JP2011003624A - Method and apparatus for manufacturing semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor wafer, capable of inhibiting adverse effects on a semiconductor and presenting difficulties in acquiring the semiconductor wafer and for simplifying a manufacturing apparatus, and to provide an apparatus therefor.SOLUTION: The semiconductor wafer 1 is mounted on a rotating stage 11, and a chamfered part 2 at its corner is brought close to a rotation shaft 14 of the rotating stage 11; an X-direction moving stage 15 is moved to locate an optical axis 27 of a condenser lens 23 toward a circumference of a surface of the semiconductor wafer 1; a laser irradiation device 20 is adjusted so that a convergent point can be formed within the semiconductor wafer; the rotating stage 11 is rotated to make a linear velocity of the convergent point constant, and also a laser beam 21 is irradiated; and the X-direction moving stage 15 is moved, and the laser beam 21 is moved from the circumference of the surface of the semiconductor wafer 1 toward the chamfered part 2, each time the rotating stage 11 rotates by a predetermined angle. Thereafter, laser irradiation is stopped to form an intermediate product when the rotation shaft 14 and the optical axis 27 of the condenser lens 23 reach a predetermined distance.

Description

  The present invention relates to a method and apparatus for manufacturing a semiconductor wafer by cutting and manufacturing a thin semiconductor wafer.

  Conventionally, as a method of cutting out a thin semiconductor wafer from a silicon ingot, or slicing the cut out semiconductor wafer, although not shown, a laser beam is passed through a condensing lens on the surface of a thick round semiconductor mounted on a processing stage. Irradiate, form a condensing point inside the thick semiconductor to form a plurality of altered layers, rotate the thick semiconductor together with the processing stage to connect the plurality of altered layers, and provide a processing region inside the thick semiconductor, A method has been proposed in which an intermediate product of a thin semiconductor wafer is formed by providing this processing region, and then the surface of the intermediate product is peeled off at the processing region to obtain a thin semiconductor wafer (Patent Document 1, 2, 3, 4, 5).

The semiconductor is formed in a planar circle and is aligned with the center of the processing stage. The laser beam is suitably a pulse laser such as a YAG laser, or a CW laser such as a CO ₂ laser, and the surface of the semiconductor is thickened from the laser irradiation device under the output control by the control device. Irradiation is performed from the center to the periphery. The laser irradiation apparatus is configured so that the whole of the thick semiconductor can be precisely moved together with the condenser lens so that a uniform altered layer can be formed by irradiating a thick laser beam on the surface of the thick semiconductor.

  The condenser lens uses a lens with a large numerical aperture from the viewpoint of appropriately providing a processing region inside the thick semiconductor without damaging the surface of the thick semiconductor, and a conically shaped laser beam that spreads widely is applied to the semiconductor. Functions to guide.

Japanese Patent Laid-Open No. 2005-294656 JP 2005-059354 A JP 2005-33190 A JP 2004-079667 A Japanese Patent Laid-Open No. 2001-102332

  However, in the conventional method, since there is a limit to the control of the laser beam, when the laser beam is irradiated near the center of the semiconductor surface, excessive irradiation is performed because the center of the semiconductor surface rotates at high speed. Invitation or irradiation may be difficult, and as a result, the semiconductor may be adversely affected. In addition, when a laser beam is irradiated to the peripheral portion of the semiconductor surface, the density of the irradiation energy is insufficient and a processing region cannot be provided sufficiently, and as a result, the surface of the intermediate product is appropriately peeled and thin It may be difficult to obtain a semiconductor wafer.

  Furthermore, in order to provide a processing region inside a thick semiconductor without damaging the surface of the semiconductor, it is necessary to move the laser irradiation device and its optical system precisely, which may make the device complicated and large. There is.

  The present invention has been made in view of the above, and a semiconductor that can appropriately irradiate a laser beam to adversely affect a semiconductor or suppress the difficulty of obtaining a semiconductor wafer, thereby simplifying a manufacturing apparatus. An object of the present invention is to provide a wafer manufacturing method and an apparatus therefor.

In order to solve the above-described problems, the present invention includes a processing stage in which a rotary stage is supported by a moving stage, and a laser irradiation means for irradiating a semiconductor mounted on the processing stage with a laser beam, and the rotary stage of the processing stage. The surface of the semiconductor mounted on the semiconductor is irradiated with a laser beam through a condensing lens to form a condensing point inside the semiconductor, the semiconductor and the condensing point are moved relatively, and a processing region is formed inside the semiconductor. By providing an intermediate product of a semiconductor wafer, a method for manufacturing a semiconductor wafer to obtain a semiconductor wafer by separating the surface of the intermediate product from the processing region,
A semiconductor is mounted on the rotary stage of the processing stage, and is moved closer to the rotary axis of the rotary stage, the moving stage of the processing stage is moved, and the optical axis of the condenser lens is positioned at a predetermined position on the semiconductor surface, Adjust the height of the laser irradiation means so that a condensing point can be formed inside the semiconductor, rotate the rotary stage so that the linear velocity of the condensing point is substantially constant, and irradiate the laser beam from the laser irradiation means, Move the moving stage of the processing stage to move the laser beam in a predetermined direction, and then stop the irradiation of the laser irradiation means when the rotation axis of the rotary stage and the optical axis of the condenser lens reach a predetermined distance Thus, an intermediate product of the semiconductor wafer is formed.

