JP2014041885A - Wafer processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer processing method capable of removing a resin protruding from a wafer to suppress resin dispersion in an etching step.SOLUTION: A wafer processing method includes the steps of: removing a chamfering part of a wafer W (chamfering part removing step); disposing a carrier plate P on a surface WS of the wafer via a resin J (carrier plate disposing step); detecting a depth of a Via electrode E (Via electrode detecting step); grinding a rear surface WR of the wafer (rear surface grinding step); protruding the Via electrode E by etching (etching step); and removing at least a resin JA protruding from an outer periphery of the wafer W in the resin J by cleaning the rear surface WR of the carrier plate P and a rear surface WR (cleaning step). The cleaning step is performed after the rear surface grinding step and before the etching step.

Description

  The present invention relates to a method for processing a wafer in which a Via electrode is embedded.

  In recent years, as a new three-dimensional mounting technology, a plurality of semiconductor chips are stacked, a through electrode (via electrode) penetrating the stacked semiconductor chips is formed, and a semiconductor chip is connected to each other, or a plurality of semiconductor wafers are stacked. A lamination technique (TSV: Through Silicon Via) for connecting semiconductor wafers by forming through electrodes penetrating the laminated semiconductor wafers is being developed (for example, see Patent Documents 1 and 2).

JP 2004-207606 A JP 2005-136187 A

  However, in the TSV process, there is a problem that when the wafer is bonded to the substrate with the resin, the resin protrudes from the outer periphery of the wafer, and the resin protruding in the etching process is scattered during the etching and adheres to the wafer surface.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a wafer processing method for removing the protruding resin in order to suppress scattering of the resin in the etching process.

  In order to solve the above-mentioned problems and achieve the object, a wafer processing method according to the present invention is characterized in that a plurality of devices are partitioned on a surface of a semiconductor substrate by lines to be divided, and the semiconductor substrate is separated from the device electrodes. A wafer processing method for dividing a wafer having a device region having a Via electrode embedded toward the back surface of the wafer and a chamfered portion in an outer peripheral surplus region surrounding the device region into individual devices, the outer peripheral surplus region A chamfered portion removing step of positioning a cutting blade at a predetermined depth to remove a chamfered portion, a carrier plate arranging step of arranging a carrier plate on the surface of the wafer via a resin, and a via electrode from the back surface of the wafer Via electrode detection process for detecting the depth of the wafer, and grinding and thinning the back surface of the wafer to the extent that the Via electrode is not exposed on the back surface A surface grinding step, an etching step of projecting a via electrode by etching a semiconductor substrate from the back surface of the wafer, an insulating film coating step of covering the back surface of the wafer with an insulating film, and a via electrode protruding from the back surface is shaved from the insulating film Finishing process of exposing and finishing the head of the Via electrode on the same surface as the insulating film, bump arranging process of arranging the bump on the head of the Via electrode, and attaching a dicing tape on the back surface of the wafer and from the surface of the wafer A transfer step of removing the carrier plate and transferring the wafer to a dicing tape, and after the back grinding step and before the etching step, a part of the resin used in the carrier plate disposing step is chamfered. Protruding from the outer periphery of the wafer, and supporting the outer periphery of the wafer, In the cleaning step of cleaning the back surface of the catcher rear plate, and removing at least that protruding resin.

  Since the present invention removes at least the resin protruding from the outer periphery of the wafer before the etching step, the resin attached to the wafer in the etching step can be prevented from scattering.

  In addition, in the cleaning process before the etching process, at least the resin protruding from the outer periphery of the wafer is removed, so there is no need to provide a separate dedicated process for removing the protruding resin, and productivity is not reduced. .

FIG. 1 is a view showing a wafer to be processed by the wafer processing method according to the embodiment. FIG. 2 is a cross-sectional view showing a chamfer removal step of the wafer processing method according to the embodiment. FIG. 3 is a cross-sectional view illustrating a carrier plate disposing step of the wafer processing method according to the embodiment. FIG. 4 is a cross-sectional view illustrating a Via electrode detection step of the wafer processing method according to the embodiment. FIG. 5 is a cross-sectional view illustrating a back surface grinding step of the wafer processing method according to the embodiment. FIG. 6 is a cross-sectional view showing a cleaning process of the wafer processing method according to the embodiment. FIG. 7 is a cross-sectional view showing an etching process of the wafer processing method according to the embodiment. FIG. 8 is a cross-sectional view showing an insulating film coating step of the wafer processing method according to the embodiment. FIG. 9 is a cross-sectional view illustrating a finishing process of the wafer processing method according to the embodiment. FIG. 10 is a cross-sectional view showing a bump disposing step of the wafer processing method according to the embodiment. FIG. 11 is a cross-sectional view illustrating a transfer process of the wafer processing method according to the embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

