KR102305385B1 - Method for maintaining spaces between chips - Google Patents

Abstract

An object of the present invention is to prevent the chips from coming into contact due to sagging of the sheets while maintaining the state in which the gap between the chips is expanded even when an expand sheet that is not heat-shrinked is adhered to a workpiece.
After the chip gap forming step of expanding the sheet T2 to form a gap between the chips, and the chip gap forming step, the sheet between the frame F and the workpiece W while maintaining the gap between the chips A sheet shrinking step of heating (T2) to shrink the stretched sheet T2 from the outer periphery of the work piece, and before the sheet shrinking step is performed, the sheet T2 between the frame F and the work piece W and bonding a plurality of heat-shrinkable tapes T3, wherein in the sheet shrinkage step, the sheet T2 between the frame F and the workpiece W is heated together with the tape T3 so that the tape T3 is adhered. The sheet T2 in the area is contracted.

Description

How to keep the chip spacing {METHOD FOR MAINTAINING SPACES BETWEEN CHIPS}

The present invention relates to a chip spacing maintenance method for maintaining a state in which the spacing between a plurality of chips constituting a workpiece is expanded on an expand sheet.

A plate-shaped to-be-processed object, such as a semiconductor wafer, is partitioned into a plurality of areas by division|segmentation lines whose surface is arranged in a grid|lattice form, for example, and various devices are respectively formed in each area|region divided by this grid|lattice form. Then, after the workpiece is ground and thinned to a predetermined thickness, it is divided along a division scheduled line to become individual device chips and the like, and is used in various electronic devices and the like.

As a method of dividing a workpiece, for example, first, a modified layer serving as a division starting point is formed by condensing a laser beam inside the workpiece, and an external force is applied to a dividing line whose strength is lowered by the modified layer. There is a method of dividing the workpiece into chips. As a means for applying an external force, a means for simultaneously expanding the to-be-processed object by expanding the expand sheet adhered to the back surface of a to-be-processed object with an expand apparatus is employ|adopted (for example, refer patent document 1). That is, by adhering the expand sheet to the work piece and adhering the outer periphery of the expand sheet to the annular frame so as to close the opening of the annular frame, the work piece is placed in a state supported by the annular frame via the expand sheet. Subsequently, the workpiece supported through the annular frame is placed on the expansion drum of the expand device, and the expand sheet is expanded in the planar direction to apply an external force to the line to be divided whose strength has been lowered by the modified layer to apply an external force to the workpiece. can be divided into chips.

[Patent Document 1] Japanese Patent Laid-Open No. 2010-147317

A pickup process in which the work piece is properly divided into chips by expanding the expand sheet, and a predetermined gap is formed between the chips, and the divided work piece picks up the chips from the expand sheet while the expand sheet is adhered is returned to In the pick-up process, for example, the chip is pushed up with a needle from below, and the chip floated from the expand sheet is picked up with a vacuum chuck. In the expand sheet, when the tension to expand is released, the area between the inner periphery of the annular frame and the outer periphery of the workpiece is stretched and drooped. As a result, there is a risk that the chips may be damaged by contacting the chips with each other due to the deflection of the expand sheet.

Therefore, as described in Patent Document 1, after dividing the workpiece into chips, only the drooping region between the inner peripheral edge of the annular frame and the outer peripheral edge of the workpiece in the expand sheet is heated to shrink, and the chip is There is a method in which the bonded parts do not shrink so that the chips do not come into contact with each other.

However, if the expand sheet to which the workpiece is adhered is of a type that does not shrink or is difficult to shrink by heating, the drooping area of the expand sheet cannot be accurately contracted even when heated, and as a result, avoid During handling through the annular frame of a workpiece, the chips may come into contact with each other and the chips may be damaged.

Therefore, even when an expand sheet that does not shrink or is difficult to shrink by heating is adhered to a workpiece, the chip-to-chip contact due to the deflection of the expand sheet is maintained while maintaining the expanded state between the chips. And there is a problem of preventing damage from occurring.