  A semiconductor is mounted on the rotary stage of the processing stage, and the chamfered portion thereof is brought close to the rotary axis of the rotary stage at a distance, and the moving stage of the processing stage is moved so that the optical axis of the condenser lens is aligned with the peripheral edge of the semiconductor surface. The height of the laser irradiation means is adjusted so that the focal point can be formed inside the semiconductor, and the rotary stage is rotated so that the linear velocity of the focal point is substantially constant. By irradiating the laser beam and moving the moving stage of the processing stage, the laser beam can be moved at a predetermined pitch in the direction of the chamfered portion of the semiconductor each time the rotary stage rotates at a predetermined rotation angle.

In addition, a plurality of semiconductors can be arranged on the rotary stage of the processing stage, and the chamfered portions of the semiconductors can be brought close to the rotary shaft of the rotary stage with an interval.
In addition, a semiconductor and a weight can be arranged on the rotary stage of the processing stage, and the chamfered portion of the semiconductor and the corner of the weight can be brought close to the rotation axis of the rotary stage, respectively.

Further, by reducing the linear velocity of the condensing point according to the approach between the rotation axis of the rotary stage and the optical axis of the condensing lens, it is possible to irradiate the chamfered portion of the semiconductor with a laser beam in a focused manner.
Further, by narrowing the pitch interval of the laser beam moving between the semiconductor surface peripheral edge side and the chamfered portion, the laser beam can be focused on the semiconductor chamfered portion.
It is also possible to remove a part of the intermediate product of the semiconductor wafer to expose the processing region.

Moreover, it is also possible to make the irradiation amount of the laser beam with respect to the peeling start area of the intermediate product more than twice the irradiation amount of the laser beam with respect to other areas other than the peeling start area.
It is also possible to fix a peeling auxiliary base material to at least the surface of the front and back surfaces of the intermediate product and peel the surface of the intermediate product together with the peeling auxiliary base material to obtain a semiconductor wafer.

Further, in the present invention, in order to solve the above problems, a processing stage for mounting a semiconductor, a laser irradiation means for irradiating a semiconductor mounted on the processing stage with a laser beam, and the processing stage and the laser irradiation means are controlled. Control means for
The surface of the semiconductor mounted on the processing stage is irradiated with a laser beam through a condenser lens to form a condensing point inside the semiconductor, and the semiconductor and the condensing point are moved relative to each other to process the semiconductor. A manufacturing apparatus for obtaining a semiconductor wafer by forming an intermediate product of a semiconductor wafer by providing a region, and peeling the surface of the intermediate product with a processing region as a boundary,
The processing stage includes a rotary stage on which a semiconductor is mounted and a movable stage that can move while supporting the rotary stage. The semiconductor is mounted on the rotary stage, and the chamfered portion is spaced from the rotation axis of the rotary stage. Approach
The control means can move the moving stage of the processing stage so that the optical axis of the condensing lens is located on the surface peripheral edge side or near the chamfered portion of the semiconductor mounted on the rotary stage, thereby forming a condensing point inside the semiconductor. The function of adjusting the height of the laser irradiation means and the rotation stage of the rotary stage are controlled so that the linear velocity of the condensing point is substantially constant, and the laser beam is irradiated from the laser irradiation means. The function of moving the moving stage to move the laser beam toward the chamfered portion of the semiconductor or the surface peripheral edge each time the rotating stage rotates at a predetermined rotation angle, the rotation axis of the rotating stage, and the optical axis of the condenser lens And a function of stopping the irradiation of the laser irradiation means when a predetermined distance is reached.

The laser irradiation means includes an aberration-enhancing glass for laser beams interposed between the semiconductor surface and the condensing lens, and a vertically movable focus position adjusting means for holding the condensing lens and the aberration-enhancing glass. And good.
In addition, the control means reduces the linear velocity of the condensing point according to the approach between the rotation axis of the rotary stage and the optical axis of the condensing lens, and moves between the semiconductor surface peripheral edge side and the chamfered portion. It is preferable to realize the function of intensively irradiating the chamfered portion of the semiconductor with the laser beam by narrowing the pitch interval of the beam.

  Here, the moving stage of the processing stage in the claims may be a uniaxial structure that moves in at least one of the X direction and the Y direction. As the semiconductor, silicon, silicon carbide, sapphire, diamond, and the like are applicable. This semiconductor corresponds to an ingot or a thick (for example, 0.1 to 10 mm) semiconductor wafer that is blocked to an appropriate length, and does not ask for a plurality of numbers. The semiconductor can be formed into a planar rectangle, polygon, triangle, circle, or the like. The chamfered portion of the semiconductor may be cut out at each of the four corners of the semiconductor, may be cut out at one of the four corners, may be oblique, or may be curved.

  The weight may be the same shape as the semiconductor, or it may not be. The laser beam may or may not be a type that generates an optical damage phenomenon called multiphoton absorption. The laser beam preferably draws a pattern such as a concentric circle, a spiral shape, or a spiral shape when moving from one of the semiconductor surface peripheral portion and the chamfered portion to the other. The condensing lens includes a concave mirror and various lenses. The aberration-enhancing glass is not particularly limited to one or more. Further, the control means may be a controller or a control program. This control means controls the laser irradiation means by the distance between the rotation axis of the rotary stage and the optical axis of the condenser lens. Specifically, it is preferable to suppress or stop laser beam irradiation.