  A wafer processing method (hereinafter simply referred to as a processing method) according to the present embodiment will be described with reference to FIGS. FIG. 1A is a perspective view showing a wafer processed by the processing method according to the embodiment, and FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. FIG. 2 is a cross-sectional view showing an outline of a chamfered portion removing step for removing the chamfered portion of the wafer shown in FIG. 1A, and FIG. 3 shows a carrier plate attached to the wafer shown in FIG. FIG. 4 is a cross-sectional view showing an outline of the carrier plate arrangement process, FIG. 4 is a cross-sectional view showing an outline of the Via electrode detection process for detecting the depth of the Via electrode of the wafer shown in FIG. 3, and FIG. FIG. 6 is a cross-sectional view showing an outline of a back surface grinding process for grinding the back surface of the wafer on which the carrier plate shown in FIG. 4 is disposed, and FIG. 6 shows the back surface of the wafer and the carrier plate shown in FIG. It is sectional drawing which shows the outline | summary of the washing | cleaning process to wash | clean FIG. 7 is a cross-sectional view showing an outline of an etching process for etching the back surface of the wafer shown in FIG. 6, and FIG. 8 shows an insulating film coating for covering the back surface of the wafer shown in FIG. FIG. 9 is a cross-sectional view showing an outline of the process, FIG. 9 is a cross-sectional view showing an outline of the finishing process for exposing the head of the Via electrode of the wafer shown in FIG. 8, and FIG. 10 is shown in FIG. FIG. 11 is a cross-sectional view showing an outline of a bump disposing process for disposing a bump on the head of a via electrode of a wafer, and FIG. 11 is a cross-sectional view showing an outline of a transfer process for transferring the wafer shown in FIG. 10 to a dicing tape. FIG.

  The processing method according to the present embodiment is a processing method for dividing the wafer W shown in FIG.

  Note that a wafer W (corresponding to a semiconductor substrate) to be divided into individual devices D by the processing method according to the present embodiment is a disk whose base material is silicon, sapphire, gallium, or the like in this embodiment. Semiconductor wafer or optical device wafer. In the wafer W, as shown in FIG. 1A, a plurality of devices D are partitioned on the surface WS by a division line S. Further, as shown in FIG. 1B, the wafer W includes a device region DR having a via electrode E embedded from the electrode of the device D toward the back surface WR, and a device region DR as shown in FIG. A chamfered portion C is provided in the outer peripheral surplus region GR that surrounds the region DR. The Via electrode E is made of a metal such as copper, and an end surface is exposed on the surface WS side of the wafer W, and is embedded from the surface WS toward the back surface WR up to the center in the thickness direction of the wafer W.

  The processing method according to the present embodiment includes a chamfered portion removing process, a carrier plate arranging process, a Via electrode detecting process, a back grinding process, an etching process, an insulating film coating process, a finishing process, and a bump arranging. At least a process and a transfer process.

  In the processing method according to this embodiment, first, in the chamfered portion removing step, as shown in FIG. 2, the back surface WR of the wafer W is placed on the chuck table 2 of the cutting apparatus 1 and the wafer W is held on the chuck table 2. To do. Then, the chuck table 2 of the cutting device 1 is rotated around the axis together with the wafer W, and the cutting blade 3 is rotated by a spindle (not shown) of the cutting device 1. Then, the cutting blade 3 is positioned on the outer peripheral surplus region GR, the cutting blade 3 is lowered by a predetermined depth, the outer peripheral portion of the wafer W is cut to a predetermined depth, and the chamfered portion C is removed. In this embodiment, the chamfered portion C is removed from the surface WS side by about half of the thickness of the chamfered portion C. In the present invention, at least a part of the chamfered portion C may be removed in the chamfered portion removing step. . And it progresses to a carrier plate arrangement | positioning process.

