CN117096103A

CN117096103A - Wafer cutting method

Info

Publication number: CN117096103A
Application number: CN202311259981.7A
Authority: CN
Inventors: 汪仲祥; 李文涛
Original assignee: Zhejiang Core Test Semiconductor Co ltd
Current assignee: Zhejiang Core Test Semiconductor Co ltd
Priority date: 2023-09-26
Filing date: 2023-09-26
Publication date: 2023-11-21

Abstract

The application provides a wafer cutting method, which comprises the following steps: providing a wafer unit to be cut, wherein the wafer unit comprises a wafer or N stacked wafers, and each wafer comprises a substrate and a circuit layer positioned on the substrate; cutting wafer units from top to bottom by laser along scribing lines line by line, cutting the wafer units into a circuit layer of one wafer to form a first groove; and cutting the circuit layer with the residual thickness and the wafer units below the circuit layer line by line along the track of the first groove by using a blade until the wafer units are cut through, so as to form a second groove. According to the application, a part of the thickness of the circuit layer (comprising the metal layer) is shared by laser cutting, and the rest of the thickness of the circuit layer is cut by the blade, so that the output per hour is improved, the serious metal wrapping cutter phenomenon and the loading force when the cutting thickness of the blade is larger are reduced, and the problems that a chip breaks and a scribing groove exceeds a protection ring in the cutting process are solved.

Description

Wafer cutting method

Technical Field

The application belongs to the technical field of integrated circuit manufacturing, and particularly relates to a wafer cutting method.

Background

The wafer includes a substrate (e.g., a silicon substrate) and a circuit layer on the substrate, the circuit layer typically including a dielectric layer and a metal layer in the dielectric layer. Wafer dicing generally employs two methods: firstly, cutting through a circuit layer by adopting a laser grooving mode, and then cutting a substrate by adopting a blade cutting mode; the second type adopts a blade cutting mode, and the blade sequentially cuts the circuit layer and the substrate.

Firstly, cutting through a circuit layer in a laser cutting mode, and forming a first groove in the circuit layer, wherein the first groove exposes a substrate; then, the substrate is cut in the first groove by means of blade cutting to form a second groove. The first scribing method adopts laser to cut through the circuit layer in the cutting channel, and the subsequent blade does not need to cut the circuit layer (comprising a metal layer) when cutting, so that the problem of chip cracking easily caused by cutting the circuit layer by the blade is avoided; but the output per hour of the laser cut-through (full cut) circuit layer is too low to realize the mass production of the product.

In the second scribing method, only a cutter blade is used for cutting the circuit layer and the substrate in sequence, the circuit layer is not required to be removed by laser, and the problem of low output per hour is avoided; however, when the blade cuts a circuit layer with a large thickness, the blade is severely wrapped, so that a large number of chip cracks and dicing grooves exceed the protection ring. Both of the above dicing methods have significant drawbacks, and improvements are needed.

Disclosure of Invention

The application aims to provide a wafer cutting method, wherein a part of circuit layers (including metal layers) with thickness are shared by laser cutting, and the rest of circuit layers with thickness are cut by a blade, so that the output per hour is improved, the serious metal wrapping cutter phenomenon and load force when the cutting thickness of the blade is larger are reduced, and the problems that chips are cracked and scribing grooves exceed protection rings in the cutting process are solved.

The application provides a wafer cutting method, which comprises the following steps:

providing a wafer unit to be cut, wherein the wafer unit comprises a wafer or N stacked wafers, and N is an integer more than or equal to 2; each wafer comprises a substrate and a circuit layer positioned on the substrate, wherein the circuit layer comprises a dielectric layer and a metal layer positioned in the dielectric layer;

cutting the wafer units from top to bottom line by line along scribing lines by adopting laser, and cutting the wafer units to the circuit layer of one wafer to form a first groove;

and cutting the circuit layer with the residual thickness and the wafer unit below the circuit layer line by line along the track of the first groove by using a blade until the wafer unit is completely cut, so as to form a second groove.

Further, the first groove is formed by cutting the laser from top to bottom into the circuit layer of the bottommost wafer.