  According to the present invention, the laser beam is irradiated to a predetermined range of the semiconductor surface, for example, the range from the surface peripheral edge side to the chamfered portion of the semiconductor. There is no need to irradiate. Accordingly, there are few cases where the laser beam irradiation is excessive in the vicinity of the rotation axis, the semiconductor surface is unintentionally processed, or the laser beam irradiation is insufficient at the periphery of the semiconductor.

ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that it can suppress that it exerts a bad influence on a semiconductor by irradiating a laser beam appropriately, or it becomes difficult to acquire a semiconductor wafer, and can simplify a manufacturing apparatus.
Moreover, if the semiconductor and the weight are arranged on the rotary stage of the processing stage, and the chamfered part of the semiconductor and the corner of the weight are brought close to the rotation axis of the rotary stage, respectively, the balance of the rotary table is achieved. Can be maintained well.

In addition, if the linear velocity of the condensing point is reduced according to the approach between the rotation axis of the rotary stage and the optical axis of the condensing lens, the separation start area when the surface of the intermediate product is peeled to the chamfered portion of the semiconductor Can be formed efficiently.
In addition, by narrowing the pitch interval of the laser beam moving from the peripheral surface side of the semiconductor to the chamfered portion, even if the laser beam is focused on the chamfered portion of the semiconductor, the chamfered portion of the semiconductor is The peeling start area | region at the time of peeling the surface of goods can be formed efficiently.

  Further, the laser irradiation means includes an aberration-enhancing glass for laser light interposed between the semiconductor surface and the condenser lens, and a vertically movable focal position adjusting means for holding the condenser lens and the aberration-enhancing glass. For example, the condensing spot can be enlarged to reduce the number of times of laser beam irradiation. Furthermore, since it is not necessary to operate components other than the condensing lens of the laser irradiation means and the aberration-enhancing glass, the structure of the manufacturing apparatus can be simplified.

It is a whole perspective explanatory view showing typically the embodiment of the manufacturing method of the semiconductor wafer concerning the present invention, and its device. It is principal part explanatory drawing which shows typically the irradiation state of the laser beam in embodiment of the manufacturing method of the semiconductor wafer which concerns on this invention, and its apparatus. It is plane explanatory drawing which shows typically the pattern of the laser beam irradiated to the semiconductor wafer in embodiment of the manufacturing method of the semiconductor wafer which concerns on this invention, and its apparatus. It is explanatory drawing which shows typically the state in the middle of peeling the surface of the intermediate | middle goods in embodiment of the manufacturing method of the semiconductor wafer which concerns on this invention, and its apparatus. It is a whole perspective explanatory view showing typically a 2nd embodiment of a manufacturing method of a semiconductor wafer concerning the present invention, and its device. It is plane explanatory drawing which shows typically the pattern of the laser beam irradiated to the semiconductor wafer in 3rd Embodiment of the manufacturing method of the semiconductor wafer which concerns on this invention, and its apparatus. It is a plane explanatory view showing a 4th embodiment of a manufacturing method of a semiconductor wafer concerning the present invention, and its device typically.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A semiconductor wafer manufacturing apparatus according to the present embodiment includes a processing stage 10 on which a plurality of thick semiconductor wafers 1 are mounted, as shown in FIGS. The semiconductor wafer includes a laser irradiation device 20 for irradiating a plurality of semiconductor wafers 1 mounted on the processing stage 10 with a laser beam 21, and a control device 30 for controlling the processing stage 10 and the laser irradiation device 20, respectively. 1 is irradiated with a laser beam 21 through a condensing lens 23 to form a condensing point 26 inside the semiconductor wafer 1, and the semiconductor wafer 1 and the condensing point 26 are moved relative to each other. The intermediate product 5 of the thin semiconductor wafer 6 is formed by forming the processing region 3 inside the substrate, and the surface of the intermediate product 5 is peeled off with the processing region 3 as a boundary. Is a manufacturing apparatus for obtaining a thin semiconductor wafer 6 of the solar cell.

  A plurality (four in this embodiment) of semiconductor wafers 1 are mounted on the processing stage 10 in an arrayed state so as to draw a plane rectangle. Each semiconductor wafer 1 is not particularly limited, but is preferably made of, for example, a planar rectangular and thick silicon wafer, and the surface irradiated with the laser beam 21 is preferably planarized in advance. At least one corner of the four corners of the semiconductor wafer 1 is cut obliquely with a grinder or the like, and the cut corner is used as a chamfer 2.

  The processing stage 10 and a part of the laser irradiation apparatus 20 are fixed to a vibration-proof base (not shown) from the viewpoint of precise rotation, movement, vertical movement, etc., and the laser irradiation apparatus 20 is located above the processing stage 10. Arranged.

  As shown in FIG. 1, the processing stage 10 supports a rotating stage 11 on which a plurality of semiconductor wafers 1 are mounted horizontally and a support shaft 12 extending vertically downward from the lower surface of the rotating stage 11 in an upright state to support the X direction. And a movable X-direction moving stage 15.

  The rotary stage 11 is mounted with a planar rectangular holding table 13 that detachably positions and fixes a plurality of semiconductor wafers 1 on the surface, and rotates by driving a predetermined motor. The rotation stage 11, the support shaft 12, and the holding table 13 are aligned at the center. A chamfered portion 2 of each semiconductor wafer 1 is located at a position slightly shifted from the center of the surface of the holding table 13 in the radially outward direction. Therefore, in the plurality of semiconductor wafers 1, the chamfered portions 2 approach the rotating shaft 14 (which is also the center of the support shaft 12) of the rotating stage 11 with a gap therebetween, and the combined center of gravity is substantially the same as the rotating shaft 14 of the rotating stage 11. Match.

