JPWO2020202975A1 - Laser processing equipment and laser processing method - Google Patents

Abstract

A holding portion for holding a substrate in which the first layer and the second layer are laminated in this order, and a condensing point for a laser beam are formed on the second layer while the substrate is held by the holding portion, and the collection is performed. A laser processing apparatus including an irradiation unit that removes the second layer while leaving the first layer at the position of a light spot, and a control unit that controls the position of the light collection point.

Description

The present disclosure relates to a laser processing apparatus and a laser processing method.

The method for manufacturing a semiconductor device described in Patent Document 1 includes forming a first silicon nitride layer, a silicon oxide layer, a second silicon nitride layer, and a hard mask layer on a substrate in this order. The hard mask layer includes a carbon layer and the like. In the method of manufacturing a semiconductor device, anisotropic dry etching is performed using a hard mask layer as a mask to form an opening penetrating the second silicon nitride layer, the silicon oxide layer, and the first silicon nitride layer. After that, the carbon layer is removed by a plasma ashing method using oxygen gas.

Japanese Patent Application Laid-Open No. 2011-228340

One aspect of the present disclosure provides a technique capable of selectively removing a desired portion of a second layer laminated on the first layer while leaving the first layer without using plasma.

The laser processing apparatus according to one aspect of the present disclosure is
A holding portion for holding a substrate in which the first layer and the second layer are laminated in this order,
An irradiation unit that forms a condensing point of a laser beam on the second layer while holding the substrate by the holding portion, and removes the second layer while leaving the first layer at the position of the condensing point.
It includes a control unit that controls the position of the condensing point.

According to one aspect of the present disclosure, it is possible to selectively remove a desired portion of the second layer laminated on the first layer while leaving the first layer without using plasma.

FIG. 1 is a cross-sectional view showing a state of a substrate before and after laser processing according to an embodiment. FIG. 2 is a cross-sectional view showing a first state of the laser processing apparatus according to the embodiment. FIG. 3 is a cross-sectional view showing a second state of the laser processing apparatus according to the embodiment. FIG. 4 is a cross-sectional view showing a third state of the laser processing apparatus according to the embodiment. FIG. 5 is a plan view showing the positional relationship between the irradiation unit, the suction unit, and the injection unit according to the embodiment. FIG. 6A is a diagram showing an example of the intensity distribution of the laser beam before passing through the homogenizer. FIG. 6B is a diagram showing an example of the intensity distribution of the laser beam after passing through the homogenizer. FIG. 7A is a plan view showing a first example of how to arrange the condensing points. FIG. 7B is a plan view showing a second example of how to arrange the condensing points. FIG. 7C is a plan view showing a third example of how to arrange the condensing points.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding configurations may be designated by the same reference numerals and description thereof may be omitted. In the present specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction are the horizontal direction, and the Z-axis direction is the vertical direction.

FIG. 1 is a cross-sectional view showing a state of a substrate before and after laser processing according to an embodiment. In FIG. 1, the state of the substrate 100 before laser processing is shown by a two-dot chain line, and the state of the substrate 100 after laser processing is shown by a solid line.

The substrate 100 is a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. The substrate 100 has a disk-shaped first main surface 101, a disk-shaped second main surface 102, and an outer peripheral surface 103. The first main surface 101 is a flat surface, and the second main surface 102 is a flat surface opposite to the first main surface 101. The outer peripheral surface 103 connects the outer edge of the first main surface 101 and the outer edge of the second main surface 102. The outer peripheral surface 103 includes a chamfered bevel. The chamfering process is R chamfering in FIG. 1, but C chamfering may be used.

The first layer 110 and the second layer 120 are laminated on the substrate 100 in this order. A base layer made of a material different from that of the first layer 110 may be formed between the first layer 110 and the substrate 100. On the other hand, the second layer 120 is exposed and is in contact with air. The first layer 110 and the second layer 120 are in contact with each other, and there is no intermediate layer between the first layer 110 and the second layer 120.

