JP5636266B2 - Workpiece processing method and dicing tape - Google Patents

Description

  In the present invention, after a rear surface side is irradiated with a laser beam from the rear surface side to the work whose back side is attached to the dicing tape to form a modified layer inside the work, an external force is applied to the modified layer. The present invention relates to a method for dividing a work into individual chips and a dicing tape suitable for carrying out the method.

  As a method of dividing a workpiece such as a semiconductor wafer or an optical device wafer along a street, there is a laser processing method in which a pulsed laser beam having transparency to a wafer is irradiated with a focusing point inside a region to be divided. Has been tried. The dividing method using this laser processing method is to irradiate a pulse laser beam having a wavelength that is transparent to the wafer by aligning the condensing point from one surface side of the wafer, and along the street along the street. The modified layer is continuously formed, and the workpiece is divided by applying an external force along the planned dividing line whose strength is reduced by the formation of the modified layer (for example, patent document). 1).

  The irradiation of the laser beam for forming the modified layer may be performed from the back side of the workpiece from the viewpoint of being able to cope with a workpiece having a narrow street street. In that case, the surface of the workpiece can be attached to the dicing tape and the laser beam can be irradiated from the back side. However, in order to pick up the individual chips after the division processing, all the chips are newly added to another tape. Must be pasted to. Therefore, from the viewpoint of avoiding such replacement and simplifying the process, the back surface of the workpiece is adhered to the dicing tape, and the laser beam is condensed from the back surface side of the workpiece through the dicing tape.

Japanese Patent No. 3408805

  However, when irradiating a laser beam through the dicing tape from the back side of the workpiece, the surface of the workpiece is generally held by the holding surface of the holding means of the laser processing apparatus. There was a problem of sticking to the holding surface.

  The present invention has been made in view of these facts, and the main technical problem thereof is a process of condensing a laser beam from the back side of a workpiece through a dicing tape attached to an annular frame. It is an object of the present invention to provide a workpiece processing method that can smoothly execute a process without sticking an adhesive surface of a dicing tape to a holding surface of a holding table.

  1st invention sticks the back surface of the workpiece | work in which the device was formed in the area | region divided by the division | segmentation line of the surface on the adhesive surface of the dicing tape arrange | positioned at the opening part of the cyclic | annular frame, and this workpiece | work is this cyclic | annular frame. A supporting step for supporting the opening of the workpiece, a holding step for sucking and holding the surface of the workpiece on the holding surface of the holding table for holding the workpiece after the supporting step, and a workpiece from the back side of the workpiece via the dicing tape after the holding step. A workpiece processing method including a processing step of forming a modified layer by irradiating a laser beam having a wavelength that passes through a predetermined division line, before the holding step, between the outer periphery of the workpiece and the inner periphery of the annular frame A release paper sticking process for sticking an annular release paper to the adhesive surface of the dicing tape corresponding to the region, a release paper peeling process for peeling the release paper after the processing process, and a peeling process. After extending the dicing tape and a dividing step of dividing along the workpiece dividing lines.

  According to a second aspect of the present invention, the back surface of the work on which the device is formed in the area defined by the division lines on the front surface is attached to the adhesive surface of the dicing tape disposed in the opening of the annular frame, and the work is attached to the annular frame. A supporting process for supporting the opening, a holding process for sucking and holding the surface of the work on the holding surface of the holding table that holds the work after the supporting process, and a work from the back side of the work via the dicing tape after the holding process. The present invention relates to a dicing tape used in a workpiece processing method including a processing step of forming a modified layer by irradiating a laser beam having a transmitted wavelength along a predetermined division line. An annular release paper is attached to the adhesive surface corresponding to the area between the two.

  In the workpiece processing method according to the present invention, an annular release paper is attached to the adhesive surface of the dicing tape in a region between the outer periphery of the workpiece and the inner periphery of the annular frame, and the surface side of the workpiece is held in this state. Therefore, even if the adhesive surface is held face down, the adhesive surface is not directly in contact with the holding table because release paper is stuck to the adhesive surface. . Therefore, the adhesive surface does not stick to the holding table, and the process can be executed smoothly.

  In the dicing tape according to the present invention, since the annular release paper is attached to the adhesive surface corresponding to the region between the outer periphery of the workpiece and the inner periphery of the annular frame, the workpiece processing method is performed. It is suitable for.