  As the predetermined motor, for example, a stepping motor capable of controlling the number of rotations or various servo motors (for example, AC servo motor) according to the irradiation characteristics of the laser beam 21 is appropriately employed. From the viewpoint of uniformly irradiating the laser beam 21 with the laser beam, a servo motor that is continuously driven, not intermittent, is preferable.

  The X-direction moving stage 15 slides horizontally, for example, by a screw rod that rotates by driving a predetermined motor, or horizontally by a plunger rod that moves forward and backward by driving a predetermined cylinder. Moreover, the structure which slides horizontally by the endless drive belt rotated by the drive of a predetermined motor may be sufficient, and the structure which slides horizontally by the drive of a linear motor may be sufficient.

  As shown in FIG. 1 and FIG. 2, the laser irradiation device 20 includes a fixed laser light source 22 that irradiates a laser beam 21 downward, and a light condensing that condenses the laser beam 21 emitted from the laser light source 22. The lens 23, the aberration-enhancing glass 24 for the laser beam 21 interposed between the surface of the semiconductor wafer 1 and the condensing lens 23, and the condensing lens 23 and the aberration-enhancing glass 24 are arranged vertically and can be moved up and down. An inspection apparatus (not shown) that includes a focal position adjustment tool 25 and that can inspect and measure the surface state of the semiconductor wafer 1 is selectively provided.

  As the laser light source 22, a light source that is transmissive to the semiconductor wafer 1 is used from the viewpoint of forming a condensing point 26 inside the semiconductor wafer 1. For example, in the case of a silicon ingot or a sliced silicon semiconductor wafer 1, an infrared laser having a wavelength of 1000 nm or more such as a fundamental wave of a YAG laser or a carbon dioxide gas laser is used.

  The condenser lens 23 functions to efficiently concentrate the energy of the laser beam 21 inside the semiconductor wafer 1. The numerical aperture (NA) of the condenser lens 23 is preferably a large numerical value, specifically 0.5 or more and 0.5 to 0.8 from the viewpoint of preventing loss due to ablation or the like on the surface of the semiconductor wafer 1. .

  The aberration-enhancing glass 24 is not particularly limited. For example, a thick cover glass, a slide glass, or the like is used. The condensing spot is enlarged to increase the interval, and the number of times the laser beam 21 is irradiated per unit area. Function to reduce. The focal position adjuster 25 is composed of, for example, a pair of left and right holding claws that oppose each other with the condenser lens 23 and the aberration-enhancing glass 24 sandwiched therebetween, and is focused in the direction of the optical axis 27 with respect to the surface of the semiconductor wafer 1. The optical lens 23 is moved up and down, the focal point is moved inside the semiconductor wafer 1, the condensing point 26 is formed, and the processing region 3 is processed.

  As shown in FIG. 1, the control device 30 includes, for example, a circuit board made of a printed circuit board, a crystal oscillation circuit, a CPU having an arithmetic processing function, a ROM, a RAM, an error detection sensor for detecting malfunctions, and other electronic devices. Components are mounted and connected to the processing stage 10 and the laser irradiation device 20 via cables, respectively, and the CPU reads a predetermined program stored in the ROM using the RAM as a work area, thereby causing a predetermined function as a computer. To realize.

  Specifically, the X-direction moving stage 15 of the processing stage 10 is moved in the X direction so that the optical axis 27 of the condenser lens 23 is positioned on the surface peripheral edge side of the semiconductor wafer 1 mounted on the rotary stage 11, and the semiconductor The function of adjusting the height of the laser irradiation device 20 so that the condensing point 26 can be formed inside the wafer 1 and the rotational speed of the rotary stage 11 are controlled so that the linear velocity of the condensing point 26 is constant. In addition to irradiating the laser beam 21 from the laser irradiation device 20, the X-direction moving stage 15 of the processing stage 10 is moved in the X direction, and the rotating stage 11 rotates the laser beam 21 at a predetermined rotation angle (eg, 360 °). Each time, the function of moving the semiconductor wafer 1 from the surface peripheral edge side toward the chamfered portion 2 at a predetermined pitch, the light of the rotating shaft 14 of the rotating stage 11 and the condenser lens 23 27, the function of reducing the linear velocity of the condensing point in accordance with the approach to 27 and narrowing the pitch interval of the laser beam 21 moving from the surface peripheral edge side of the semiconductor wafer 1 toward the chamfered portion 2, and the rotation of the rotary stage 11 The function of stopping the irradiation of the laser irradiation device 20 when the axis 14 and the optical axis 27 of the condenser lens 23 reach a predetermined short distance is realized (see FIGS. 1 and 3).

  In the above configuration, when the semiconductor wafer 1 is cut out and the thin semiconductor wafer 6 is manufactured, first, a plurality of semiconductor wafers 1 to be processed are arranged on the rotary stage 11 of the processing stage 10 via the holding table 13. The chamfered portion 2 of the semiconductor wafer 1 is positioned around the central portion of the holding table 13, the surfaces of the plurality of semiconductor wafers 1 are made to be substantially flush, and the X-direction moving stage 15 of the processing stage 10 is moved in the X direction. Thus, the optical axis 27 of the condensing lens 23 of the laser irradiation apparatus 20 is positioned on the surface peripheral edge side of the semiconductor wafer 1 mounted on the rotary stage 11.

