JP2022100502A - Device chip manufacturing method - Google Patents

Abstract

To provide a manufacturing method of a high quality device chip without a damage like a crack.SOLUTION: A device chip manufacturing method which divides a wafer 1 to manufacture each device chip includes: a preparation step which prepares a cutting device having a chuck table, which can hold the wafer 1, and a cutting unit having a rotatable cutting blade 34 which can cut the wafer 1 held on the chuck table; a wafer holding step which holds the wafer 1 with the chuck table; a half-cut groove formation step which cuts the wafer 1 with the cutting blade 34 along a first division scheduled line to form a half-cut groove 13; a first full-cut step which cuts the wafer 1 with the cutting blade along a second division scheduled line to form a first division groove; and a second full-cut step which cuts the wafer 1 with the cutting blade 34 along the first division scheduled line to form a second division groove and thus to form each device chip.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for manufacturing a device chip, which manufactures a device chip by cutting and dividing a wafer made of a material such as a semiconductor.

In the manufacturing process of device chips used in electronic devices such as mobile phones and personal computers, first, a plurality of planned division lines (streets) intersecting each other are set on the surface of a wafer made of a material such as a semiconductor. Then, devices such as ICs (Integrated Circuits) and LSIs (Large-scale Integration) are formed in each area partitioned by the planned division line. After that, the wafer is ground from the back surface side to be thinned, and the wafer is divided along the planned division line to form individual device chips.

Wafer division is performed, for example, by a cutting device equipped with an annular cutting blade. The cutting device includes a chuck table capable of holding a wafer to be a workpiece, and a cutting unit equipped with a cutting blade and capable of cutting the wafer held on the chuck table.

Here, the back surface of the wafer may be previously covered with a metal film. When a wafer whose back surface is covered with a metal film is cut from the front surface side with a cutting blade to form a dividing groove, metal protrusions called burrs tend to occur on the edge of the dividing groove reaching the back surface side. Therefore, in order to reduce burrs, the wafer is placed on the chuck table with the back surface side facing upward, and the wafer is cut from the back surface side with a cutting blade (see Patent Document 1).

Here, in the case of a wafer not covered with a metal film, the position of the planned division line can be specified when cutting the wafer from the back surface side by using an infrared camera capable of photographing the front surface side through the wafer. However, if the wafer is covered with a metal film, infrared rays are shielded by the metal film, so that the position of the planned division line cannot be specified. Therefore, the metal film is partially removed from the outer peripheral portion of the wafer in advance, and the position of the planned division line is specified by photographing the surface side of the wafer in the region where the metal film is removed (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2012-227251 Japanese Unexamined Patent Publication No. 2020-136445

Due to the metal film formed on the back surface side, the device formed on the front surface side, and the like, a large stress that gives warpage may be applied to the wafer. When a wafer that exerts a stress that causes warping is cut from the back surface side, a chip called chipping or a crack called a crack may occur at the edge of the dividing groove that reaches the front surface side of the wafer.

In particular, when performing the process of cutting a wafer along a plurality of planned division lines along one direction and then cutting along a plurality of planned division lines along the other directions intersecting the wafer. It was confirmed that the quality tends to be low at the edge of the dividing groove formed in the first step.

This is because the stress applied to the wafer is biased depending on the direction due to the formation of the dividing groove in the first process, and when the wafer is cut in the next process, it is along the cutting direction (machining feed direction) of the cutting blade. It is considered that this is due to the reduced stress. In other words, in the first step, the stress applied to the wafer is not biased, and the wafer is cut with a large stress along the cutting direction of the cutting blade applied to the wafer, so that the edge of the split groove formed is formed. It is thought that cracks are likely to occur.

The present invention has been made in view of such problems, and an object of the present invention is to provide a method for manufacturing a device chip for manufacturing a high-quality device chip without damage such as cracks.

According to one aspect of the present invention, a plurality of first planned division lines set along the first direction and a plurality of sets along a second direction intersecting the first direction. A chuck that is a device chip manufacturing method for manufacturing individual device chips by dividing a waha having a surface in which a device is formed in each region divided by two scheduled division lines, and which can hold the waha. A preparatory process for preparing a cutting device equipped with a table, a cutting unit rotatably equipped with a cutting blade capable of cutting a wafer held on the chuck table, and an imaging unit, and a protective member is arranged on the surface side. A waiha holding step of placing the waha on the chuck table with the surface side of the provided waha facing the chuck table and holding the waha on the chuck table, and the first division scheduled line. After the half-cut groove forming step of cutting the waha with a cutting blade to form a half-cut groove and the half-cut groove forming step, the waha is cut with the cutting blade along the second scheduled division line. After the first full-cut step of forming the first split groove leading to the protective member and the first full-cut step, the wafer is cut with the cutting blade along the first scheduled split line. A method for manufacturing a device chip is provided, which comprises a second full-cut step of forming a second dividing groove leading to the protective member and forming an individual device chip.

