JP2005277136A - Method and apparatus of manufacturing substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a substrate which can surely manufacture the substrate from an ingot and readily, without scraps. <P>SOLUTION: The condensing point 5a of a laser beam 5 is relatively moved to the ingot 1, in a state with the condensing point 5a of the laser beam 5 matching the interior of the ingot 1. A processing region 10 by substantially planar multiphoton absorption, extending in a direction perpendicular direction to the radiating direction of the laser beam 5 is formed in the interior of the ingot 1. In a part 11 of one side, bordered on the processing region 10 in the ingot 1 and a part 12 of other side are separated in the processing region 12, and the substrate 2, is manufactured from the ingot 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, a substrate manufacturing method and a substrate manufacturing apparatus for manufacturing a thin substrate without chips from an ingot.

  As a method for manufacturing a substrate from an ingot, for example, a process of cutting a wafer used for manufacturing a semiconductor device from a cylindrical or prismatic ingot made of a crystal such as Si or GaAs can be cited.

  As a method of cutting a wafer from such an ingot, there is a method of physically cutting the ingot with a diamond blade saw or a wire saw. With diamond blade saws, it takes time to cut one piece, and at present, wire saws are the mainstream because a plurality of wafers can be cut simultaneously from an ingot.

  However, with this cutting method, it is difficult to obtain a thin wafer having a thickness of 100 μm or less, and the thickness of the wire becomes chips, resulting in a lot of waste in machining.

  For this reason, in order to minimize waste of the ingot as much as possible, the excimer laser device that continuously oscillates the ultraviolet excimer laser light and the condensing optical system that condenses and irradiates the excimer laser light on the surface of the crystal ingot are provided. In a crystal ingot cutting device that cuts perpendicularly to the longitudinal direction, a continuous wave of excimer laser light is focused on the peripheral surface of the crystal ingot to cause a local temperature rise, and the crystal ingot is cleaved by thermal stress. There is a method of cutting the substrate perpendicularly to the longitudinal direction to create a substrate (see JP 2002-184724 A: Patent Document 1).

  However, in the cutting method disclosed in Patent Document 1, the plane orientation of the ingot is important. If the crystal of the ingot is mica-like, the ingot can be cut by a plane, but if the crystal of the ingot is not mica-like, The ingot cannot be cut on the surface.

  As another method, an ultrasonic oscillator is arranged so that the focal point of the ultrasonic wave is inside the surface of the ingot, and this ultrasonic oscillator is moved to form a cut surface at the focal point of the ultrasonic wave. There is a method of peeling the surface portion from the cut surface as a substrate (see JP-A-8-39500: Patent Document 2).

  However, in the cutting method disclosed in Patent Document 2, since the ultrasonic wave has a long wavelength and no power, it is difficult to narrow down the focal point of the ultrasonic wave in order to form a cut surface.

  As another method for forming and peeling a processed surface inside an ingot, a hydrogen negative ion is implanted from the main surface of the semiconductor crystal substrate, so that the depth from the main surface is reduced in the hydrogen concentration profile in the depth direction. There is a method in which a high-concentration hydrogen layer having a concentration peak at a position of 5 μm or more is formed, and then the semiconductor thin film is peeled off from the semiconductor crystal substrate in the high-concentration hydrogen layer (see Japanese Patent Application Laid-Open No. 2003-17723: Patent Document 3). .

However, in the exfoliation method disclosed in Patent Document 3, when an attempt is made to produce a semiconductor thin film (substrate) having a thickness of 30 μm or more, for example, when negative hydrogen ions are implanted, the negative ion implantation energy must be extremely high. In addition, damage is increased, and a substrate having a thickness of 30 μm or more cannot be formed.
JP 2002-184724 A JP-A-8-39500 JP 2003-17723 A

  Then, the subject of this invention is providing the board | substrate manufacturing method and board | substrate manufacturing apparatus which can manufacture a board | substrate from an ingot reliably and simply, without chips.