  In the carrier plate disposing step, as shown in FIG. 3, an adhesive resin J is attached to the surface WS of the wafer W, and a carrier plate P is further attached to the resin J. Thus, the carrier plate P is disposed on the surface WS of the wafer W via the resin J. In addition, as a material constituting the resin J, for example, a UV curing type that cures when irradiated with ultraviolet rays, an epoxy resin or an acrylic resin that cures when heated, and the carrier plate P has a chamfered outer diameter is removed. It is formed in a disk shape substantially equal to the outer diameter of the wafer W after the process. Further, when the carrier plate P is disposed on the surface WS of the wafer W via the resin J, as shown in FIG. 3, a part of the resin J (the protruding resin is replaced with another resin). Is indicated by the symbol JA below) and protrudes from the outer periphery of the wafer W after the chamfered portion C is removed. And it progresses to a Via electrode detection process.

  In the Via electrode detection process, as shown in FIG. 4, the carrier plate P disposed on the wafer W via the resin J is placed on the chuck table 11 of the electrode detection device 10, and the wafer W is held on the chuck table 11. To do. Then, near-infrared light or infrared light that passes through the wafer W is irradiated from the scanner unit 12 of the electrode detection device 10 toward the back surface WR of the wafer W, and the front surface WS of the wafer W and the back surface WR side of the Via electrode E The scanner unit 12 is moved along the back surface WR while receiving the light reflected from the end surface Ea of the wafer W and the back surface WR of the wafer W. Then, based on the refractive index of the wafer W, the depth H of the end surface Ea on the back surface WR side of the Via electrode E from the back surface WR of the wafer W is detected. And it progresses to a back surface grinding process.

  In the back grinding process, as shown in FIG. 5, the carrier plate P disposed on the wafer W via the resin J is placed on the chuck table 21 of the grinding device 20, and the wafer W is held on the chuck table 21. . Then, the chuck table 21 of the grinding device 20 is rotated around the axis together with the wafer W, and the grinding wheel 22 of the grinding device 20 is brought into contact with the back surface WR of the wafer W while rotating around the axis in the same direction as the chuck table 21. . Then, based on the depth H of the end surface Ea on the back surface WR side of the Via electrode E detected in the Via electrode detection step, the grinding wheel 22 is moved downward at a predetermined feed rate so that the end surface Ea of the Via electrode E is not exposed. A predetermined amount is ground and fed, and the back surface WR of the wafer W is ground by the grinding wheel 22 to thin the wafer W. Then, half the thickness of the wafer W is removed, and the chamfered portion C is removed.

  In the etching process, the back surface WR side of the wafer W that has been ground in the back surface grinding process is etched by plasma etching or the like, and the back surface WR of the wafer W is dissolved and etched. Then, as shown in FIG. 7, the end surface Ea of the Via electrode E is protruded from the back surface WR of the wafer W. Then, the process proceeds to the insulating film coating step.

  In the insulating film coating step, as shown in FIG. 8, the back surface WR of the wafer W is coated with an insulating film Z that covers the back surface WR and the end surface Ea of the Via electrode E. Note that the thickness of the insulating film Z is uniform. Then, the process proceeds to the finishing process.

  In the finishing process, as shown in FIG. 9, the carrier plate P disposed on the wafer W via the resin J is placed on the chuck table 31 of the grinding device 30, and the wafer W is held on the chuck table 31. Then, the chuck table 31 of the grinding device 30 is rotated around the axis together with the wafer W, and the back surface WR of the wafer W is coated while the grinding wheel 32 of the grinding device 30 is rotated around the axis in the same direction as the chuck table 31. Contact with the insulating film Z. The grinding wheel 32 is ground by a predetermined amount at a predetermined feed rate, and the insulating film Z on the end surface Ea of the Via electrode E and the Via electrode E protruding from the back surface WR are ground by the grinding wheel 32 to be removed from the insulating film Z. The head Eb of the Via electrode E is finished on the same surface as the insulating film Z while being exposed. Note that the grinding device 30 used in the finishing process may be the same as or different from the grinding device 20 used in the back surface grinding process, and a part of the configuration may be the same and the rest may be different. . And it progresses to a bump arrangement | positioning process.

  In the bump disposing step, the bump V is disposed on the head Eb of each Via electrode E as shown in FIG. Then, the process proceeds to the transfer process. In the transfer step, the wafer W is reversed for each carrier plate P, and the dicing tape T with the annular frame F attached to the outer edge portion is attached to the back surface WR of the wafer W via the bumps V. Then, the resin J is cured, for example, and the carrier plate P is removed together with the resin J from the surface WS of the wafer W, and the wafer W is transferred from the carrier plate P to the dicing tape T as shown in FIG. Thereafter, the wafer W is divided into individual devices D by cutting or laser processing.