The first layer 110 and the second layer 120 may be formed on the entire surface of the substrate 100. The second layer 120 has a first flat portion 121, a second flat portion 122, and an outer peripheral portion 123. The first flat portion 121 is formed in a disk shape on the first main surface 101 of the substrate 100. The second flat portion 122 is formed in a disk shape on the second main surface 102 of the substrate 100. The first flat portion 121 and the second flat portion 122 are arranged on opposite sides of the substrate 100. The outer peripheral portion 123 is formed on the outer peripheral surface 103 of the substrate 100. The first layer 110 also has a first flat portion, a second flat portion, and an outer peripheral portion, similarly to the second layer 120.

The first layer 110 is, for example, an insulating layer formed of an insulating material. The insulating layer is, for example, a silicon nitride layer. The insulating layer may be a silicon oxide layer. Further, the insulating layer may be a single layer or a plurality of layers, and for example, the insulating layer may be a plurality of layers of a silicon nitride layer and a silicon oxide layer. The insulating layer is formed by a CVD (Chemical Vapor Deposition) method, an ALD (Atomic Layer Deposition) method, or the like.

The second layer 120 is, for example, a mask layer that protects a part of the insulating layer when the insulating layer is etched. The mask layer is a so-called carbon hard mask and contains carbon. The mask layer may contain carbon, and may contain a compound mainly composed of carbon. The carbon hard mask may be a single layer or a plurality of layers. The carbon hard mask is formed by a CVD method, a spin-on method, or the like.

A resist pattern (not shown) is formed on the surface of the mask layer, and the mask layer is etched into the same pattern as the resist pattern. After that, the insulating layer is etched in the same pattern as the mask layer. As a result, the insulating layer is formed with an opening that penetrates the insulating layer in the thickness direction. The opening is formed in the portion where the semiconductor chip is formed.

The second layer 120 has a portion on which the semiconductor chip is formed and a portion on which the semiconductor chip is not formed. As portions where the semiconductor chip is not formed, for example, a portion 124 within a desired range radially inward from the outer edge of the first flat portion 121 and a portion within a desired range radially inward from the outer edge of the second flat portion 122. 125 and the outer peripheral portion 123 are mentioned. If the three portions 123, 124, and 125 are peeled off during the manufacturing process of the semiconductor chip, they may adhere to the portion where the semiconductor chip is formed, which may cause a malfunction of the semiconductor chip.

The laser processing device 10 is used to remove a desired portion of the second layer 120 while leaving the first layer 110. The portion to be removed may be, for example, one or more of the above three portions 123, 124, 125. There is also a plasma ashing method as a method for removing a desired portion of the second layer 120 while leaving the first layer 110, but a vacuum processing container is required. According to the laser processing apparatus 10, since plasma is not used, a desired portion of the second layer 120 can be selectively removed while leaving the first layer 110 in the atmosphere.

FIG. 2 is a cross-sectional view showing a first state of the laser processing apparatus according to the embodiment. The first state is a state in which the relative position between the holding portion 20 and the galvano scanner 31 in the Z-axis direction is the first position. FIG. 3 is a cross-sectional view showing a second state of the laser processing apparatus according to the embodiment. The second state is a state in which the relative position between the holding portion 20 and the galvano scanner 31 in the Z-axis direction is the second position. FIG. 4 is a cross-sectional view showing a third state of the laser processing apparatus according to the embodiment. The third state is a state in which the relative position between the holding portion 20 and the galvano scanner 31 in the Z-axis direction is the third position. The third position is a position opposite to the first position with respect to the second position. As shown in FIGS. 2 to 4, the laser processing apparatus 10 includes, for example, a holding unit 20, an irradiation unit 30, a rotation driving unit 40, a first moving driving unit 50, and a second moving driving unit 60. A control unit 90 is provided.