Preferably, the back surface of the woofer is covered with a metal film, the imaging unit is equipped with an infrared camera, and the outer peripheral portion of the metal film covering the back surface of the waiha is cut into a ring shape. After the metal film removing step of removing the metal film and the metal film removing step, the imaging unit is positioned above the region where the metal film has been removed, and the surface side of the waha is imaged through the waha. The first division scheduled line and the division schedule line detection step for detecting the second division schedule line set on the surface thereof are performed after the wafer holding step and before the half-cut groove forming step. implement.

According to the method for manufacturing a device chip according to one aspect of the present invention, before the wafer is fully cut to form the first dividing groove, the wafer is cut along the direction intersecting the dividing groove to form a half-cut groove. Form. In this case, since the first dividing groove can be formed in the wafer in a state where the stress applied to the wafer is biased, cracks are less likely to occur at the edge of the divided groove formed first, and the quality of the dividing groove is also improved.

Therefore, according to one aspect of the present invention, there is provided a method for manufacturing a device chip for manufacturing a high-quality device chip without damage such as cracks.

FIG. 1A is a perspective view schematically showing the front surface of the wafer, and FIG. 1B is a perspective view schematically showing the back surface of the wafer. It is a perspective view which shows typically the cutting apparatus. It is a perspective view which shows typically the metal film removal process. It is a perspective view which shows typically the process of forming a half-cut groove. It is a perspective view which shows typically the 1st full-cut process. It is a perspective view which shows typically the 2nd full-cut process. FIG. 7A is a flowchart showing the flow of each step of the device chip manufacturing method according to one example, and FIG. 7B shows the flow of each step of the device chip manufacturing method according to another example. It is a flowchart.

A method for manufacturing a device chip according to an aspect of the present invention will be described with reference to the accompanying drawings. In the device chip manufacturing method according to the present embodiment, a wafer made of a material such as a semiconductor is processed.

First, a wafer to be a workpiece will be described. FIG. 1A is a perspective view schematically showing the front surface 1a side of the wafer 1, and FIG. 1B is a perspective view schematically showing the back surface 1b side of the wafer 1. The wafer 1 is a disk-shaped wafer made of a material such as a semiconductor such as silicon, SiC (silicon carbide), or GaN (gallium nitride). The wafer 1 may be made of a material such as sapphire, glass, or quartz.

On the surface 1a of the wafer 1, a plurality of scheduled division lines 3 that intersect each other, which are called streets, are set. More specifically, on the surface 1a of the wafer 1, a plurality of first planned division lines 3a along the first direction and a plurality of second lines along the second direction intersecting the first direction are provided. Scheduled division line 3b and is set. Devices 5 such as ICs and LSIs are formed in each region of the surface 1a of the wafer 1 partitioned by the scheduled division line 3. When the wafer 1 is divided along the scheduled division line 3, a plurality of device chips are manufactured.

The division of the wafer 1 along the scheduled division line 3 is performed by, for example, the cutting apparatus 2 shown in FIG. FIG. 2 is a perspective view schematically showing the cutting device 2. The cutting device 2 photographs the cutting unit 32 provided with the annular cutting blade 34, the chuck table 20 holding the wafer 1, and the wafer 1 held by the chuck table 20 to detect the position of the scheduled division line 3. An image pickup unit 30 is provided.

Here, a metal film 1c (see FIG. 1) may be formed on the back surface 1b side of the wafer 1. When the wafer 1 is held by the chuck table 20 with the front surface 1a facing upward and the wafer 1 is cut along the planned division line 3 with the cutting blade 34, a metal protrusion called a burr is formed on the back surface 1b side. Therefore, the quality of the formed device chip is low. Therefore, the wafer 1 is held by the chuck table 20 with the back surface 1b side facing upward, and the cutting blade 34 is cut from the back surface 1b side to divide the wafer 1.

When the wafer 1 is carried into the cutting device 2, for example, a tape-shaped protective member 9 having a diameter larger than that of the wafer 1 is attached to the surface 1a side of the wafer 1. The protective member 9 is also called a dicing tape. The protective member 9 includes a flexible film-like base material layer and an adhesive layer (glue layer) provided on one surface of the equipment layer.