The present invention for solving the above problems is to maintain the chip spacing for maintaining the spacing between a plurality of chips constituting a workpiece supported by an annular frame through the expand sheet in a state of being adhered to the expand sheet in an expanded state. A method comprising: a chip gap forming step of expanding the expand sheet to form a gap between the chips; an expand sheet shrinking step of heating the expand sheet between the outer peripheral edges of the workpiece to shrink the expanded sheet stretched from the outer peripheral side of the workpiece, wherein at least before performing the expand sheet shrinking step, the annular frame A heat shrink tape bonding step of adhering a plurality of heat shrink tapes to the expanded sheet between the inner peripheral edge and the outer circumferential edge of the work piece, wherein in the expand sheet shrinking step, between the inner circumferential edge of the annular frame and the outer circumferential edge of the work piece and heating the expand sheet together with the heat shrink tape to shrink the expand sheet in an area to which the heat shrink tape is adhered.

The method for maintaining the chip spacing according to the present invention comprises, at least before carrying out the step of shrinking the expand sheet, a heat shrink tape bonding step of adhering a plurality of heat shrink tapes to the expand sheet between the inner peripheral edge of the annular frame and the outer peripheral edge of the workpiece. In the expand sheet shrinking step, by heating the expand sheet between the inner periphery of the annular frame and the outer periphery of the workpiece together with the heat shrink tape, the heat shrink tape is contracted by heating to expand the area to which the heat shrink tape is adhered. Since the expand sheet is contracted, even an expand sheet that is not contracted by heating can be contracted, and the gap between the chips can be maintained in an expanded state. Accordingly, it is possible to prevent damage to the chips caused by the sagging of the expand sheet and the chips being brought into contact with each other.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows an example of a to-be-processed object and a protective tape.
Fig. 2 is a cross-sectional view showing a state in which a modified layer is formed inside a workpiece by a laser processing apparatus.
3 is a perspective view showing a state in which the back surface of the workpiece is ground to a predetermined thickness by grinding the workpiece with a grinding device, and the workpiece is divided into chips by grinding pressure.
Fig. 4 is a perspective view showing a state in which the work piece is adhered to the expand sheet and supported by the annular frame, and the protective tape is peeled off from the work piece.
Fig. 5 is a plan view showing an example of a state in which a plurality of heat-shrinkable tapes are adhered to an expand sheet between the inner periphery of the annular frame and the outer periphery of the workpiece.
Fig. 6 is a cross-sectional view showing a state in which a workpiece after division, which is adhered to an expand sheet and supported by an annular frame, is set in the chip gap expansion device.
7 is a cross-sectional view showing a state in which a predetermined gap is formed between chips by expanding an expand sheet by a chip gap expanding device.
Fig. 8 is a cross-sectional view showing a state in which the expand sheet in an area to which the heat shrink tape is adhered is contracted by heating the expand sheet between the inner peripheral edge of the annular frame and the outer peripheral edge of the work piece together with the heat shrink tape.

The workpiece W shown in FIG. 1 is, for example, a semiconductor wafer having a circular shape, and on the surface Wa of the workpiece W, in a grid-like region partitioned by a line S to be divided. A number of devices D are formed. When the to-be-processed object W is divided|segmented into each chip provided with the device D along the division|segmentation schedule line S, for example, the modified layer used as a division|segmentation origin by the laser processing apparatus 1 shown in FIG. It is formed inside this to-be-processed object W. Therefore, the protective tape T1 shown in Fig. 1 is in a state where it is adhered to the surface Wa.

The protective tape T1 is, for example, a disk-shaped film having an outer diameter about the same as the outer diameter of the workpiece W, and has an adhesive surface T1a with adhesive force. For example, a UV curing paste made of an acrylic base resin or the like that is cured when irradiated with ultraviolet rays to decrease adhesive strength is used for the adhesive surface T1a. When the adhesive surface T1a of the protective tape T1 is adhered to the surface Wa of the workpiece W, the surface Wa of the workpiece W is in a state protected by the protective tape T1.