In order to solve the above problems, the substrate manufacturing method of the present invention is:
With the laser beam condensing point set inside the ingot, the laser beam condensing point is moved relative to the ingot, and the laser beam is irradiated into the ingot with respect to the irradiation direction of the laser beam. A first step of forming a processing region by substantially planar multiphoton absorption extending in a substantially vertical direction;
And a second step of separating the one side portion and the other side portion of the ingot at the processing region with the processing region as a boundary.

  Here, in this specification, for example, the one side portion is peeled off from the other side portion to become a substrate.

  According to the substrate manufacturing method of the present invention, the processing region by multiphoton absorption of the laser light is formed inside the ingot, and the one side portion and the other side portion of the ingot are separated in the processing region. Therefore, the substrate can be easily manufactured from the ingot without chips.

  In addition, since the processing region extending in a direction substantially perpendicular to the irradiation direction of the laser beam is formed inside the ingot, the positional relationship between the laser beam and the ingot is improved. For example, when the ingot has a cylindrical shape, the ingot is arranged so that the axis of the ingot is in the vertical direction, the laser beam is irradiated from above the ingot, and the axis of the ingot is placed inside the ingot. A processing region extending in a direction perpendicular to the direction is formed. At this time, since the laser device for irradiating the laser light is disposed above the ingot, the overall width of the device for manufacturing the substrate from the ingot can be reduced, and the installation space can be reduced. Can be small.

  In addition, since a substantially planar processing region is formed inside the ingot, the one part and the other part of the ingot can be reliably and easily separated in the processing region, and the substrate can be separated from the ingot. Can be reliably and easily manufactured.

  In one embodiment of the substrate manufacturing method, the laser beam is a pulsed laser beam, and the pulse width of the laser beam is 1 μs or less.

  According to the substrate manufacturing method of this embodiment, since the pulse width of the laser light is 1 μs or less, optical damage due to multiphoton absorption is caused inside the ingot without causing extra damage to the surface of the ingot. Damage can be reliably done.

  In one embodiment of the substrate manufacturing method, the ingot is silicon, and the wavelength of the laser light is 800 nm or more.

  According to the substrate manufacturing method of this embodiment, the laser beam can be made highly transparent to the ingot, and a processing region by multiphoton absorption can be reliably formed inside the ingot.

  In one embodiment of the substrate manufacturing method, in the first step, the ingot is rotated about an axis substantially parallel to the irradiation direction of the laser beam, and the condensing point of the laser beam is set to the laser beam. The processing region is formed by moving in a direction substantially perpendicular to the irradiation direction.

  According to the substrate manufacturing method of this one embodiment, the processing region can be formed by simple movement of the ingot and the laser beam (to draw a spiral or a plurality of concentric circles), and the ingot and the laser beam can be formed. Operation control becomes easy. Further, the stroke of the laser beam can be reduced, and the apparatus can be miniaturized.

The substrate manufacturing apparatus of the present invention is
Laser light irradiation means for irradiating the ingot with laser light;
A processing region by absorption of substantially planar multiphotons extending in a direction substantially perpendicular to the irradiation direction of the laser light inside the ingot in a state where the condensing point of the laser light is aligned inside the ingot. Moving means for moving the condensing point of the laser beam relative to the ingot so as to form
Separating means for separating the one side portion and the other side portion of the ingot at the processing region with the processing region as a boundary is provided.

  According to the substrate manufacturing apparatus of the present invention, the laser light irradiating means and the moving means for forming the processing region by multiphoton absorption of the laser light inside the ingot, and one side of the ingot in the processing region Since the separation means for separating the other part and the other part is provided, the substrate can be easily produced from the ingot without chips.

  Further, since the processing region extending in a direction substantially perpendicular to the irradiation direction of the laser beam is formed inside the ingot, the positional relationship between the laser beam irradiation means and the ingot is improved. For example, when the ingot has a cylindrical shape, the ingot is arranged so that the axis of the ingot is in the vertical direction, the laser beam is irradiated from above the ingot, and the axis of the ingot is placed inside the ingot. A processing region extending in a direction perpendicular to the direction is formed. At this time, since the laser beam irradiation means is disposed above the ingot, the overall width of the substrate manufacturing apparatus can be reduced, and the installation space can be reduced.

