JP2003338467A - Method for cutting semiconductor substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cutting a semiconductor substrate capable of efficiently cutting a semiconductor substrate, along with a die bond resin layer, on which a sheet is pasted with the die bond resin layer interposed. <P>SOLUTION: A planned cut 9 by a melting process region 13 is formed inside a silicon wafer 11 by generating multiphoton absorption. Then an adhesive sheet 20 pasted on the silicon wafer 11 is expanded. Thus, the silicon wafer 11 is precisely cut into semiconductor chips 25 along the planned cut 9. Since cut surfaces 25a and 25a, facing each other, of adjoining semiconductor chips 25 and 24 come apart from each other from a tightly contacted state, a die bond resin layer 23 is also cut along the planned cut 9. Thus, the silicon wafer 11 and the die bond resin layer 23 are cut more efficiently than by cutting them with a blade not to cut a base material 21. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor substrate cutting method used for cutting a semiconductor substrate in a semiconductor device manufacturing process or the like.

[0002]

2. Description of the Related Art As conventional techniques of this type, the following techniques are described in Patent Documents 1 and 2. First, an adhesive sheet is attached to the back surface of a semiconductor wafer via a die bond resin layer, and the semiconductor wafer is held on the adhesive sheet to cut the semiconductor wafer with a blade to obtain a semiconductor chip. Then, when picking up the semiconductor chip on the adhesive sheet, the die bond resin is peeled off from the adhesive sheet together with the individual semiconductor chips. This makes it possible to bond the semiconductor chip onto the lead frame by omitting steps such as applying an adhesive to the back surface of the semiconductor chip.

[0003]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-158276

[Patent Document 2] Japanese Patent Application Laid-Open No. 2000-104040

[0004]

However, in the technique as described above, when the semiconductor wafer held on the adhesive sheet is cut by the blade, the adhesive sheet is not cut and the semiconductor wafer is not cut. It is necessary to surely cut the die bond resin layer existing between the pressure sensitive adhesive sheet and the pressure sensitive adhesive sheet. Therefore, the cutting of the semiconductor wafer by the blade in such a case is to be performed with extreme caution.

Therefore, the present invention has been made in view of the above circumstances, and a semiconductor capable of efficiently cutting together with a die bond resin layer a semiconductor substrate to which a sheet is attached with a die bond resin layer interposed therebetween. An object is to provide a method for cutting a substrate.

[0006]

In order to achieve the above-mentioned object, a method for cutting a semiconductor substrate according to the present invention provides a condensing point inside a semiconductor substrate to which a sheet is attached with a die bond resin layer interposed. By irradiating with a laser beam in combination, a modified region by multiphoton absorption is formed inside the semiconductor substrate, and a step of forming a planned cutting part with the modified region, and a step of forming the planned cutting part, And a step of cutting the semiconductor substrate and the die bond resin layer along the planned cutting portion by expanding the sheet.

In this method of cutting a semiconductor substrate, a laser beam is irradiated with a focusing point inside the semiconductor substrate,
Since the phenomenon of multiphoton absorption is generated inside the semiconductor substrate to form the modified region, the modified region is planned to be cut inside the semiconductor substrate along the desired cut line to cut the semiconductor substrate. Parts can be formed.
When the portion to be cut is formed inside the semiconductor substrate in this manner, a crack is generated in the thickness direction of the semiconductor substrate from the portion to be cut as a starting point with a relatively small force. Therefore, when the sheet attached to the semiconductor substrate is expanded, the semiconductor substrate can be accurately cut along the planned cutting portion. At this time, the cut surfaces of the cut semiconductor substrate facing each other are initially in a state of being in close contact with each other, and are separated as the sheet expands, so that the die bond resin layer existing between the semiconductor substrate and the sheet is also cut. It will be cut along the scheduled part. Therefore, it is possible to cut the semiconductor substrate and the die bond resin layer along the planned cutting portion much more efficiently than in the case where the semiconductor substrate and the die bond resin layer are cut with a blade while leaving the sheet. Moreover, since the cut surfaces of the cut semiconductor substrate facing each other are initially in close contact with each other, the cut individual semiconductor substrates and the cut individual die bond resin layers have substantially the same outer shape, and It is also possible to prevent the die bond resin from protruding from the cut surface of the substrate.

Further, in the method for cutting a semiconductor substrate according to the present invention, the focus point is aligned inside the semiconductor substrate to which the sheet is attached with the die bond resin layer interposed, and the peak power density at the focus point is 1 or less. By irradiating a laser beam under the condition of × 10 ⁸ (W / cm ² ) or more and a pulse width of 1 μs or less, a modified region including a melt processed region is formed inside the semiconductor substrate, and the melt processed region is The method includes a step of forming a planned cutting part with the modified region including the step, and a step of cutting the semiconductor substrate and the die bond resin layer along the planned cutting part by expanding the sheet after the step of forming the planned cutting part. It is characterized by

In this method of cutting a semiconductor substrate, in the step of forming the planned cutting portion, the focus point is aligned inside the semiconductor substrate, and the peak power density at the focus point is 1 × 1.
The laser light is irradiated under the condition that the pulse width is 0 ⁸ (W / cm ² ) or more and the pulse width is 1 μs or less. Therefore, the inside of the semiconductor substrate is locally heated by multiphoton absorption. By this heating, a melt processing region is formed inside the semiconductor substrate.
Since this melt-processed area is an example of the above-mentioned modified area, the method for cutting the semiconductor substrate is far more efficient than the case where the semiconductor substrate and the die bond resin layer are cut with a blade while leaving the sheet. It becomes possible to cut the semiconductor substrate and the die bond resin layer along the planned cutting portion.

Further, in the method for cutting a semiconductor substrate according to the present invention, by irradiating a laser beam with a condensing point aligned with the inside of the semiconductor substrate to which the sheet is attached with a die bond resin layer interposed therebetween. Forming a modified region in the interior of the substrate and forming a planned cutting portion with the modified region, and after the step of forming the planned cutting region, the sheet is expanded to extend the semiconductor substrate and the die bond along the planned cutting portion. And a step of cutting the resin layer.
The modified region may be a melt-processed region.

This semiconductor substrate cutting method is also much more efficient than the case of cutting the semiconductor substrate and the die bond resin layer with a blade while leaving the sheet for the same reason as the above-mentioned semiconductor substrate cutting method. It becomes possible to cut the semiconductor substrate and the die bond resin layer along the planned cutting portion. However, the modified region may be formed by multiphoton absorption or may be formed by other causes.

