JP5657946B2 - Split method - Google Patents

Description

  The present invention relates to a dividing method for dividing a workpiece having a metal film laminated on the back surface side along a planned dividing line formed on the front surface side.

  In the semiconductor device manufacturing process, a plurality of areas are defined by division lines arranged in a lattice pattern on the surface side of a substantially disk-shaped semiconductor wafer, and devices such as ICs and LSIs are formed in the partitioned areas. The Each device is manufactured by dividing each region by cutting the semiconductor wafer along the planned dividing line. Similarly, an optical device wafer in which light-emitting elements such as light-emitting diodes are stacked on the surface of a sapphire substrate is cut into individual optical devices along a predetermined division line.

  As a dividing method for dividing a workpiece such as a semiconductor wafer or an optical device wafer along a predetermined division line, a laser processing method is known (see Patent Document 1). In this laser processing method, a laser beam having a wavelength that is transmissive to the workpiece is irradiated from one side of the workpiece to the inside of the workpiece, so that the inside of the workpiece is improved along the division line. A quality layer is continuously formed. Then, by applying an external force (displacement amount) to the workpiece along the planned division line whose strength has been reduced by forming the modified layer, the workpiece is divided along the planned division line.

Japanese Patent No. 3408805

  By the way, when a conventional laser processing method is used to divide a workpiece having a metal film laminated on the back side of an optical device wafer or the like, when an external force is applied to the workpiece, the substrate is hard and brittle, so it is quickly broken. The metal film is not easily broken because it has ductility. For this reason, when a work having a metal film laminated on the back side is divided using a conventional laser processing method, it is necessary to apply a larger external force to the work in order to break the metal film. However, when the external force applied to the workpiece is increased, the stress applied to the fulcrum of the workpiece increases, or the device located on both sides of the planned dividing line comes into contact with the adjacent device, resulting in damage to the device. There was a thing.

  The present invention has been made in view of the above problems, and an object thereof is to provide a dividing method capable of dividing a workpiece in which a metal film is laminated on the back surface side without increasing the amount of displacement given to the workpiece. It is in.

In order to solve the above problems and achieve the object, the dividing method according to the present invention is a dividing method for dividing a work in which a metal film is laminated on the back surface side of a substrate having a dividing line on the front surface side, A step of attaching a protective tape to the back side of the workpiece, and a laser beam having a wavelength that passes through the substrate from the front side of the workpiece is irradiated along the division line to form a modified layer inside the substrate. A step of forming and a pressing blade extending in the same direction as the planned dividing line on the back side of the planned dividing line on which the modified layer is formed, and straddling the planned dividing line and the pressing blade A first dividing step of dividing the substrate on the line to be divided by applying pressure to the pressing blade in a state where a supporting blade is set on the surface side, and the pressing after the first dividing step. the dividing la adjoining the blade and the support blade The shearing force is generated by applying pressure to the pressing blade in a state where the support blade is set on the surface side across the line to be divided and the pressing blade. A second dividing step of dividing the metal film.

  According to the dividing method of the present invention, it is possible to divide a work in which a metal film is laminated on the back surface side without increasing the amount of displacement applied to the device.

FIG. 1 is a perspective view showing a configuration of a work to which a dividing method according to an embodiment of the present invention is applied. FIG. 2 is a cross-sectional view of a workpiece in a direction orthogonal to a planned dividing line for explaining a dividing method according to an embodiment of the present invention, and is a diagram for explaining an attaching process. FIG. 3 is a cross-sectional view of a workpiece in a direction orthogonal to a planned dividing line for explaining a dividing method according to an embodiment of the present invention, and is a view for explaining a modified layer forming step. FIG. 4 is a cross-sectional view of the workpiece in a direction perpendicular to the planned dividing line for explaining the dividing method according to the embodiment of the present invention, and is a view for explaining the first dividing step. FIG. 5 is a cross-sectional view of a workpiece in a direction orthogonal to a planned dividing line for explaining a dividing method according to an embodiment of the present invention, and is a diagram for explaining a second dividing step.

  Hereinafter, a dividing method according to an embodiment of the present invention will be described with reference to the drawings.

[Work structure]
First, with reference to FIG. 1, the structure of the workpiece | work to which the division | segmentation method which is this Embodiment is applied is demonstrated.

  FIG. 1 is a perspective view showing a configuration of a work to which a dividing method according to an embodiment of the present invention is applied. As shown in FIG. 1, a grid-like division planned line 11 is formed on the surface 1 a side of the work 1 to which the division method according to an embodiment of the present invention is applied, and each area partitioned by the division planned line 11. A light emitting element portion 100 is formed on the substrate. A metal film (not shown) for reflecting light emitted from the light emitting element unit 100 is laminated on the back side of the work 1.

[Division method]
Next, a division method for dividing the workpiece 1 shown in FIG. 1 along the planned division line 11 will be described with reference to FIGS.

  FIG. 2 is a cross-sectional view of a workpiece in a direction orthogonal to a planned dividing line for explaining a dividing method according to an embodiment of the present invention, and is a diagram for explaining an attaching process. FIG. 3 is a cross-sectional view of a workpiece in a direction orthogonal to a planned dividing line for explaining a dividing method according to an embodiment of the present invention, and is a view for explaining a modified layer forming step. FIG. 4 is a cross-sectional view of the workpiece in a direction perpendicular to the planned dividing line for explaining the dividing method according to the embodiment of the present invention, and is a view for explaining the first dividing step. FIG. 5 is a cross-sectional view of a workpiece in a direction orthogonal to a planned dividing line for explaining a dividing method according to an embodiment of the present invention, and is a diagram for explaining a second dividing step.