Further, the N stacked wafers form a layer of wafer, a layer of wafer and a layer of wafer from bottom to top to N layers of wafer; and when N is more than or equal to 4 and less than or equal to 8, cutting the laser from top to bottom into the circuit layer of the wafer of any one layer of N/2 layers to form the first groove.

Further, the thickness of the circuit layer in the wafer unit cut by laser is 25% -85% of the total thickness of all the circuit layers in the wafer unit.

Further, the forming the first trench by laser cutting specifically includes: providing a laser beam machine comprising a laser transmitter, a chuck table and a moving mechanism; the chuck table is used for fixing the wafer unit, and the moving mechanism drives the wafer unit fixed on the chuck table to move.

Further, in the step of forming the first trench by laser cutting, the process parameters include: the wavelength of the laser is 300 nm-400 nm; the laser output power is 1.0W-4.0W; the repetition frequency is 40 kHz-200 kHz; the pulse width is 8 ns-13 ns; the cutting feed speed at which the laser beam and the wafer unit are moved relative to each other is 50mm/sec to 400mm/sec.

Further, the projection of the first trench on the substrate covers the projection of the second trench on the substrate.

Further, the cutting of the blade to form the second groove specifically comprises providing a cutting machine, wherein the cutting machine comprises a motor, a main shaft, a hub and the blade, and the hub and the blade are sleeved on the main shaft in sequence; the blades are fixed on the radial peripheral edge of the hub, the motor drives the spindle to rotate, the blades are driven to rotate through the hub, the circuit layer with the residual thickness and the wafer units below the circuit layer are cut line by line along the track of the first groove until the wafer units are completely cut, and the second groove is formed.

Further, in the step of cutting the blade to form the second groove, the blade: the outer diameter is 40 mm-60 mm, and the width is 50 μm-70 μm; the revolution of the blade is 25000 rpm-50000 rpm; the cutting feed speed at which the blade and the wafer unit move relative to each other is 20mm/sec to 40mm/sec.

Further, in a plane parallel to the front surface of the wafer unit, the number of the dicing channels is multiple, and the dicing channels respectively extend along a first direction and a second direction which are perpendicular to each other; the wafer is overlooked, and the first grooves and the second grooves are staggered in a grid shape;

and a mucous membrane is adhered to the back surface of the wafer unit, and in the step of cutting to form the second groove by the blade, the wafer unit is cut through to the mucous membrane, and the mucous membrane is not cut through.

Compared with the prior art, the application has the following beneficial effects:

the application provides a wafer cutting method, which comprises the steps of providing a wafer unit to be cut, wherein the wafer unit comprises a wafer or N stacked wafers, and N is an integer more than or equal to 2; each wafer comprises a substrate and a circuit layer positioned on the substrate, wherein the circuit layer comprises a dielectric layer and a metal layer positioned in the dielectric layer; cutting the wafer units from top to bottom by laser along scribing lines line by line, and cutting the wafer units into the circuit layer of one of the wafers to form a first groove; and cutting the circuit layer with the residual thickness and the wafer unit below the circuit layer line by line along the track of the first groove by using a blade until the wafer unit is completely cut, so as to form a second groove. According to the application, the circuit layer (comprising the metal layer) with partial thickness is firstly cut by laser, and compared with the circuit layer with the whole thickness is cut by laser, the thickness of the circuit layer is reduced by laser, so that the output per hour is improved; meanwhile, the circuit layer with a part of thickness is shared by laser cutting, the thickness of the rest circuit layer which is cut by the blade is reduced, the serious metal wrapping cutter phenomenon and load force when the blade cutting thickness is larger are reduced, and the problems that a chip breaks and a scribing groove exceeds a protection ring due to the fact that the wrapping cutter is serious are solved.

Drawings

Fig. 1 is a flow chart of a wafer dicing method according to an embodiment of the application.

Fig. 2 is a schematic diagram of laser dicing in a wafer dicing method according to an embodiment of the application.

Fig. 3 is a schematic diagram of a dicing machine in a wafer dicing method according to an embodiment of the application.

Fig. 4 is a schematic view of a dicing blade in a dicing method according to an embodiment of the application.