  In addition, since a substantially planar processing region is formed inside the ingot, the one part and the other part of the ingot can be reliably and easily separated in the processing region, and the substrate can be separated from the ingot. Can be reliably and easily manufactured.

  According to the substrate manufacturing method of the present invention, the processing region by multiphoton absorption of the laser light is formed inside the ingot, and the one side portion and the other side portion of the ingot are separated in the processing region. Therefore, the substrate can be easily manufactured from the ingot without chips.

  Further, according to the substrate manufacturing apparatus of the present invention, the laser beam irradiating means and the moving means for forming the processing region by multiphoton absorption of the laser light inside the ingot, and the processing region in the ingot Since the separation means for separating the one side portion and the other side portion is provided, the substrate can be easily manufactured from the ingot without chips.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a simplified configuration diagram showing an embodiment of a substrate manufacturing apparatus according to the present invention. The substrate manufacturing apparatus 3 is an apparatus that manufactures a substrate 2 from an ingot 1, and includes a laser beam irradiation means 20 that irradiates the ingot 1 with a laser beam 5 and a condensing point 5 a of the laser beam 5. Moving means 30 for moving the condensing point 5a of the laser beam 5 relative to the ingot 1 so as to form a processing region 10 by multiphoton absorption, and the processing region 10 in the ingot 1 as a boundary. Separating means 40 for separating the one-side portion 11 and the other-side portion 12 in the processing region 10 is provided.

  In the following description, a direction in which the laser light irradiation unit 20 emits the laser light 5 is referred to as a Z direction, and a direction perpendicular to the irradiation direction (Z direction) of the laser light 5 is referred to as an XY direction. That's it.

  The ingot 1 is a cylindrical silicon ingot, and the substrate 2 is a circular silicon wafer.

  The laser beam irradiation means 20 includes a laser oscillator 4 that oscillates the laser beam 5 and a condenser lens 6 that condenses the laser beam 5 oscillated from the laser oscillator 4.

  The moving means 30 includes a rotary stage 7 on which the ingot 1 is mounted and rotates the ingot 1 about an axis in the Z direction, and a laser apparatus that moves the laser light irradiation means 20 in the XY direction and the Z direction. And a drive unit 21.

  Then, the moving means 30 rotates the ingot 1 around the axis while keeping the condensing point 5a of the laser beam 5 inside the ingot 1, and the condensing point 5a of the laser beam 5 is changed. By moving in the XY direction, a processing area 10 by absorption of a substantially planar multiphoton extending in the XY direction is formed inside the ingot 1.

  Here, the multiphoton absorption is a phenomenon that occurs when the intensity of the laser beam is extremely increased, and optical damage is caused inside the ingot 1 without causing extra damage to the surface of the ingot 1. Give. The optical damage induces thermal strain in the ingot 1 and can generate cracks in the ingot 1. That is, the inside of the ingot 1 is locally heated by multiphoton absorption, and the processing region 10 is formed inside the ingot 1 by this heating. This processing region 10 makes it easy to cut the silicon bond of the ingot 1, and it is possible to obtain a circular substrate 2 easily by performing suitable peeling.

  The separating means 40 includes an arm 8 that holds the one-side portion 11 and peels the one-side portion 11 from the other-side portion 12. That is, the peeled one side portion 11 becomes the substrate 2.

  The separating means 40 needs to be handled using, for example, a vacuum chuck, an electrostatic chuck, or a Bernoulli method so as not to damage the substrate 2 (peeled wafer). Alternatively, the release wafer may be handled by bonding the holding base with an adhesive or attaching a pressure-sensitive adhesive tape or the like.

  In order to handle the large area substrate 2 without damaging it, it is necessary to hold the entire surface with a uniform holding force. At this time, as the separating means 40, for example, a vacuum chuck is used, and it is preferable to use a vacuum chuck in which minute suction holes are uniformly and densely formed on the entire holding surface. The arm 8 at this time has an adsorption | suction mechanism in the front-end | tip, for example.

  Next, a method for manufacturing the substrate 2 from the ingot 1 using the substrate manufacturing apparatus 3 having the above configuration will be described.