An inner peripheral portion of a ring frame 7 made of a metal such as aluminum or stainless steel is attached to the outer peripheral portion of the protective member 9. The ring frame 7 has an opening having a diameter larger than the diameter of the wafer 1. The frame unit 11 is formed by attaching the protective member 9 to the ring frame 7 and attaching the protective member 9 exposed in the opening of the ring frame to the surface 1a side of the wafer 1. At this time, the back surface 1b side of the wafer 1 on which the metal film 1c is formed is exposed upward.

Next, the cutting device 2 according to the present embodiment will be described. A cassette table 6 on which the cassette 6a is placed is provided at the corner of the base 4 of the cutting device 2. The cassette table 6 can be raised and lowered in the vertical direction (Z-axis direction) by an elevating mechanism (not shown). In FIG. 2, the outline of the cassette 6a placed on the cassette table 6 is shown by a two-dot chain line.

Temporarily placed at a position adjacent to the cassette table 6 on the upper surface of the base 4 including a pair of guide rails 8 that are approached and separated from each other while maintaining a state parallel to the Y-axis direction (left-right direction, indexing feed direction). A table 10 is provided. Further, at a position adjacent to the temporary placement table 10 on the upper surface of the base 4, a carry-out unit 12 for carrying out the frame unit 11 housed in the cassette 6a placed on the cassette table 6 from the cassette 6a is provided. .. The carry-out unit 12 has a grip portion on the front surface capable of gripping the ring frame 7.

When carrying out the frame unit 11 housed in the cassette 6a, the carry-out unit 12 is moved toward the cassette 6a, the ring frame 7 is gripped by the grip portion, and then the carry-out unit 12 is separated from the cassette 6a. Move to. Then, the frame unit 11 is pulled out from the cassette 6a to the temporary table 10. At this time, when the pair of guide rails 8 are moved in an interlocking direction in the X-axis direction and the ring frame 7 is sandwiched between the pair of guide rails 8, the frame unit 11 is positioned at a predetermined position.

A long opening 4a is formed in the X-axis direction (front-rear direction, machining feed direction) at a position adjacent to the cassette table 6 on the upper surface of the base 4. Inside the opening 4a, a ball screw type X-axis moving mechanism (machining feed unit) (not shown) and a bellows-shaped dust-proof / drip-proof cover 26 that covers the upper part of the X-axis moving mechanism are arranged.

The X-axis movement mechanism is connected to the lower part of the X-axis movement table 16 and has a function of moving the X-axis movement table 16 in the X-axis direction. For example, the X-axis moving table 16 moves between a loading / unloading area close to the cassette table 6 and a machining area below the cutting unit 32 described later.

A table base 18 and a chuck table 20 mounted on the table base 18 are provided on the X-axis moving table 16. A porous plate (not shown) is provided on the upper portion of the chuck table 20, and one end of a suction path (not shown) formed in the chuck table 20 is connected to the porous plate. A suction source (not shown) is connected to the other end of the suction path. When the suction source is operated, a negative pressure is generated on the surface of the porous plate. As a result, the surface of the porous plate functions as a holding surface 22 that attracts and holds the wafer 1.

Below the chuck table 20, a rotation drive mechanism (not shown) for rotating the chuck table 20 around a predetermined rotation axis is provided. Further, a clamp 24 for gripping the ring frame 7 is provided on the radial outer side of the chuck table 20. The chuck table 20 moves in the X-axis direction by the X-axis movement mechanism described above.

The transfer of the frame unit 11 from the temporary table 10 to the chuck table 20 is carried out by the temporary transfer table 10 on the upper surface of the base 4 and the first transfer unit 14 provided at a position adjacent to the opening 4a. The first transport unit 14 has a shaft portion that can be raised and lowered and is rotatable upward from the upper surface of the base 4, an arm portion that extends horizontally from the upper end of the shaft portion, and a lower tip of the arm portion. It has a holding portion provided.

When the frame unit 11 is transported from the temporary placement table 10 to the chuck table 20 by the first transport unit 14, the X-axis moving table 16 is moved to position the chuck table 20 in the loading / unloading area. Then, the ring frame 7 of the frame unit 11 temporarily placed on the temporary placement table 10 is held by the holding portion, the frame unit 11 is lifted, the shaft portion is rotated, and the frame unit 11 is moved above the chuck table 20. Move to.

After that, the frame unit 11 is lowered and placed on the holding surface 22 of the chuck table 20. Then, the ring frame 7 is fixed by the clamp 24, and the wafer 1 is sucked and held by the chuck table 20 via the protective member 9 of the frame unit 11.