Fig. 5 is a schematic view of a wafer after dicing by a blade in the wafer dicing method according to the embodiment of the application.

Fig. 6 is a schematic diagram of a first example of dicing a two-layer wafer in a wafer dicing method according to an embodiment of the application.

Fig. 7 is a schematic diagram of a second example of dicing a two-layer wafer in the wafer dicing method according to the embodiment of the application.

Fig. 8 is a schematic diagram of dicing a three-layer wafer according to the wafer dicing method of the embodiment of the application.

Wherein, the reference numerals are as follows:

01-hub; 02-a blade; 03-a base; 04-motor; 05-a main shaft; an o-axis; v (V) _1a 、V _1b 、V _1c 、V _1d -a first trench; v (V) ₂ -a second trench; 10-a first wafer; 11-a first substrate; 12-a first circuit layer; 20-a second wafer; 21-a second substrate; 22-a second circuit layer; 30-a third wafer; 31-a third substrate; 32-a third circuit layer; a-mucosa; b-laser beam.

Detailed Description

The application is described in further detail below with reference to the drawings and the specific examples. The advantages and features of the present application will become more apparent from the following description. It should be noted that the drawings are in a very simplified form and are not to scale precisely, but rather merely for the purpose of facilitating and clearly aiding in the description of the embodiments of the application.

For ease of description, some embodiments of the application may use spatially relative terms such as "above" …, "" below "…," "top," "below," and the like to describe one element or component's relationship to another element(s) or component(s) as illustrated in the figures of the embodiments. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or components described as "below" or "beneath" other elements or components would then be oriented "above" or "over" the other elements or components. The terms "first," "second," and the like, herein below, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that such terms so used are interchangeable under appropriate circumstances.

The embodiment of the application provides a wafer cutting method, as shown in fig. 1, comprising the following steps:

step S1, providing a wafer unit to be cut, wherein the wafer unit comprises a wafer or N stacked wafers, and N is an integer more than or equal to 2; each wafer comprises a substrate and a circuit layer positioned on the substrate, wherein the circuit layer comprises a dielectric layer and a metal layer positioned in the dielectric layer;

step S2, cutting wafer units from top to bottom by laser along scribing lines line by line, and cutting the wafer units into a circuit layer of one wafer to form a first groove;

and S3, cutting the circuit layer with the residual thickness and the wafer unit below the circuit layer into the through wafer unit line by line along the track of the first groove by using a blade to form a second groove.

Fig. 2 to 5 show a case where the wafer unit includes one wafer. The steps of the wafer dicing method according to the embodiment of the present application will be described in detail below with reference to fig. 2 to 5, taking an example that the wafer unit includes one wafer.

As shown in fig. 2, in step S1, a wafer unit to be diced is provided, wherein the wafer unit includes a wafer, i.e., a first wafer 10, and the first wafer 10 includes a first substrate 11 and a first circuit layer 12 disposed on the first substrate 11. The first circuit layer 12 includes a dielectric layer and a metal layer located in the dielectric layer. The dielectric layer may be a low dielectric insulating film formed of a film of an inorganic material such as SiOF or BSG (SiOB), or a film of an organic material such as polyimide-based or parylene-based polymer. The dielectric layer is formed with a metal interconnection structure and/or a bonding pad.

Step S2, cutting the wafer units from top to bottom along scribe lanes by laser, and cutting into the first circuit layer 12 of the first wafer 10, i.e. cutting out a part of the first circuit layer 12 to form a first trench V _1a . The surface of the first circuit layer 12 on the side far from the first substrate 11 is the front surface of the first wafer 10, and the surface of the first substrate 11 on the side far from the first circuit layer 12 is the back surface of the first wafer 10. The back side of the first wafer 10 is stuck with a film a so that the chips do not scatter when the first wafer 10 is divided into individual chips. Illustratively, the number of scribe lanes is multiple in a plane parallel to the front side of the first wafer 10, and the multiple scribe lanes extend in a first direction and a second direction, respectively, the first direction and the second direction being perpendicular. First trench V in plan view of first wafer 10 _1a Are staggered in a grid shape. At the time of forming the first trench V _1a After that, a first groove V _1a The first wafer 10 is not penetrated, that is, the first wafer 10 is not cut through.