It is a disassembled perspective view which shows the release paper stuck to the workpiece | work supported by the cyclic | annular frame via the dicing tape, and the dicing tape. It is sectional drawing which shows schematically the state which sticks a release paper on a dicing tape, and sticks a protective tape on a workpiece | work. It is sectional drawing which shows roughly the state which reversed the front and back of the workpiece | work. It is sectional drawing which shows roughly the state which mounted the workpiece | work which reversed the front and back on the holding table. It is sectional drawing which shows schematically the state which hold | maintained the workpiece | work which reversed the front and back to the holding table. It is a perspective view which shows the state which irradiates a laser beam from the back surface side of a workpiece | work. It is sectional drawing which shows schematically the state which irradiates a laser beam from the back surface side of a workpiece | work. It is sectional drawing which shows schematically the workpiece | work in which the modified layer was formed in the inside. It is sectional drawing which shows schematically the state which peels a release paper from a dicing tape, and peels a protective tape from a workpiece | work. It is sectional drawing which shows schematically the state which divided | segmented the workpiece | work into each device.

(1) Supporting Process A dividing line 100 is formed vertically and horizontally on the surface 10 of the workpiece 1 shown in FIG. 1, and a device 101 is formed in a region partitioned by the dividing line 100. The back surface 11 of the workpiece 1 is attached to the adhesive surface 20 of the dicing tape 2 having a larger diameter than the workpiece 1. An annular frame 3 is attached to the peripheral edge of the adhesive surface 20 of the dicing tape 2, and the dicing tape 2 is disposed in a state of closing the opening 30 formed in the annular frame 3, and the workpiece W is annular. The state is supported at the opening 30 of the frame 3.

  The workpiece W is not particularly limited. For example, a semiconductor wafer such as a silicon wafer, gallium arsenide, or silicon carbide, an adhesive member such as DAF (Die Attach Film) provided on the back surface of the wafer for chip mounting, a semiconductor product Examples include various electronic components such as packages, ceramics, glass, sapphire-based inorganic material substrates, liquid crystal display drivers, and various processing materials that require processing position accuracy on the micron order.

(2) Release paper sticking process As shown in FIG.1 and FIG.2, the exposed part 200 where the workpiece | work 1 and the cyclic | annular flame | frame 3 are not stuck exists in the adhesion surface 20 of the dicing tape 2. FIG. The exposed portion 200 is an exposed portion corresponding to a region between the outer periphery 12 of the work 1 and the inner periphery 31 of the annular frame F, and is formed in an annular shape.

  As shown in FIG.1 and FIG.2, the cyclic | annular release paper 4 corresponding to the shape is stuck to the exposed part 200. FIG. The release paper 4 has the same width W1 in the radial direction of the release paper 4 shown in FIG. 2 as the radial width W2 of the exposed portion 200, and is the same as the exposed portion 200 so that the release paper 4 can completely cover the exposed portion 200. Although it is desirable to have a shape, the radial width W1 of the release paper 4 is shorter than the radial width W2 of the exposed portion 200, and a part of the exposed portion 200 is exposed when pasted. It may be a shape.

  When the surface of the workpiece 1 cannot be directly held on the holding surface 60 from the viewpoint of protecting the device 101, the device 101 formed on the surface 10 is protected on the surface 10 of the workpiece 1 as shown in FIG. You may stick the protective tape 5 for doing.

  The release paper sticking step is performed before the holding step described later. Note that the release paper 4 can be attached to the exposed portion 200 before the back surface 11 of the work 1 is attached to the dicing tape 2. That is, you may make it perform a release paper sticking process prior to a support process.

(3) Holding process When the release paper sticking process is performed after the support process, after the release paper sticking process, after the support process when the release paper sticking process is performed before the support process, 3, the front and back of the workpiece 1 are reversed together with the annular frame 3, and the workpiece 1 is held on the holding table 6 of the laser processing apparatus. The holding table 6 has a holding surface 60 for sucking and holding the workpiece. A frame fixing portion 61 for fixing the annular frame F is fixedly provided on the outer peripheral side of the holding table 6. The frame fixing portion 61 includes a base portion 610 extending in the horizontal direction from the lower portion of the holding table 6, and a pressing member 611 that rotates about a horizontal rotation axis with respect to the base portion 610, and the pressing member 611 is an arrow A It is possible to hold the frame 3 by rotating in this direction and pressing the annular frame 3 downward. The holding table 6 and the frame fixing part 61 are movable in the horizontal direction.

