JP2012129233A - Dividing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a case that when dividing a workpiece by expansion after an adhesive film is irradiated with ultraviolet rays, a part of the adhesive film on which the workpiece is not stuck is scattered or curled up, and fragments thereof result in riding on the workpiece.SOLUTION: When dividing a workpiece 1 stuck on an adhesive film 13 of an adhesive tape 11 formed of ultraviolet curable adhesive films 13 stacked on a base 12 into many devices 3, a dividing method includes: an ultraviolet ray irradiating step of irradiating only a part 13b of the adhesive film 13 which sticks to the workpiece 1 with the ultraviolet rays by using a mask 25 and curing only the part 13b; and a subsequent dividing step of expanding the adhesive tape 11 to divide the workpiece 1. The part 13a of the adhesive film 13 which does not stick to the workpiece 1 is not cured and the part 13a is suppressed from being scattered or curled up during extension of the tape.

Description

  The present invention relates to a dividing method suitable for use in dividing a workpiece such as a semiconductor wafer to obtain a large number of devices.

  In the semiconductor device manufacturing process, a large number of electronic circuits such as IC and LSI are formed on the surface of a substantially disk-shaped wafer made of semiconductor, and then the back surface of the wafer is ground and processed to a predetermined thickness. A large number of devices are divided from a single wafer by cutting a device region in which an electronic circuit is formed along a predetermined division line. In this type of wafer, a bonding adhesive film called DAF (Die Attach Film) having a thickness of several μm to 100 μm made of epoxy resin or the like is pasted on the back surface and divided together with the device. The device is bonded to a die bonding frame or the like through an adhesive film.

  On the other hand, as a method of dividing the workpiece such as the wafer, a division starting point is provided in advance along the planned division line, and an external force is applied to the planned division line by expanding the adhesive tape attached to the back surface of the workpiece. A method of dividing a work along a starting point is known (Patent Document 1). In this document, the adhesive tape attached to the work is attached to an annular frame, and the adhesive tape is expanded to give external force by separating the annular frame and the work in a direction perpendicular to the surface of the work. ing. Further, the division starting point is provided by forming a modified layer inside the workpiece by irradiating the inside of the workpiece with a laser beam having transparency so that the focusing point is aligned. Note that the adhesive tape generally has an adhesive layer formed on one side of the base, but since the device after splitting becomes easy to peel off, an adhesive layer that cures by UV irradiation and lowers the adhesive strength is used. What you have is considered useful.

  By the way, instead of adhering the adhesive film to the back surface of the wafer, as shown in FIG. 8, an adhesive film 103 similar to the DAF is laminated on the entire one surface of the base 102, and the back surface of the work 1 is laminated on the adhesive film 103. There is provided an adhesive tape 101 of the type in which the film is directly attached. In this pressure-sensitive adhesive tape 101, the annular frame 104 is attached to the pressure-sensitive adhesive layer 105 that is circularly laminated on the outer periphery of the adhesive film 103, the base 102 and the adhesive film 103 are expanded, and both the workpiece 1 and the adhesive film 103 are combined. Divided. Here, in order to facilitate peeling from the base 102, the adhesive film 103 is of a type in which the adhesive strength is reduced by being irradiated with ultraviolet rays in the same manner as the adhesive layer.

JP 2007-27250 A

  Thus, in order to attach and divide the workpiece 1 on the adhesive tape 101 shown in FIG. 8, after forming the division starting point along the planned division line of the workpiece 1, the base 102 side of the adhesive tape 101. Then, the adhesive film 103 is cured by irradiating ultraviolet rays to reduce the adhesive strength, and then the adhesive tape 101 is expanded to divide the workpiece 1 and the adhesive film 103. Here, when the pressure-sensitive adhesive tape 101 is expanded, the portion of the adhesive film 103 between the work 1 and the annular frame 104 (indicated by 103a in FIG. 8) is cured and the pressure-sensitive adhesive force is reduced. In some cases, such problems as turning up and the fragments falling on the workpiece 1 may occur.

  The present invention has been made in view of the above circumstances, and its main technical problem is to irradiate the adhesive film with ultraviolet light, and then to divide the work by expansion, the adhesive film where the work is not adhered. It is an object of the present invention to provide a dividing method in which the case where the debris is scattered or turned up and the fragments are placed on the workpiece is reduced.

  In the dividing method of the present invention, a sheet-like base, an adhesive film laminated on the entire surface of the base and cured by ultraviolet rays, an adhesive layer annularly laminated on the outer periphery of the adhesive film, and attached to the adhesive film A dividing method of dividing the workpiece of a workpiece unit composed of a workpiece smaller than the adhesive film and an annular frame attached to the adhesive layer along a division starting point formed on a division division line of the workpiece. And the ultraviolet irradiation process which irradiates only the location stuck to the work among the adhesive films, and cures the adhesive film, and the direction perpendicular to the surface of the work after the ultraviolet irradiation process The base is expanded by separating the work and the annular frame, and the work and the adhesive film are separated from each other at the division starting point formed on the planned division line. Characterized in that it comprises a a dividing step of dividing I.