  When the optical axis 27 of the condensing lens 23 is thus positioned on the surface peripheral edge side of the semiconductor wafer 1, the focal position adjusting tool 25 of the laser irradiation device 20 is lowered so that the condensing point 26 is located on the surface of the semiconductor wafer 1. Thereafter, the focal position adjuster 25 is lowered so that the condensing point 26 for the processing region 3 can be formed inside the semiconductor wafer 1, and the condensing lens 23 and the aberration enhancing glass 24 are brought close to the surface of the semiconductor wafer 1. .

  Next, the rotation speed of the rotary stage 11 is controlled so that the linear velocity of the condensing point 26 becomes a constant value. When the linear velocity of the condensing point 26 reaches a constant value, the laser beam 21 is emitted from the laser irradiation device 20. , The X-direction moving stage 15 of the processing stage 10 is moved in the X direction, and the laser beam 21 is rotated in a predetermined direction from the surface peripheral edge side of the semiconductor wafer 1 to the chamfered portion 2 each time the rotary stage 11 rotates once. Move with pitch.

At this time, the rotary stage 11 continues to rotate so that the linear velocity of the condensing point 26 maintains a constant value. In addition, the laser beam 21 forms a concentric pattern from the surface peripheral edge side of the semiconductor wafer 1 toward the chamfered portion 2 when the rotating shaft 14 of the rotating stage 11 rotating by the movement of the X-direction moving stage 15 approaches. It moves while drawing, and the processing region 3 is continuously formed inside the semiconductor wafer 1 parallel to the surface of the semiconductor wafer 1 (see FIG. 2).
When the laser beam 21 is irradiated, the laser beam 21 can be irradiated while being scanned by an inspection apparatus that images and measures the surface state of the semiconductor wafer 1.

  When the rotating shaft 14 of the rotating stage 11 and the optical axis 27 of the condensing lens 23 approach each other and the optical axis 27 of the condensing lens 23 is positioned in front of the chamfered portion 2 of the semiconductor wafer 1, the rotational speed of the rotating stage 11 is set. By reducing the linear velocity of the condensing point and reducing the pitch interval of the laser beams 21 moving from the surface peripheral edge side of the semiconductor wafer 1 toward the chamfered portion 2, the laser beam is applied to the chamfered portion 2 of the semiconductor wafer 1. The peeling start area | region 4 at the time of peeling the surface of the intermediate article 5 by irradiating 21 mainly is formed.

  The optical axis 27 of the condenser lens 23 passes through the chamfered portion 2 of the semiconductor wafer 1 and is located near the center of the holding table 13, and the rotational axis 14 of the rotary stage 11 and the optical axis 27 of the condenser lens 23 are predetermined. When the rotation speed of the rotary stage 11 reaches the upper limit value, the rotation of the rotary stage 11 and the irradiation of the laser irradiation device 20 are stopped to form the intermediate product 5 of the thin semiconductor wafer 6. be able to.

  When the intermediate product 5 of the thin semiconductor wafer 6 is formed, the peeling auxiliary plate 40 is detachably adhered and fixed to the entire surface of the intermediate product 5, and then the intermediate product 5 is peeled off with the continuous processing region 3 as a boundary surface. At the same time, if peeling is performed upward from the peeling start region 4 (see FIG. 4), the intermediate product 5 is peeled from the semiconductor wafer 1, whereby the intermediate product 5 becomes a thin semiconductor wafer 6. The thin semiconductor wafer 6 is used as it is or bonded to the end face of another semiconductor wafer 6 as necessary.

  The auxiliary peeling plate 40 is not particularly limited. For example, the peeling auxiliary plate 40 is made of a flat plate larger than the semiconductor wafer 1, and a self-adhesive sheet adheres to a flat facing surface facing the intermediate product 5 of the thin semiconductor wafer 6. Is done. As the peeling auxiliary plate 40, for example, an acrylic plate or the like can be used as appropriate.

  When the peeling auxiliary plate 40 is adhesively fixed, another peeling auxiliary plate 40 may be detachably attached to the back surface of the semiconductor wafer 1 detached from the rotary stage 11 to further facilitate the peeling of the intermediate product 5. .

  According to the above configuration, the chamfered portion 2 of the semiconductor wafer 1 is positioned around the center portion of the holding table 13, and the laser beam 21 is irradiated to the range from the surface peripheral edge side of the semiconductor wafer 1 to the chamfered portion 2. There is no need to irradiate the laser beam 21 near the center of the surface of the semiconductor wafer 1, and the irradiation of the laser beam 21 does not become excessive or difficult. Therefore, the semiconductor wafer 6 is not adversely affected.

  In addition, when the laser beam 21 is irradiated to the peripheral edge of the surface of the semiconductor wafer 1, the rotation stage 11 is rotated so that the linear velocity of the condensing point 26 is maintained at a constant value, so that the density of the irradiation energy is an appropriate value. Thus, a sufficient processing region 3 is provided, and the surface of the intermediate product 5 is appropriately peeled off so that a thin semiconductor wafer 6 can be easily obtained. Furthermore, since the laser light source 22 and the laser oscillator of the laser irradiation device 20 are fixed and only the focus position adjustment tool 25 needs to be moved up and down precisely, there is an adverse effect caused by vibration during the operation of the laser light source 22 and the laser oscillator. It is possible to effectively eliminate the risk of being eliminated or making the apparatus complicated and large.