The cutting device 2 includes a support structure 28 arranged so as to cross the opening 4a above the movement path from the loading / unloading region of the X-axis moving table 16 to the machining region. The support structure 28 is provided with an image pickup unit 30 facing downward. The image pickup unit 30 is, for example, an infrared camera.

The image pickup unit 30 takes an image of the wafer 1 sucked and held by the chuck table 20 from the back surface 1b side, and detects the position and orientation of the scheduled division line 3 set on the front surface 1a. However, as described later, when the infrared ray transmitted through the wafer 1 is photographed by the image pickup unit 30, it is preferable to partially remove the metal film 1c that shields the infrared ray from the back surface 1b of the wafer 1.

In the machining area where the wafer 1 is cut, a cutting unit 32 for cutting the wafer 1 of the frame unit 11 held on the chuck table 20 is provided. The cutting unit 32 includes a cutting blade 34 having an annular cutting blade on the outer periphery, and a spindle 36 having a cutting blade 34 mounted on the tip end and along the Y-axis direction which is the rotation axis of the cutting blade 34.

A rotary drive source (not shown) such as a motor is connected to the base end side of the spindle 36, and the cutting blade 34 mounted on one end of the spindle 36 rotates by the force generated by the rotary drive source. The cutting blade 34 includes an annular base made of aluminum or the like, and an annular cutting blade fixed to the outer peripheral portion of the base. The cutting edge is formed, for example, by fixing abrasive grains such as diamond with a binder such as resin or metal.

Further, the cutting device 2 includes an indexing feed unit (not shown) inside the support structure 28 that moves the cutting unit 32 along the indexing feed direction (Y-axis direction) orthogonal to the machining feed direction (X-axis direction). .. When the machining feed unit and the index feed unit are operated, the chuck table 20 that sucks and holds the wafer 1 and the cutting unit 32 can be relatively moved.

When the rotating cutting blade 34 is cut into the wafer 1 included in the frame unit 11 held by the chuck table 20, the wafer 1 is cut to form a dividing groove reaching the surface 1a. When the wafer 1 is cut along all the scheduled division lines 3, the wafer 1 is divided to form individual device chips. After that, the chuck table 20 is moved to the loading / unloading region by the X-axis moving mechanism.

An opening 4b is formed at a position adjacent to the temporary placement table 10 and the opening 4a on the upper surface of the base 4, and the cleaning unit 38 for cleaning the processed frame unit 11 is housed in the opening 4b. The cleaning unit 38 includes a spinner table that holds the frame unit 11.

The cutting device 2 includes a second transfer unit 40 that transfers the frame unit 11 from the chuck table 20 located in the carry-in / out area to the cleaning unit 38. The second transport unit 40 has an arm portion that can move along the Y-axis direction and a holding portion provided below the tip of the arm portion.

When the frame unit 11 is transported from the chuck table 20 to the cleaning unit 38 by the second transport unit 40, the frame unit 11 is first held by the holding portion. Then, the arm portion is moved along the Y-axis direction, and the frame unit 11 is placed on the spinner table of the cleaning unit 38. After that, the frame unit 11 is held on the spinner table to wash the wafer 1.

When the wafer 1 is cleaned by the cleaning unit 38, a cleaning fluid (typically, a mixed fluid in which water and air are mixed) is injected toward the surface of the wafer 1 while rotating the spinner table. Then, the frame unit 11 washed by the washing unit 38 is housed in the cassette 6a placed on the cassette table 6.

When accommodating the frame unit 11 in the cassette 6a, the frame unit 11 is conveyed from the cleaning unit 38 to the temporary placement table 10 by using the first transfer unit 14. Then, the carry-out unit 12 is moved toward the cassette 6a, and the frame unit 11 is pushed into the cassette 6a.

In this way, in the cutting device 2, the frame unit 11 is carried out from the cassette 6a, the frame unit 11 is sucked and held by the chuck table 20, and the wafer 1 included in the frame unit 11 is cut by the cutting unit 32. After that, the frame unit 11 is washed by the washing unit 38 and is housed in the cassette 6a again. In the cutting device 2, the frame units 11 are carried out one after another from the cassette 6a, and the wafer 1 is cut one after another by the cutting unit 32 on the chuck table 20.