  A cylindrical ingot 1 is mounted on the rotary stage 7 so that the axis of the ingot 1 is in the vertical direction (the Z direction). The laser beam irradiating means 20 is disposed on the upper surface of the ingot 1 by the laser device driving unit 21.

  Then, the laser beam 5 is irradiated from the laser beam irradiation means 20 toward the upper surface side of the ingot 1. The surface (upper surface) that is the laser incident surface of the ingot 1 is kept flat.

  Thereafter, the rotating stage 7 rotates the ingot 1 around its axis in a state where the condensing point 5a of the laser beam 5 is aligned with a position at a certain depth from the upper surface of the ingot 1 (inside the ingot 1). And the laser device driving unit 21 moves the condensing point 5a of the laser beam 5 in the XY direction.

  Here, as the moving direction of the condensing point 5a of the laser beam 5, for example, the condensing point 5a of the laser beam 5 is moved from the center of the ingot 1 outward in the radial direction. When viewed from above the ingot 1, the inside of the ingot 1 is irradiated so as to draw a spiral or a plurality of concentric circles.

  As a result, in the inside of the ingot 1, the processing region 10 due to absorption of substantially planar multiphotons extending in a direction (XY direction) substantially perpendicular to the irradiation direction of the laser light 5 (Z direction). Is formed.

Here, the laser beam 5 is a pulse laser beam, and the laser beam 5 is irradiated under the condition that the electric field intensity at the condensing point 5a is 1 × 10 ⁸ (W / cm ² ) or more and the pulse width is 1 μms or less. Is done. By irradiation under these conditions, optical damage due to multiphoton absorption can be reliably given to the inside of the ingot 1. Further, the wavelength of the laser beam 5 is 800 nm or more, and the transparency of the laser beam 5 with respect to the silicon ingot 1 can be increased, so that the processing region 10 by multiphoton absorption can be surely provided inside the ingot 1. Can be formed.

  Then, the arm 8 of the separating means 40 holds the one side portion 11 and peels it from the other side portion 12 to obtain the substrate 2.

  Thereafter, in order to obtain a new substrate 2, the laser device driving unit 21 lowers the laser light irradiation means 20 by a predetermined length in the Z direction and irradiates the laser light 5 to a place where the laser light is lowered. A new circular substrate 2 is manufactured by the same method as described above.

  In the above method, the laser beam irradiation means 20 is lowered by a predetermined length in the Z direction, but the rotary stage 7 may be raised by a predetermined length in the Z direction. Alternatively, the predetermined length may be obtained by adding the distance by which the laser beam irradiation means 20 is lowered in the Z direction and the distance by which the rotary stage 7 is raised in the Z direction.

  As described above, according to the substrate manufacturing apparatus 3 having the above-described configuration, the processing region 10 by multiphoton absorption of the laser beam 5 is formed in the ingot 1, and the processing region 10 has the one side on the one side. Since the portion 11 and the other portion 12 are separated, the substrate 2 can be easily manufactured from the ingot 1 without chips, and the material of the ingot 1 is not wasted.

  Further, since the processing region 10 extending in a direction substantially perpendicular to the irradiation direction of the laser beam 5 is formed inside the ingot 1, the positional relationship between the laser beam irradiation means 20 and the ingot 1 is Become good. That is, since the laser beam irradiation means 20 is disposed above the ingot 1, the overall width of the substrate manufacturing apparatus 3 can be reduced and the installation space can be reduced.

  Moreover, since the substantially planar processing region 10 is formed inside the ingot 1, the one side portion 11 and the other side portion 12 can be reliably and easily separated in the processing region 10, and The substrate 2 can be reliably and easily manufactured from the ingot 1.

  Next, the Example which manufactures the board | substrate 2 from the ingot 1 using the said board | substrate manufacturing apparatus 3 is shown.

  A cylindrical silicon ingot 1 having a diameter of 150 mm was prepared. The laser beam irradiation means 20 is moved above the silicon ingot 1, the laser beam 5 is focused to a depth of 50 μm from the upper surface, which is the horizontal plane of the ingot 1, the ingot 1 is rotated, and the laser beam 5 The laser beam 5 was irradiated while moving radially outward from the center of the ingot 1 under the condition that the spot diameter at the condensing point 5a was 20 μm and the wavelength was 1064 nm.