Further, in the method for cutting a semiconductor substrate according to the present invention, a modified region is formed inside the semiconductor substrate by irradiating the inside of the semiconductor substrate to which the sheet is attached with a laser beam with a converging point. And a step of forming a planned cutting portion with the modified region, and a step of cutting the semiconductor substrate along the planned cutting portion by expanding the sheet after the step of forming the planned cutting portion. Is characterized by.

According to this method of cutting a semiconductor substrate, the semiconductor substrate can be cut along the planned cutting portion much more efficiently than in the case of cutting the semiconductor substrate with a blade while leaving the sheet. .

In the method of cutting a semiconductor substrate according to the present invention described above, in the step of forming the planned cutting portion, a crack reaches the surface of the semiconductor substrate on the laser light incident side from the starting cutting portion as a starting point. Alternatively, the crack may reach the back surface of the semiconductor substrate on the opposite side of the laser light incident side from the planned cutting portion, or alternatively, the laser light incident side of the semiconductor substrate may start from the planned cutting portion. The crack may reach the front surface and the back surface on the opposite side.

Further, in the method for cutting a semiconductor substrate according to the present invention, the semiconductor substrate to which the sheet is attached with the die-bonding resin layer interposed is irradiated with a laser beam so that the focusing point is aligned with the inside of the semiconductor substrate. Forming a modified region by multiphoton absorption in the inside of the substrate, and forming a planned cutting part with the modified region, and after the step of forming the planned cutting part, stress is generated in the semiconductor substrate along the planned cutting part. By doing so, a step of cutting the semiconductor substrate along the planned cutting portion, and a step of cutting the die bond resin layer along the cut surface of the semiconductor substrate by expanding the sheet after the step of cutting the semiconductor substrate are provided. It is characterized by that.

Also in this semiconductor substrate cutting method, the planned cutting portion is formed inside the semiconductor substrate along the desired planned cutting line for cutting the semiconductor substrate by the modified region formed by multiphoton absorption. be able to. Therefore, when stress is applied to the semiconductor substrate along the planned cutting portion, the semiconductor substrate can be accurately cut along the planned cutting portion. When the sheet attached to the semiconductor substrate is expanded, the cut surfaces facing each other of the cut semiconductor substrate are separated from each other as the sheet is expanded from the state in which they are in close contact with each other. The die bond resin layer existing between the two is cut along the cut surface of the semiconductor substrate. Therefore, it is possible to cut the semiconductor substrate and the die bond resin layer along the planned cutting portion much more efficiently than in the case where the semiconductor substrate and the die bond resin layer are cut with a blade while leaving the sheet. Moreover, since the cut surfaces of the cut semiconductor substrate facing each other are initially in close contact with each other, the cut individual semiconductor substrates and the cut individual die bond resin layers have substantially the same outer shape, and It is also possible to prevent the die bond resin from protruding from the cut surface of the substrate.

Further, in the semiconductor substrate cutting method according to the present invention, the converging point is aligned inside the semiconductor substrate to which the sheet is attached with the die bond resin layer interposed, and the peak power density at the converging point is reduced. By irradiating a laser beam under the condition of 1 × 10 ⁸ (W / cm ² ) or more and a pulse width of 1 μs or less, a modified region including a melt-processed region is formed inside the semiconductor substrate, and the melt-processed region is formed. After the step of forming the planned cutting portion with the modified region including, and the step of forming the planned cutting portion, stress is applied to the semiconductor substrate along the planned cutting portion, so that the semiconductor substrate is cut along the planned cutting portion. The method is characterized by including a step of cutting and a step of cutting the die bond resin layer along the cut surface of the semiconductor substrate by expanding the sheet after the step of cutting the semiconductor substrate.

Further, in the method for cutting a semiconductor substrate according to the present invention, the semiconductor substrate is irradiated with a laser beam with a focusing point aligned with the inside of the semiconductor substrate to which the sheet is attached with the die bond resin layer interposed. By forming a modified region in the inside of, the step of forming the planned cutting portion in the modified region, and after the step of forming the planned cutting portion, by causing stress on the semiconductor substrate along the planned cutting portion, It is characterized by comprising a step of cutting the semiconductor substrate along the planned cutting portion and a step of cutting the die bond resin layer along the cut surface of the semiconductor substrate by expanding the sheet after the step of cutting the semiconductor substrate. And The modified region may be a melt-processed region.

These semiconductor substrate cutting methods are also used for the same reason as the above-described semiconductor substrate cutting method.
It is possible to cut the semiconductor substrate and the die bond resin layer along the planned cutting portion much more efficiently than in the case of cutting the semiconductor substrate and the die bond resin layer with a blade while leaving the sheet.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a method for cutting a semiconductor substrate according to the present invention will be described in detail below with reference to the drawings.

In the method of cutting a semiconductor substrate according to this embodiment, a modified region by multiphoton absorption is formed inside the semiconductor substrate by irradiating a laser beam with the focusing point aligned inside the semiconductor substrate, A planned cutting portion is formed by this modified region. Therefore, prior to the description of the method of cutting the semiconductor substrate according to the present embodiment, a laser processing method that is performed to form the planned cutting portion will be described focusing on multiphoton absorption.

When the photon energy hν is smaller than the absorption band gap E _G of the material, it becomes optically transparent. Therefore, the condition under which absorption occurs in the material is hν> E _G. However, even if it is optically transparent, if the intensity of the laser light is made extremely high, the condition of nhν> E _G (n = 2, 3, 4, ...
・) Absorption occurs in the material. This phenomenon is called multiphoton absorption. In the case of a pulse wave, the intensity of the laser light is determined by the peak power density (W / cm ² ) at the condensing point of the laser light. For example, the multiphoton is generated under the condition that the peak power density is 1 × 10 ⁸ (W / cm ² ) or more. Absorption occurs. The peak power density is (energy per pulse of laser light at the condensing point) ÷
It is calculated by (beam spot cross-sectional area of laser light × pulse width). Further, in the case of a continuous wave, the intensity of the laser light is determined by the electric field intensity (W / cm ² ) at the condensing point of the laser light.