When the waha 1 is cut by the cutting blade 34, first, the chuck table 20 that holds the waha 1 is rotated around an axis perpendicular to the holding surface 22, and the machining feed direction (X-axis direction) of the cutting device 2 is obtained. And the direction of the planned division line 3 of the wayha 1 are matched. For example, the direction of the first scheduled division line 3a along the first direction is aligned with the machining feed direction.

Then, while rotating the cutting blade 34, the cutting unit 32 is lowered until the lower end of the cutting blade 34 reaches the protective member 9, and then the chuck table 20 is moved along the X-axis direction. Then, the cutting blade 34 cuts into the wafer 1 and a dividing groove is formed in the wafer 1. After that, the cutting unit 32 is raised, and the wafer 1 is similarly cut by the cutting blade 34 one after another along the plurality of first scheduled division lines 3a.

Then, after forming a split groove in the wafer 1 along all the first scheduled split lines 3a, the chuck table 20 is rotated to align the direction of the uncut scheduled split line 3 with the X-axis direction. That is, the direction of the second scheduled division line 3b along the second direction is aligned with the machining feed direction. Then, similarly, the wafer 1 is cut along all the second scheduled division lines 3b to form a division groove. Then, the wafer 1 is divided into individual device chips.

Here, if the back surface 1b side is covered with the metal film 1c and the device 5 is formed on the front surface 1a side, a stress that gives a warp is applied to the wafer 1. When the wafer 1 is cut to form a dividing groove in this state, a chip called chipping or a crack called a crack may occur at the edge of the dividing groove reaching the surface 1a side of the wafer 1. In particular, it is confirmed that the quality tends to be low at the edge of the dividing groove formed in the first step.

That is, when the wafer 1 is cut along the first scheduled division line 3a along the first direction and then the wafer 1 is cut along the second scheduled division line 3b along the second direction, the first The quality of the dividing groove formed in the wafer 1 along the direction of is low. When the wafer 1 is first divided along the second scheduled division line 3b along the second direction, the quality of the dividing groove formed in the wafer 1 along the second direction is lowered. ..

This is because the stress applied to the wafer 1 is biased depending on the direction due to the formation of the dividing groove in the first step, and when the wafer 1 is cut in the next step, the cutting direction (machining feed direction) of the cutting blade 34 is formed. ) Is reduced. In other words, in the first step, the stress applied to the wafer 1 is not biased, and the wafer 1 is cut in a state where a large stress along the cutting direction of the cutting blade 34 is applied to the wafer 1, so that the wafer 1 is formed. It is considered that cracks are likely to occur at the edge of the dividing groove.

Therefore, in the device chip manufacturing method according to the present embodiment, the stress applied to the wafer 1 is biased in advance even when the dividing groove is first formed in the wafer 1 by the cutting blade 34. Hereinafter, each step of the device chip manufacturing method according to the present embodiment will be described. FIG. 7B is a flowchart showing the flow of each step of the device chip manufacturing method according to the present embodiment.

First, in the device chip manufacturing method according to the present embodiment, the preparation step S10 for preparing the cutting device 2 shown in FIG. 2 is carried out. As described above, the cutting device 2 includes a chuck table 20 capable of holding the waha 1 and a cutting unit 32 rotatably provided with a cutting blade 34 capable of cutting the waha 1 held by the chuck table 20.

Further, the cutting device 2 has a machining feed unit that feeds the chuck table 20 and the cutting unit 32 relatively in the X-axis direction, and the chuck table 20 and the cutting unit 32 in the Y-axis direction orthogonal to the X-axis direction. It is provided with an indexing feed unit for relatively indexing and feeding. Further, the cutting device 2 includes an image pickup unit 30 that captures an image of the wafer 1 sucked and held by the chuck table 20.

Next, the wafer holding step S20 is carried out. In the wafer holding step S20, the wafer 1 is placed on the chuck table 20 with the surface 1a side of the wafer 1 having the protective member 9 arranged on the surface 1a side facing the chuck table 20. The wafer 1 is conveyed from the cassette 6a onto the chuck table 20 by the carry-out unit 12, the first transfer unit 14, and the like. Then, the suction source of the chuck table 20 is operated, and the wafer 1 is sucked and held by the chuck table 20 via the protective member 9. At this time, the back surface 1b side of the wafer 1 is exposed upward.

After that, the chuck table 20 is rotated around an axis perpendicular to the holding surface 22, and the first scheduled division line 3a of the wafer 1 is aligned with the machining feed direction (X-axis direction). The detection of the first scheduled division line 3a is performed by the image pickup unit 30. The image pickup unit 30 is, for example, an infrared camera, observes the surface 1a side from above through the wafer 1, and detects the orientation and position of the first scheduled division line 3a.