First trenches V are formed by cutting the first circuit layer 12 by applying a laser beam B to scribe streets of the first wafer 10 _1a . The formation of marks in the first substrate 11 during laser cutting of the first circuit layer 12 is referred to as laser marks. The width of the knife mark formed by the subsequent blade cutting is smaller than that of the laser mark.

The step S2 specifically comprises the following steps: providing a laser beam machine, wherein the laser beam machine comprises a laser emitter, a chuck table and a moving mechanism; the chuck table fixes the first wafer 10, and the moving mechanism drives the first wafer 10 fixed on the chuck table to move. The first wafer 10 is placed on a chuck table of a laser beam machine, and the first wafer 10 is right side up and held on the chuck table. The chuck table holding the first wafer 10 is disposed directly below the image pickup device by a moving mechanism. The alignment operation of the laser to-be-cut region of the first wafer 10 is performed by the image pickup device and the moving mechanism. The image pickup device and the moving mechanism perform image processing such as pattern matching, and perform alignment of the application position of the laser beam B. The laser beam B is, for example, a pulsed laser beam. The technological parameters of laser cutting include: the wavelength of the laser is 300 nm-400 nm; the laser output power is 1.0W-4.0W; the repetition frequency is 40 kHz-200 kHz; the pulse width is 8 ns-13 ns; the cutting feed speed at which the laser beam B and the first wafer 10 move relative to each other is 50mm/sec to 400mm/sec. Illustratively, the laser beam B is emitted from a fixed position, and the moving mechanism moves the first wafer 10 at the dicing feed speed.

Fig. 3 is a schematic diagram of a dicing machine in a wafer dicing method according to an embodiment of the application. Fig. 4 is a schematic view of a dicing blade in a dicing method according to an embodiment of the application. Fig. 5 is a schematic view of a wafer after dicing by a blade in the wafer dicing method according to the embodiment of the application.

As shown in fig. 3 to 5, step S3 is performed along the first groove V by using the blade 02 _1a The remaining thickness of the first circuit layer 12 and the first substrate 11 thereunder are cut line by line to form a second trench V ₂ The method comprises the steps of carrying out a first treatment on the surface of the The first wafer 10 is cut through to the mucosa a, which is not cut through. First groove V _1a The projection onto the first substrate 11 covers the second trench V ₂ Projection onto the first substrate 11. Correspondingly, the second groove V ₂ Is smaller than the width e of the first groove V _1a Is a width d of (c). Illustratively, the blade cutting width is 60% -90% of the laser cutting width.

The step S3 specifically comprises the following steps: the cutting machine comprises a hub 01, a blade 02 and a motor 04 which are sequentially arranged along the axial direction, wherein the blade 02 is in a ring shape, and the blade 02 is fixed on the hub 01. The blade 02 and the hub 01 may be integrally formed or may be separately formed. The base 03 is located on the side of the blade 02 remote from the hub 01 and secures the blade 02. The cutter has a main shaft 05 rotating at a high speed and a hub 01 fitted over the main shaft 05, and a blade 02 is fixed to a radially peripheral edge of the hub 01. The blade 02 is used to cut a first wafer 10 held on a chuck table. The motor 04 drives the main shaft 05 to rotate, and the hub 01 drives the blade 02 to rotate along the first groove V _1a The remaining thickness of the first circuit layer 12 and the first substrate 11 thereunder are cut line by line to form a second trench V ₂ 。

The width of the blade 02 is, for example, 50 μm to 70 μm. Illustratively, the blade 02 is in the shape of a circular ring, the center of the circular ring is on the axis o of the spindle 05, and the thickness direction of the blade 02 is parallel to the axial direction of the spindle 05. The hub 01 is coaxial with the blade 02, the blade 02 comprises diamond, and the particle size of the diamond is 2-3 mu m.

The dicing machine of this embodiment further includes a chuck table having a holding means for holding the first wafer 10; an image pickup device for picking up an image of the first wafer 10 held on the chuck table; and a moving means for moving the first wafer 10 and the blade 02 on the chuck table relative to each other.

