TW201608617A - Chip interval maintenance method - Google Patents

Abstract

To remove sagging of a tensed adhesive tape accurately and in a short time. A chip interval maintenance method is disclosed for maintaining an interval of a plurality of chips of a workpiece supported on an annular frame via an adhesive tape in the state where the adhesive tape is extended and tensed. The workpiece held by a holding table and the annular frame held by frame holding means are relatively moved in a perpendicular direction, and the adhesive tape is extended to form an interval between the plurality of chips of the workpiece. The adhesive tape is sucked and held by the holding table so as to maintain the interval of the plurality of chips and while returning the holding table and the frame holding means to an initial state step by step and cancelling a tension of the adhesive tape, sagging of the adhesive tape caused by the cancellation of the tension in each of steps is thermally shrunk by heating means.

Description

Wafer interval maintenance method Field of invention

The present invention relates to a wafer interval maintaining method in which a wafer interval of one wafer divided by a workpiece supported by an annular frame through an adhesive tape is maintained in an expanded state.

Background of the invention

Conventionally, there has been known a method of dividing a workpiece into a wafer by forming a reforming layer, a laser processing groove, a cutting groove, and the like along a dividing line after being bonded to a workpiece of an adhesive tape. (refer to, for example, Patent Document 1). In the dividing method described in Patent Document 1, the adhesive tape attached to the annular frame is expanded, and an external force is applied to the dividing starting point formed along the dividing line, and the strength is applied along the strength. The reduced starting point of the split divides the workpiece into individual wafers. However, once the tension of the adhesive tape is released, the adhesive tape causes a large slack, and there is a possibility that adjacent wafers come into contact with each other to cause breakage and breakage.

Therefore, in a state in which the interval between the wafers is maintained (fixed), a method of imparting external stimuli such as heat to the periphery of the workpiece having a large slack of the adhesive tape to cause relaxation and contraction of the adhesive tape is proposed. here In the method, there are the following cases of concern: due to the difference in material and thickness of the adhesive tape, there is a case where the contraction of the slack formed by the external stimulus is insufficient, or the slack does not shrink. For this reason, a method of manufacturing a tension on an adhesive tape by thermocompression bonding by holding the adhesive tape is proposed (see, for example, Patent Document 2). In the method described in Patent Document 2, the slack of the adhesive tape formed around the workpiece is raised upward, and the ridge is held and thermocompression bonded in a range covering the entire circumference. To remove the slack of the adhesive tape.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2007-189057

Patent Document 2: Japanese Patent Laid-Open Publication No. 2013-239557

Summary of invention

However, in the method of Patent Document 2, it is necessary to thermally press-bond the ridge of the adhesive tape in a range covering the entire circumference, particularly in order to remove slack from the adhesive tape of the large-diameter workpiece. It takes a lot of time.

The present invention has been made in view of such problems, and an object thereof is to provide a wafer interval maintaining method capable of reliably removing slack of an expanded adhesive tape in a short time.

The wafer spacing maintenance method of the present invention is used to make the composition sticky The interval between the plurality of wafers attached to the adhesive tape and the workpiece to be mounted on the annular frame is maintained in an expanded state. The wafer spacing maintaining method includes: a step of holding a workpiece through the adhesive tape on a holding table capable of attracting a workpiece, and holding the annular frame by a frame holding means; after performing the holding step, borrowing And moving the holding table and the frame holding means relative to each other in the vertical direction by a predetermined distance, pushing the holding table up and stretching the adhesive tape with respect to the frame holding means, and forming a space between the plurality of wafers a wafer spacing expansion step; after performing the wafer interval expansion step, a suction holding step of holding the workpiece by the adhesive tape on the holding table to maintain an interval between the adjacent wafers; and at the beginning After the attraction holding step, the holding table and the frame holding means are relatively moved in the vertical direction to lift the predetermined distance of the holding table relative to the frame holding means by a plurality of stages, and At each stage, the workpiece and the stretched adhesive tape between the inner circumferences of the annular frame are heated to be processed in stages. Contraction of the adhesive tape, and the wafer to be fixed interval of spacing between the fixing step of the wafer adjacent thereto.