The principle of laser processing according to this embodiment utilizing such multiphoton absorption will be described with reference to FIGS. 1 is a plan view of the semiconductor substrate 1 during laser processing, FIG. 2 is a sectional view taken along line II-II of the semiconductor substrate 1 shown in FIG. 1, and FIG. 3 is a plan view of the semiconductor substrate 1 after laser processing. FIG. 4 is a plan view, and FIG. 4 shows the semiconductor substrate 1 shown in FIG.
4 is a sectional view taken along line IV-IV, FIG. 5 is a sectional view taken along line VV of the semiconductor substrate 1 shown in FIG. 3, and FIG. 6 is a plan view of the cut semiconductor substrate 1.

As shown in FIGS. 1 and 2, the semiconductor substrate 1
The surface 3 has a desired planned cutting line 5 for cutting the semiconductor substrate 1. The planned cutting line 5 is an imaginary line extending in a straight line (a line may actually be drawn on the semiconductor substrate 1 to form the planned cutting line 5). In the laser processing according to the present embodiment, the modified region 7 is formed by irradiating the semiconductor substrate 1 with the laser light L by aligning the focus point P inside the semiconductor substrate 1 under the condition that multiphoton absorption occurs. The converging point means the laser beam L
Is the point where the light is collected.

By moving the laser beam L relatively along the planned cutting line 5 (that is, along the direction of arrow A), the focal point P is moved along the planned cutting line 5. As a result, as shown in FIG. 3 to FIG.
Is formed only inside the semiconductor substrate 1 along the planned cutting line 5, and the modified region 7 forms the planned cutting portion 9. In the laser processing method according to this embodiment, the semiconductor substrate 1 does not generate the modified region 7 by absorbing the laser light L to heat the semiconductor substrate 1. The laser light L is transmitted through the semiconductor substrate 1 to cause multiphoton absorption inside the semiconductor substrate 1 to form the modified region 7. Therefore, the surface 3 of the semiconductor substrate 1 hardly absorbs the laser light L, so that the surface 3 of the semiconductor substrate 1 is not melted.

In the cutting of the semiconductor substrate 1, if there is a starting point at the cutting point, the semiconductor substrate 1 is broken from the starting point, so that the semiconductor substrate 1 can be cut with a relatively small force as shown in FIG. Therefore, the surface 3 of the semiconductor substrate 1
The semiconductor substrate 1 can be cut without causing unnecessary cracks.

There are two possible ways of cutting the semiconductor substrate starting from the planned cutting part. One is a case where an artificial force is applied to the semiconductor substrate after the planned cutting portion is formed, so that the semiconductor substrate is cracked starting from the planned cutting portion and the semiconductor substrate is cut. This is cutting, for example, when the thickness of the semiconductor substrate is large. The artificial force is applied, for example, to apply a bending stress or a shear stress to the semiconductor substrate along the cut portion of the semiconductor substrate, or to generate a thermal stress by giving a temperature difference to the semiconductor substrate. That is. The other one is a case in which, by forming the planned cutting portion, the semiconductor substrate is naturally broken in the cross-sectional direction (thickness direction) of the semiconductor substrate starting from the planned cutting portion, and as a result, the semiconductor substrate is cut. . This can be achieved, for example, when the thickness of the semiconductor substrate is small, by forming the planned cutting portion by one row of modified regions, and when the thickness of the semiconductor substrate is large, a plurality of regions are formed in the thickness direction. This is possible because the planned cutting portion is formed by the modified regions formed in rows. Even in the case of this natural breakage, the part to be cut does not have a crack that extends to the surface of the part corresponding to the part where the part to be cut is not formed, and the part corresponding to the part where the part to be cut is formed. Since only the cleaving can be performed, the cleaving can be controlled better. In recent years, since the thickness of a semiconductor substrate such as a silicon wafer tends to be thin, such a cleaving method with good controllability is very effective.

In the present embodiment, the modified region formed by multiphoton absorption includes the melt-processed region described below.

A focusing point is set inside the semiconductor substrate, and the laser beam is irradiated under the condition that the electric field intensity at the focusing point is 1 × 10 ⁸ (W / cm ² ) or more and the pulse width is 1 μs or less. As a result, the inside of the semiconductor substrate is locally heated by multiphoton absorption. By this heating, a melt processing region is formed inside the semiconductor substrate. The melt-processed region is a region that has been once melted and then re-solidified, a region that is just in a molten state, or a region that is in a state where it is re-solidified from the molten state, and can also be referred to as a phase-changed region or a region in which the crystal structure is changed. Also,
It can be said that the melt-processed region is a region in which one structure is changed to another structure in a single crystal structure, an amorphous structure, or a polycrystalline structure. That is, for example, a region in which a single crystal structure is changed to an amorphous structure, a region in which a single crystal structure is changed to a polycrystalline structure, or a region in which a single crystal structure is changed to a structure including an amorphous structure and a polycrystalline structure is meant. To do. When the semiconductor substrate has a silicon single crystal structure, the melt-processed region has, for example, an amorphous silicon structure. The upper limit value of the electric field strength is, for example, 1
It is × 10 ¹² (W / cm ² ). The pulse width is, for example, 1n
s-200 ns is preferable.

The present inventor has confirmed by experiments that a melt-processed region is formed inside a silicon wafer. The experimental conditions are as follows.

(A) Semiconductor substrate: Silicon wafer (thickness 350 μm, outer diameter 4 inches) (B) Laser light source: Semiconductor laser excitation Nd: YAG laser Wavelength: 1064 nm Laser beam spot cross-sectional area: 3.14 × 10 ⁻⁸ cm ² Oscillation form: Q switch pulse repetition frequency: 100 kHz Pulse width: 30 ns Output: 20 μJ / pulse Laser beam quality: TEM ₀₀ Polarization characteristic: Linearly polarized light (C) Condensing lens magnification: 50 times N.M. A. : 0.55 Transmittance for laser light wavelength: 60% (D) Moving speed of mounting table on which semiconductor substrate is mounted: 10
0 mm / sec

FIG. 7 is a view showing a photograph of a cross section of a part of a silicon wafer cut by laser processing under the above conditions. A melt processing region 13 is formed inside the silicon wafer 11. The size in the thickness direction of the melt-processed region 13 formed under the above conditions is 100 μm.
It is a degree.

It will be described that the melt-processed region 13 is formed by multiphoton absorption. FIG. 8 is a graph showing the relationship between the wavelength of laser light and the transmittance inside the silicon substrate.
However, the reflection components on the front surface side and the back surface side of the silicon substrate are removed, and the transmittance of only the inside is shown. The thickness t of the silicon substrate is 50 μm, 100 μm, 200 μm,
The above relationship is shown for each of 500 μm and 1000 μm.