In general, the laser beam machine and the cutting machine are independent machine devices having a chuck table, a moving mechanism, and an image pickup device, respectively. In other examples, the laser beam machine and the cutting machine may also share a set of chuck table, moving mechanism, and image pickup device, set according to the machine equipment.

The laser diced wafer unit, such as the first wafer 10, is placed on a chuck table of a dicing machine, with the front side of the first wafer 10 facing upward, and is secured to the chuck table by a holding device. The chuck table holding the first wafer 10 is disposed directly below the image pickup device by a moving mechanism. The alignment operation of the region to be cut of the first wafer 10 is performed by the image pickup device and the moving device. That is, the image pickup device and the moving device perform image processing such as pattern matching, and the blade 02 of the dicing lane is aligned in a predetermined direction, thereby performing alignment of the region to be diced.

After detecting that alignment of the region to be cut is performed on the first wafer 10 held on the chuck table, the chuck table holding the first wafer 10 is moved to a cutting start position of the region to be cut. The blade 02 is rotated at a predetermined number of revolutions, and the moving means moves the first wafer 10 and the blade 02 on the chuck table relative to each other at a predetermined dicing feed rate. Dicing is performed along dicing street regions from the front side to the back side of the first wafer 10. For example, cutting at the blade 02 to form the second grooves V ₂ In the step (2), the outer diameter of the blade 02 is 40 mm-60 mm, and the thickness is thickThe degree is 50-70 μm; the rotation number of the blade 02 is 25000rpm to 50000rpm; the dicing feed speed at which the blade 02 and the first wafer 10 move relative to each other is 20mm/sec to 40mm/sec. The dicing feed speed at which the blade 02 and the wafer unit (e.g., the first wafer 10) move relative to each other should not be too small or too large. If the cutting feed speed is too small, the wear of the blade 02 is relatively large and the equipment output is low; if the cutting feed speed is too high, the edge is likely to be broken, resulting in deterioration of the cutting quality.

The material of the blade 02 comprises diamond, the hardness of the diamond is larger, the sharpness of the blade 02 can be improved, and the cutting efficiency and the second groove V are improved ₂ Is provided. The diamond particle size is, for example, 2 μm to 3 μm.

Fig. 6 is a schematic diagram of a first example of dicing a two-layer wafer in a wafer dicing method according to an embodiment of the application. A wafer unit to be diced is provided, the wafer unit comprising two stacked wafers, a first wafer 10 and a second wafer 20. The first wafer 10 includes a first substrate 11 and a first circuit layer 12 on the first substrate 11. The second wafer 20 includes a second substrate 21 and a second circuit layer 22 on the second substrate 21.

In a first example shown in fig. 6, the first circuit layer 12 of the first wafer 10 is bonded facing the second circuit layer 22 of the second wafer 20. Cutting the laser from top to bottom into a circuit layer of the bottommost wafer to form a first groove; accordingly, in the present example, the first trench V is formed by cutting through the second wafer 20 from top to bottom with the laser and continuing to cut down to a partial thickness of the first circuit layer 12, i.e., the first circuit layer 12 of the bottommost wafer (first wafer 10) _1b . Then, a blade is used to follow the first groove V _1b The remaining thickness of the first circuit layer 12 and the underlying first substrate 11 are cut line by line through the wafer unit to form a second trench.

Fig. 7 is a schematic diagram of a second example of dicing a two-layer wafer in the wafer dicing method according to the embodiment of the application. In fig. 7, the first circuit layer 12 of the first wafer 10 is bonded to the second substrate 21 side of the second wafer 20, the first circuit layer 12 and the second substrateAnd corresponding bonding layers can be manufactured according to requirements between the two layers 21. Forming a first trench V by laser top-down dicing through the second wafer 20 and continuing to cut down to a partial thickness of the first circuit layer 12 _1c . Then, a blade is used to follow the first groove V _1c The remaining thickness of the first circuit layer 12 and the underlying first substrate 11 are cut line by line through the wafer unit to form a second trench.