  Next, FIG. 5 shows a second embodiment of the present invention. In this case, the processing stage 10 includes a rotating stage 11 on which a plurality of semiconductor wafers 1 are mounted horizontally, and a support for the rotating stage 11. A multi-axis structure including an X-direction moving stage 15 that supports the shaft 12 upright and can move in the X-direction, and a Y-direction moving stage 16 that supports the X-direction moving stage 15 and can move in the Y-direction. I am trying to configure it. The other parts are the same as those in the above embodiment, and the description is omitted.

  In this embodiment, the same effect as that of the above embodiment can be expected, and the semiconductor wafer 1 can be processed while moving the Y-direction moving stage 16 as necessary. Obviously, it can be made easier, faster and easier.

Next, FIG. 6 shows a third embodiment of the present invention. In this case, a plurality of semiconductor wafers 1 are arranged on the holding table 13 of the turntable 11 at intervals of 90 °. The number of semiconductor wafers 1 is reduced from four to two. The other parts are the same as those in the above embodiment, and the description thereof is omitted.
Obviously, in this embodiment, the same effect as that of the above embodiment can be expected.

  Next, FIG. 7 shows a fourth embodiment of the present invention. In this case, a plurality of semiconductor wafers 1 and a plurality of weight bodies 41 with a reduced number of sheets are placed on the holding table 13 of the rotary table 11. The chamfered portions 2 of the respective semiconductor wafers 1 and the corner portions of the respective weight bodies 41 are respectively brought close to the rotary shaft 14 of the rotary stage 11 with a space therebetween to prevent rotation unevenness of the rotary table 11. .

  The plurality of semiconductor wafers 1 and the plurality of weight bodies 41 are alternately arranged. The weight body 41 is not particularly limited. For example, the weight body 41 is formed of a planar rectangular and thick dummy wafer having substantially the same weight as the semiconductor wafer 1, and at least one corner portion of the four corner portions is slanted by a grinder or the like. The chamfered portion 42 is formed by the cut corner. The other parts are the same as those in the above embodiment, and the description thereof is omitted.

  Also in this embodiment, the same effect as the above embodiment can be expected, and in addition to the semiconductor wafer 1, a plurality of weights 41 are also arranged on the holding table 13, so that the rotation balance of the turntable 11 is kept good. Moreover, it is possible to suppress and prevent vibration during rotation accompanying unbalance.

  In the above embodiment, the rotary stage 11 of the processing stage 10 is simply rotated. However, the rotary stage 11 may be moved up and down as necessary. Further, although the semiconductor wafer 1 is fixed and mounted on the holding table 13 of the rotary stage 11, the semiconductor wafer 1 may be mounted on the rotary stage 11 via wax, adhesive tape, a clamp tool, or the like. Further, if there is no particular hindrance, only the condenser lens 23 may be used and the aberration enhancing glass 24 may be omitted. Further, the irradiation start point of the laser beam 21 may be the central portion of the holding table 13 or the peripheral portion. In short, the semiconductor wafer 1 can be moved by being irradiated with a laser beam from the vicinity of the chamfered portion 2 of the semiconductor wafer 1 toward the surface peripheral portion.

  In the above embodiment, the auxiliary peeling plate 40 is adhered and fixed to the surface of the intermediate product 5, and the intermediate product 5 is peeled off from the peeling start area 4 together with the peeling auxiliary plate 40, but the intermediate product 5 is peeled off from the peeling start area 4. Before, it is possible to remove the intermediate product 5 easily by removing a part of the surface and the peripheral surface of the semiconductor wafer 1 and exposing the processing region 3 to the side surface (peripheral surface) of the separation start region 4.

  As a method of exposing the processing region 3, the depth from the surface of the semiconductor wafer 1 to the processing region 3 is predicted from the position and refractive index of the condenser lens 23, and the peripheral surface of the semiconductor wafer 1 is irradiated with the laser beam 21. And a method of partially removing the surface of the semiconductor wafer 1 by means such as diamond cutter or laser ablation. Thus, if the process area | region 3 is exposed to the side surface of the peeling start area | region 4 and it is set as the starting point of a peeling operation | work, the intermediate product 5 can be peeled smoothly and easily.

  Embodiments of a semiconductor wafer manufacturing method and apparatus according to the present invention will be described below together with comparative examples.

  First, a plurality of semiconductor wafers made of mirror-polished 10 □ mm single crystal silicon ingots, a processing stage for positioning and holding the plurality of semiconductor wafers via an adhesive tape, and a semiconductor wafer mounted on the processing stage A laser irradiation device for irradiating a laser beam and a control device for controlling the processing stage and the laser irradiation device were prepared, and the processing stage and the laser irradiation device were fixed to a vibration-proof base.

  In a plurality (four in this embodiment) of semiconductor wafers, the chamfered portions approach the rotation axis of the rotary stage of the processing stage at intervals, and the resultant center of gravity substantially coincides with the rotation axis of the rotary stage. Each semiconductor wafer has a chamfered portion of 1 mm at the corner and has a thickness of 2 mm. Further, as shown in FIG. 1, the processing stage can be moved with a stroke of 10 mm in the X direction by supporting a rotating stage on which a plurality of semiconductor wafers are horizontally arranged and supporting shafts of the rotating stage in an upright state. A stage with an X-direction moving stage was used.