For example, when the wavelength of the Nd: YAG laser is 1064 nm, the thickness of the silicon substrate is 500 μm.
If it is less than m, the laser light will be 80 inside the silicon substrate.
It can be seen that more than% is transmitted. Since the thickness of the silicon wafer 11 shown in FIG. 7 is 350 μm, the melt-processed region 13 by multiphoton absorption is formed near the center of the silicon wafer, that is, at a portion 175 μm from the surface. In this case, the transmittance is 90% or more when a silicon wafer having a thickness of 200 μm is referred to.
There is little absorption inside 1 and most penetrates. This means that the laser light is absorbed inside the silicon wafer 11 so that the melt processing region 13 is exposed to the silicon wafer 1.
It means that the melt-processed region 13 is formed by multiphoton absorption, not that formed inside 1 (that is, the melt-processed region is formed by normal heating with laser light). The formation of the melt-processed region by multiphoton absorption is described, for example, in No. 7 of Proceedings of the 66th Annual Meeting of the Welding Society (April 2000)
It is described in "Evaluation of processing characteristics of silicon by picosecond pulse laser" on pages 2 to 73.

The silicon wafer is cracked in the cross-sectional direction starting from the planned cutting portion formed in the melt-processed region, and the cracks reach the front surface and the back surface of the silicon wafer. Be disconnected. The crack reaching the front surface and the back surface of the silicon wafer may grow naturally, or may grow when a force is applied to the silicon wafer. When a crack naturally grows from the planned cutting part on the front surface and the back surface of the silicon wafer, when the crack grows from the molten state of the melting treatment region forming the planned cutting part, There is also a case where cracks grow when the melt-processed region forming the is solidified from a molten state. However, in both cases, the melt-processed region is formed only inside the silicon wafer, and the cut surface after cutting has the melt-processed region formed only inside as shown in FIG. 7. If the planned cutting portion is formed in the semiconductor substrate in the melt-processed region, unnecessary cracks that deviate from the planned cutting portion line are unlikely to occur at the time of cutting, which facilitates cutting control.

Next, a laser processing apparatus used in the above laser processing method will be described with reference to FIG.
FIG. 9 is a schematic configuration diagram of the laser processing apparatus 100.

The laser processing apparatus 100 includes a laser light source 101 for generating a laser light L, a laser light source controller 102 for controlling the laser light source 101 to adjust the output and pulse width of the laser light L, and a laser light L. A dichroic mirror 103 which has a reflection function and is arranged to change the direction of the optical axis of the laser light L by 90 °, and a condenser lens 105 which condenses the laser light L reflected by the dichroic mirror 103. A mounting table 10 on which the semiconductor substrate 1 irradiated with the laser light L condensed by the condensing lens 105 is mounted.
7, an X-axis stage 109 for moving the mounting table 107 in the X-axis direction, a Y-axis stage 111 for moving the mounting table 107 in the Y-axis direction orthogonal to the X-axis direction, and the mounting table 107 for the X-axis. A Z-axis stage 113 for moving in the Z-axis direction orthogonal to the axes and the Y-axis direction, and a stage control unit 115 for controlling the movement of these three stages 109, 111, 113 are provided.

Since the Z-axis direction is the direction orthogonal to the surface 3 of the semiconductor substrate 1, it is the direction of the depth of focus of the laser light L incident on the semiconductor substrate 1. Therefore, set the Z-axis stage 113 to Z
By moving in the axial direction, the condensing point P of the laser light L can be aligned inside the semiconductor substrate 1. Also,
The movement of the condensing point P in the X (Y) axis direction is caused by the semiconductor substrate 1
X (Y) by the X (Y) axis stage 109 (111)
This is done by moving in the axial direction.

The laser light source 101 is an Nd: YAG laser which generates pulsed laser light. Other lasers that can be used for the laser light source 101 include Nd: YVO
_{There are 4} lasers, Nd: YLF lasers and titanium sapphire lasers. Nd: Y when forming the melt-processed region
It is preferable to use an AG laser, an Nd: YVO ₄ laser, or an Nd: YLF laser. In this embodiment, pulsed laser light is used for processing the semiconductor substrate 1, but continuous wave laser light may be used as long as it can cause multiphoton absorption.

The laser processing apparatus 100 further includes a mounting table 1
For observing the light source 117 for illuminating the semiconductor substrate 1 mounted on 07 with visible light, the dichroic mirror 103 and the condenser lens 105 are arranged on the same optical axis. Beam splitter 119
With. Beam splitter 119 and condenser lens 1
The dichroic mirror 103 is arranged between the dichroic mirror 05 and the camera. The beam splitter 119 has a function of reflecting approximately half of visible light and transmitting the other half, and is arranged so as to change the direction of the optical axis of visible light by 90 °. About half of the visible light emitted from the observation light source 117 is reflected by the beam splitter 119, and the reflected visible light passes through the dichroic mirror 103 and the condenser lens 105, and cuts the planned cutting line 5 of the semiconductor substrate 1. Illuminate the containing surface 3.

The laser processing apparatus 100 further includes an image pickup device 12 arranged on the same optical axis as the beam splitter 119, the dichroic mirror 103 and the condenser lens 105.
1 and the imaging lens 123. The image sensor 121 is, for example, a CCD camera. The reflected light of visible light that illuminates the surface 3 including the planned cutting line 5 and the like passes through the condenser lens 105, the dichroic mirror 103, and the beam splitter 119, is imaged by the imaging lens 123, and is imaged by the imaging element 121. And becomes imaging data.

The laser processing apparatus 100 further includes an image data processing section 125 to which the image data output from the image sensor 121 is input, an overall control section 127 for controlling the entire laser processing apparatus 100, and a monitor 129. The imaging data processing unit 125 calculates focus data for focusing the visible light generated by the observation light source 117 on the surface 3 based on the imaging data. The stage control unit 115 controls the movement of the Z-axis stage 113 based on this focus data, so that the visible light is focused on the surface 3. Therefore, the imaging data processing unit 125 functions as an autofocus unit. Further, the imaging data processing unit 125 calculates image data such as an enlarged image of the surface 3 based on the imaging data. This image data is sent to the overall control unit 1.
27 is sent to the monitor 129. As a result, an enlarged image or the like is displayed on the monitor 129.

