Figure 7 As shown, the wafer cutting method includes:

[0071] S500: Use a fine-grained and thin diamond grinding wheel to step-cut the silicon wafer layer along the first cutting groove between the grains from the side of the silicon wafer layer away from the glass layer. The cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer.

[0072] Specifically, Figure 2 and Figure 3 As shown, the silicon wafer layer 1 is first cut using a dedicated wafer grinding wheel cutting machine, using a diamond grinding wheel cutter with fine grain and thin thickness. For example, the diamond grinding wheel cutter may have a blade thickness of 25 um. The silicon wafer layer 1 is cut stepwise from the side of the silicon wafer layer 1 away from the glass layer 2 along each first cutting groove 12 between the grains, and the cutting depth is from the side of the silicon wafer layer 1 away from the glass layer 2 to the bonding surface of the silicon wafer layer 1 and the glass layer 2.

[0073] S510: Rotate the wafer 90°, use a fine-grained and thin diamond grinding wheel cutter to step-cut the silicon wafer layer along the second cutting groove between the grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

[0074] Specifically, Figure 2 and Figure 3 As shown, after the step-cutting of the silicon wafer layer 1 from the side of the silicon wafer layer 1 away from the glass layer 2 along each first cutting groove 12 is completed, the wafer is horizontally rotated 90°, and the silicon wafer layer 1 is continued to be step-cut from the side of the silicon wafer layer 1 away from the glass layer 2 along the second cutting groove 13 between the grains using a fine-grained and thin-thickness diamond grinding wheel cutter, and the cutting depth is from the side of the silicon wafer layer 1 away from the glass layer 2 to the bonding surface of the silicon wafer layer 1 and the glass layer 2. Cutting the silicon wafer layer 1 using a conventional fine-grained and thin-thickness diamond grinding wheel cutter can effectively ensure the yield of the chip grains on the wafer.

[0075] S520: flipping the wafer, and laser cutting the glass layer from the side of the glass layer away from the silicon wafer layer; the cutting depth reaches the bonding surface between the silicon wafer layer and the glass layer; wherein the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0076] S530: performing a wafer splitting process.

[0077] Optionally, based on the above embodiments, Figure 8 is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Figure 8 As shown, the wafer cutting method includes:

[0078] S600: Using a silicon material laser, the silicon wafer layer is step-cut along the first cutting groove between the grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer.

[0079] Specifically, Figure 2 and Figure 3 As shown, the silicon wafer layer 1 is first cut, and a silicon material laser is used to step-cut the silicon wafer layer 1 from the side of the silicon wafer layer 1 away from the glass layer 2 along each first cutting groove 12 between the grains, and the cutting depth is from the side of the silicon wafer layer 1 away from the glass layer 2 to the bonding surface of the silicon wafer layer 1 and the glass layer 2. The width of the laser cutting is relatively small, and for example, the width of the laser cutting is about 5um.

[0080] S610: Rotate the wafer 90°, use a silicon material laser to step-cut the silicon wafer layer along the second cutting groove between the grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

[0081] Specifically, Figure 2 and Figure 3 As shown, after the step-cutting of the silicon wafer layer 1 along each first cutting groove 12 from the side of the silicon wafer layer 1 away from the glass layer 2 is completed, the wafer is rotated horizontally by 90°, and the silicon wafer layer 1 is continued to be step-cut from the side of the silicon wafer layer 1 away from the glass layer 2 using a silicon material laser along the second cutting groove 13 between the grains, and the cutting depth is from the side of the silicon wafer layer 1 away from the glass layer 2 to the bonding surface of the silicon wafer layer 1 and the glass layer 2. The width of the laser cutting is relatively small, and for example, the width of the laser cutting is about 5um. Cutting the silicon wafer layer 1 by laser cutting can further reduce the cutting groove width and the actual cut width between the grains on the front side of the wafer, and more chip grains can be arranged on the front side of the wafer, effectively improving the wafer utilization rate.

[0082] S620: flipping the wafer, and laser cutting the glass layer from the side of the glass layer away from the silicon wafer layer; the cutting depth reaches the bonding surface between the silicon wafer layer and the glass layer; wherein the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0083] S630: performing a wafer splitting process.

[0084] Optionally, based on the above embodiments, Fig. 9 is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Fig. 9 As shown, the wafer cutting method includes:

[0085] S800: Use a diamond grinding wheel with fine grain and a blade thickness of 25um to step-cut the silicon wafer layer from the side of the silicon wafer layer away from the glass layer along the first cutting groove between the grains.

[0086] Specifically, Figure 2 and Figure 3 As shown, the silicon wafer layer 1 is first cut using a dedicated wafer grinding wheel cutting machine, using a diamond grinding wheel cutter with fine grain size and a blade thickness of 25 um, and the silicon wafer layer 1 is step-cut along each first cutting groove 12 between the grains from the side of the silicon wafer layer 1 away from the glass layer 2, and the cutting depth is from the side of the silicon wafer layer 1 away from the glass layer 2 to approximately the bonding surface of the silicon wafer layer 1 and the glass layer 2.