The laser processing apparatus 1 includes, for example, a chuck table 10 for suctioning and holding a workpiece W, and laser beam irradiation means for irradiating a laser beam to the workpiece W held by the chuck table 10 . (11) is provided at least. The chuck table 10 has, for example, a circular shape and a holding surface 10a made of a porous member or the like to hold the workpiece W by suction. The chuck table 10 is rotatable around an axis in the vertical direction, and is reciprocally moved in the X-axis direction by the machining feed means 12 .

The laser beam irradiation means 11 includes, for example, a laser beam oscillator (not shown) capable of oscillating a laser beam of a predetermined wavelength having transparency to the workpiece W, and the laser beam oscillated from the laser beam oscillator. By entering the light on the condensing lens 112 inside the condenser 111, the laser light can be condensed into the inside of the workpiece W. For example, when the to-be-processed object W is a silicon wafer and it is desired to form a favorable modified layer inside the to-be-processed object W by the laser beam irradiation means 11, the laser beam of the wavelength of an infrared region is converted into a laser beam oscillator. originate from

In the vicinity of the laser beam irradiation means 11, the alignment means 14 which detects the division|segmentation schedule line S of the to-be-processed object W is arrange|positioned. The alignment means 14 includes an infrared ray irradiating means (not shown) for irradiating infrared rays, an infrared camera 140 including an optical system for capturing infrared rays, and an imaging device (infrared CCD) for outputting an electric signal corresponding to infrared rays. Based on the image acquired by the infrared camera 140, the division|segmentation schedule line S of the surface Wa of the to-be-processed object W can be detected by image processing, such as pattern matching. The laser beam irradiation means 11 is constituted integrally with the alignment means 14, and both move in the Y-axis direction and the Z-axis direction in conjunction with each other.

Below, the case where the modified layer used as a division|segmentation origin is formed in the to-be-processed object W along the division schedule line S using the laser processing apparatus 1 is demonstrated. First, so that the holding surface 10a of the chuck table 10 of the laser processing apparatus 1 shown in FIG. 2 and the surface Wa side protected by the protective tape T1 of the workpiece W face each other Alignment is performed, and the workpiece W is placed on the chuck table 10 with the back surface Wb side facing upward. Then, a suction source (not shown) connected to the chuck table 10 operates to suction and hold the workpiece W on the chuck table 10 .

Subsequently, the workpiece W held by the chuck table 10 is sent in the -X direction (thin direction) by the machining transfer means 12 , and the division scheduled line S by the alignment means 14 . This is detected. Here, the surface Wa of the workpiece W on which the division scheduled line S shown in FIG. 1 is formed is located on the lower side and is not directly opposed to the alignment means 14, but the infrared camera 140 Thus, the division scheduled line S can be imaged by transmitting it from the back surface Wb side of the workpiece W. With the image of the division scheduled line S captured by the infrared camera 140, the alignment means 14 executes image processing such as pattern matching, and the position of the division scheduled line S is detected.

As the division scheduled line S is detected, the laser beam irradiation means 11 is driven in the Y-axis direction, and the position in the Y-axis direction between the division scheduled line S to be irradiated with the laser beam and the condenser 111 . customization is made This alignment is performed, for example, so that the center line of the dividing line S is located just below the condenser lens 112 provided in the condenser 111 .

Subsequently, the condensing point of the laser beam of a predetermined wavelength is positioned at a predetermined height inside the workpiece W corresponding to the dividing line S by the condenser 111 . Then, while irradiating the laser beam oscillated from the laser beam oscillator and focused by the condensing lens 112 along the dividing line S, the workpiece W is processed and transported in the -X direction at a predetermined processing feed rate. , to form a modified layer (M) on the inside of the workpiece (W) as shown in FIG. The formation position of the modified layer M is, for example, a position between the position above the back surface Wb and the front surface Wa of the workpiece W by the finished thickness of the device chip.