The overall controller 127 includes the stage controller 1
Data from the image pickup device 15, image data from the image pickup data processing unit 125, and the like are input, and the laser light source control unit 102, the observation light source 117, and the stage control unit 115 are controlled based on these data, thereby the laser processing apparatus. Control 100 as a whole. Therefore, the overall control unit 127 functions as a computer unit.

Laser processing apparatus 1 configured as described above
A procedure of forming the planned cutting portion by 00 will be described with reference to FIGS. 9 and 10. FIG. 10 shows a laser processing apparatus 1.
10 is a flowchart for explaining a procedure of forming a planned cutting portion by 00.

The light absorption characteristics of the semiconductor substrate 1 are measured by a spectrophotometer (not shown) or the like. Based on this measurement result,
A laser light source 101 that emits laser light L having a wavelength transparent to the semiconductor substrate 1 or a wavelength with little absorption is selected (S101). Then, the thickness of the semiconductor substrate 1 is measured. The amount of movement of the semiconductor substrate 1 in the Z-axis direction is determined based on the thickness measurement result and the refractive index of the semiconductor substrate 1 (S1).
03). This is because the focusing point P of the laser light L is at the semiconductor substrate 1
In order to locate the inside of the semiconductor substrate 1, the semiconductor substrate 1 located on the surface 3 of the semiconductor substrate 1 with the condensing point P of the laser light L as a reference.
Is the amount of movement in the Z-axis direction. This movement amount is the total control unit 1
27 is input.

The semiconductor substrate 1 is mounted on the mounting table 107 of the laser processing apparatus 100. Then, visible light is generated from the observation light source 117 to illuminate the semiconductor substrate 1 (S10).
5). Semiconductor substrate 1 including illuminated planned cutting line 5
The surface 3 of the image is imaged by the image sensor 121. The planned cutting line 5 is a desired virtual line for cutting the semiconductor substrate 1. The image data captured by the image sensor 121 is sent to the image data processing unit 125. Based on the imaged data, the imaged data processing unit 125 calculates focus data such that the visible light focus of the observation light source 117 is located on the surface 3 (S107).

This focus data is sent to the stage controller 115. The stage control unit 115 moves the Z-axis stage 113 in the Z-axis direction based on this focus data (S109). As a result, the focus of visible light from the observation light source 117 is located on the surface 3 of the semiconductor substrate 1. The imaging data processing unit 125 calculates the enlarged image data of the surface 3 of the semiconductor substrate 1 including the planned cutting line 5 based on the imaging data. This magnified image data is sent to the monitor 129 via the overall control unit 127, whereby the monitor 129
An enlarged image near the planned cutting line 5 is displayed at.

In step S10, the overall control unit 127 is set in advance.
The movement amount data determined in 3 is input, and the movement amount data is sent to the stage control unit 115. Based on this movement amount data, the stage control unit 115 sets Z at the position where the condensing point P of the laser light L is inside the semiconductor substrate 1.
The semiconductor substrate 1 is moved in the Z-axis direction by the axis stage 113 (S111).

Next, the laser light L from the laser light source 101
Is generated to irradiate the planned cutting line 5 on the surface 3 of the semiconductor substrate 1 with the laser light L. Since the condensing point P of the laser light L is located inside the semiconductor substrate 1, the melting processed region is formed only inside the semiconductor substrate 1. Then, the X-axis stage 109 and the Y-axis stage 111 are moved along the planned cutting line 5, and the planned cutting portion along the planned cutting line 5 is formed in the melting processing region formed along the planned cutting line 5 as a semiconductor. It is formed inside the substrate 1 (S11
3).

As described above, the formation of the planned cutting portion by the laser processing apparatus 100 is completed, and the planned cutting portion is formed inside the semiconductor substrate 1. When the planned cutting portion is formed inside the semiconductor substrate 1, a crack can be generated in the thickness direction of the semiconductor substrate 1 with the comparatively small force as the starting point.

Next, a method of cutting the semiconductor substrate according to this embodiment will be described. Here, a silicon wafer 11 which is a semiconductor wafer was used as the semiconductor substrate.

First, as shown in FIG. 11A, an adhesive sheet 20 is attached to the back surface 17 of the silicon wafer 11 so as to cover the back surface 17. The adhesive sheet 20 has a base material 21 having a thickness of about 100 μm, and a UV curable resin layer 22 having a layer thickness of about several μm is provided on the base material 21. Further, on the UV curable resin layer 22, the die bond resin layer 2 which functions as an adhesive agent for die bonding.
3 is provided. A plurality of functional elements are formed in a matrix on the surface 3 of the silicon wafer 11. Here, the functional element means a light receiving element such as a photodiode, a light emitting element such as a laser diode, or a circuit element formed as a circuit.

Subsequently, as shown in FIG. 11B, for example, by using the above-described laser processing apparatus 100, a focusing point is aligned inside the silicon wafer 11 and a laser beam is irradiated from the surface 3 side. A melt-processed region 13 that is a modified region is formed inside the silicon wafer 11, and the melt-processed region 13 forms the planned cutting portion 9. In the formation of the planned cutting portion 9, laser light is irradiated so as to travel between the plurality of functional elements arranged in a matrix on the surface 3 of the silicon wafer 11, whereby the planned cutting portions 9 are adjacent to each other. It is formed like a grid so that it runs just below.

After forming the portion 9 to be cut, as shown in FIG. 12A, the adhesive sheet 2 is expanded by the sheet expanding means 30.
The adhesive sheet 20 is expanded by pulling the periphery of 0 toward the outside. The expansion of the adhesive sheet 20 causes cracks in the thickness direction from the planned cutting portion 9 as a starting point, and the cracks reach the front surface 3 and the back surface 17 of the silicon wafer 11. As a result, the silicon wafer 11 is accurately cut into each functional element, and the semiconductor chip 25 having one functional element is obtained.

At this time, the adjacent semiconductor chips 2
The cut surfaces 25a, 25a facing each other of 5 and 25 are initially in a state of being in close contact with each other and are separated from each other as the adhesive sheet 20 is expanded. The die bond resin layer 23 that was in close contact with the back surface 17 is also cut along the planned cutting portion 9.

The sheet expanding means 30 may or may not be provided on the stage on which the silicon wafer 11 is placed when the planned cutting portion 9 is formed. If not provided on that stage, the silicon wafer 11 placed on that stage
After the planned cutting portion 9 is formed, the sheet is conveyed to another stage provided with the sheet expanding means 30 by the conveying means.