According to this configuration, by holding the holding table holding the workpiece upward with respect to the frame holding means for holding the annular frame, the adhesive tape is stretched to form a space between the wafers. Then, in a state where the interval between the wafers of the workpiece is maintained, the push-up of the holding table is released stepwise, and the slack of the adhesive tape is gradually contracted by heating before the slack becomes large. Therefore, in a state in which the gap between the wafers of the workpiece is maintained, the slack of the adhesive tape is contracted and fixed, so that there is no adjacent wafer. Contact with each other to cause defects and breakage. Further, in comparison with the method of holding the adhesive tape by slack and performing thermocompression bonding, it is possible to produce tension on the adhesive tape in a short time.

Further, in the above-described wafer interval maintaining method, a workpiece having a plurality of intersecting plural dividing lines is formed, and a dividing starting point is formed along the dividing line to be placed in the wafer interval expanding step. The workpiece is divided into a plurality of wafers and spaces are formed between the wafers.

According to the present invention, the slack of the adhesive tape is released in a stepwise manner, and the slack of the adhesive tape is contracted by heating, so that the slack of the expanded adhesive tape can be surely removed in a short time.

1‧‧‧ Wafer interval maintenance device

11‧‧‧ Keeping the table

12‧‧‧Framework means

13‧‧‧Attraction source

14‧‧‧Switching valve

21‧‧‧Outer wall

22‧‧‧Support board

23‧‧‧Perforated plate

24‧‧‧ Keep face

25‧‧‧Roller

31‧‧‧ mounting table

32‧‧‧ Cover

33, 37‧‧‧round opening

34‧‧‧lifting cylinder

35‧‧‧Cylinder rod

36‧‧‧Upper wall

41‧‧‧heating means

42‧‧‧ lifting plate

43‧‧‧Rotary axis

51‧‧‧ surface

52‧‧‧Division line

53‧‧‧ Scotch

54‧‧‧Modified layer

C‧‧‧ wafer

F‧‧‧Ring frame

S‧‧‧relaxation

T‧‧‧Adhesive tape

W‧‧‧Processed objects

Fig. 1 is a perspective view of the wafer interval maintaining device of the embodiment.

Fig. 2 is a view showing an example of the holding step of the embodiment.

Fig. 3 is a view showing an example of a wafer interval expansion step in the embodiment.

Fig. 4 is a view showing an example of the suction holding step of the embodiment.

5A to 5C are views showing an example of a step of fixing the wafer interval in the embodiment.

Form for implementing the invention

The wafer interval maintaining device of this embodiment will be described below. Fig. 1 is a perspective view of the wafer interval maintaining device of the embodiment. Furthermore, this is The wafer interval maintaining device of the embodiment is not limited to the configuration shown in FIG. The wafer interval maintaining device may be configured as long as it can remove the expanded state of the adhesive tape in stages and remove the slack of the adhesive tape by heating.

As shown in FIG. 1, the wafer interval maintaining device 1 is a disk-shaped workpiece W that is supported by the adhesive tape T on the annular frame F, and is expanded by a tape of the adhesive tape T to be divided into one. Wafers. Further, the wafer interval maintaining device 1 is configured to release the tension of the adhesive tape T in stages while maintaining the wafer interval, and to remove the heat shrinkage (heat shrink) repeatedly at the time of releasing each tension. The resulting slack. In this manner, the adhesive tape T is thermally contracted only when it is stretched and largely slackened, and can be fixed while maintaining the wafer interval after the workpiece W is divided.

A grid-shaped dividing line 52 is provided on the surface 51 of the workpiece W, and various elements (not shown) are formed in each of the regions defined by the dividing line 52. A score 53 showing a crystal orientation is provided on the outer edge of the workpiece W. In addition, the workpiece W may be a semiconductor wafer in which an element such as an IC or an LSI is formed on a semiconductor substrate such as tantalum or gallium arsenide, or an LED may be formed on an inorganic material substrate such as ceramic, glass or sapphire. Optical element wafer of the optical element. The workpiece W is carried into the wafer interval maintaining device 1 while being supported by the annular frame F through the adhesive tape T.