Fig. 8 is a schematic diagram of dicing a three-layer wafer according to the wafer dicing method of the embodiment of the application. A wafer unit to be diced is provided, the wafer unit comprising three stacked wafers, a first wafer 10, a second wafer 20 and a third wafer 30. The first wafer 10 includes a first substrate 11 and a first circuit layer 12 on the first substrate 11. The second wafer 20 includes a second substrate 21 and a second circuit layer 22 on the second substrate 21. The third wafer 30 includes a third substrate 31 and a third circuit layer 32 on the third substrate 31.

The first groove V is formed by cutting through the third wafer 30, the second wafer 20 and continuing to cut down part of the thickness of the first circuit layer 12 by laser, i.e. cutting into the first circuit layer 12 of the bottommost wafer (first wafer 10) _1d . The laser cutting process can be stopped in the middle link, and the depth of the laser to be cut can be accumulated and finished for a plurality of times.

During the laser dicing, the third circuit layer 32 in the third wafer 30, the second circuit layer 22 in the second wafer 20, and a portion of the thickness of the first circuit layer 12 in the first wafer 10 are cut away. The thickness of the circuit layer in the wafer unit cut by laser is 25% -85% of the total thickness of all the circuit layers in the wafer unit. Along the first groove V with a blade _1d The remaining thickness of the first circuit layer 12 and the underlying first substrate 11 are cut line by line through the wafer unit to form a second trench.

The application provides a wafer unit to be cut, which comprises one wafer or N stacked wafers. When N is less than or equal to 3, laser is adopted to cut into the circuit layer of the bottommost wafer from top to bottom, so as to form a first groove. And cutting the circuit layer with the residual thickness and the wafer units below the circuit layer line by line along the track of the first groove by using a blade until the wafer units are cut through, so as to form a second groove. Thus, a portion of the circuit layer (including the metal layer) has been removed by laser dicing; the metal layer with partial thickness is cut by laser, and compared with the metal layer with the whole thickness by laser, the thickness of the metal layer is reduced by laser cutting, so that the output per hour is improved; meanwhile, the circuit layer with a part of thickness is shared by laser cutting, the thickness of the rest circuit layer (comprising a metal layer) which is cut by the blade is also reduced, the serious metal wrapping cutter phenomenon and load force during blade cutting are reduced, and the problems that a chip breaks and a scribing groove exceeds a protection ring due to the fact that the wrapping cutter is serious are solved.

Forming a layer of wafers, a layer of wafers and a layer of wafers from the N stacked wafers from bottom to top to N layers of wafers; when N is more than or equal to 4 and less than or equal to 8, laser is adopted to cut into the circuit layer of any one layer of wafer in the N/2 layers from top to bottom, so as to form a first groove. In the present application, the cutting into the circuit layer of a certain layer of wafer refers to the circuit layer with the partial thickness of the certain layer of wafer cut, and the lowest boundary of laser cutting is located in the circuit layer. Illustratively, when n=4, the first trench is formed by cutting the laser from top to bottom into the circuit layer of the wafer of any one of the layers less than or equal to 2, i.e., into the circuit layer of the 1-layer wafer or into the circuit layer of the 2-layer wafer. When n=7, the first trench is formed by cutting the laser from top to bottom into the circuit layer of any one of the wafers of less than or equal to 3.5 layers, i.e., into the circuit layer of any one of the wafers of the first layer, the second layer and the third layer.

The thickness of the circuit layer (including the metal layer) in the wafer unit to be cut by the blade after laser cutting is less than or equal to 15 mu m, so that the serious blade wrapping phenomenon is avoided in the subsequent cutting by the blade. Under the condition that severe knife wrapping does not occur, the cutting thickness of the blade can be shared as much as possible, the cutting thickness of the laser cutting is shared as little as possible, and under the condition that the quality is ensured (the severe knife wrapping does not occur), the whole hourly output of the cut wafer unit is improved as much as possible.