The holding portion 20 holds the substrate 100. For example, the holding portion 20 holds the substrate 100 horizontally from below with the first main surface 101 of the substrate 100 facing upward. The holding portion 20 is a vacuum chuck, an electrostatic chuck, or the like. The holding portion 20 has a holding surface 21 for holding the substrate 100. The diameter of the holding surface 21 may be larger than the diameter of the substrate 100, but may be smaller. If the diameter of the holding surface 21 is smaller than the diameter of the substrate 100, the outer edge of the substrate 100 protrudes from the holding portion 20, and as will be described in detail later, the protruding portion can be irradiated with the laser beam LB from the side or below.

The irradiation unit 30 forms a condensing point P of the laser beam LB on the second layer 120 while the substrate 100 is held by the holding unit 20, and the second layer 120 leaves the first layer 110 at the position of the condensing point P. To remove. The laser beam LB has an absorbent property with respect to the second layer 120 and a transmissive property with respect to the first layer 110. Examples of such a laser beam LB include those having a wavelength of 190 nm or more and 1500 nm or less. The wavelength of the laser beam LB can be selected based on the material of the second layer 120 and the material of the first layer 110. The second layer 120 absorbs the laser beam LB and changes its state from the solid phase to the gas phase and scatters, or scatters in the solid phase.

The irradiation unit 30 includes, for example, a galvano scanner 31. According to the galvano scanner 31, the light collecting point P in the second layer 120 can be displaced even when the relative positions of the galvano scanner 31 and the holding portion 20 are fixed. The galvano scanner 31 is, for example, a so-called 3D galvano scanner. The region A in which the focusing point P can be formed by the galvano scanner 31 is shown in FIGS. 2 to 5. The 3D galvano scanner can displace the focusing point P in the X-axis direction, the Y-axis direction, and the Z-axis direction within the region A. In this embodiment, the function of displacing the focusing point P in the Y-axis direction of the galvano scanner 31 is not used.

The 3D galvano scanner includes two galvano mirrors and a movable lens. When the movable lens moves in the optical axis direction, the focal position is displaced. The galvano scanner 31 rotates one galvano mirror to displace the focusing point P in the Z-axis direction. Further, the galvano scanner 31 moves the movable lens in the optical axis direction and displaces the focusing point P in the X-axis direction. Since the focusing point P can be displaced in the X-axis direction, the focusing point P can be displaced along the bevel even when the relative positions of the galvano scanner 31 and the holding portion 20 are fixed.

The galvano scanner 31 is arranged, for example, radially outward of the substrate 100 held by the holding portion 20. As a result, the galvano scanner 31 can irradiate the laser beam LB diagonally downward from the first position shown in FIG. 2 to remove the upward portion 124 of the second layer 120. Further, the galvano scanner 31 can irradiate the laser beam LB laterally from the second position shown in FIG. 3 to remove the lateral portion 123 of the second layer 120. Further, the galvano scanner 31 can irradiate the laser beam LB diagonally upward from the third position shown in FIG. 4 to remove the downward portion 125 of the second layer 120. If the galvano scanner 31 and the holding portion 20 are relatively moved in the Z-axis direction, the upward portion 124, the lateral portion 123, and the downward portion 125 of the second layer 120 can all be removed. Therefore, for example, it is possible to save the trouble of changing the orientation of the substrate 100, such as removing the substrate 100 from the holding portion 20 and turning the substrate 100 upside down.

The rotation drive unit 40 rotates the holding unit 20. The rotation drive unit 40 rotates the holding unit 20 around, for example, a vertical rotation center line 41. By rotating the holding portion 20, the condensing point P can be displaced in the circumferential direction of the substrate 100. The rotary drive unit 40 includes, for example, a rotary motor.

The first moving drive unit 50 relatively moves the holding unit 20 and the galvano scanner 31 in the first direction (for example, the X-axis direction) orthogonal to the rotation center line 41 of the holding unit 20. As a result, the condensing point P can be displaced in the radial direction of the substrate 100.

