JP4979291B2 - Laser cutting device - Google Patents

Description

  The present invention relates to a laser cutting device for cutting a workpiece such as a semiconductor substrate by irradiating the workpiece with a laser beam.

  Various apparatuses for irradiating a workpiece with laser light to cut the workpiece have been proposed. For example, as a device for cutting out individual semiconductor devices by cutting a semiconductor substrate having a plurality of semiconductor device regions such as BGA (ball grid array) and CSP (chip size package) by laser light along a predetermined cutting line There are laser cutting devices disclosed in Documents 1 and 2.

  In the laser cutting device, the laser light is scanned along a predetermined cutting line by using a scanning means such as a galvanometer mirror without moving the semiconductor substrate, the stage holding the semiconductor substrate, or the laser oscillator. It is also possible to cut the semiconductor substrate along a predetermined cutting line in all the semiconductor device regions.

In such a laser cutting device, a laser receiving member formed of a refractory material such as aluminum is provided on the opposite side of the workpiece from the laser oscillator so that the laser beam penetrating the workpiece does not damage the device. Be placed. In Patent Document 3, a laser beam attenuation structure and a scattering reflection structure are added to a flat plate-shaped laser receiving member arranged parallel to the workpiece so that the laser beam reflected by the laser receiving member is not irradiated again. A method is disclosed.
JP 2005-142303 A (paragraphs 0019 to 0022, etc.) JP-A-2005-238246 (paragraph 0014, etc.) JP-A-10-328875 (paragraphs 0021 to 0025, etc.)

  However, if the laser receiving member is provided with a laser light attenuation structure or a scattering reflection structure as disclosed in Patent Document 3, the structure of the laser receiving member becomes complicated, resulting in an increase in size and cost of the laser receiving member. Invite.

  Further, the region where the laser receiving member as described above is arranged may be a dust collecting air flow path for removing soot and dust generated by cutting the workpiece. However, in the conventional laser cutting apparatus, soot and dust that cannot be removed by dust collection air adhere to the workpiece and the laser receiving member, and frequent cleaning is required.

  One object of the present invention is to provide a laser cutting device that uses a laser receiving member having a simple structure and prevents the laser beam reflected by the laser receiving member from damaging the workpiece. Yes.

  Another object of the present invention is to provide a laser cutting device that can improve the function of removing soot and dust by air for collecting dust using a laser receiving member.

A laser cutting device according to one aspect of the present invention is a laser cutting device that cuts a workpiece disposed in a workpiece installation region with a laser beam, and is provided in a laser oscillator that emits the laser beam and a flow path of dust collection air. And a laser receiving member that receives the laser beam that has passed through the workpiece installation region. And a laser receiving member has a laser receiving surface which approaches a workpiece | work installation area | region toward the downstream from the upstream of the flow of this dust collection air, It is characterized by the above-mentioned.

  According to the present invention, the laser beam reflected by the laser receiving member can be obtained by using the laser receiving member having a simple structure in which the laser receiving surface is an inclined surface or the like approaching the work installation area (that is, the work) as described above. The work damage due to can be effectively avoided.

  Further, the laser receiving member provided in the dust collecting air flow path is provided with a laser receiving surface that approaches the work installation region from the upstream side to the downstream side of the air, thereby providing the laser receiving member. It is possible to increase the flow velocity of the dust collection air flowing along the surface or to deflect the flow direction of the dust collection air toward the workpiece installation area. As a result, the function of removing soot and dust by the dust collecting air can be improved.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of a laser cutting apparatus that is Embodiment 1 of the present invention as viewed from above. In FIG. 1, 100 is a laser cutting device.

  The laser cutting device 100 includes a base 101 and a laser oscillator 110 installed on the base 101. Reference numeral 102 denotes a first substrate magazine in which a large number of semiconductor substrates 120 before laser cutting are stored, and the first substrate I is moved from the first substrate magazine 102 to a first position I on the base 101 by a first transport mechanism (not shown). One by one.

  The semiconductor substrate 120 before cutting is shown in FIG. Here, a memory card substrate 120 is shown as an example of one of the semiconductor substrates. The memory card substrate 120 is formed by mounting a memory chip or a controller chip on a printed wiring board on which a plurality of memory card circuits are formed, and then sealing (coating) with a resin.