For example, when the workpiece W advances in the -X direction to a predetermined position in the X-axis direction where the laser beam irradiation is finished on one dividing line S, the laser beam irradiation is stopped and the The processing feed in the -X direction (thin direction) is temporarily stopped, the laser beam irradiation means 11 is moved in the +Y direction, and the laser beam is positioned next to the divided line S irradiated with the laser beam and the laser beam is still irradiated. Positioning in the Y-axis direction between the non-division scheduled line S and the condenser 111 is performed. Then, the processing transfer means 12 processes and transports the workpiece W in the +X direction (return direction), and the laser beam is irradiated to the dividing line S similarly to the laser beam irradiation in the thin direction. becomes By sequentially irradiating the same laser beam, the laser beam is irradiated from the back surface Wb side of the workpiece W along all the division scheduled lines S extending in the X-axis direction, and divided into the workpiece W. A modified layer M serving as a starting point is formed. Further, if the chuck table 10 is rotated 90 degrees and then the same laser beam is irradiated, the modified layer M is formed along all the vertical and horizontal divisional lines S.

The workpiece W on which the modified layer M is formed is, for example, thinned to a finished thickness by grinding the back surface Wb of the workpiece W by the grinding device 2 shown in FIG. By using the modified layer M as a division starting point and extending the crack toward the surface Wa side, the crack is divided into individual device chips.

The grinding apparatus 2 is equipped with at least the holding table 20 which suction-holds the to-be-processed object W, and the grinding means 21 which grind-processes the to-be-processed object W hold|maintained by the holding table 20, for example. do. The holding table 20 has, for example, a circular shape and a holding surface 20a made of a porous member or the like to hold the workpiece W by suction. The holding table 20 is rotatable around the axis of the vertical direction, and is reciprocally moved in the Y-axis direction by the Y-axis direction feed means 23 .

The grinding means 21 is made vertically movable by the grinding transfer means 22 which grind-transfers the grinding means 21 in the Z-axis direction spaced apart or approaching with respect to the holding table 20. As shown in FIG. The grinding transfer means 22 is, for example, a ball screw mechanism operated by a motor or the like. The grinding means 21 includes a rotary shaft 210 whose axial direction is a vertical direction (Z-axis direction), a motor 212 for rotationally driving the rotary shaft 210 , and an annular shape connected to the lower end of the rotary shaft 210 . A mount 213 and a grinding wheel 214 detachably connected to the lower surface of the mount 213 are provided.

The grinding wheel 214 includes a wheel base 214a and a plurality of grinding grindstones 214b in a substantially rectangular parallelepiped shape disposed annularly on the bottom surface of the wheel base 214a. The grinding wheel 214b is formed so that the diamond abrasive grains or the like are fixed by, for example, a resin bond, a metal bond, or the like. In addition, the shape of the grinding wheel 214b may be formed integrally in an annular shape.

For example, in the inside of the rotating shaft 210 , a flow path (not shown) communicating with the grinding water supply source and serving as a path for grinding water is formed to penetrate in the axial direction (Z-axis direction) of the rotating shaft 210 , and the flow path It passes through the mount 213 and is opened so that grinding water can be jetted toward the grinding wheel 214b in the bottom surface of the wheel base 214a.

Below, the case where the to-be-processed object W is grinded and divided|segmented by the grinding device 2 is demonstrated. First, the center of the holding table 20 and the center of the work W are approximately coincident, and the work W is placed on the holding surface 20a with the back surface Wb side facing upward. . And the holding table 20 attracts|sucks and holds the to-be-processed object W by the attraction|suction force produced|generated by the suction source (not shown) being transmitted to the holding surface 20a.

Then, the holding table 20 holding the workpiece W moves in the +Y direction to the bottom of the grinding means 21 , and the grinding wheel 214 provided in the grinding means 21 and the workpiece W ) is aligned. Positioning is, for example, as shown in FIG. 3 , the rotation center of the grinding wheel 214 is shifted in the +Y direction by a predetermined distance with respect to the rotation center of the holding table 20, and the rotation of the grinding wheel 214b The trajectory is made to pass through the rotation center of the holding table 20 .