In summary, the present application provides a wafer dicing method, including providing a wafer unit to be diced, where the wafer unit includes one wafer or N stacked wafers, and N is an integer greater than or equal to 2; each wafer comprises a substrate and a circuit layer positioned on the substrate, wherein the circuit layer comprises a dielectric layer and a metal layer positioned in the dielectric layer; cutting wafer units from top to bottom by laser along scribing lines line by line, cutting the wafer units into a circuit layer of one wafer to form a first groove; and cutting the circuit layer with the residual thickness and the wafer units below the circuit layer line by line along the track of the first groove by using a blade until the wafer units are cut through, so as to form a second groove. According to the application, the circuit layer (comprising the metal layer) with partial thickness is firstly cut by laser, and compared with the circuit layer with the whole thickness is cut by laser, the thickness of the circuit layer is reduced by laser, so that the output per hour is improved; meanwhile, the circuit layer with a part of thickness is shared by laser cutting, the thickness of the rest circuit layer which is cut by the blade is reduced, the serious metal wrapping cutter phenomenon and load force when the blade cutting thickness is larger are reduced, and the problems that a chip breaks and a scribing groove exceeds a protection ring due to serious wrapping cutter are solved.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the method disclosed in the embodiment, the description is relatively simple since it corresponds to the device disclosed in the embodiment, and the relevant points refer to the description of the method section.

The foregoing description is only illustrative of the preferred embodiments of the present application, and is not intended to limit the scope of the claims, and any person skilled in the art may make any possible variations and modifications to the technical solution of the present application using the method and technical content disclosed above without departing from the spirit and scope of the application, so any simple modification, equivalent variation and modification made to the above embodiments according to the technical matter of the present application fall within the scope of the technical solution of the present application.

Claims

1. A method of dicing a wafer, comprising:

2. The wafer dicing method of claim 1, wherein the first trench is formed in the circuit layer of the lowermost wafer with laser top-down dicing when N is less than or equal to 3.

3. The wafer dicing method of claim 1, wherein the N stacked wafers form a one-layer wafer, a two-layer wafer, to an N-layer wafer from bottom to top; and when N is more than or equal to 4 and less than or equal to 8, cutting the laser from top to bottom into the circuit layer of the wafer of any one layer of N/2 layers to form the first groove.

4. The wafer dicing method of claim 1, wherein the thickness of the circuit layer in the wafer cell diced using laser is 25% to 85% of the total thickness of all the circuit layers in the wafer cell.

5. The wafer dicing method of claim 1, wherein the laser dicing to form the first grooves specifically comprises providing a laser beam machine comprising a laser emitter, a chuck table, and a moving mechanism; the chuck table is used for fixing the wafer unit, and the moving mechanism drives the wafer unit fixed on the chuck table to move.

6. The method of claim 5, wherein in the step of forming the first trench by laser dicing, the process parameters include: the wavelength of the laser is 300 nm-400 nm; the laser output power is 1.0W-4.0W; the repetition frequency is 40 kHz-200 kHz; the pulse width is 8 ns-13 ns; the cutting feed speed at which the laser beam and the wafer unit are moved relative to each other is 50mm/sec to 400mm/sec.

7. The wafer dicing method of claim 1, wherein a projection of the first trench onto the substrate covers a projection of the second trench onto the substrate.

8. The method of claim 1, wherein the cutting by the blade to form the second groove comprises providing a cutter comprising a motor, a spindle, and a hub and the blade sequentially sleeved on the spindle; the blades are fixed on the radial peripheral edge of the hub, the motor drives the spindle to rotate, the blades are driven to rotate through the hub, the circuit layer with the residual thickness and the wafer units below the circuit layer are cut line by line along the track of the first groove until the wafer units are completely cut, and the second groove is formed.

9. The wafer dicing method of claim 8, wherein in the step of dicing the blade to form the second grooves, the blade: the outer diameter is 40 mm-60 mm, and the width is 50 μm-70 μm; the revolution of the blade is 25000 rpm-50000 rpm; the cutting feed speed at which the blade and the wafer unit move relative to each other is 20mm/sec to 40mm/sec.

10. The wafer dicing method according to any one of claims 1 to 9, wherein the number of the dicing streets is plural in a plane parallel to the front surface of the wafer unit, the plural dicing streets extending in a first direction and a second direction perpendicular to each other, respectively; the wafer is overlooked, and the first grooves and the second grooves are staggered in a grid shape;