After the expansion of the pressure-sensitive adhesive sheet 20, as shown in FIG. 12B, the pressure-sensitive adhesive sheet 20 is irradiated with ultraviolet rays from the back side to cure the UV curable resin layer 22. As a result, the UV curable resin layer 22 and the die bond resin layer 23
Adhesion with will be reduced. The irradiation of ultraviolet rays may be performed before the expansion of the adhesive sheet 20 is started.

Subsequently, as shown in FIG. 13A, the semiconductor chips 25 are sequentially picked up by using a suction collet or the like which is a pickup means. At this time, the die-bonding resin layer 23 is cut into the same outer shape as the semiconductor chip 25, and the adhesive force between the die-bonding resin layer 23 and the UV curable resin layer 22 is reduced. The die bond resin layer 23 cut on the back surface is picked up in close contact. Then, as shown in FIG. 13B, the semiconductor chip 25 is
It is placed on the die pad of the lead frame 27 via the die bond resin layer 23 adhered to the back surface thereof, and filler bonding is performed by heating.

As described above, in the method for cutting the silicon wafer 11, the silicon wafer 11 is cut along the desired cutting line to be cut by the melt processing region 13 formed by multiphoton absorption. A planned cutting portion 9 is formed inside. Therefore, when the pressure-sensitive adhesive sheet 20 attached to the silicon wafer 11 is expanded, the silicon wafer 11 is cut along the planned cutting portion 9.
Is accurately cut, and the semiconductor chip 25 is obtained. At this time, the cut surfaces 25a, 25a facing each other of the adjacent semiconductor chips 25, 25 are initially in a state of being in close contact with each other, and are separated as the adhesive sheet 20 is expanded, so that they are in close contact with the back surface 17 of the silicon wafer 11. The die bond resin layer 23 that has been cut is also cut along the planned cutting portion 9.
Therefore, the silicon wafer 11 and the die bond resin layer 23 can be cut along the planned cutting portion 9 much more efficiently than the case where the silicon wafer 11 and the die bond resin layer 23 are cut by a blade without cutting the base material 21. It becomes possible to disconnect.

Moreover, the adjacent semiconductor chips 25, 25
Since the cut surfaces 25a, 25a opposed to each other are initially in close contact with each other, the cut individual semiconductor chips 25 and the cut individual die bond resin layers 23 have substantially the same outer shape, and each semiconductor chip 25 It is also possible to prevent the die bond resin from protruding from the cut surface 25a.

The above-described method for cutting the silicon wafer 11 is
As shown in FIG. 14A, until the adhesive sheet 20 was expanded, the silicon wafer 11 was not cracked from the planned cutting portion 9 as a starting point.
As shown in (b), before the adhesive sheet 20 is expanded, even if a crack 15 is generated starting from the planned cutting portion 9 and the crack 15 reaches the front surface 3 and the back surface 17 of the silicon wafer 11. Good. As a method of generating the crack 15, for example, a stress applying means such as a knife edge is pressed against the back surface 17 of the silicon wafer 11 along the planned cutting portion 9 to bend the silicon wafer 11 along the planned cutting portion 9. The portion to be cut 9 can be cut by applying a stress or shear stress or by applying a temperature difference to the silicon wafer 11.
There is a method of causing a thermal stress to the silicon wafer 11 along the direction.

As described above, after the planned cutting portion 9 is formed, stress is generated in the silicon wafer 11 along the planned cutting portion 9 and the silicon wafer 11 is cut along the planned cutting portion 9 so that the accuracy is extremely high. Well cut semiconductor chip 25
Can be obtained. Then, also in this case, when the adhesive sheet 20 attached to the silicon wafer 11 is expanded, the cut surfaces 25a, 25a of the adjacent semiconductor chips 25, 25 facing each other are brought into close contact with each other.
Since the adhesive sheets 20 are separated from each other as the adhesive sheet 20 is expanded, the die bond resin layer 23 adhered to the back surface 17 of the silicon wafer 11 is cut along the cut surface 25a. Therefore, even with this cutting method, the silicon wafer 11 and the die bond resin layer 23 are much more efficiently compared to the case where the silicon wafer 11 and the die bond resin layer 23 are cut by the blade without cutting the base material 21. It becomes possible to cut along the planned cutting part 9.

When the thickness of the silicon wafer 11 becomes thin, even if stress is not generated along the planned cutting portion 9, as shown in FIG. Is the front surface 3 and the back surface 17 of the silicon wafer 11.
And may be reached.

Further, as shown in FIG. 15A, if a portion 9 to be cut by the melt processing region 13 is formed in the vicinity of the surface 3 inside the silicon wafer 11 and the crack 15 reaches the surface 3, Semiconductor chip 25 obtained by cutting
The cutting accuracy of the surface (that is, the functional element forming surface) can be made extremely high. On the other hand, as shown in FIG. 15 (b), if the planned cut portion 9 by the melt processing region 13 is formed in the vicinity of the back surface 17 inside the silicon wafer 11 and the crack 15 reaches the back surface 17, the adhesive sheet 20 will be formed. The die-bonding resin layer 23 can be cut with high precision by the expansion.

Next, the experimental results when "LE-5000 (trade name)" of Lintec Co., Ltd. is used as the adhesive sheet 20 will be described. 16 and 17 are schematic diagrams showing a series of states when the adhesive sheet 20 is expanded after forming the planned cutting portion 9 by the melt processing region 13 inside the silicon wafer 11, and FIG.
Is a state immediately after the expansion of the adhesive sheet 20 is started, FIG.
6 (b) shows a state where the adhesive sheet 20 is being expanded, FIG. 17 (a) is a state after the expanding of the adhesive sheet 20, and FIG. 17 (b) is a state when the semiconductor chip 25 is picked up.

As shown in FIG. 16A, the adhesive sheet 2
Immediately after the start of the expansion of 0, the silicon wafer 11 is cut along the planned cutting portion 9, and the facing cut surfaces 25a, 25a of the adjacent semiconductor chips 25 are in close contact with each other. At this time, the die bond resin layer 23 has not been cut yet. Then, as shown in FIG.
Along with the expansion of the adhesive sheet 20, the die bond resin layer 23
Is cut along the planned cutting portion 9 so as to be torn.