After positioning of the grinding wheel 214 provided in the grinding means 21 and the workpiece W is performed, the rotation shaft 210 is rotated counterclockwise as viewed from the +Z direction side to rotate the grinding wheel 214 it rotates Further, the grinding means 21 is sent in the -Z direction by the grinding transfer means 22, and the grinding wheel 214b of the rotating grinding wheel 214 comes into contact with the back surface Wb of the workpiece W. Grinding is performed. During grinding, as the holding table 20 rotates, the workpiece W held on the holding surface 20a also rotates, so that the grinding wheel 214b is the front surface of the back surface Wb of the workpiece W. Grinding of the entire surface is performed. In addition, during grinding, grinding water is supplied to the contact part of the grinding wheel 214b and the to-be-processed object W through the flow path in the rotating shaft 210, and the back surface of the grinding wheel 214b and the to-be-processed object W. Cool and clean the contact area of (Wb).

When grinding is continued and the workpiece W is thinned to a finished thickness, grinding pressure is applied along the modified layer M, so that cracks extend toward the surface Wa of the workpiece W, and the workpiece W is divided into individual device chips C having a rectangular shape, as shown in FIG. 3 .

The workpiece W divided into the chips C is adhered to the expand sheet T2 and supported by the annular frame F through the expand sheet T2 as shown in FIG. 4 . is maintained so that handling through the annular frame F is possible, and the protective tape T1 is peeled off.

The expanded sheet T2 is, for example, a disk-shaped sheet having an outer diameter larger than the outer diameter of the workpiece W, for example, PET (polyethylene) having low heat shrinkage and adequate elasticity against mechanical external force. A substrate layer made of a stretched terephthalate) resin film or a PEN (polyethylene naphthalate) resin film, etc., is provided on the substrate layer, and UV curing glue, which cures when irradiated with ultraviolet rays and reduces adhesive strength, is laminated and formed and an adhesive surface T2a to be used. In addition, the material, thickness, etc. of the base material layer of the expand sheet T2 can be changed suitably according to the kind of to-be-processed object W, the thickness of to-be-processed object W, etc.

In Fig. 4, the back surface Fb of the annular frame F having a circular opening is adhered to the outer peripheral portion of the adhesive surface T2a of the expand sheet T2 facing upward. Further, the workpiece W is positioned above the adhesive surface T2a of the expand sheet T2 exposed in the opening of the annular frame F with the back surface Wb side facing downward. At this time, it is positioned so that the center of the workpiece W substantially coincides with the center of the opening of the annular frame F. And the back surface Wb of the to-be-processed object W is pressed against the adhesive surface T2a of the expand sheet T2, and the expand sheet T2 is adhere|attached to the back surface Wb of the to-be-processed object. In this way, the to-be-processed object W is brought into the state supported by the annular frame F via the expand sheet|seat T2, and the protective tape T1 is peeled from the surface Wa of the to-be-processed object W further.

Subsequently, the expand sheet T2 is expanded so that a predetermined gap is formed between the chips C supported by the annular frame F through the expand sheet T2. In this case, the workpiece W in a state of being divided into chips C and supported by the annular frame F through the expand sheet T2 maintains the shape of the workpiece W as a whole so that the chips C Since there is no gap therebetween, when the next workpiece W is conveyed or when the chip C is picked up from the expand sheet T2, the adjacent chips C rub against each other, so that chip breakage is prevented. This is to prevent the quality of the chip C from being deteriorated.

However, the area T2c between the inner peripheral edge Fe of the annular frame F of the expanded expand sheet T2 and the outer peripheral edge Wd of the workpiece W is stretched and sagged, so that the annular frame ( When handling the workpiece W through F), it is necessary to prevent the chips C from being damaged due to contact between the chips C due to the sagging of the expand sheet T2. Then, the chip space|interval maintenance method which concerns on this invention is implemented below.

(1) Adhesive step of heat shrink tape

For example, in the present embodiment, a plurality of heat-shrinkable tapes T3 are placed in a region T2c between the inner peripheral edge Fe of the annular frame F of the expand sheet T2 and the outer peripheral edge Wd of the workpiece W. ), the heat-shrinkable tape bonding step is performed first. The heat-shrinkable tape T3 is, for example, made of at least a resin (for example, polypropylene or polyvinyl chloride, etc.) having greater heat shrinkability than that of the expanded sheet T2 and adequate elasticity against mechanical external force, and has a rectangular shape. formed in the shape Although the heat-shrinkable tape T3 is provided with the adhesive surface which consists of a glue layer in this embodiment, the thing which is not provided with an adhesive surface may be sufficient. On the other hand, the heat-shrinkable tape T3 having a rectangular shape can be more easily bonded than a heat-shrinkable tape having an outer ring shape, for example. That is, for example, the rectangular heat-shrinkable tape T3 can be cut by simply cutting the elongated heat-shrinkable tape in a straight line. This is because it entails complexity, and there are many parts to be discarded.