  A dotted line 130 is a planned cutting line of the memory card substrate 120. The planned cutting line 130 includes a first straight line portion 131 extending in the horizontal direction in the drawing, a second straight line portion 132 extending in the vertical direction, and the first and second straight line portions 131, 131. And four corner portions 133 a to 133 d having a ¼ arc curve shape as a deformed line portion connecting the 132. However, the planned cutting line 130 is a virtual line, and is not actually drawn on the memory card substrate 120, but is stored in the controller (computer) 150 provided in the laser cutting unit 100 and the blade cutting unit 200. Is remembered.

  Each region 135 surrounded by the two straight portions 131 and 132 and the four corner portions 133a to 133d is cut into the individual semiconductors by cutting the substrate 120 along the predetermined cutting line 130. This is a semiconductor device area to be a memory card as a device. Hereinafter, each semiconductor device area (planned cutting area) before cutting is referred to as a memory card area 135. The semiconductor device may be other than a memory card, such as a chip element such as an IC or LSI.

  In FIG. 1, the substrate 120 disposed at the first position I is transported to a second position II which is the front of the laser oscillator 110 by a second transport mechanism (not shown). A movable stage, which will be described later, is provided at the second position II, and the substrate 120 transported on the movable stage is fixed on the movable stage by the negative pressure adsorption of the lower surface thereof. As shown in FIG. 2, the movable stage is driven so that the center of the memory card area 135 is positioned on the central axis LO of the laser oscillator 110.

  The laser oscillator 110 is configured as shown in FIG. 3, for example. The laser light L emitted from the laser light source 111 is reflected by the Y-axis and X-axis galvanometer mirrors 113 and 114 as scanning means after the beam diameter is enlarged by the beam expander 112. The laser light L reflected by the galvanometer mirrors 113 and 114 forms a spot image on the substrate 120 disposed at the cutting position by a condensing optical system 115 such as an f-θ lens.

  The spot image is scanned in the Y-axis direction (vertical direction in FIG. 4) and the X-axis direction (horizontal direction in FIG. 4) according to the rotation of the galvanometer mirrors 113 and 114. For this reason, by controlling the rotation angle of the galvanometer mirrors 113 and 114, the spot image of the laser beam L can be moved along the planned cutting line 130, whereby the movement trajectory of the spot image on the substrate 120 is melted. To be cut. Thus, the memory card 135 can be cut out.

  That is, in the laser cutting apparatus 100 of the present embodiment, when cutting one memory card area 135, the laser beam L is scanned without moving the substrate 120 in the X-axis direction and the Y-axis direction.

  In this embodiment, a YAG laser (wavelength: 1.06 μm) is used as the laser light source 111. Further, in this embodiment, when cutting the substrate 120 with the resin coating on the printed circuit board, the wavelength of the laser light is made constant and the resin portion (package resin layer described later) is cut and the printed circuit board portion (described later). The pulse irradiation frequency (Q switch frequency), current value, cutting speed, and the like of the laser light are changed depending on when the printed circuit board layer is cut. In this embodiment, laser cutting is performed without placing the substrate 120 in a gas atmosphere. This simplifies the configuration of the laser cutting unit 100 and, unlike laser cutting in a gas atmosphere where it is difficult to perform operations other than linear cutting, the planned cutting line 130 including a deformed line portion such as a curve is converted into the laser beam. The substrate 120 can be cut without being moved by scanning.

  Further, in the laser cutting apparatus 100 of the present embodiment, by cutting a predetermined amount (small amount) of the predetermined cutting line 130 in one memory card area 135 in the substrate 120, that is, by repeating the laser beam circumferential scanning a plurality of times, The memory card area 135 is completely cut.

  In FIG. 1, the semiconductor substrate 120 ′ after cutting all the memory card areas 135 is taken out from the second position II (movable stage) to the third position III on the base 101 by a third transport mechanism (not shown). It is. The substrate 120 'is actually a plurality of memory cards separated by laser cutting. In the third position III, processing waste such as soot and dust adhering to the substrate 120 ′ by laser cutting is removed by a cleaning mechanism (not shown). Then, the cleaned substrate 120 ′ is stored in the second substrate magazine 103 from the third position III by a fourth transport mechanism (not shown).

  In FIG. 2, reference numeral 160 denotes the movable stage described above, and the movable stage 160 is provided with a suction head (support member) 161 that sucks the lower surface of the substrate 120 (memory card area 135) with a negative pressure.