  The rotation stage is adjusted together with the laser irradiation device so that the laser beam can be irradiated in a range of −2 to 18 mm across the support shaft, and the rotation speed is adjusted in the range of 0 to 60 rpm. The X-direction moving stage is adjusted with the laser irradiation device so that the moving speed is adjusted in the range of 0 to 15 mm / second and the laser beam can be irradiated in the range of −0.050 to 19.950 mm from the support shaft.

  As the laser irradiation apparatus, as shown in FIG. 1, a YAG laser irradiation apparatus having a wavelength of 1064 nm, a repetition oscillation frequency of 10 kHz, an output of 0.68 W, and a pulse width of 200 nsec was used. The condenser lens of this laser irradiation apparatus had a numerical aperture (NA) of 0.8 and a focal length of 2 mm. As the aberration-enhancing glass, a cover glass having a thickness of 0.15 mm and a refractive index of 1.5 was used.

  The control device is composed of a controller and used to control the position, rotation speed, and movement speed of the rotary stage of the processing stage and the X-direction moving stage, and to control ON / OFF of laser irradiation of the laser irradiation apparatus.

  Next, a plurality of semiconductor wafers are arranged on the rotation stage of the processing stage, the chamfered portions of each semiconductor wafer are positioned around the central portion of the holding table, and the surfaces of the plurality of semiconductor wafers are aligned to ± 3 μm. The X-direction moving stage was moved in the X direction so that the optical axis of the condenser lens of the laser irradiation apparatus was positioned on the peripheral edge side of the surface of the semiconductor wafer mounted on the rotating stage.

  When the optical axis of the condensing lens is thus positioned on the peripheral edge side of the surface of the semiconductor wafer, the focus adjustment tool of the laser irradiation device is lowered so that the condensing point is located on the surface of the semiconductor wafer, and then the inside of the semiconductor wafer Then, the focal position adjuster was lowered so as to form a condensing point for the processing area, and the condensing lens and the aberration-enhancing glass were brought close to the surface of the semiconductor wafer. The distance at this time is 0.3 to 0.4 times the depth of the condensing point when the depth of the condensing point is in the range of 0.05 to 0.2 mm.

  Next, the rotation speed of the rotating stage is controlled so that the linear velocity at the focal point becomes 10 mm / second, and when the linear velocity at the focal point reaches 10 mm / second, the laser beam is emitted from the laser irradiation device. At the same time, the X-direction moving stage of the processing stage was moved in the X direction, and the rotation axis of the rotation stage was moved at a pitch of 1 μm in the optical axis direction every time the rotation stage rotated once.

  Next, when the optical axis of the condensing lens is positioned in front of the chamfered portion of the semiconductor wafer, the rotational speed of the rotary stage is suppressed and the linear velocity of the condensing point is adjusted to 3 mm / second, and the surface peripheral portion side of the semiconductor wafer By narrowing the pitch interval of the laser beam moving from the chamfered part to the chamfered part to 0.5 μm pitch, the peeling start region when peeling the surface of the intermediate product by irradiating the chamfered part of the semiconductor wafer with focus on the laser beam After forming and forming an intermediate product of a thin semiconductor wafer, irradiation of the laser beam was stopped.

  During the above operation, the X-direction moving stage of the processing stage was reciprocated in 10 mm seconds. Further, after the laser beam irradiation was stopped, the appearance of the intermediate product was observed, but the surface remained a mirror surface, and no change was observed in the appearance.

  After the thin semiconductor wafer intermediate product is formed, the thin semiconductor wafer intermediate product is removed from the rotating stage of the processing stage, the peripheral surface of the separation start region is removed by cleavage, and the processing region is exposed to the peripheral surface of the separation start region. , Acrylic plate peeling auxiliary plates having a thickness of 5 mm are adhesively fixed to the front and back surfaces of the intermediate product, and then the intermediate product is peeled from the peeling start region together with the peeling auxiliary plate with the continuous processing region as a boundary surface. Thus, a thin semiconductor wafer could be easily manufactured.

Comparative example

Although basically the same as the embodiment, the rotation speed of the rotary stage was fixed to 1 rotation per second, and the surface of the semiconductor wafer was irradiated with a laser beam.
Other than that, an intermediate product of a thin semiconductor wafer was formed in the same manner as in the example. When the appearance of the intermediate product was observed after stopping the laser beam irradiation, whitening was observed at the center of the surface of the intermediate product.

  The intermediate product is removed, the peripheral surface of the peeling start region is removed by cleavage, the processing region is exposed on the peripheral surface of the peeling start region, and an acrylic plate peeling auxiliary plate having a thickness of 5 mm on the front and back surfaces of the intermediate product However, it was not possible to peel off using the processing region as a boundary surface, and a thin semiconductor wafer could not be obtained.