  According to the present invention, the adhesive film after the ultraviolet irradiation step is cured only at the portion attached to the work and the adhesive force is reduced, while the portion not attached to the work remains in the original state. It is not cured with. For this reason, when the base is expanded in the splitting process, the part of the adhesive film that is not attached to the work is expanded following the base, and it is possible to prevent the fragments from being scattered or turned up. The case where it falls on is reduced.

The work referred to in the present invention is not particularly limited. For example, semiconductor wafers made of silicon, gallium arsenide (GaAs), silicon carbide (SiC), etc., semiconductor product packages, ceramics, glass, sapphire (Al ₂ O ₃ ) series Inorganic material substrates, various electronic components such as LCD drivers that control and drive liquid crystal display devices, and various processing materials that require micron-order processing position accuracy.

  According to the present invention, when the workpiece is divided by expansion after irradiating the adhesive film with ultraviolet rays, the adhesive film in a portion where the workpiece is not adhered is scattered or turned up, and the fragments are placed on the workpiece. Thus, there is an effect that a division method that reduces the number of cases is provided.

It is a perspective view of the work unit containing the workpiece | work divided | segmented with the division | segmentation method of one Embodiment of this invention. It is the perspective view which isolate | separated each component of the work unit. It is a side view of the work unit. It is sectional drawing which shows the state in which the modified layer was formed as a division | segmentation starting point inside a workpiece | work. It is a side view which shows the state which is performing the ultraviolet irradiation process of one Embodiment. It is a side view which shows the state which is performing the division | segmentation process of one Embodiment. It is a side view which shows the state by which the workpiece | work was divided | segmented into the device. It is a side view for demonstrating the conventional subject at the time of dividing | segmenting a workpiece | work.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(1) Work unit FIGS. 1-3 has shown the work unit 10 containing the disk-shaped workpiece | work 1 divided | segmented by applying the division | segmentation method of one Embodiment. This work unit 10 is positioned concentrically with the opening 14a of the annular frame 14 in a state where the surface of the work 1 is exposed to the adhesive tape 11 attached to the annular frame 14 via the adhesive layer 15, and the back surface 1b. Is affixed.

  As shown in FIG. 3, the adhesive tape 11 is formed by laminating an adhesive film 13 similar to the aforementioned DAF on the entire surface of one side of a sheet-like base 12. As shown in FIGS. 2 and 3, an adhesive layer 15 is annularly laminated on the outer periphery of the adhesive film 13, and an annular frame 14 is adhered to the adhesive layer 15. As the base 12 of the adhesive tape 11, a synthetic resin sheet having elasticity such as polyvinyl chloride, polypropylene, polyethylene, and polyolefin is used.

  The adhesive film 13 is made of an ultraviolet curable resin that is cured by being irradiated with ultraviolet rays and has reduced adhesive strength. Specific examples of the adhesive tape 11 comprising a combination of this type of adhesive film 13 and base 12 include a dicing die bonding tape (LE tape) manufactured by Lintec Corporation. The annular frame 14 has rigidity made of a plate material such as metal, and the work 1 is handled by supporting the annular frame 14.

  The workpiece 1 is a thin plate having a diameter smaller than that of the adhesive film 13, and is, for example, a semiconductor wafer made of silicon. As shown in FIG. 1, a large number of device regions 3 are partitioned on the surface 1a of the workpiece 1 by division lines 2 set in a lattice pattern, and electronic devices are formed in these device regions 3, for example. Yes. The workpiece 1 is cut along the division line 2 and divided into a number of device regions 3, that is, devices.

(2) Formation of division start point In dividing the work 1 in this embodiment, as shown in FIG. 4, a reformed layer 4 that is a division start point is formed in advance along the division planned line 2 inside the work 1. Keep it. The modified layer 4 can be formed by irradiating a laser beam having transparency from the surface 1a side of the work 1 with the converging point inside. The modified layer 4 referred to here is a region where the density, refractive index, mechanical strength, or other physical characteristics are different from the surroundings, such as a melt-treated layer, a crack layer, or an insulating layer. Examples thereof include a destructive layer and a refractive index changing layer, and further include a single state or a mixed state thereof.

  The division starting point is not limited to the modified layer 4, and a groove formed on the surface 1a of the workpiece 1 by cutting with a cutting blade, ablation processing by laser beam irradiation, or the like can be used as the division starting point.

(3) Division of Work Once the modified layer 4 is formed along the planned division line 2 inside the work 1, the work unit 10 is set in the ultraviolet irradiation means 20 as shown in FIG. The ultraviolet irradiation means 20 includes a UV lamp 22 that irradiates ultraviolet rays upward in a glass table 21 that transmits ultraviolet rays. For example, when the combination of the base 12 and the adhesive film 13 in the adhesive tape 11 is the LE tape, the ultraviolet irradiation means 20 emits ultraviolet rays to the object on the glass table 21 at an illuminance of 200 mW and a light amount of 400 mJ. What is irradiated is used.