5, for the region T2c between the inner peripheral edge Fe of the annular frame F of the expand sheet T2 and the outer peripheral edge Wd of the workpiece W, the workpiece ( At regular intervals in the circumferential direction of W), a plurality of rectangular heat-shrinkable tapes T3 (eg, a total of 18 in the illustrated example) are adhered in an annular shape. When the heat-shrinkable tape T3 has the property of being more easily stretchable in either the vertical or horizontal direction, it is preferable to match the direction in which the heat-shrinkable tape T3 easily expands and contracts and the radial direction of the workpiece W coincide.

In addition, with respect to the region T2c of the expand sheet T2, at regular intervals in the circumferential direction of the workpiece W, a plurality of rectangular heat-shrinkable tapes T3 are attached in an annular shape (for example, 18 sheets in total). After this, a plurality of heat-shrinkable tapes T3 (eg, a total of 12 sheets) may be adhered to the outer side in the radial direction in a circular annular shape.

(2) chip gap forming step

For example, after performing the heat-shrinkable tape bonding step, the workpiece W in a state supported by the annular frame F via the expand sheet T2 is conveyed to the chip gap expansion device 5 shown in FIG. 6 . do. The chip gap extending device 5 is a device capable of expanding the gap between the respective chips C by expanding the expand sheet T2. The chip spacing expanding device 5 has, for example, an annular table 50 having an outer diameter larger than the outer diameter of the expanded sheet T2, and the diameter of the opening 50c of the annular table 50 is It is formed smaller than the outer diameter of the pan sheet T2. On the outer periphery of the annular table 50, for example, four fixing clamps 52 (only two are shown in the illustrated example) are equally arranged. The fixing clamp 52 is made rotatable about the rotation shaft 52c by a spring or the like not shown, and is provided between the holding surface 50a of the annular table 50 and the lower surface of the fixing clamp 52. F) and the expand sheet T2 can be inserted.

In the opening 50c of the annular table 50, a cylindrical expansion drum 53 is disposed with a fixed height position, and the center of the annular table 50 and the center of the expansion drum 53 approximately coincide. The outer diameter of this expansion drum 53 is smaller than the outer diameter of the expand sheet T2, and is formed larger than the outer diameter of the to-be-processed object W. As shown in FIG.

On the inner peripheral side of the expansion drum 53, a suction holding table 6 for holding the workpiece W by suction is disposed. The suction holding table 6 is formed of a porous member and includes a suction unit 60 having a suction surface 600 on its upper surface, a frame 61 supporting the suction unit 60 , and the suction unit 60 . A suction source 62 for transmitting a suction force is provided. The suction surface 600 and the upper surface 610 of the frame 61 are formed on the same surface, and the suction force generated by the suction source 62 is transmitted to the suction surface 600, so that the The workpiece W can be sucked and held through the pan sheet T2.

The annular table 50 is made to be movable up and down in the Z-axis direction by the annular table raising/lowering means 55, for example. The annular table lifting means 55 is, for example, an air cylinder, a cylindrical cylinder tube 550 having a piston (not shown) therein, and a bottomed bottom on the proximal end side (-Z direction side), and a cylinder tube ( It is inserted into the 550 and has a piston rod 551 having one end attached to the piston. The other end of the piston rod 551 is fixed to the lower surface of the annular table 50 . When air is supplied (or discharged) to the cylinder tube 550 and the pressure inside the cylinder tube 550 changes, the piston rod 551 moves in the Z-axis direction, and the annular table 50 moves in the Z-axis direction. move to