[0087] S810: Rotate the wafer 90°, and use a diamond grinding wheel with fine grain and a blade thickness of 25um to step-cut the silicon wafer layer along the second cutting groove between the grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

[0088] Specifically, Figure 2 and Figure 3 As shown, after the step-cutting of the silicon wafer layer 1 from the side away from the glass layer 2 along each first cutting groove 12 is completed, the wafer is rotated horizontally 90°, and the silicon wafer layer 1 is continued to be step-cut from the side away from the glass layer 2 along the second cutting groove 13 between the grains using a diamond grinding wheel cutter with fine grain and a blade thickness of 25um, and the cutting depth is from the side away from the glass layer 2 to the bonding surface of the silicon wafer layer 1 and the glass layer 2. At this time, the width of the cutting groove between the grains on the front side of the wafer only needs to be set to about 30um-80um. It has been tested and verified that for a 6-inch wafer, the grain size is 1.8mm*1.8mm, and about 5,000 chip grains can be cut in the end. Compared with the traditional cutting process, when the grain size of a 6-inch wafer is 1.8mm*1.8mm, only about 3500 chip grains can be cut. The technical solution of the embodiment of the present invention increases the number of chip grains finally cut from 3500 to 5000 when the grain size of a 6-inch wafer is 1.8mm*1.8mm, thereby effectively improving the wafer utilization rate.

[0089] S820: flipping the wafer, and laser cutting the glass layer from the side of the glass layer away from the silicon wafer layer; the cutting depth reaches the bonding surface between the silicon wafer layer and the glass layer; wherein the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer.

[0090] S830: performing a wafer splitting process.

[0091] Optionally, based on the above embodiments, Fig.10 is a flow chart of another wafer cutting method provided by an embodiment of the present invention, such as Fig.10 As shown, the wafer cutting method includes:

[0092] S900: Use a fine-grained and thin diamond grinding wheel to step-cut the silicon wafer layer along the first cutting groove between the grains from the side of the silicon wafer layer away from the glass layer. The cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer.

[0093] S910: Rotate the wafer 90°, use a fine-grained and thin diamond grinding wheel cutter to step-cut the silicon wafer layer along the second cutting groove between the grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

[0094] S920: Using a glass material laser, the glass layer is step-cut from the side of the glass layer away from the silicon wafer layer corresponding to the first cutting groove between the grains, and the cutting depth is from the side of the glass layer away from the silicon wafer layer to the bonding surface of the silicon wafer layer and the glass layer.

[0095] Specifically, Figure 2 and Figure 3 As shown, the glass layer 2 is laser cut using a glass material laser, and the first cutting grooves 12 between the corresponding grains are step-cut from the side of the glass layer 2 away from the silicon wafer layer 1, and the cutting depth is from the side of the glass layer 2 away from the silicon wafer layer 1 to approximately the bonding surface of the silicon wafer layer 1 and the glass layer 2.

[0096] S930: Rotate the wafer 90° and use a glass material laser to step-cut the glass layer from the side of the glass layer away from the silicon wafer layer corresponding to the second cutting groove between the grains. The cutting depth is from the side of the glass layer away from the silicon wafer layer to the bonding surface between the silicon wafer layer and the glass layer. The first cutting groove and the second cutting groove are perpendicular to each other.

[0097] Specifically, Figure 2 and Figure 3As shown, after the first cutting groove 12 between the corresponding crystal grains is completed by step-cutting the glass layer 2 from the side of the glass layer 2 away from the silicon wafer layer 1, the wafer is horizontally rotated 90°, and the second cutting groove 13 between the corresponding crystal grains is step-cutting the glass layer 2 from the side of the glass layer 2 away from the silicon wafer layer 1, and the cutting depth is from the side of the glass layer 2 away from the silicon wafer layer 1 to the bonding surface of the silicon wafer layer 1 and the glass layer 2. The glass layer 2 is laser cut from the side of the glass layer 2 away from the silicon wafer layer 1, and there is no need to use a large-grained diamond grinding wheel with a blade width of about greater than or equal to 100um to cut the glass layer 2. When designing the cutting grooves between the crystal grains on the front side of the wafer, there is no need to consider the blade thickness of the diamond grinding wheel for cutting the glass material. Therefore, the cutting groove width and the actual cutting mark width between the crystal grains on the front side of the wafer can be greatly reduced, and more chip crystal grains can be arranged on the front side of the wafer, effectively improving the wafer utilization rate.

[0098] S940: performing wafer splitting processing.