Further, inside the workpiece W, a reforming layer 54 (see FIG. 2) which can be a starting point of division is formed along the dividing line 52. Furthermore, the modified layer 54 refers to the inside of the workpiece W by the irradiation of the laser light. Degrees, refractive index, mechanical strength, and other physical properties become areas that are different from the surroundings and that are lower in intensity than the surroundings. The reforming layer 54 may be, for example, a molten processed region, a cracked region, an insulating fracture region, a refractive index change region, or a region in which the regions are mixed. In the following description, the reforming layer 54 is exemplified as the starting point of the division, but the starting point of the division may be a starting point at the time of division as long as the strength of the workpiece W can be lowered, for example, a laser processing groove , cutting groove, scribe line can also be.

In the wafer interval maintaining device 1, a holding table 11 capable of sucking and holding the workpiece W is disposed at the center, and a frame holding means 12 for holding the annular frame F is disposed around the holding table 11. In the holding table 11, a porous porous plate 23 is disposed on the upper side of the cylindrical outer wall portion 21 through the support plate 22 (see FIG. 2). By the porous porous plate 23, a holding surface 24 for adsorbing the workpiece W is formed on the upper surface of the holding table 11. The holding surface 24 is connected to the suction source 13 (see FIG. 2) through the flow path in the holding table 11, and can hold and hold the workpiece W by the negative pressure generated on the holding surface 24.

Further, the on-off valve 14 (see FIG. 2) is provided on the flow path that communicates with the suction source 13 from the holding surface 24, and the suction and retention of the holding surface 24 and the suction release can be switched by the on-off valve 14. At the upper end portion of the outer wall portion 21 of the holding table 11, that is, the outer peripheral edge of the holding table 11, a plurality of roller portions 25 are provided along the entire circumference. The plurality of roller portions 25 are in contact with the adhesive tape T around the workpiece W from the lower side while the workpiece W is held by the holding surface 24. By rotating the plurality of roller portions 25 in contact with the adhesive tape T, it is possible to suppress the friction generated at the outer peripheral edge of the holding table 11 when the adhesive tape T is expanded.

The frame holding means 12 is formed so as to sandwich the annular frame F on the mounting table 31 from above by the cover plate 32 to hold the annular frame F on the mounting table 31. The mounting table 31 has a quadrangular shape in plan view, and a circular opening 33 having a larger diameter than the holding table 11 is formed at the center. The four corners of the mounting table 31 are supported by the cylinder rods 35 of the four lifting cylinders 34 for lifting the mounting table 31 from the lower side. The four lift cylinders 34 are constituted by an electric cylinder or the like, and the mounting table 31 is raised and lowered by controlling the amount of protrusion of the cylinder rod 35.

The cover plate 32 is formed in a box shape in which the bottom surface is open so as to be covered on the mounting table 31. The upper wall portion 36 of the cover plate 32 is formed with a circular opening 37 having a larger diameter than the holding table 11 at the center. When the cover 32 is placed on the mounting table 31, the annular frame F can be held by the cover 32 and the mounting table 31, and a part of the workpiece W and the adhesive tape T will come from the circle of the cover 32. The shaped opening 37 is exposed above. Further, the cover 32 is attached to the mounting table 31 in a state of being placed on the mounting table 31, and is fixed to the mounting table 31 by, for example, a clamp portion (not shown).

Above the cover plate 32, a disk-shaped lifting plate 42 including a plurality of heating means 41 is provided. The lift plate 42 is fixed to a lower end of a rotary shaft 43 that is rotated by a motor or the like (not shown), and is moved in the vertical direction by an elevating mechanism (not shown). The plurality of heating means 41 are far-infrared heaters and are positioned in an annular region between the annular frame F and the workpiece W. The heating means 41 is, for example, a far-infrared ray having a peak waveform of 3 μm to 25 μm which is hardly absorbed by the metal material, and is formed to be heated to control the respective portions of the device, and only the irradiation portion of the adhesive tape T is appropriately heated. .