In order to form a predetermined gap between the chips C, for example, on the holding surface 50a of the annular table 50 positioned at the reference height position, the annular frame F is disposed through the expand sheet T2. do. Then, the fixing clamp 52 is rotated so that the annular frame F and the expand seat T2 are fitted between the fixing clamp 52 and the holding surface 50a of the annular table 50 in a fixed state. . In this state, the holding surface 50a of the annular table 50 and the annular top surface of the expansion drum 53 are at the same height position, and the top surface of the expansion drum 53 is the top surface of the expand sheet T2. In the region T2c between the inner periphery Fe of the annular frame F and the outer periphery Wd of the workpiece W, the expand sheet T2 comes into contact with the substrate surface side (the lower surface side in Fig. 6). do. In addition, the inner peripheral side of the expand sheet T2 from the base surface side of the base material surface side is supported by the adsorption|suction surface 600 and the upper surface 610, but suction holding|maintenance in the adsorption|suction surface 600 is not performed.

As shown in FIG. 7 , the annular table lifting means 55 lifts the annular table 50 with the annular frame F and the expand seat T2 sandwiched between the fixing clamp 52 and the annular table 50 -Z By lowering in the direction, the holding surface 50a of the annular table 50 is positioned at the expand seat extension position lower than the upper end surface of the expansion drum 53 . As a result, the expansion drum 53 rises relatively with respect to the fixing clamp 52 , and the expand sheet T2 is pushed up by the top surface of the expansion drum 53 and radially expands outward in the radial direction. do. In addition, the heat-shrinkable tape T3 is also expanded by the adhesive force of the expand sheet T2 and the tension applied in the horizontal direction. And, as the expand sheet T2 is expanded, a predetermined gap V is formed between the respective chips C. As shown in FIG. In addition, the magnitude|size of the space|interval V is a magnitude|size which can be suitably changed according to the descent|fall position of the annular table 50. As shown in FIG.

On the other hand, the step of attaching the heat-shrinkable tape may be performed, for example, after the step of forming the chip gap.

(3) Expand sheet shrinkage step

After a predetermined gap V is formed between the chips, the suction source 62 and the suction unit 60 communicate with each other to apply a suction action to the suction surface 600 so that the region T2c of the expand sheet T2 is Suction and hold the inner periphery. And, as shown in FIG. 8, for example, the annular table lifting means 55 is annular so that the holding surface 50a of the annular table 50 and the annular top surface of the expansion drum 53 are at the same height position. When the table 50 is raised in the +Z direction, the force that pulls the expand sheet T2 in the horizontal direction is lost, and the tension of the expand sheet T2 is released. Accordingly, the region T2c between the inner peripheral edge Fe of the annular frame F of the expand sheet T2 and the outer peripheral edge Wd of the workpiece W is stretched and drooping. Therefore, the area T2c of the expand sheet T2 is heated together with the heat shrinkable tape T3 by the heating means 7 shown in FIG. 8 .

The heating means 7 is, for example, an infrared heater capable of emitting infrared rays, and heats the region T2c of the heat shrinkable tape T3 and the expand sheet T2 in a non-contact manner from above. In addition, a contact type may be sufficient as the heating means 7, and the hot-air heater which can inject hot air from a nozzle may be sufficient as it. The heat shrinkage rate of the heat shrink tape T3 is large, and since the heat shrink tape T3 is expanded in the chip gap forming step, it is heated by the heating means 7, for example, it is contracted radially inward to the size before expansion. . Although the expand sheet T2 hardly undergoes thermal shrinkage due to heating by the heating means 7, the shrinking force of the heat shrink tape T3 is the same as that of the expand sheet T2 to which the heat shrink tape T3 is adhered. Since it propagates as a mechanical external force to the region T2c, the region T2c of the drooping expand sheet T2 is pulled inward in the radial direction and contracted to the state before expansion. In addition, since the heating by the heating means 7 is performed only for the area T2c of the heat shrinkable tape T3 and the expand sheet T2, the space V between the adjacent chips C is increased after the expansion size can be maintained. In addition, since the inner peripheral side of the region T2c is sucked and held by the suction surface 600 , the chips C do not move, and the interval V between the adjacent chips C can be reliably maintained.