When the expansion of the adhesive sheet 20 is completed in this manner, the die bond resin layer 23 is also cut into individual semiconductor chips 25, as shown in FIG. 17 (a). At this time, the semiconductor chips 25, 25 separated from each other
A part 23b of the die bond resin layer 23 remained thin on the base material 21 of the adhesive sheet 20 in between. Further, the cut surface 23a of the die bond resin layer 23 cut together with the semiconductor chip 25 was slightly concave with respect to the cut surface 25a of the semiconductor chip 25. This reliably prevents the die bond resin from protruding from the cut surface 25a of each semiconductor chip 25. Then, as shown in FIG. 17B, the semiconductor chip 25 could be picked up together with the die-bonding resin layer 23 cut by using a suction collet or the like.

When the die-bonding resin layer 23 is made of a non-stretchable material, etc., as shown in FIG. 18, the die-bonding resin layer 23 is placed on the base material 21 of the adhesive sheet 20 between the semiconductor chips 25 and 25 which are separated from each other. Does not leave the die bond resin layer 23. Thereby, the cut surface 25a of the semiconductor chip 25
And the cut surface 23a of the die-bonding resin layer 23 adhered to the back surface thereof can be made to substantially coincide with each other.

Further, as shown in FIG. 19 (a), the substrate 2
1. Adhesive sheet 20 having 1 and UV curable resin layer 22
The silicon wafer 1 through the UV curable resin layer 22.
19 is adhered to the back surface 17 of the melt-processed region 13 to form the planned cutting portion 9 by the melt processing region 13, and then the periphery of the adhesive sheet 20 is expanded outward as shown in FIG. May be cut into semiconductor chips 25. Also in this case, it is possible to cut the silicon wafer 11 along the planned cutting portion 9 with higher efficiency than in the case where the silicon wafer 11 is cut with a blade while leaving the adhesive sheet 20.

Then, the substrate 21 and the UV curable resin layer 22
Wafer 1 Using Adhesive Sheet 20 Having
Also in the cutting method of No. 1, as described with reference to FIG. 19, not only when the silicon wafer 11 is not cracked from the planned cutting portion 9 until the adhesive sheet 20 is expanded, as shown in FIG. As shown in FIG. 20, before the adhesive sheet 20 is expanded (FIG. 20 (b)), the crack 15 starting from the planned cutting portion 9 is made into the silicon wafer 11
It may reach the front surface 3 and the back surface 17 (see FIG. 20).
(A)). In addition, as shown in FIG. 21, the adhesive sheet 20
Before expanding (FIG. 21 (b)), cracks 15 starting from the planned cutting portion 9 are formed on the surface 3 of the silicon wafer 11.
May be reached (Fig. 21 (a)) or Fig. 22.
As shown in FIG. 22, before the adhesive sheet 20 is expanded (FIG. 22B), cracks 15 originating from the planned cutting portion 9 start.
May reach the back surface 17 of the silicon wafer 11 (FIG. 22A).

[0071]

As described above, according to the semiconductor substrate cutting method of the present invention, the semiconductor substrate to which the sheet is attached with the die bond resin layer interposed can be efficiently cut together with the die bond resin layer. It will be possible.

[Brief description of drawings]

FIG. 1 is a plan view of a semiconductor substrate during laser processing by a laser processing method according to this embodiment.

FIG. 2 is a sectional view taken along line II-II of the semiconductor substrate shown in FIG.

FIG. 3 is a plan view of the semiconductor substrate after laser processing by the laser processing method according to the present embodiment.

FIG. 4 is a sectional view taken along line IV-IV of the semiconductor substrate shown in FIG.

5 is a cross-sectional view of the semiconductor substrate shown in FIG. 3, taken along line VV.

FIG. 6 is a plan view of a semiconductor substrate cut by a laser processing method according to this embodiment.

FIG. 7 is a view showing a photograph of a cross section of a part of a silicon wafer cut by the laser processing method according to the present embodiment.

FIG. 8 is a graph showing the relationship between the wavelength of laser light and the transmittance inside the silicon substrate in the laser processing method according to the present embodiment.

FIG. 9 is a schematic configuration diagram of a laser processing apparatus according to the present embodiment.

FIG. 10 is a flowchart for explaining a procedure for forming a planned cutting portion by the laser processing apparatus according to the present embodiment.

11A and 11B are schematic diagrams for explaining the method of cutting a silicon wafer according to the present embodiment, where FIG. 11A is a state in which an adhesive sheet is attached to the silicon wafer, and FIG. This is a state in which the planned cutting portion is formed by the processing region.

12A and 12B are schematic views for explaining the method for cutting a silicon wafer according to the present embodiment, where FIG. 12A is a state where the adhesive sheet is expanded, and FIG. 12B is a state where the adhesive sheet is irradiated with ultraviolet rays. is there.

13A and 13B are schematic views for explaining the method for cutting a silicon wafer according to the present embodiment, where FIG. 13A is a state in which a semiconductor chip is picked up together with the cut die bond resin layer, and FIG. It is in a state of being bonded to the lead frame via the die bond resin layer.

FIG. 14 is a schematic diagram showing a relationship between a silicon wafer and a planned cutting portion in the method for cutting a silicon wafer according to the present embodiment, in which (a) is a state in which no crack has occurred starting from the planned cutting portion, (B) shows a state in which cracks starting from the planned cutting portion reach the front and back surfaces of the silicon wafer.

FIG. 15 is a schematic diagram showing a relationship between a silicon wafer and a planned cutting part in the method for cutting a silicon wafer according to the present embodiment, and FIG. 15 (a) shows that a crack starting from the planned cutting part reaches the surface of the silicon wafer. In the state shown in FIG. 3B, the crack starting from the planned cutting portion reaches the back surface of the silicon wafer.

16A and 16B are schematic views for explaining an example of the method for cutting a silicon wafer according to the present embodiment, where FIG. 16A is a state immediately after the expansion of the pressure-sensitive adhesive sheet is started, and FIG. Is the state of.

17A and 17B are schematic diagrams for explaining an example of the method for cutting a silicon wafer according to the present embodiment, where FIG. 17A is a state after completion of expansion of an adhesive sheet, and FIG. Is the state of.

FIG. 18 is a schematic diagram for explaining another example of the method for cutting a silicon wafer according to the present embodiment.

FIG. 19 is a view for explaining a case where a crack originating from a planned cutting portion does not occur in still another example of the method for cutting a silicon wafer according to the present embodiment, and FIG. The state after the planned cutting part is formed,
(B) is a state in which the adhesive sheet is expanded.

FIG. 20 is a diagram for explaining a case where a crack starting from a planned cutting portion reaches the front surface and the back surface of the silicon wafer in still another example of the method for cutting a silicon wafer according to the present embodiment, (A) is a state after the planned cut portion is formed by the melt processing region, and (b) is a state in which the adhesive sheet is expanded.