The first moving drive unit 50 includes, for example, a guide 51 extending in the X-axis direction and a drive source 52 including a motor for moving the holding unit 20 along the guide 51. The first moving drive unit 50 may move the galvano scanner 31 in the X-axis direction, but it does not have to move it. Since the galvano scanner 31 does not move in the X-axis direction, it can always receive the laser beam LB from the Z-axis direction perpendicular to the X-axis direction at the same point.

The second moving drive unit 60 relatively moves the holding unit 20 and the galvano scanner 31 in a second direction (for example, the Z-axis direction) parallel to the rotation center line 41 of the holding unit 20. As a result, as described above, if the galvano scanner 31 and the holding portion 20 are relatively moved in the Z-axis direction, the upward portion 124, the lateral portion 123, and the downward portion 125 of the second layer 120 can all be removed. .. Therefore, for example, it is possible to save the trouble of changing the orientation of the substrate 100, such as removing the substrate 100 from the holding portion 20 and turning the substrate 100 upside down.

The second moving drive unit 60 includes, for example, a guide 61 extending in the Z-axis direction and a drive source 62 including a motor for moving the galvano scanner 31 along the guide 61. Even if the galvano scanner 31 is moved in the Z-axis direction, the laser beam LB from the Z-axis direction hits the same point of the galvano scanner 31. The second moving drive unit 60 may move the holding unit 20 in the Z-axis direction.

The control unit 90 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs that control various processes executed by the laser processing apparatus 10. The control unit 90 controls the operation of the laser processing device 10 by causing the CPU 91 to execute the program stored in the storage medium 92. Further, the control unit 90 includes an input interface 93 and an output interface 94. The control unit 90 receives a signal from the outside through the input interface 93, and transmits the signal to the outside through the output interface 94.

The program is stored in a storage medium readable by a computer, and is installed from the storage medium in the storage medium 92 of the control unit 90. Examples of the storage medium readable by a computer include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical desk (MO), a memory card, and the like. The program may be downloaded from the server via the Internet and installed in the storage medium 92 of the control unit 90.

The control unit 90 controls the position of the condensing point P. For example, as will be described later, the control unit 90 controls the rotation drive unit 40, the first movement drive unit 50, the second movement drive unit 60, and the galvano scanner 31, and controls the position of the condensing point P. As a result, the desired portion of the second layer 120 can be selectively removed while leaving the first layer 110 in the atmosphere.

First, as shown in FIG. 2, the control unit 90 collects light in the circumferential direction and the radial direction of the substrate 100 in a state where the relative positions of the holding unit 20 and the galvano scanner 31 in the Z-axis direction are fixed to the first position. The point P is displaced to remove the portion 124 of the first flat portion 121. The control unit 90 moves the substrate 100 in the X-axis direction while rotating the substrate 100 in order to displace the condensing point P in the circumferential direction and the radial direction of the substrate 100. At this time, the propagation direction of the laser beam LB from the galvano scanner 31 toward the substrate 100 is fixed diagonally downward.

Next, as shown in FIG. 3, the control unit 90 keeps the relative positions of the holding unit 20 and the galvano scanner 31 in the Z-axis direction fixed at the second position, and in the circumferential direction and the plate thickness direction of the substrate 100. The light collecting point P is displaced and the outer peripheral portion 123 is removed. The control unit 90 swings the propagation direction of the laser beam LB from the galvano scanner 31 toward the substrate 100 up and down while rotating the substrate 100 in order to displace the condensing point P in the circumferential direction and the plate thickness direction of the substrate 100.

Next, as shown in FIG. 4, the control unit 90 collects in the circumferential direction and the radial direction of the substrate 100 in a state where the relative positions of the holding unit 20 and the galvano scanner 31 in the Z-axis direction are fixed to the third position. The light spot P is displaced to remove the portion 125 of the second flat portion 122. The control unit 90 moves the substrate 100 in the X-axis direction while rotating the substrate 100 in order to displace the condensing point P in the circumferential direction and the radial direction of the substrate 100. At this time, the propagation direction of the laser beam LB from the galvano scanner 31 toward the substrate 100 is fixed diagonally upward.