[0099] An embodiment of the present invention provides a wafer, such as Figure 2 and Figure 3 As shown, the wafer includes a silicon wafer layer 1 and a glass layer 2, and the silicon wafer layer 1 and the glass layer 2 are bonded. A plurality of crystal grains 11 are formed on the wafer, and a first cutting groove 12 and a second cutting groove 13 are provided between the crystal grains 11. The wafer provided in the embodiment of the present invention can be cut using the wafer cutting method provided in any of the above embodiments, and has the beneficial effects of the wafer cutting method provided in any of the above embodiments of the present invention.

[0100] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0101] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer cutting method, characterized in that: The wafer comprises a silicon wafer layer and a glass layer, and the silicon wafer layer and the glass layer are bonded to each other; the cutting method comprises: The silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer, and the glass layer is laser cut from a side of the glass layer away from the silicon wafer layer; wherein the cutting depth reaches the bonding surface of the silicon wafer layer and the glass layer; and the cutting position of the glass layer corresponds to the cutting position of the silicon wafer layer; The wafer is subjected to a splitting process.

2. The wafer cutting method according to claim 1, characterized in that: Cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer, comprising: Cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer; The wafer is turned over, and the glass layer is laser cut from a side of the glass layer away from the silicon wafer layer.

3. The wafer cutting method according to claim 1, characterized in that: Cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer, comprising: Laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer; The wafer is turned over, and the silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer.

4. The wafer cutting method according to claim 1, characterized in that: Cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer, and laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer, comprising: The silicon wafer layer is cut from a side of the silicon wafer layer away from the glass layer, and at the same time, the glass layer is laser cut from a side of the glass layer away from the silicon wafer layer.

5. The wafer cutting method according to any one of claims 1 to 4, characterized in that: The wafer includes a plurality of crystal grains, and a first cutting groove and a second cutting groove are provided between the crystal grains; cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer includes: Using a diamond grinding wheel cutter with fine grain and thin thickness, the silicon wafer layer is step-cut from the side of the silicon wafer layer away from the glass layer along the first cutting groove between the grains, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; The wafer is rotated 90°, and a diamond grinding wheel cutter with fine grain and thin thickness is used to step-cut the silicon wafer layer from the side of the silicon wafer layer away from the glass layer along the second cutting groove between the grains, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

6. The wafer cutting method according to any one of claims 1 to 4, characterized in that: The wafer includes a plurality of crystal grains, and a first cutting groove and a second cutting groove are provided between the crystal grains; cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer includes: Using a silicon material laser, step-cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer along the first cutting groove between the crystal grains, with a cutting depth from a side of the silicon wafer layer away from the glass layer to a bonding surface between the silicon wafer layer and the glass layer; The wafer is rotated 90°, and a silicon material laser is used to step-cut the silicon wafer layer along the second cutting groove between the grains from the side of the silicon wafer layer away from the glass layer, and the cutting depth is from the side of the silicon wafer layer away from the glass layer to the bonding surface of the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

7. The wafer cutting method according to claim 5, characterized in that: Using a diamond grinding wheel with fine grain and thin thickness, step-cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer along a first cutting groove between the crystal grains, rotating the wafer by 90°, and using a diamond grinding wheel with fine grain and thin thickness, step-cutting the silicon wafer layer from a side of the silicon wafer layer away from the glass layer along a second cutting groove between the crystal grains, comprising: Using a diamond grinding wheel with fine grain and a blade thickness of 25 μm, the silicon wafer layer is step-cut along the first cutting groove between the grains from the side of the silicon wafer layer away from the glass layer; The wafer is rotated 90°, and a diamond grinding wheel cutter with fine grain and a blade thickness of 25 um is used to step-cut the silicon wafer layer along the second cutting grooves between the grains from the side of the silicon wafer layer away from the glass layer.

8. The wafer cutting method according to any one of claims 1 to 4, characterized in that: The wafer includes a plurality of crystal grains, and a first cutting groove and a second cutting groove are provided between the crystal grains; laser cutting the glass layer from a side of the glass layer away from the silicon wafer layer includes: Using a glass material laser, the glass layer is step-cut from a side of the glass layer away from the silicon wafer layer corresponding to the first cutting groove between the grains, and the cutting depth is from a side of the glass layer away from the silicon wafer layer to a bonding surface between the silicon wafer layer and the glass layer; The wafer is rotated 90°, and a glass material laser is used to step-cut the glass layer from the side of the glass layer away from the silicon wafer layer corresponding to the second cutting groove between the grains, and the cutting depth is from the side of the glass layer away from the silicon wafer layer to the bonding surface between the silicon wafer layer and the glass layer; the first cutting groove and the second cutting groove are perpendicular to each other.

9. A wafer, characterized in that: The wafer includes a silicon layer and a glass layer, and the silicon layer and the glass layer are bonded to each other; a plurality of crystal grains are made on the wafer, and a first cutting groove and a second cutting groove are arranged between the crystal grains; the wafer is cut using the wafer cutting method described in any one of claims 1 to 8.

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