FIG. 21 is a view for explaining a case where a crack starting from a planned cutting portion reaches the surface of the silicon wafer in still another example of the method for cutting a silicon wafer according to the present embodiment, (a) Shows a state after the planned cutting portion by the melt processing region is formed, and (b) shows a state in which the adhesive sheet is expanded.

FIG. 22 is a view for explaining a case where a crack starting from a planned cutting portion reaches the back surface of the silicon wafer in still another example of the method for cutting a silicon wafer according to the present embodiment, (a) Shows a state after the planned cutting portion by the melt processing region is formed, and (b) shows a state in which the adhesive sheet is expanded.

[Explanation of symbols]

1 ... Semiconductor substrate, 3 ... Surface, 5 ... Planned cutting line, 7 ...
Modified region, 9 ... Planned cutting portion, 11 ... Silicon wafer, 1
3 ... Melt processing area, 15 ... Crack, 17 ... Back surface, 20 ... Adhesive sheet, 21 ... Base material, 23 ... Die bond resin layer, 25
... semiconductor chip, L ... laser light, P ... condensing point.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoki Uchiyama             1 Hamamatsuho, 1126 Nomachi, Hamamatsu City, Shizuoka Prefecture             Tonics Co., Ltd. (72) Inventor Ryuji Sugiura             1 Hamamatsuho, 1126 Nomachi, Hamamatsu City, Shizuoka Prefecture             Tonics Co., Ltd. F term (reference) 3C069 AA01 BA08 BB03 BB04 CA05                       CB01 EA01 EA02 EA05                 4E068 AA02 AD01 CA01 CA03 CA11                       DA11                 5F047 BB03 BB19 FA21

Claims (12)

[Claims] 1. A modified region by multiphoton absorption inside the semiconductor substrate by irradiating a laser beam with a focusing point aligned inside the semiconductor substrate to which a sheet is attached with a die bond resin layer interposed. And a step of forming a planned cutting portion in the modified region, and after the step of forming the planned cutting portion, by expanding the sheet, the semiconductor substrate and the die bond resin along the planned cutting portion. A method of cutting a semiconductor substrate, comprising: a step of cutting a layer. 2. A sheet with a die bond resin layer interposed
Align the focusing point inside the attached semiconductor substrate,
Peak power density at condensing point is 1 × 10 ⁸(W / c
m²) Above and a pulse width of 1 μs or less
Melting inside the semiconductor substrate by irradiating with light
A modified region including the treatment region is formed, and the melting treatment region is
A step of forming a planned cutting portion with the modified region including After the step of forming the planned cutting portion, the sheet is expanded.
The semiconductor substrate along the planned cutting portion by
And a step of cutting the die bond resin layer.
A method of cutting a semiconductor substrate, comprising: 3. A modified region is formed in the inside of the semiconductor substrate by irradiating a laser beam with a focusing point aligned with the inside of the semiconductor substrate to which the sheet is attached with a die bond resin layer interposed therebetween. After the step of forming the planned cutting part in the modified region and the step of forming the planned cutting part, the sheet is expanded to cut the semiconductor substrate and the die bond resin layer along the planned cutting part. A method of cutting a semiconductor substrate, comprising: 4. A semiconductor substrate having a sheet attached thereto is irradiated with a laser beam with a focus point aligned.
A step of forming a modified region inside the semiconductor substrate, and forming a planned cutting part with the modified region, and a step of forming the planned cutting part, and then expanding the sheet to the planned cutting part. And a step of cutting the semiconductor substrate along the same. 5. The method of cutting a semiconductor substrate according to claim 3, wherein the modified region is a region subjected to melt processing. 6. The step of forming the portion to be cut has a crack reaching the surface of the semiconductor substrate on the laser light incident side from the portion to be cut as a starting point. A method of cutting a semiconductor substrate according to claim 1. 7. The step of forming the portion to be cut has a crack reaching the back surface of the semiconductor substrate opposite to the laser light incident side from the portion to be cut as a starting point. 4. The method for cutting a semiconductor substrate according to claim 4. 8. In the step of forming the planned cutting portion, cracks are made to reach the laser light incident side surface of the semiconductor substrate and the opposite back surface of the semiconductor substrate, starting from the planned cutting portion. The method for cutting a semiconductor substrate according to any one of claims 1 to 4. 9. A modified region by multiphoton absorption inside the semiconductor substrate by irradiating a laser beam with a focusing point aligned inside the semiconductor substrate to which a sheet is attached with a die bond resin layer interposed. And forming a planned cutting part in the modified region, and after the step of forming the planned cutting part, stress is generated in the semiconductor substrate along the planned cutting part, thereby the planned cutting A step of cutting the semiconductor substrate along a portion, and a step of cutting the die bond resin layer along the cut surface of the semiconductor substrate by expanding the sheet after the step of cutting the semiconductor substrate. A method for cutting a semiconductor substrate, which is characterized by the above. 10. The peak power density at the converging point is 1 × 10 ⁸ (W) by aligning the converging point inside the semiconductor substrate to which the sheet is attached with the die bond resin layer interposed.
/ Cm ² ) or more and a pulse width of 1 μs or less, a modified region including a melt-processed region is formed inside the semiconductor substrate, and a modified region including the melt-processed region is formed. Therefore, after the step of forming the planned cutting portion, and the step of forming the planned cutting portion, by causing stress on the semiconductor substrate along the planned cutting portion, the semiconductor substrate along the planned cutting portion. A semiconductor substrate comprising: a step of cutting, and a step of cutting the die bond resin layer along a cut surface of the semiconductor substrate by expanding the sheet after the step of cutting the semiconductor substrate. Cutting method. 11. A modified region is formed inside the semiconductor substrate by irradiating a laser beam with a focusing point aligned inside the semiconductor substrate to which the sheet is attached with a die bond resin layer interposed therebetween. After the step of forming the planned cutting portion in the modified region, and the step of forming the planned cutting portion, by causing stress on the semiconductor substrate along the planned cutting portion, along the planned cutting portion A step of cutting the semiconductor substrate, and a step of cutting the die bond resin layer along a cut surface of the semiconductor substrate by expanding the sheet after the step of cutting the semiconductor substrate. And a method for cutting a semiconductor substrate. 12. The method of cutting a semiconductor substrate according to claim 11, wherein the modified region is a region subjected to a melting process.