Here, when the back surface 1b side of the wafer 1 is covered with the metal film 1c, the image pickup unit 30 cannot photograph the front surface 1a side of the wafer 1 through the wafer 1. This is because the metal film 1c does not transmit infrared rays. Therefore, it is preferable that the metal film removing step S21 for removing a part of the metal film 1c is carried out before the detection of the scheduled division line 3 is carried out.

FIG. 3 is a perspective view schematically showing the metal film removing step S21. In FIG. 3 and the like, the main body of the chuck table 20 and the cutting unit 32 excluding the cutting blade 34 whose contour is shown by the alternate long and short dash line are omitted. In the metal film removing step S21, the outer peripheral portion 1d of the metal film 1c covering the back surface 1b of the wafer 1 is cut to remove the metal film 1c in a ring shape. The outer peripheral portion 1d of the wafer 1 is referred to as an outer peripheral surplus region because the device 5 is not formed on the surface 1a. Removing the metal film 1c in this region does not affect the chips manufactured from the wafer 1.

In the metal film removing step S21, first, the cutting blade 34 is positioned above the outer peripheral portion 1d of the wafer 1. At this time, it is preferable to position the cutting blade 34 above the end portion of the wafer 1 in the Y-axis direction. Then, the rotation of the cutting blade 34 is started, and the cutting blade 34 is lowered. Then, the cutting blade 34 comes into contact with the metal film 1c, and the metal film 1c is cut. At this time, when the lower end of the cutting blade 34 reaches the lower part of the metal film 1c, the lowering of the cutting blade 34 ends.

After that, when the chuck table 20 is rotated once around the axis perpendicular to the holding surface 22, the metal film 1c is removed along the outer peripheral portion 1d. When the metal film removing step S21 is carried out, the back surface 1b of the wafer 1 is exposed upward in the annular region along the outer peripheral portion 1d. Therefore, in this region, the image pickup unit 30 can observe the surface 1a side through the wafer 1.

After the metal film removing step S21, the scheduled division line detection step S22 is carried out. The image pickup unit 30 is positioned above the region from which the metal film 1c has been removed, and the surface 1a side of the wafer 1 is imaged through the wafer 1 and the first division scheduled line 3a and the second division set on the surface 1a are performed. The scheduled line 3b is detected.

As a result, the cutting apparatus 2 can perform cutting along the first scheduled division line 3a and the second scheduled division line 3b. In the device chip manufacturing method according to the present embodiment, after the wafer holding step S20 is carried out, the metal film removing step S21 and the planned division line detection step S22 are carried out before the half-cut groove forming step S30 described below is carried out. It is good to do.

Next, the half-cut groove forming step S30 for cutting the wafer 1 with the cutting blade 34 along the first scheduled division line 3a to form the half-cut groove is carried out. FIG. 4 is a perspective view schematically showing the half-cut groove forming step S30. In FIG. 4, the main body and the like of the chuck table 20 are omitted.

When the half-cut groove forming step S30 is performed, the chuck table 20 is rotated around the axis perpendicular to the holding surface 22 in advance, and the first scheduled division line 3a of the weight 1 is set in the machining feed direction (X-axis direction). match. Then, the cutting blade 34 is positioned above the extension line of the first scheduled division line 3a of the wafer 1, the rotation of the cutting blade 34 is started, and the cutting blade 34 is lowered. At this time, the lower end of the cutting blade 34 is positioned at a predetermined height position between the height position of the front surface 1a of the wafer 1 and the height position of the back surface 1b.

The height position of the lower end of the cutting blade 34 at this time is the height position of the bottom surface of the half-cut groove 13 formed in the wafer 1. Here, it is preferable that the bottom surface of the half-cut groove 13 is located at a height intermediate between the front surface 1a and the back surface 1b of the wafer 1.

Next, when the machining feed unit is operated and the chuck table 20 is machined and fed along the X-axis direction, the wafer 1 is cut along the first scheduled division line 3a, and a half cut groove 13 is formed in the wafer 1. To. Then, the indexing feed unit is operated to index and feed the cutting unit 32 along the Y-axis direction, and the wafer 1 is similarly cut along the other first scheduled division line 3a. In this way, cutting is repeated to form a half-cut groove 13 in the wafer 1 along all the first scheduled division lines 3a.

When the half-cut groove 13 is formed along the plurality of first scheduled division lines 3a along the first direction, the stress acting on the wafer 1 is biased depending on the direction. As described above, in the device chip manufacturing method according to the present embodiment, the stress acting on the wafer 1 is biased before the dividing groove is first formed in the wafer 1.