The portion 124 of the first flat portion 121, the outer peripheral portion 123, and the portion 125 of the second flat portion 122 are removed in this order, but the order is not particularly limited. Further, one or more of the above-mentioned portion 124 of the first flat portion 121, the outer peripheral portion 123, and the above-mentioned portion 125 of the second flat portion 122 may be removed.

When the laser processing apparatus 10 removes only the portion 124 of the first flat portion 121, the galvano scanner 31 may be arranged directly above the portion 124. In this case, the galvano scanner 31 may be a 2D galvano scanner because it does not have to have a function of changing the focal position. The 2D galvano scanner rotates one galvano mirror to displace the focusing point P in the X-axis direction. Further, the 2D galvano scanner rotates another galvano mirror to displace the focusing point P in the Y-axis direction.

FIG. 5 is a plan view showing the positional relationship between the irradiation unit, the suction unit, and the injection unit according to the embodiment. As shown in FIG. 5, the laser processing device 10 may further include at least one of the suction unit 70 and the injection unit 75 in addition to the irradiation unit 30.

The suction unit 70 sucks the scattered material from the light collecting point P. At the condensing point P, the second layer 120 absorbs the laser beam LB and changes its state from the solid phase to the gas phase and scatters, or scatters in the solid phase. Since the scattered material is sucked toward the suction unit 70, it does not contaminate the irradiation unit 30. Therefore, it is possible to suppress a decrease in the intensity of the laser beam LB.

The suction unit 70 includes, for example, a suction nozzle 72 having a suction port 71 toward the condensing point P, and a vacuum pump 73 connected to the suction nozzle 72 via a pipe. The vacuum pump 73 generates a negative pressure inside the suction nozzle 72, and the suction nozzle 72 sucks the scattered material inside the suction nozzle 72.

Since the injection unit 75 injects the gas toward the condensing point P, the scattered matter from the condensing point P can be swept away in a direction different from the direction toward the irradiation unit 30. It is possible to suppress the irradiation portion 30 from being contaminated by scattered objects, and it is possible to suppress a decrease in the intensity of the laser beam LB.

The injection unit 75 includes, for example, an injection nozzle 77 having an injection port 76 toward the condensing point P, and a compressed gas source 78 connected to the injection nozzle 77 via a pipe. The compressed gas source 78 supplies the compressed gas to the injection nozzle 77, and the injection nozzle 77 injects the compressed gas.

The suction port 71 of the suction unit 70 and the injection port 76 of the injection unit 75 may be arranged in a straight line with the condensing point P interposed therebetween. The gas injected from the injection port 76 passes through the condensing point P and is sucked into the suction port 71. Since the gas injection direction and the gas suction direction coincide with each other, the scattered matter from the condensing point P can be efficiently recovered.

As shown in FIGS. 2 to 4, the laser processing apparatus 10 may include a homogenizer 80. FIG. 6A is a diagram showing an example of the intensity distribution of the laser beam before passing through the homogenizer. FIG. 6B is a diagram showing an example of the intensity distribution of the laser beam after passing through the homogenizer. The homogenizer 80 changes the intensity distribution of the laser beam LB from the Gaussian distribution shown in FIG. 6A to the top hat distribution shown in FIG. 6B to make the intensity distribution uniform.

Further, as shown in FIGS. 2 to 4, the laser processing apparatus 10 may include an aperture 85. The aperture 85 shapes the cross-sectional shape of the laser beam LB into a rectangular shape. The rectangle includes not only a rectangle but also a square. The aperture 85 is a light-shielding film having a rectangular opening. The opening allows, for example, the laser beam LB in the range indicated by the arrow B in FIG. 6B to pass through.

The homogenizer 80 and the aperture 85 can form a rectangular condensing point P having a uniform intensity distribution. By arranging the condensing points P regularly and two-dimensionally without gaps as described later, the integrated irradiation amount (J) of the laser beam LB per unit area can be made uniform, and local heating can be suppressed. The desired portion of the second layer 120 can be selectively removed while suppressing damage to the first layer 110. Further, since the intensity distribution changes discontinuously at the outer edge of the condensing point P, the boundary between the removed portion of the second layer 120 and the remaining portion of the second layer 120 can be sharply formed.