  The work unit 10 is placed on the upper surface of the glass table 21 of the ultraviolet irradiation means 20 with the adhesive tape 11 side facing down and the work 1 is exposed upward. In this embodiment, the work unit 10 is bonded to the glass table. The work unit 10 is placed with a mask 25 that does not transmit ultraviolet rays between the tape 11 and the tape 11. A transmission hole 25 a having the same shape and size as the workpiece 1 is formed in the mask 25. The mask 25 is first placed on the upper surface of the glass table 21, and then the workpiece unit 10 is placed on the mask 25 and the workpiece 1. Is placed in correspondence with the transmission hole 25a. Thereby, only the location where adhesive tape 11 is stuck to work 1 to ultraviolet irradiation means 20 is exposed, and it will be in the state where locations other than this location were covered with mask 25.

  When the work unit 10 is placed on the glass table 21 of the ultraviolet irradiation means 20 via the mask 25 as described above, ultraviolet rays are irradiated upward from the UV lamp 22 (ultraviolet irradiation step). Then, only the ultraviolet rays that pass through the transmission holes 25 a of the mask 25 are irradiated to the adhesive tape 11. That is, ultraviolet rays are irradiated only on the portion 13b of the adhesive film 13 that is adhered to the workpiece 1, whereby only the portion 13b of the adhesive film 13 is cured and the adhesive strength is reduced. On the other hand, the part (except 13b) where ultraviolet rays were not irradiated by the mask 25 is maintained in its original state and is not cured.

  When the ultraviolet irradiation is finished, the workpiece 1 and the adhesive film 13 are divided from the modified layer 4 formed along the planned division line 2 (division step). The work 1 and the adhesive film 13 are divided by extending the base 12 of the adhesive tape 11 by separating the work 1 and the annular frame 14 in a direction perpendicular to the surface 1a of the work 1. Specifically, for example, as shown in FIG. 6, the work 1 is placed on the work placing table 30 having a circular upper surface via the adhesive tape 11, and the annular frame 14 is pushed down. Thereby, the adhesive tape 11 is expanded in the radial direction.

  When the adhesive tape 11 is expanded, the work 1 is divided into each device region 3, that is, the device 3 as shown in FIG. 7 starting from the modified layer 4, and is attached to the back surface 1 b of the work 1. The adhesive film 13 is also divided for each device 3 in a state of being adhered to the individual devices 3.

  When the workpiece 1 is divided into a large number of devices 3 with the adhesive film 13 in this way, the device 3 is peeled off from the base 12 together with the adhesive film 13. The device 3 is bonded to a die bonding frame or the like via the adhesive film 13. When the device 3 is peeled from the base 12, the adhesive film 13 attached to the workpiece 1 is cured by being irradiated with ultraviolet rays, and the adhesive strength is reduced. It has become.

(4) Effects of this embodiment According to this embodiment, the mask 25 is used in the ultraviolet irradiation step to irradiate only the portion 13b of the adhesive film 13 adhered to the workpiece 1 with ultraviolet rays, Only 13b is cured. And the adhesive film 13 of the location which was covered with the mask 25 and was not irradiated with an ultraviolet-ray maintains the original state, and does not harden | cure. For this reason, when the adhesive tape 11 is expanded in the dividing step, the portion of the adhesive film 13 that is not adhered to anything between the work 1 and the annular frame 14 (shown by 13a in FIGS. 5 and 6) It expands with the base 12. As a result, it is possible to prevent the adhesive film 13 at this portion 13a from being scattered or turned up, and the case where the debris is placed on the workpiece 1 is reduced.

  DESCRIPTION OF SYMBOLS 1 ... Work, 1a ... Work surface, 1b ... Back surface of work, 2 ... Planned division line, 4 ... Modified layer (division start point), 10 ... Work unit, 11 ... Adhesive tape, 12 ... Base, 13 ... Adhesion Film, 14 ... annular frame, 15 ... adhesive layer, 25 ... mask.

Claims (1)

A sheet-like base, an adhesive film laminated on the entire surface of the base and cured by ultraviolet rays, a pressure-sensitive adhesive layer annularly laminated on the outer periphery of the adhesive film, and a work smaller than the adhesive film attached to the adhesive film And a dividing method of dividing the work of a work unit consisting of an annular frame attached to the adhesive layer along a dividing starting point formed on a division line of the work,
An ultraviolet irradiation step of curing the adhesive film by irradiating ultraviolet rays only on the portion of the adhesive film that is adhered to the workpiece;
After the ultraviolet irradiation step, the base is expanded by separating the work and the annular frame in a direction perpendicular to the surface of the work, so that the work and the adhesive film are formed on the planned dividing line. A dividing step of dividing along the dividing start point;
A dividing method characterized by including:

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