After the half-cut groove forming step S30, the first full-cut step S40 for cutting the wafer 1 with the cutting blade 34 along the second scheduled division line 3b to form the first dividing groove leading to the protective member 9 is performed. implement. FIG. 5 is a perspective view schematically showing the first full-cut step S40. After forming the half-cut groove 13 along the first scheduled division line 3a, the chuck table 20 is rotated to cut the wafer 1 along the second scheduled division line 3b, and the second scheduled division line 3b is formed. Align the direction of 3b with the machining feed direction (X-axis direction).

In the first full-cut step S40, the cutting blade 34 is positioned above the extension line of the second scheduled division line 3b, the rotation of the cutting blade 34 is started, and the cutting blade 34 is lowered. In the first full-cut step S40, the cutting blade 34 is cut into the protective member 9 below the surface 1a of the wafer 1 in order to form the first dividing groove 15 that divides the wafer 1. That is, the cutting unit 32 is lowered so that the lower end of the cutting blade 34 is positioned at a height position between the upper surface and the lower surface of the protective member 9.

After that, when the machining feed unit is operated and the chuck table 20 is machined and fed along the X-axis direction, the wafer 1 is cut along the second scheduled division line 3b, and the first division groove 15 is formed in the wafer 1. Will be done. Then, the indexing feed unit is operated to index and feed the cutting unit 32 along the Y-axis direction, and the wafer 1 is similarly cut along the other second scheduled division line 3b. In this way, cutting is repeated to form the first dividing groove 15 in the wafer 1 along all the second scheduled division lines 3b.

After the first full-cut step S40, the wafer 1 is cut by the cutting blade 34 along the first scheduled division line 3a to form a second division groove leading to the protective member 9, and individual device chips are formed. The second full-cut step S50 is carried out. FIG. 6 is a perspective view schematically showing the second full-cut step S50.

After forming the first dividing groove 15 along the second scheduled division line 3b, the chuck table 20 is rotated to cut the waha 1 along the first scheduled division line 3a, and the first division is performed. Align the direction of the scheduled line 3a with the machining feed direction (X-axis direction).

In the second full-cut step S50, the cutting blade 34 is positioned above the extension line of the first scheduled division line 3a, the rotation of the cutting blade 34 is started, and the cutting blade 34 is lowered. Also in the second full-cut step S50, the cutting unit 32 is lowered so that the lower end of the cutting blade 34 is positioned at a height position between the upper surface and the lower surface of the protective member 9.

After that, when the machining feed unit is operated to machine feed the chuck table 20 along the X-axis direction, the wafer 1 is cut along the first scheduled division line 3a, and the second division groove 17 is formed in the wafer 1. Will be done. Then, the indexing feed unit is operated to index and feed the cutting unit 32 along the Y-axis direction, and the wafer 1 is similarly cut along the other first scheduled division line 3a. In this way, cutting is repeated to form a second dividing groove 17 in the wafer 1 along all the first scheduled division lines 3a.

Here, the wafer 1 is previously formed with a half-cut groove 13 along the first scheduled division line 3a. Therefore, in the second full-cut step S50, it is preferable to form the second dividing groove 17 including the half-cut groove 13 by cutting the cutting blade 34 at the forming position of the half-cut groove 13. In this case, the cutting load applied to the wafer 1 is smaller than that when the wafer 1 is cut at a position where the half-cut groove 13 is not formed. Therefore, the wafer 1 is less likely to be damaged around the formed second dividing groove 17.

When the wafer 1 is cut along the first scheduled division line 3a and the second scheduled division line 3b to form the second division groove 17 and the first division groove 15, the wafer 1 is divided into individual device chips. Will be done. That is, a device chip is manufactured.

As described above, according to the method for manufacturing a device chip according to the present embodiment, the wafer 1 is fully cut to form the first dividing groove 15 along the second direction. The wafer 1 is cut along the first direction intersecting the directions to form the half-cut groove 13. When the half-cut groove 13 along the first direction is formed in the wafer 1, the stress acting to give the wafer 1 a warp is biased depending on the direction.

Therefore, when the first full-cut step S40 is carried out, the stress along the second direction, which is the cutting direction (machining feed direction) of the cutting blade 34, is reduced. In this case, since the first first dividing groove 15 can be formed in the wafer 1 in a state where the stress applied to the wafer 1 is biased, damage such as cracks is caused on the edge of the first dividing groove 15 formed first. It is less likely to occur, and the quality of the first dividing groove 15 is improved.