FIG. 7A is a plan view showing a first example of how to arrange the condensing points. In FIG. 7A, the R direction is the radial direction of the substrate 100, and the θ direction is the circumferential direction of the substrate 100. The condensing point P is a rectangle having a uniform intensity distribution, the two sides of the rectangle are parallel to the R direction, and the remaining two sides of the rectangle are parallel to the θ direction. The θ-direction dimension θ0 of the condensing point P is sufficiently shorter than the peripheral length of the substrate 100 so that the outer edge of the substrate 100 can be regarded as a straight line. The R-direction dimension R0 of the light-collecting point P may be the same as or different from the θ-direction dimension θ0 of the light-collecting point P. The same applies to FIGS. 7B and 7C.

As shown in FIG. 7A, the control unit 90 moves the focusing point P by θ0 in the θ direction during the off time of the pulse while oscillating the laser beam LB in a pulse, and causes the focusing point P over the entire θ direction. Line up in a row without any gaps. After that, the control unit 90 moves the focusing point P in the R direction by R0 during the pulse off time while oscillating the laser beam LB in a pulse, and moves the focusing point P in the θ direction during the pulse off time. By repeating the movement by θ0, the focusing points P are arranged two-dimensionally without any gaps. According to the arrangement of the condensing points P shown in FIG. 7A, the integrated irradiation amount of the laser beam LB per unit area can be made uniform, and local heating can be suppressed.

FIG. 7B is a plan view showing a second example of how to arrange the condensing points. As shown in FIG. 7B, the control unit 90 moves the focusing point P in the θ direction by half the value of θ0 while oscillating the laser beam LB in a pulsed manner during the off time of the pulse, and the focusing point over the entire θ direction. Arrange P in a row while stacking them. After that, the control unit 90 moves the focusing point P in the R direction by R0 during the pulse off time while oscillating the laser beam LB in a pulse, and moves the focusing point P in the θ direction during the pulse off time. By repeating the process of moving by half the value of θ0, the focusing points P are arranged two-dimensionally without any gap. According to the arrangement of the condensing points P shown in FIG. 7B, the integrated irradiation amount of the laser beam LB per unit area can be made uniform, and local heating can be suppressed. The control unit 90 uses the laser beam LB to oscillate the pulse, and instead of moving the focusing point P in the R direction by R0 during the pulse off time, the control unit 90 sets the focusing point P during the pulse off time. It may be carried out to move by half price of R0 in the R direction.

FIG. 7C is a plan view showing a third example of how to arrange the condensing points. As shown in FIG. 7C, the control unit 90 moves the focusing point P twice in the θ direction in the θ direction while oscillating the laser beam LB in a pulsed manner during the off time of the pulse, and the gap SP covers the entire θ direction. The light collecting points P are arranged in a row while forming the above. Next, the control unit 90 moves the focusing point P twice in the θ direction in the θ direction while oscillating the laser beam LB again so as to fill the gap SP with the focusing point P. .. After that, the control unit 90 moves the focusing point P in the R direction by R0 during the pulse off time while oscillating the laser beam LB in a pulse, and moves the focusing point P in the θ direction during the pulse off time. The light collection point P is moved twice in the θ direction in the θ direction during the pulse off time so as to fill the gap SP with the light collection point P. The light spots P are arranged two-dimensionally without any gaps. According to the arrangement of the condensing points P shown in FIG. 7C, the integrated irradiation amount of the laser beam LB per unit area can be made uniform, and local heating can be suppressed.

Although the laser processing apparatus and the laser processing method according to the present disclosure have been described above, the present disclosure is not limited to the above-described embodiment and the like. Various changes, modifications, replacements, additions, deletions, and combinations are possible within the scope of the claims. Of course, they also belong to the technical scope of the present disclosure.