  When dividing the workpiece 1 shown in FIG. 1 along the planned dividing line 11, first, as shown in FIG. 2, a protective tape 102 is attached on the metal film 101 laminated on the back side of the workpiece 1. Do (sticking process). The protective tape 102 is in the form of a sheet having an area larger than that of the work 1, and includes, for example, a resin tape main body and an adhesive layer that are deformed so as to expand when pulled. In FIG. 1, reference numerals 11 a to 11 c indicate division planned lines.

  Next, the work 1 is placed and held on a chuck table of a well-known laser processing apparatus (not shown) so that the surface 1a side of the work 1 faces the pulse laser beam irradiation port. Then, a pulsed laser beam having a wavelength having transparency to the substrate 1b is irradiated along the planned division lines 11a to 11c from the surface 1a side of the workpiece 1 to the inside of the substrate 1b on which the workpiece 1 is formed. Modified layer forming step). As a result, as shown in FIG. 3, the modified layer 104 is formed inside the substrate 1b on which the workpiece 1 is formed along the scheduled division lines 11a to 11c.

  Next, as shown in FIG. 4, the position on the protective tape 102 corresponding to the division lines 11a to 11c to be divided on which the modified layer 104 is formed (in the example shown in FIG. The pressing blades 112 extending in the same direction as the division lines 11a to 11c (in the direction perpendicular to the paper surface in FIG. 4) are arranged at corresponding positions on the protective tape 102, and both sides of the division lines 11a to 11c to be divided ( In the example shown in FIG. 4, a pair of support blades 111 a and 111 b that support the workpiece 1 are arranged on both sides of the planned division line 11 b. Then, by applying an external force (pressure) to the work 1 by the pressing blade 112 with a contact point between the support blades 111a and 111b and the surface 1a of the work 1 as a fulcrum, division lines 11a to 11c (in the example shown in FIG. The workpiece 1 is displaced along the planned line 11b) (first division step). Thereby, the board | substrate 1b which forms the workpiece | work 1 is fractured | ruptured along the division | segmentation planned lines 11a-11c.

  Next, as shown in FIG. 5, the arrangement positions of the pressing blade 112 and the support blades 111 a and 111 b are arranged on the adjacent division line 11 side (in the example shown in FIG. 5, the direction of arrow A on the adjacent division line 11 a side). ). Then, in the same manner as in the first dividing step, an external force is applied to the workpiece 1 by the pressing blade 112 with a contact point between the support blades 111a and 111b and the surface 1a of the workpiece 1 as a fulcrum (second dividing step). That is, a device on one side of the planned division line 11 (in the example shown in FIG. 5, the planned division line 11b) is obtained by shifting the fulcrum to the adjacent division planned line 11 side after the first division step and applying external force to the work 1 again. The external force is applied only to the device 100a) on the side of the device. As a result, a shear force F is applied to the metal film 101, and the metal film 101 is broken. Thereby, the workpiece | work 1 can be divided | segmented along the division planned line 11 (In the example shown in FIG. 5, the division planned line 11b.).

  As is clear from the above description, the dividing method according to an embodiment of the present invention includes a sticking step of sticking the protective tape 102 on the back side of the work 1 and the substrate 1b from the front surface 1a side of the work 1 A modified layer forming step of forming a modified layer 104 inside the substrate 1b by irradiating a laser beam having a wavelength to be divided along the scheduled division line 11, and a division schedule to be divided on which the modified layer 104 is formed A first dividing step of setting a pressing blade 112 extending in the same direction as the division line 11 on the back side of the line 11 and dividing the substrate 1b on the division line 11 by applying pressure to the pressing blade 112; After one division step, the pressing blade 112 is set so as to be shifted to the adjacent division planned line 11 side, and the support blades 111a and 111 are placed on the surface 1a side of the workpiece 1 across the division planned line 11 and the pressing blade 112. Including, a second dividing step of dividing the metal film 101 on the dividing line 11 shearing force is generated by applying pressure to the pressing blade 112 in a state of setting the.

  That is, in the dividing method according to an embodiment of the present invention, the work in which the metal film 101 is laminated on the back surface side by two steps of breaking the substrate 1b forming the work 1 and breaking the metal film 101 is performed. 1 is divided along the division line 11. According to such a dividing method, a large shearing force can be applied to the metal film 101 even with a small amount of displacement, so that the metal film 101 can be easily broken, and as a result, the amount of displacement applied to the workpiece 1. The workpiece 1 having the metal film 101 laminated on the back side can be divided without increasing the size.

  The embodiment to which the invention made by the present inventors has been described has been described above, but the present invention is not limited by the description and drawings that form part of the disclosure of the present invention according to the above embodiment. That is, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Work 1a Surface 1b Substrate 11,11a-11c Scheduled division line 100 Light emitting element part 101 Metal film 102 Protective tape 104 Modified layer 111a, 111b Support blade 112 Press blade F Shear force

Claims (1)

A dividing method for dividing a work in which a metal film is laminated on the back side of a substrate having a division planned line on the front side,
Attaching a protective tape to the back side of the workpiece;
Irradiating a laser beam having a wavelength that passes through the substrate from the surface side of the workpiece along a line to be divided to form a modified layer inside the substrate;
A pressing blade extending in the same direction as the planned dividing line is set on the back side of the planned dividing line on which the modified layer is formed, and on the front surface side across the dividing planned line and the pressing blade. A first dividing step of dividing the substrate on the division line by applying pressure to the pressing blade in a state where the support blade is set ;
After the first dividing step, the pressing blade and the supporting blade are set to be shifted to the adjacent dividing line side, and the supporting blade is set on the surface side across the dividing line and the pressing blade. A second dividing step in which a shearing force is generated by applying pressure to the pressing blade in a state where the metal film on the division line is divided;
A dividing method characterized by including:

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