  Reference numeral 165 denotes a work placement area where the substrate 120 is positioned and placed by being sucked by the suction head 161. The lower surface (work installation reference plane) 165a of the workpiece installation region 165 and the upper and lower surfaces of the substrate 120 arranged in the workpiece installation region 165 are orthogonal to the central axis (scanning central axis) LO of the laser oscillator 110.

  Inside the movable stage 160, a flow path 162 of dust collection air A is formed so as to extend in the X direction. A dust collection pump 170 is connected to the flow path 162, and the flow of dust collection air A is generated in the flow path 162 by the suction force of the dust collection pump 170.

  As shown in the figure, soot and dust are generated from the substrate 120 when the substrate 120 is irradiated with the laser beam L from the laser oscillator 110 and cut. The dust collection air A prevents these soot and dust from adhering to the substrate 120 and a laser receiving member 180 described later, and has a role of collecting on a filter attached to the dust collection pump 170.

  The laser receiving member 180 is provided below the work installation area 165 in the flow path 162 so as to have an area equivalent to the work installation area 165. However, in this embodiment, since the suction head 161 is provided on the scanning center axis LO of the laser oscillator 110, the laser receiving member 180 is provided so as to surround the suction head 161 on the XY plane.

  The laser receiving member 180 is preferably formed of a material having excellent heat resistance (fire resistance) and heat dissipation, such as aluminum and ceramics.

  The upper surface (front surface) of the laser receiving member 180 is a laser receiving surface 181 that receives the laser light L that has been cut through the substrate 120 installed in the work installation region 165 and passed therethrough.

  The laser receiving surface 181 is inclined so as to continuously approach the workpiece installation region 165 from the outer portions E1 and E2 toward the inside, that is, the center-side portions C1 and C2, that is, obliquely upward. is doing. The portions C1 and C2 are portions along the side surface of the suction head 161.

  In other words, the laser receiving surface 181 is inclined so as to continuously approach the workpiece installation region 165 as it is closer to the scanning center axis LO of the laser light and the suction head 161.

  On the other hand, in FIG. 2, when attention is paid to a portion 181a on the left side of the laser receiving surface 181 (hereinafter referred to as an upstream laser receiving surface) 181a, the upstream laser receiving surface 181a It is inclined so as to gradually approach the workpiece installation region 165 from the upstream side to the downstream side of the flow of dust collection air A). On the other hand, a portion of the laser receiving surface 181 on the right side of the suction head 161 (hereinafter referred to as a downstream laser receiving surface) 181b is gradually separated from the workpiece installation region 165 from the upstream side toward the downstream side. That is, it is inclined so as to extend obliquely downward.

  Note that the fact that the laser receiving surface 181 is inclined so as to approach or move away from the workpiece installation region 165 can also be said to be inclined or non-parallel to the workpiece installation reference surface 165a.

  The laser beam L that has entered the laser receiving surface 181 after passing through the substrate 120 (work setting area 165) is inclined, as shown in FIG. 5, because the laser receiving surface 181 is inclined. Irrespective of the incident angle with respect to the laser receiving surface 181, the light is reflected in a direction different from that of the workpiece installation region 165. In other words, it is desirable to set the inclination angle θ of the laser receiving surface 181 with respect to the workpiece setting reference surface 165a so that the laser light L reflected by the laser receiving surface 181 does not go to the workpiece setting region 165.

  The inclined laser receiving surface 181 may be provided with a shape for scattering and reflecting laser light, such as a satin shape or a shape in which fine peaks and valleys are alternately arranged. In this case, when viewed microscopically, the scattering-shaped surface does not continuously approach or separate from the workpiece placement region 165, but the laser receiving surface 181 as the scattering-shaped base surface continuously places the workpiece. Approaching or leaving the region 165. In the present invention, including such a case, the laser receiving surface is inclined so as to continuously approach (or leave) the workpiece installation area.

  Further, in the laser receiving surface 181 of this embodiment, the center side portions C1 and C2 are closest to the workpiece installation region 165, and the outer portions E1 and E2 are farthest from the workpiece installation region 165. On the other hand, for example, the laser receiving surface is continuously extended from one end side to the other end side so that one outer portion E1 is farthest from the workpiece placement region 165 and the other outer portion E2 is closest to the workpiece placement region 165. It may be formed as an inclined unidirectional inclined surface.

  However, in this case, the overall height of the laser receiving member is increased, and accordingly, the thickness of the movable stage 160 is increased, or the cross-sectional area of the flow path 162 is increased and the flow velocity of the dust collection air A is decreased. To do. Therefore, it is desirable that the laser receiving surface 181 be formed so that the center side portions C1 and C2 are closest to the workpiece installation region 165 and the outer portions E1 and E2 are farthest from the workpiece installation region 165. However, the present invention includes the case where the laser receiving surface is the one-way inclined surface described above.