For example, the technique of the present disclosure can also be applied to the removal of a portion where a semiconductor chip is formed. Further, the substrate 100 does not have to be a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer, and may be, for example, a glass substrate.

The laser processing apparatus of the above embodiment can be applied to processing other than processing for removing the second layer 120 while leaving the first layer 110 at the position of the condensing point P. The laser processing apparatus of the above embodiment is applicable as long as it is a processing for removing at least a part of a desired layer.

This application claims priority based on Japanese Patent Application No. 2019-067891 filed with the Japan Patent Office on March 29, 2019, and the entire contents of Japanese Patent Application No. 2019-067891 are incorporated in this application. ..

10 Laser processing device 20 Holding unit 30 Irradiating unit 31 Galvano scanner 40 Rotational drive unit 50 1st moving drive unit 60 2nd moving drive unit 90 Control unit 100 Board 110 1st layer 120 2nd layer 121 1st flat part 122 2nd Flat part 123 Outer part

One aspect of the present disclosure provides a technique capable of suppressing damage to a substrate.

The laser processing apparatus according to one aspect of the present disclosure is
A holding unit for holding a board,
An irradiation unit that forms a condensing point of a laser beam on the substrate while the substrate is held by the holding portion.
A control unit that controls the position of the condensing point is provided .
The irradiation unit includes a homogenizer that equalizes the intensity distribution of the laser beam and an aperture that shapes the cross-sectional shape of the laser beam into a rectangle.
The control unit oscillates the laser beam and moves the condensing point with respect to the substrate during the off time of the pulse to obtain the integrated laser beam irradiation amount per unit area of the substrate. Make it uniform.

According to one aspect of the present disclosure, damage to the substrate can be suppressed.

Claims (20)