The wafer interval maintaining device 1 is lowered by the frame holding means 12 while holding the annular frame F, so that the holding table 11 is covered from the cover. The circular openings 33, 37 of the plate 32 and the mounting table 31 protrude. By pushing the holding table 11 relatively upward with respect to the frame holding means 12, the adhesive tape T is expanded in the radial direction, and the workpiece W is divided into individual wafers. Further, when the frame holding means 12 is raised and the push-up of the holding table 11 is released, the tension of the adhesive tape T can be relaxed, and slack can be generated around the workpiece W. The relaxation of the adhesive tape T is removed by irradiation of far infrared rays from a plurality of heating means 41.

At this time, when the frame holding means 12 is once raised in a concentrated manner to release the push-up of the holding table 11, the slack of the adhesive tape T becomes large, and it is difficult to appropriately remove the heat by the heating means 41. Therefore, in the wafer interval maintaining device 1 of the present embodiment, the frame holding means 12 is gradually increased in a plurality of times to release the push-up of the holding table 11 in a stepwise manner, and the push-up can be released. The slack of the adhesive tape T generated in each stage is removed by the heating of the heating means 41.

Hereinafter, a wafer interval maintaining method of the wafer interval maintaining device will be described with reference to FIGS. 2 to 5. Fig. 2 is a view showing an example of a holding step in the embodiment. Fig. 3 is a view showing an example of a wafer interval expansion step in the embodiment. Fig. 4 is a view showing an example of the suction holding step of the embodiment. Fig. 5 is a view showing an example of a wafer interval fixing step in the embodiment. In addition, the workpiece to be processed by the step of the above paragraph is formed on the workpiece.

As shown in Fig. 2, the holding step is first carried out. In the holding step, the workpiece W is placed on the holding table 11 via the adhesive tape T, and the annular frame F around the workpiece W is held by the frame holding means 12. At this time, yes The holding table 11 is formed to have a larger diameter than the workpiece W, and the roller portion 25 of the outer peripheral edge of the holding table 11 contacts the adhesive tape T between the workpiece W and the annular frame F from the lower side. Further, the on-off valve 14 is closed to block the suction force from the suction source 13 to the perforated plate 23. Further, inside the workpiece W, a reforming layer 54 as a starting point of division is formed along the dividing line 52 (see FIG. 1).

As shown in FIG. 3, the wafer spacer expansion step is performed after the holding step. In the wafer interval expanding step, the holding table 11 is relatively pushed up relative to the frame holding means 12 by lowering the frame holding means 12 by a predetermined distance (for example, 15 mm) in the vertical direction from the starting position. As a result, the adhesive tape T to which the workpiece W is adhered is expanded in the radial direction, and an external force is applied to the reforming layer 54 of the workpiece W through the adhesive tape T. The workpiece W is divided into individual wafers C by using the modified layer 54 (see FIG. 2) whose strength has decreased as a starting point of division. The adhesive tape T is stretched until the immediately adjacent wafer C is completely separated, and a space is formed between the plurality of wafers C.

At this time, since the adhesive tape T is rotationally contacted on the plurality of roller portions 25 at the outer peripheral edge of the holding table 11, the friction or the like during the expansion of the adhesive tape T can be suppressed. Further, in the wafer interval expansion step, the adhesive tape T is expanded by the method of lowering the frame holding means 12 with respect to the holding table 11, but the configuration is not limited thereto. The adhesive tape T can be expanded as long as the holding table 11 and the frame holding means 12 are relatively moved in the vertical direction. For example, the holding table 11 may be raised with respect to the frame holding means 12 to expand the adhesive tape T, or the holding table 11 may be raised and the frame holding means 12 may be lowered to expand the adhesive tape T.

As shown in FIG. 4, the attraction holding step can be performed after the wafer interval expansion step. In the suction holding step, the opening and closing valve 14 is opened to communicate the suction source 13 and the perforated plate 23, and the perforated plate 23 is attracted to the holding table 11. At this time, since the adhesive tape T has been stretched, the workpiece W can be sucked and held by the adhesive tape T on the holding table 11, and the interval between the adjacent wafers C can be maintained. In this manner, when the wafer interval is expanded, the adhesive tape T is not attracted and held on the holding table 11, so as not to hinder the expansion of the adhesive tape T, and after the wafer is expanded, the adhesive tape T is attracted to the holding table 11. Hold to maintain wafer spacing.