After that, when the second dividing groove 17 is formed in the wafer 1 along the first scheduled division line 3a, the stress applied to the wafer 1 is biased by the first dividing groove 15 formed in advance. It becomes the state that occurred. Therefore, damage such as cracks is less likely to occur on the edge of the second dividing groove 17 formed in the second full-cut step S50, and the quality of the second dividing groove 17 is also improved. Therefore, according to the device chip manufacturing method according to the present embodiment, the wafer 1 can be cut with high quality, the quality of all the divided grooves 15 and 17 formed is high, and the device chip can be manufactured with high quality.

The present invention is not limited to the description of the above embodiment, and can be modified in various ways. For example, in the above-described embodiment, the case where the metal film 1c is formed on the back surface 1b side of the wafer 1 and the metal film 1c exerts a stress that causes the wafer 1 to warp has been described. However, one aspect of the present invention is not limited to this.

That is, the wafer processed by the method for manufacturing a device chip according to one aspect of the present invention is not limited to this, and the metal film 1c may not be formed on the back surface 1b side, and stress is applied to the wafer 1 for other reasons. May be working. Further, the wafer 1 does not need to have a strong stress that causes warping.

For example, an organic resin film may be provided on the surface 1a of the wafer 1, and the stress that gives the wafer 1 a warp may be exerted by the organic resin film. Even in this case, according to one aspect of the present invention, the half-cut groove 13 is formed in the wafer 1 in advance to cause stress bias, so that the wafer 1 can be processed with high quality and a high-quality device chip. Can be manufactured.

When the metal film 1c is not formed on the back surface 1b side, the metal film 1c is removed in order to observe the front surface 1a side through the wafer 1 with the image pickup unit 30 and specify the positions of the scheduled division lines 3a and 3b. The film removing step S21 becomes unnecessary. FIG. 7A is a flowchart showing the flow of each step of the device chip manufacturing method according to one aspect of the present invention when the metal film removing step S21 or the like is not carried out.

In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented as long as they do not deviate from the scope of the object of the present invention.

1 Waha 1a Front surface 1b Back surface 1c Metal film 1d Outer circumference 3, 3a, 3b Scheduled division line 5 Device 7 Ring frame 9 Protective member 11 Frame unit 13 Half cut groove 15, 17 Division groove 2 Cutting device 4 Base 4a, 4b Opening 6 Cassette table 6a Cassette 8 Guide rail 10 Temporary placement table 12 Carry-out unit 14, 40 Transport unit 16 X-axis moving table 18 Table base 20 Chuck table 22 Holding surface 24 Clamp 26 Dust-proof and drip-proof cover 28 Support structure 30 Imaging unit 32 Cutting unit 34 Cutting blade 36 Spindle 38 Cleaning unit

Claims (2)

Partitioned by a plurality of first scheduled split lines set along the first direction and a plurality of second scheduled split lines set along a second direction intersecting the first direction. It is a method of manufacturing a device chip in which a wafer having a surface on which a device is formed in each of the formed regions is divided to manufacture individual device chips.
A preparatory step for preparing a cutting device equipped with a chuck table capable of holding a wafer, a cutting unit rotatably equipped with a cutting blade capable of cutting a wafer held by the chuck table, and an imaging unit.
A wafer holding step of placing the wafer on the chuck table with the surface side of the wafer having a protective member disposed on the surface side facing the chuck table and holding the wafer on the chuck table.
A half-cut groove forming step of cutting the wafer with the cutting blade along the first scheduled division line to form a half-cut groove.
After the half-cut groove forming step, a first full-cut step of cutting the wafer with the cutting blade along the second scheduled split line to form a first split groove leading to the protective member.
After the first full-cut step, the wafer is cut with the cutting blade along the first scheduled split line to form a second split groove leading to the protective member to form individual device chips. The second full-cut process and
A method for manufacturing a device chip, which comprises. The back surface of the wafer is covered with a metal film, and the back surface of the wafer is covered with a metal film.
The image pickup unit is equipped with an infrared camera.
A metal film removing step of cutting the outer peripheral portion of the metal film covering the back surface of the wafer to remove the metal film in a ring shape.
After the metal film removing step, the imaging unit is positioned above the area where the metal film has been removed, and the surface side of the wafer is imaged through the wafer and the first division set on the surface. The scheduled division line detection step for detecting the scheduled line and the second scheduled division line, and
The method for manufacturing a device chip according to claim 1, wherein the method is carried out after the wafer holding step and before the half-cut groove forming step.

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