  In this embodiment, the upstream laser receiving surface 181a is inclined so as to continuously approach the workpiece installation region 165 from the upstream side to the downstream side of the flow path 162. Thereby, the cross-sectional area of the flow path 162 gradually decreases from the position of the outer portion E1 of the upstream laser receiving surface 181a to the position of the center side portion C1. For this reason, the flow velocity of the air A for dust collection flowing here increases toward the center side portion C1. Moreover, the flow of the dust collection air A in the vicinity of the substrate 120 is deflected toward the substrate 120 by the guide function of the upstream laser receiving surface 181a. Therefore, the dust collection performance can be improved without changing the suction capability of the dust collection pump 170.

  Further, the flow rate of the dust collection air A flowing along the laser receiving surface 181 increases, whereby the laser receiving member 180 can be efficiently cooled.

  In the present embodiment, as described with reference to FIG. 4, since a plurality of memory card areas 135 are formed on the substrate 120, the actual configuration of the movable stage 160 is as shown in FIG. Become. That is, the movable stage 160 is provided with a plurality of suction heads 161 at predetermined intervals, and a laser receiving member 180 having an inclined laser receiving surface is provided around each suction head 161. In this case, as shown in FIG. 7, a laser receiving member 180 may be provided for each memory card area 135 (suction head 161). As shown in FIG. It may be provided for each (suction head 161).

  7 and 8 is a top view, and the lower view is a side view. In FIG. 7, each of the suction heads 161 is provided with a truncated cone-shaped laser receiving member 180 centered on the suction head 161. In FIG. 8, a laser receiving member 180 having a mountain-shaped cross section in a side view and extending in the direction of the suction head row is provided for each suction head row composed of a plurality of suction heads 161.

  FIG. 9 shows the configuration of a laser cutting apparatus that is Embodiment 2 of the present invention. In the first embodiment, a case where a laser beam capable of scanning with laser light is used as the laser oscillator has been described. In this embodiment, a laser oscillator that emits laser light only in a certain direction is used, and a semiconductor substrate is installed. An apparatus for cutting the substrate along the predetermined cutting line by driving the movable stage in the XY directions will be described.

  In FIG. 9, 260 is a movable stage. The movable stage 260 is provided with a suction head 261 that sucks the lower surface of the memory card area 135 on the substrate 120 with a negative pressure.

  Reference numeral 265 denotes a work placement area where the substrate 120 is placed by being sucked by the suction head 261. The workpiece placement reference surface 265 a that is the lower surface of the workpiece placement region 265 and the upper and lower surfaces of the substrate 120 disposed in the workpiece placement region 265 are orthogonal to the central axis LO of the laser oscillator 210.

  The laser oscillator 210 includes a laser light source (not shown) and an optical system that condenses the laser light emitted from the laser light source in a direction (directly downward direction) along the central axis LO.

  Inside the movable stage 260, a flow path 262 of dust collection air A is formed so as to extend in the X direction. A dust collection pump 170 is connected to the flow path 262, and the flow of dust collection air A is generated in the flow path 262 by the suction force of the dust collection pump 170.

  A laser receiving member 280 is provided below the work installation area 265 in the flow path 262 so as to have an area equivalent to the work installation area 265.

  The laser receiving member 280 is preferably formed of a material excellent in heat resistance (fire resistance) and heat dissipation, such as aluminum and ceramics.

  The upper surface (front surface) of the laser receiving member 280 is a laser receiving surface 281 that receives the laser light L that has been cut through the substrate 120 installed in the work installation region 265 and passed therethrough.

  The laser receiving surface 281 is inclined so as to continuously approach the workpiece installation area 265 from the outer portions E1 and E2 toward the center-side portions C1 and C2. Further, the laser receiving surface 281 is inclined so as to continuously approach the workpiece installation area 265 as it is closer to the suction head 261.

  Further, of the laser receiving surfaces 281, the upstream laser receiving surface 281 a is inclined so as to continuously approach the workpiece installation region 265 from the upstream side to the downstream side of the flow path 262. On the other hand, the downstream laser receiving surface 281b of the laser receiving surface 281 is inclined so as to be continuously away from the work installation region 265 from the upstream side to the downstream side of the flow path 262.