As shown in FIG. 5, the wafer spacer fixing step is performed after the attraction holding step. Further, in the present embodiment, the frame holding means 12 which is lowered in the wafer interval expansion step is divided into three stages and the wafer interval fixing step is carried out. As shown in FIG. 5A, in the first stage of the wafer interval fixing step, the frame holding means 12 rises only slightly (for example, 3 mm) from the lowered position, and the push-up of the holding stage 11 is released by only one stage. Since the adhesive tape T is sucked and held on the holding table 11, even if the tension of the adhesive tape T around the workpiece W is relaxed, there is no possibility of slack on the adhesive tape T on the holding table 11.

Due to the release of the push-up of the holding table 11, only a slight slack S is generated along the entire circumference of the annular region between the annular frame F and the workpiece W in the adhesive tape T. At this time, the plurality of heating means 41 are brought close to the annular region between the annular frame F and the workpiece W, and the slack S of the adhesive tape T is heated by the irradiation of far infrared rays from the plurality of heating means 41. Then, a plurality of heating means 41 are rotated around the vertical axis to loosen the adhesive tape T The relaxation S is subjected to heat shrinkage along the entire circumference. In this manner, the slack S generated in the first stage of the wafer spacer fixing step can be removed.

Next, as shown in FIG. 5B, in the second stage of the wafer interval fixing step, the frame holding means 12 is further raised (for example, 4 [mm]), and the push-up of the holding table 11 is released again by one step. . By the release of the push-up of the further formed holding table 11, a new slack S is generated along the entire circumference of the annular region between the workpiece W and the annular frame F in the adhesive tape T. At this time, the plurality of heating means 41 also rises as the frame holding means 12 rises, and the slack S of the adhesive tape T can be made to follow the entire circumference by the irradiation of the far infrared rays from the plurality of heating means 41. Was removed. This is done to remove the slack S generated in the second stage of the wafer spacer fixing step.

Further, as shown in FIG. 5C, in the third stage of the wafer interval fixing step, the frame holding means 12 is raised to the initial position, and the push-up of the holding table 11 is further released by one step. By the release of the push-up of the further formed holding table 11, a new slack S is generated along the entire circumference of the annular region between the workpiece W and the annular frame F in the adhesive tape T. At this time, the plurality of heating means 41 also rises as the frame holding means 12 rises, and the relaxation S of the adhesive tape T can be made along the entire circumference by the irradiation of the far infrared rays from the plurality of heating means 41. Was removed. This is done to remove the slack S generated in the third stage of the wafer spacer fixing step.

In this way, the predetermined distance from the holding table 11 of the frame holding means 12 is pushed up and released in stages, in order to In one stage, the stretched adhesive tape T between the workpiece W and the inner circumference of the annular frame F is heated, and the adhesive tape T is shrunk in a plurality of stages in stages. Thereby, the slack of the adhesive tape T does not become too large, and the slack of the adhesive tape T can be slowly removed by the heating of the heating means 41. In the wafer spacer fixing step, since only the adhesive tape T around the workpiece W is thermally contracted, even if the suction of the holding table 11 is released, the interval between the adjacent wafers C is fixed in a maintained state.

Further, in the wafer spacer fixing step of the present embodiment, the adhesive tape T is thermally contracted in three stages, but the configuration is not limited thereto. It is also possible to subdivide the action of the wafer spacer fixing step so that the wafer spacer fixing step is close to a continuous motion. In other words, in the middle of the process of returning the frame holding means 12 from the processing position to the initial position, the number of operations of the heating operation of the adhesive tape T by the lifting operation of the holding table 11 and the heating means 41 can be performed (stage The number is increased and subdivided, and the slack of the adhesive tape T is removed substantially continuously.