A holding portion for holding a substrate in which the first layer and the second layer are laminated in this order,
An irradiation unit that forms a condensing point of a laser beam on the second layer while holding the substrate by the holding portion, and removes the second layer while leaving the first layer at the position of the condensing point. ,
A laser processing apparatus including a control unit that controls the position of the condensing point. The first layer is an insulating layer formed of an insulating material.
The second layer is a mask layer that protects a part of the insulating layer when the insulating layer is etched.
The laser processing apparatus according to claim 1, wherein the mask layer contains carbon. The substrate connects a disk-shaped first main surface, a disk-shaped second main surface opposite to the first main surface, and an outer edge of the first main surface and an outer edge of the second main surface. Has an outer peripheral surface and
The second layer has a first flat portion formed on the first main surface, a second flat portion formed on the second main surface, and an outer peripheral portion formed on the outer peripheral surface.
The control unit includes a portion within a desired range radially inward from the outer edge of the first flat portion, a portion within a desired range radially inward from the outer edge of the second flat portion, and the outer peripheral portion. The laser processing apparatus according to claim 1 or 2, which controls the position of the condensing point in order to remove at least one of the above. The laser processing apparatus according to claim 3, wherein the irradiation unit includes a galvano scanner that displaces the condensing point in the second layer. The diameter of the holding surface of the holding portion for holding the substrate is smaller than the diameter of the substrate.
The laser processing apparatus according to claim 4, wherein the galvano scanner is arranged outside the radial direction of the substrate held by the holding portion. A rotary drive unit that rotates the holding unit, and
A first moving drive unit that relatively moves the holding unit and the galvano scanner in a first direction orthogonal to the rotation center line of the holding unit.
A second moving drive unit for relatively moving the holding unit and the galvano scanner in a second direction parallel to the rotation center line of the holding unit is provided.
The laser processing according to claim 5, wherein the control unit controls the rotation drive unit, the first movement drive unit, the second movement drive unit, and the galvano scanner to control the position of the light collection point. Device. The control unit
With the relative position of the holding portion and the galvano scanner in the second direction fixed at the first position, the condensing point is displaced in the circumferential direction and the radial direction of the substrate, and the outer edge of the first flat portion is displaced. To remove the part within the desired range in the radial direction from
With the relative position of the holding portion and the galvano scanner in the second direction fixed at a second position different from the first position, the light collecting point is displaced in the circumferential direction and the plate thickness direction of the substrate. , Removing the outer peripheral part, and
With the relative position of the holding portion and the galvano scanner in the second direction fixed at the third position opposite to the first position with respect to the second position, the circumferential direction and the diameter of the substrate. The laser processing apparatus according to claim 6, wherein the light collecting point is displaced in the direction, and a portion within a desired range is removed radially inward from the outer edge of the second flat portion. The laser processing apparatus according to any one of claims 1 to 7, wherein the irradiation unit includes a homogenizer for equalizing the intensity distribution of the laser beam and an aperture for shaping the cross-sectional shape of the laser beam into a rectangular shape. The laser processing apparatus according to any one of claims 1 to 8, further comprising a suction unit for sucking scattered matter from the condensing point. The laser processing apparatus according to any one of claims 1 to 9, further comprising an injection unit that injects gas toward the condensing point. Holding the substrate in which the first layer and the second layer are laminated in this order by the holding portion,
In a state where the substrate is held by the holding portion, a condensing point of a laser beam is formed on the second layer, and the second layer is removed while leaving the first layer at the position of the condensing point.
A laser processing method comprising controlling the position of the condensing point. The first layer is an insulating layer formed of an insulating material.
The second layer is a mask layer that protects a part of the insulating layer when the insulating layer is etched.
The laser processing method according to claim 11, wherein the mask layer contains carbon. The substrate connects a disk-shaped first main surface, a disk-shaped second main surface opposite to the first main surface, and an outer edge of the first main surface and an outer edge of the second main surface. Has an outer peripheral surface and
The second layer has a first flat portion formed on the first main surface, a second flat portion formed on the second main surface, and an outer peripheral portion formed on the outer peripheral surface.
At least a portion within a desired range radially inward from the outer edge of the first flat portion, a portion within a desired range radially inward from the outer edge of the second flat portion, and the outer peripheral portion. The laser processing method according to claim 11 or 12, which comprises controlling the position of the condensing point in order to remove one. 13. The laser processing method according to claim 13, wherein the focusing point in the second layer is displaced by a galvano scanner. The diameter of the holding surface of the holding portion for holding the substrate is smaller than the diameter of the substrate.
The laser processing method according to claim 14, wherein the galvano scanner is arranged outside the radial direction of the substrate held by the holding portion. A rotary drive unit that rotates the holding unit, and
A first moving drive unit that relatively moves the holding unit and the galvano scanner in a first direction orthogonal to the rotation center line of the holding unit.
A second moving drive unit that relatively moves the holding unit and the galvano scanner in a second direction parallel to the rotation center line of the holding unit.
The laser processing method according to claim 15, which comprises controlling the galvano scanner and controlling the position of the condensing point. With the relative position of the holding portion and the galvano scanner in the second direction fixed at the first position, the condensing point is displaced in the circumferential direction and the radial direction of the substrate, and the outer edge of the first flat portion is displaced. To remove the part within the desired range in the radial direction from
With the relative position of the holding portion and the galvano scanner in the second direction fixed at a second position different from the first position, the light collecting point is displaced in the circumferential direction and the plate thickness direction of the substrate. , Removing the outer peripheral part, and
With the relative position of the holding portion and the galvano scanner in the second direction fixed at the third position opposite to the first position with respect to the second position, the circumferential direction and the diameter of the substrate. The laser processing method according to claim 16, further comprising displacing the light collecting point in the direction and removing a portion within a desired range in the radial direction from the outer edge of the second flat portion. To homogenize the intensity distribution of the laser beam with a homogenizer,
The laser processing method according to any one of claims 11 to 17, wherein the cross-sectional shape of the laser beam is shaped into a rectangle by an aperture. The laser processing method according to any one of claims 11 to 18, which comprises sucking scattered matter from the condensing point. The laser processing method according to any one of claims 11 to 19, which comprises injecting gas toward the condensing point.

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