After the expand sheet shrinking step is completed, the plurality of chips C in a state supported by the annular frame F via the expand sheet T2 are conveyed to a pickup device (not shown). Since the state in which the gap V is expanded is maintained, and the expand sheet T2 is returned to the state attached to the annular frame F in a taut state without sagging, the work piece through the annular frame F is It is possible to prevent the chips (C) from being damaged by contact with each other during the handling of (W).

On the other hand, the chip gap maintaining method according to the present invention is not limited to the above embodiment, and the configuration of the laser processing device 1, the grinding device 2 and the chip gap expansion device 5 shown in the accompanying drawings. It is not limited to this also about etc., It can change suitably within the range which can exhibit the effect of this invention.

For example, in this embodiment, after the modified layer M is formed on the workpiece W by the laser processing apparatus 1, grinding and division of the workpiece W are performed by the grinding apparatus 2, , the work W is divided not by grinding by the grinding device 2, but by expanding the expand sheet T2 by the chip gap expansion device 5 to divide the work W, , at the same time, a predetermined interval may be formed between the chips.

In addition, you may perform division|segmentation of the to-be-processed object W, without using the laser processing apparatus 1 . That is, first, by a cutting device having a rotatable cutting blade, cutting is performed on the workpiece W from the surface Wa side along the division scheduled line S, and the workpiece W is subjected to a predetermined After forming a deep machining groove, it is good also as dividing the to-be-processed object W into chips by grinding from the back surface Wb side to a height position where the bottom of the machining groove is exposed. Thereafter, the expand sheet T2 may be expanded by the chip gap expansion device 5 to form a predetermined gap between the chips.

W: workpiece Wa: surface of workpiece
Wb: the back side of the workpiece S: the line to be split
D: device M: modified layer
C: Chip T1: Protective Tape
T1a: adhesive side of protective tape T2: expand sheet
T2a: adhesive surface of expand sheet T2b: base material surface of expand sheet
T3: heat shrink tape 1: laser processing unit
10: chuck table 10a: holding surface of the chuck table
11: laser light irradiation means 111: condenser
112: condensing lens 12: processing transport means
14: alignment means 140: infrared camera
2: grinding device 20: holding table
20a: holding surface of holding table 23: Y-axis direction feed means
21: grinding means 210: rotation shaft
212: motor 213: mount
214: grinding wheel 214a: wheel base
214b: grinding wheel 5: chip spacing extender
50: annular table 50a: holding surface of the annular table
50c: opening of annular table 52: fixing clamp
53: expansion drum 55: annular table lifting means
550: cylinder tube 551: piston rod
6: Suction holding table 60: Suction part
600: adsorption surface 61: frame
610: upper surface 62: suction source
7: heating device

Claims (1)

A chip spacing maintenance method for maintaining in an expanded state the spacing of a plurality of chips constituting a workpiece supported by an annular frame through the expand sheet in a state of being adhered to the expand sheet,
Fixing the expand sheet on a holding surface of the annular table, and supporting the expand sheet in a state of not being sucked and held by a suction surface of a suction holding table disposed on an inner peripheral side of the annular table, wherein the holding surface and the A chip gap forming step of forming a gap between the chips by expanding the expand sheet by relatively moving the adsorption surface up and down;
After performing the step of forming the chip gap, the region corresponding to the chip of the expand sheet is sucked and held by the suction surface of the suction holding table to maintain the gap between the chips, the inner peripheral edge of the annular frame and the an expand sheet shrinking step of heating the expand sheet between the outer peripheral edges of the workpiece to shrink the expanded sheet stretched from the outer peripheral side of the workpiece;
At least before performing the expand sheet shrinking step, a heat shrink tape bonding step of adhering a plurality of rectangular heat shrink tapes to the expand sheet between the inner peripheral edge of the annular frame and the outer peripheral edge of the workpiece further comprising:
In the step of shrinking the expand sheet, the expand sheet between the inner periphery of the annular frame and the outer periphery of the workpiece is heated together with the heat shrink tape to shrink the expand sheet in the area to which the heat shrink tape is adhered. How to keep spacing.

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