As described above, in the wafer interval maintaining method of the present embodiment, the holding table 11 holding the workpiece W is pushed up with respect to the frame holding means 12 for holding the annular frame F, so that the adhesive tape T is stretched. A space is formed between the wafers C. Then, in a state where the interval between the wafers C of the workpiece W is maintained, the push-up of the holding table 11 is released in stages, and the slack S of the adhesive tape T is slowly heated by the heating before the slack S becomes large. Shrinked. Thereby, even if the slack S of the adhesive tape T is sufficiently shrunk, the interval between the wafers C of the workpiece W can be fixed while being maintained, so that adjacent wafers C do not come into contact with each other. Defects and damage situation.

Further, the present invention is not limited to the above embodiment, and can be implemented after various modifications. In the above-described embodiments, the size, shape, and the like shown in the drawings are not limited thereto, and can be appropriately changed within a range in which the effects of the present invention can be exerted. Others may be carried out with appropriate modifications without departing from the scope of the invention.

For example, in the wafer interval expansion step of the present embodiment, the workpiece W is divided into a plurality of wafers C by the expansion of the adhesive tape T, and a space is formed between the plurality of wafers C, but It is not limited to this configuration. For example, when the workpiece W has been divided, in the wafer interval expansion step, a space may be formed between the plurality of wafers C by the expansion of the adhesive tape T.

Further, in the present embodiment, the heating means 41 is formed by irradiating the adhesive tape T with far infrared rays to cause heat shrinkage, but the configuration is not limited thereto. The heating means 41 can be configured as long as it is possible to thermally shrink the adhesive tape T. Further, in the present embodiment, the heating means 41 is configured to follow the frame holding means 12, but is not limited to this configuration. The heating means 41 may be configured to heat the adhesive tape T in a state of being fixed to a predetermined height position above the holding table 11.

Further, in the present embodiment, the frame holding means 12 is configured to sandwich the annular frame F by the mounting table 31 and the cover 32, but the configuration is not limited thereto. The frame holding means 12 is only required to hold the annular frame F. For example, the frame holding means 12 is formed such that a clamp portion driven by an air actuator or the like is disposed around the mounting table 31 to maintain The configuration of the circumference of the annular frame F.

Industrial availability

As described above, the present invention has an effect of reliably removing the slack of the expanded adhesive tape in a short time, in particular, the expansion of the plurality of wafers of the small wafer and the large-diameter workpiece. The wafer spacing maintenance method of the state is useful.

11‧‧‧ Keeping the table

12‧‧‧Framework means

13‧‧‧Attraction source

14‧‧‧Switching valve

21‧‧‧Outer wall

22‧‧‧Support board

23‧‧‧Perforated plate

31‧‧‧ mounting table

32‧‧‧ Cover

34‧‧‧lifting cylinder

41‧‧‧heating means

C‧‧‧ wafer

F‧‧‧Ring frame

S‧‧‧relaxation

T‧‧‧Adhesive tape

W‧‧‧Processed objects

Claims (2)

A wafer spacing maintaining method for maintaining an interval between a plurality of wafers constituting a workpiece to be attached to an adhesive tape and attached to an annular frame, wherein the wafer spacing maintaining method comprises: a holding step of placing the workpiece through the adhesive tape on a holding table capable of attracting the workpiece, and holding the annular frame by the frame holding means; the wafer spacing expanding step, after performing the holding step, The holding table and the frame holding means are relatively moved in a vertical direction by a predetermined distance to push up the holding table relative to the frame holding means and stretch the adhesive tape to form a space between the plurality of wafers; a step of, after performing the wafer spacing expansion step, holding the workpiece by the adhesive tape on the holding table to maintain the interval between the adjacent wafers; and the wafer spacing fixing step, starting the suction retention After the step, the holding table and the frame holding means are relatively moved in a vertical direction to hold the means relative to the frame The push-up of the predetermined distance of the holding table is released in stages, and the workpiece and the stretched adhesive tape between the inner circumferences of the annular frame are heated at each stage to be staged. The adhesive tape is shrunk several times and the spacing between adjacent wafers is fixed. The wafer interval maintaining method of claim 1, wherein the intersection is set A plurality of slits are formed on the workpiece of the predetermined line, and a dividing start point is formed along the dividing line to divide the workpiece into a plurality of wafers and form a space between the wafers in the wafer spacing expansion step. .