  In addition, the fact that the laser receiving surface 281 is inclined so as to approach or move away from the workpiece installation area 265 can also be said to be inclined or non-parallel to the workpiece installation reference surface 265a.

  The laser light L (each light beam) incident on the laser receiving surface 281 is reflected in a direction different from the workpiece installation region 265 because the laser receiving surface 281 is inclined. In other words, it is desirable to set an inclination angle of the laser receiving surface 281 with respect to the workpiece setting reference surface 265a so that the laser light L reflected by the laser receiving surface 281 does not go to the workpiece setting region 265.

  Also in this embodiment, the inclined laser receiving surface 281 may be provided with a shape for scattering and reflecting laser light, such as a satin shape or a shape in which very small peaks and valleys are alternately arranged. In this case as well, it may be considered that the laser receiving surface 282 as the scattering-shaped base surface continuously approaches (or leaves) the workpiece installation region 265.

  Further, in the laser receiving surface 281 of this embodiment, the center side portions C1 and C2 are closest to the workpiece installation region 265, and the outer portions E1 and E2 are farthest from the workpiece installation region 265. However, for example, the laser receiving surface may be formed as a unidirectional inclined surface so that the outer portion E1 is farthest from the workpiece placement region 265 and the outer portion E2 is closest to the workpiece placement region 265.

  Also in this embodiment, the upstream laser receiving surface 281a is inclined so as to continuously approach the workpiece installation region 165 from the upstream side to the downstream side of the flow path 262. Accordingly, the cross-sectional area of the flow path 262 gradually decreases from the end portion E1 of the upstream laser receiving surface 281a to the central portion C. For this reason, the flow velocity of the dust collecting air A flowing there increases toward the center portion C. Moreover, the flow of dust collection air A in the vicinity of the substrate 120 is deflected toward the substrate 120 by the guide function of the upstream laser receiving surface 281a. Therefore, the dust collection performance can be improved without changing the suction capability of the dust collection pump 170.

  In each of the above embodiments, the case where the laser receiving surface of the laser receiving member is an inclined surface (planar surface) has been described, but the laser receiving surface may be formed as a curved surface such as a concave surface.

1 is a plan view of a laser cutting apparatus that is Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view of a movable stage in the laser cutting apparatus according to the first embodiment. FIG. 3 is a schematic diagram illustrating a configuration of a laser oscillator in the laser cutting device according to the first embodiment. FIG. 3 is a plan view of a semiconductor substrate cut by the laser cutting apparatus according to the first embodiment. FIG. 3 is a diagram for explaining a reflection action of a laser receiving member in the laser cutting device according to the first embodiment. FIG. 3 is a cross-sectional view of a movable stage in the laser cutting apparatus according to the first embodiment. FIG. 3 is a top view and a side view showing a shape example of a laser receiving member in the laser cutting device of Embodiment 1. The top view and side view which show the other example of a shape of the laser receiving member in the laser cutting apparatus of Example 1. FIG. Sectional drawing of the movable stage in the laser cutting device which is Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,200 Laser cutting device 110 Laser oscillator 111 Laser light source 113,114 Galvano mirror 120,120 'Memory card board 130 Planned cutting line 135 Memory card area 161 Adsorption head 180,280 Laser receiving member 181,281 Laser receiving surface L Laser light LO Scanning center axis A Dust collection air

Claims (5)

A laser cutting device for cutting a workpiece placed in a workpiece installation area with a laser beam,
A laser oscillator that emits laser light;
A laser receiving member that is provided in the dust collecting air flow path and receives the laser beam that has passed through the workpiece installation region;
The laser cutting device, wherein the laser receiving member has a laser receiving surface that approaches the work installation area from the upstream side to the downstream side of the flow of the dust collection air. The laser cutting device according to claim 1, wherein the laser receiving surface approaches the workpiece installation region from an outer portion to an inner portion of the laser receiving member . The laser oscillator is capable of scanning the laser beam,
3. The laser cutting device according to claim 1 , wherein the laser receiving surface is closer to the workpiece installation region as being closer to a scanning center axis of the laser light . 4. A support member for supporting the laser receiving member side surface of the workpiece;
4. The laser cutting device according to claim 1 , wherein the laser receiving surface is closer to the workpiece installation region as being closer to the support member . 5. The laser cutting apparatus according to claim 1 , wherein the workpiece is a semiconductor substrate and cuts a semiconductor device region formed in the workpiece.