  As shown in FIG. 4, the protective tape 5 side is placed on the holding table 6, and the work 1 is sucked and held on the holding surface 60 via the protective tape 5. Then, as shown in FIG. 5, the frame F is sandwiched between the pressing member 611 and the upper surface of the base 610. Then, as shown in an enlarged view in FIG. 5, the release paper 4 comes into contact with the holding table 6, and the adhesive surface 20 of the dicing tape 2 is prevented from coming into direct contact with the holding table 6. Therefore, the adhesive surface 20 does not stick to the holding table 6 and the process can be executed smoothly. The release paper 4 does not need to cover the entire exposed portion 200 as long as it is attached to at least a portion that contacts the holding table 6.

(4) Processing step Laser processing is performed on the workpiece after the holding step. Prior to laser processing, the division line 100 shown in FIG. 1 formed on the front surface 10 of the workpiece 1 is detected from the back surface 11 side by infrared imaging through the dicing tape 2 or the like. Then, the holding table 6 and the frame fixing unit 61 are moved in the horizontal direction, and as shown in FIG. 6, a laser beam 7a having a wavelength that transmits the workpiece W is irradiated from the irradiation head 7 of the laser processing apparatus toward the workpiece W. . As shown in FIG. 7, the laser beam 7 a is incident from the back surface 11 side of the workpiece 1 through the dicing tape 2 and is condensed inside the workpiece W.

  When laser beam irradiation is performed in this way along all the division lines 100 shown in FIG. 1, the modified layer 13 is formed along the division line 100 inside the work 1 as shown in FIG. It is formed. The modified layer 13 refers to a region where the density, refractive index, mechanical strength, and other physical characteristics are different from the surroundings. The modified layer includes, for example, a) a melt treatment region, a) a crack region, a dielectric breakdown region, and c) a refractive index change region, and there are also regions where these are mixed.

(5) Release paper peeling process Next, as shown in FIG. 9, the release paper 4 is peeled from the exposed part 200 of the adhesive surface 20 of the dicing tape 2. The protective tape 5 is also peeled off from the surface 10 of the work 1. Then, the exposed portion 200 of the dicing tape 2 and the surface 10 of the work 1 are exposed.

(6) Dividing Step After the release paper peeling step, the dicing tape 2 is expanded in the surface direction of the workpiece 1 to divide the chip 14 for each device in the modified layer 13 formed along the division line L. To do. Since the release paper 4 is peeled off in the release paper peeling step before the dividing step, no trouble occurs when the dicing tape 2 is expanded.

1: Workpiece 10: Front surface 100: Divided line 101: Device 11: Back surface 12: Outer periphery 13: Modified layer 2: Dicing tape 20: Adhesive surface 200: Exposed portion 3: Ring frame 30: Opening portion 31: Inner periphery 4 : Release paper 5: Protection tape 6: Holding table 60: Holding surface 61: Frame fixing part 610: Base part 611: Pressing member 7: Irradiation head 7a: Laser beam

Claims (2)

Attach the back side of the work on which the device is formed in the area defined by the division lines on the front surface to the adhesive surface of the dicing tape provided in the opening of the annular frame, and support the work on the opening of the annular frame A supporting process to
After the supporting step, a holding step for holding the surface of the work by suction on the holding surface of the holding table for holding the work;
After the holding step, a processing step of forming a modified layer by irradiating a laser beam having a wavelength that passes through the workpiece from the back side of the workpiece through the dicing tape along the planned division line;
A method of machining a workpiece including
Before the holding step, a release paper adhering step of adhering an annular release paper to the adhesive surface of the dicing tape corresponding to a region between the outer periphery of the work and the inner periphery of the annular frame;
A release paper peeling step for peeling the release paper after the processing step;
After the peeling step, the workpiece processing method includes a dividing step of expanding the dicing tape and dividing the workpiece along the division planned line. Attach the back side of the work on which the device is formed in the area defined by the division lines on the front surface to the adhesive surface of the dicing tape provided in the opening of the annular frame, and support the work on the opening of the annular frame A supporting process to
After the supporting step, a holding step for holding the surface of the work by suction on the holding surface of the holding table for holding the work;
After the holding step, a processing step of forming a modified layer by irradiating a laser beam having a wavelength that passes through the workpiece from the back side of the workpiece through the dicing tape along the planned division line;
A dicing tape used in a workpiece processing method including:
A dicing tape in which an annular release paper is attached to an adhesive surface corresponding to a region between the outer periphery of a workpiece and the inner periphery of the annular frame.

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