  Since the processing region 10 is formed inside the ingot 1, the silicon bond of the ingot 1 can be easily cut, and the one side portion 11 can be suitably peeled from the other side portion 12, The circular substrate 2 could be easily obtained by the arm 8 having a suction mechanism at the tip.

(Second Embodiment)
FIG. 2 shows another embodiment of the present invention. The substrate manufacturing apparatus further includes a notch laser beam irradiation means 50 in addition to the configuration of the first embodiment. In FIG. 2, the ingot 1 and the notch laser beam irradiation means 50 are shown, and the configuration of the first embodiment is omitted.

  Similar to the laser light irradiation means 20, the notch laser light irradiation means 50 includes a laser oscillator 54 that oscillates the laser light 55 and a condenser lens 56 that condenses the laser light 55 oscillated from the laser oscillator 54. With.

  Then, before separating the one-side portion 11 and the other-side portion 12, the laser light 55 oscillated from the laser oscillator 54 is condensed by the condenser lens 56 and separated into the ingot 1. A notch 9 serving as a starting point is formed. The notch 9 may be formed at a part of the end of the processing region 10 of the ingot 1 or may be formed at the circumference of the ingot 1.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the ingot 1 may be in the shape of a prism, and the ingot 1 may be a crystal ingot, for example, a GaAs ingot. Further, the processing region 10 may extend in an inclined direction that is not perpendicular to the axis of the ingot 1, and a substrate 2 having a constant thickness that is inclined with respect to the axis of the ingot 1 is obtained. Also good. Further, in place of the rotating stage 7, the ingot 1 is placed on a stage that moves in the XY direction, and the converging point 5 a of the laser beam 5 is aligned inside the ingot 1. Then, the processing region 10 may be formed by relatively moving the condensing point 5a of the laser beam 5.

It is a simplified lineblock diagram showing a 1st embodiment of a substrate manufacture device of the present invention. It is a simplified block diagram which shows 2nd Embodiment of the board | substrate manufacturing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ingot 2 Substrate 3 Substrate manufacturing apparatus 4 Laser oscillator 5 Laser light 5a Condensing point 6 Condensing lens 7 Rotating stage 8 Arm 9 Notch 10 Processing area 11 One side part 12 The other side part 20 Laser light irradiation means 21 Laser Device driving unit 30 moving means 40 separating means

Claims (5)

With the laser beam condensing point set inside the ingot, the laser beam condensing point is moved relative to the ingot, and the laser beam is irradiated into the ingot with respect to the irradiation direction of the laser beam. A first step of forming a processing region by substantially planar multiphoton absorption extending in a substantially vertical direction;
A substrate manufacturing method comprising: a second step of separating a portion on one side and a portion on the other side of the ingot at the processing region with the processing region as a boundary. In the board | substrate manufacturing method of Claim 1,
The laser beam is a pulse laser beam, and a pulse width of the laser beam is 1 μs or less. In the board | substrate manufacturing method of Claim 1,
The substrate manufacturing method, wherein the ingot is silicon, and the wavelength of the laser beam is 800 nm or more. In the board | substrate manufacturing method of Claim 1,
In the first step, the ingot is rotated about an axis substantially parallel to the irradiation direction of the laser beam, and the condensing point of the laser beam is set in a direction substantially perpendicular to the irradiation direction of the laser beam. A substrate manufacturing method, wherein the processing region is formed by moving the substrate. Laser light irradiation means for irradiating the ingot with laser light;
A processing region by absorption of substantially planar multiphotons extending in a direction substantially perpendicular to the irradiation direction of the laser light inside the ingot in a state where the condensing point of the laser light is aligned inside the ingot. Moving means for moving the condensing point of the laser beam relative to the ingot so as to form
A substrate manufacturing apparatus, comprising: a separating unit that separates a portion on one side and a portion on the other side of the ingot at the processing region.

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