1 Semiconductor wafer (semiconductor)
2 Chamfered part 3 Processing area 4 Peeling start area 5 Intermediate product 6 Thin semiconductor wafer (semiconductor wafer)
DESCRIPTION OF SYMBOLS 10 Processing stage 11 Rotating stage 12 Support shaft 13 Holding table 14 Rotating shaft 15 X direction moving stage (moving stage)
16 Y-direction moving stage 20 Laser irradiation device (laser irradiation means)
21 Laser beam 22 Laser light source 23 Condensing lens 24 Aberration enhancing glass 25 Focus position adjuster (focal position adjusting means)
26 Condensing point 27 Optical axis 30 Control device (control means)
40 Peeling auxiliary plate 41 Weight 42 Chamfer (corner)

Claims (9)

A processing stage in which a rotary stage is supported by a moving stage and a laser irradiation means for irradiating a semiconductor mounted on the processing stage with a laser beam are provided, and the laser beam is applied to the surface of the semiconductor mounted on the rotating stage of the processing stage. Form an intermediate product of a semiconductor wafer by irradiating through a condenser lens to form a condensing point inside the semiconductor, moving the semiconductor and the condensing point relative to each other, and providing a processing region inside the semiconductor. And a method for manufacturing a semiconductor wafer by separating the surface of the intermediate product from the processing region to obtain a semiconductor wafer,
A semiconductor is mounted on the rotary stage of the processing stage, and is moved closer to the rotary axis of the rotary stage, the moving stage of the processing stage is moved, and the optical axis of the condenser lens is positioned at a predetermined position on the semiconductor surface, Adjust the height of the laser irradiation means so that a condensing point can be formed inside the semiconductor, rotate the rotary stage so that the linear velocity of the condensing point is substantially constant, and irradiate the laser beam from the laser irradiation means, Move the moving stage of the processing stage to move the laser beam in a predetermined direction, and then stop the irradiation of the laser irradiation means when the rotation axis of the rotary stage and the optical axis of the condenser lens reach a predetermined distance And forming an intermediate product of the semiconductor wafer.   A semiconductor is mounted on the rotating stage of the processing stage, and the chamfered portion is moved closer to the rotating shaft of the rotating stage with a space between them, and the moving stage of the processing stage is moved so that the optical axis of the condenser lens is on the semiconductor surface peripheral side. The height of the laser irradiation means is adjusted so that the focal point can be formed inside the semiconductor, the rotary stage is rotated so that the linear velocity of the focal point is substantially constant, and the laser beam from the laser irradiation means And moving the moving stage of the processing stage to move the laser beam at a predetermined pitch in the direction of the chamfered portion of the semiconductor each time the rotary stage rotates at a predetermined rotation angle. .   3. The method of manufacturing a semiconductor wafer according to claim 2, wherein a plurality of semiconductors are arranged on a rotating stage of a processing stage, and a chamfered portion of each semiconductor is brought close to a rotating shaft of the rotating stage with an interval.   3. A semiconductor wafer according to claim 2, wherein a semiconductor and a weight are arranged on a rotary stage of a processing stage, and a chamfered portion of the semiconductor and a corner of the weight are brought close to a rotation axis of the rotary stage, respectively. Method.   The laser beam is intensively applied to the chamfered portion of the semiconductor by reducing the linear velocity of the condensing point according to the approach between the rotation axis of the rotary stage and the optical axis of the condensing lens. 4. A method for producing a semiconductor wafer according to 4.   6. The semiconductor wafer according to claim 2, wherein the laser beam is preferentially irradiated to the chamfered portion of the semiconductor by narrowing a pitch interval of the laser beam moving between the peripheral surface side of the semiconductor and the chamfered portion. Manufacturing method. A processing stage for mounting a semiconductor; a laser irradiation means for irradiating a semiconductor mounted on the processing stage with a laser beam; and a control means for controlling the processing stage and the laser irradiation means.
The surface of the semiconductor mounted on the processing stage is irradiated with a laser beam through a condenser lens to form a condensing point inside the semiconductor, and the semiconductor and the condensing point are moved relative to each other to process the semiconductor. A semiconductor wafer manufacturing apparatus for forming a semiconductor wafer intermediate product by providing a region, and peeling the surface of the intermediate product from the processing region to obtain a semiconductor wafer,
The processing stage includes a rotary stage on which a semiconductor is mounted and a movable stage that can move while supporting the rotary stage. The semiconductor is mounted on the rotary stage, and the chamfered portion is spaced from the rotation axis of the rotary stage. Approach
The control means can move the moving stage of the processing stage so that the optical axis of the condensing lens is located on the surface peripheral edge side or near the chamfered portion of the semiconductor mounted on the rotary stage, thereby forming a condensing point inside the semiconductor. The function of adjusting the height of the laser irradiation means and the rotation stage of the rotary stage are controlled so that the linear velocity of the condensing point is substantially constant, and the laser beam is irradiated from the laser irradiation means. The function of moving the moving stage to move the laser beam toward the chamfered portion of the semiconductor or the surface peripheral edge each time the rotating stage rotates at a predetermined rotation angle, the rotation axis of the rotating stage, and the optical axis of the condenser lens And a function of stopping the irradiation of the laser irradiation means when a predetermined distance is reached.   The laser irradiating means includes an aberration-enhancing glass for laser light interposed between the semiconductor surface and the condensing lens, and a vertically movable focus position adjusting means for holding the condensing lens and the aberration-enhancing glass. The semiconductor wafer manufacturing apparatus according to claim 7.   The control means reduces the linear velocity of the condensing point in accordance with the approach between the rotation axis of the rotary stage and the optical axis of the condensing lens, and the laser beam moving between the chamfered portion and the peripheral surface of the semiconductor surface. 9. The semiconductor wafer manufacturing apparatus according to claim 7, wherein a function of intensively irradiating a chamfered portion of the semiconductor with a laser beam is realized by narrowing the pitch interval.

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