  Moreover, the processing method of this embodiment includes a cleaning step. The cleaning process is performed after the back grinding process and before the etching process. In the cleaning process, as shown in FIG. 6, the wafer W is a wafer W in which a carrier plate P is disposed via a resin J between edge clamps 41 that are rotatable around a plurality of axes of the cleaning device 40. The carrier plate P is sandwiched so that the carrier plate P is located on the lower side. Then, the resin JA (corresponding to a part of the resin) protruding from the outer periphery of the chamfered wafer W in the resin J used in the carrier plate arranging step is the outer peripheral surface in the center of the edge clamp 41 in the axial center direction. Abuts against the grindstone 42 provided on the surface. Thus, in the cleaning process, the wafer W is sandwiched between a plurality (three in the present embodiment) of the edge clamps 41 to support the outer periphery of the wafer W.

  Then, one edge clamp 41 of the plurality of edge clamps 41 is rotated around the axis by the motor 43. Then, the wafer W is rotated by the rotation of one edge clamp 41, and the remaining edge clamp 41 is also rotated by the rotation of the wafer W. Further, a cleaning liquid 45 such as pure water is ejected from the cleaning liquid injection nozzle 44 disposed above the wafer W of the cleaning apparatus 40 toward the back surface WR of the wafer W, and is disposed below the wafer W of the cleaning apparatus 40. The cleaning roller 46 thus rotated is brought into contact with the back surface Pa of the carrier plate P. Then, due to the centrifugal force caused by the rotation of the wafer W, the cleaning liquid 45 sprayed toward the wafer W flows on the wafer W in the outer peripheral direction, and flows down from the wafer W together with the contamination adhered to the back surface WR of the wafer W, The back surface WR of the wafer W is cleaned.

  Further, the cleaning device 40 has a plurality of cleaning water supply ports (not shown) in the cleaning roller 46, and cleaning water is jetted from these cleaning water supply ports, and the cleaning roller 46 causes the carrier plate P to The back surface Pa is cleaned. Further, the grinding wheel 42 grinds the resin JA due to the difference in rotational speed between the wafer W and the edge clamp 41 that rotates with the wafer W without being directly rotated by the motor 43, and scrapes off the resin JA protruding from the outer periphery of the wafer W. ,Remove. When cleaning is performed by the cleaning device 40 for a predetermined time, the process proceeds to an etching process. In order to cause a difference in rotational speed between the edge clamp 41 that rotates with the wafer W and the wafer W, rotation suppression means that suppresses the rotation of the edge clamp 41 that rotates with the wafer W without being rotated by the motor 43 is provided. May be.

  As described above, the processing method according to this embodiment removes the resin JA that protrudes from the outer periphery of the wafer W before the etching process, so that the resin J attached to the wafer W in the etching process is scattered. Can be suppressed.

  In addition, since the resin JA that protrudes from the outer periphery of the wafer W is removed in the cleaning process for cleaning the wafer W, it is not necessary to perform a separate dedicated process to remove the protruding resin JA, and productivity is also reduced. There is no. Further, since the cleaning device 40 removes the resin JA that protrudes from the outer periphery of the wafer W in the cleaning process, it is not necessary to provide a dedicated resin removing device to remove the protruding resin JA, thereby suppressing an increase in cost. it can.

  In the processing method according to the present embodiment, the resin JA protruding from the outer periphery of the wafer W chamfered in the chamfered portion removing step is removed, but the resin J is within a range in which the wafer W and the carrier plate P are not misaligned. The outer peripheral portion of the resin J sandwiched between the wafer W and the carrier plate P may be removed without protruding from the outer periphery of the wafer W. In short, in the present invention, at least the resin JA protruding from the outer periphery of the wafer W may be removed in the cleaning process.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

3 Cutting blade W Wafer (semiconductor substrate)
WS surface WR back surface J, JA Resin P Carrier plate Pa back surface D Device S Divided line E Via electrode Eb Head H Depth DR Device region GR Peripheral surplus region C Chamfer T Dicing tape V Bump Z Insulating film

Claims (1)

A plurality of devices are partitioned by dividing lines on the surface of the semiconductor substrate, a device region having a Via electrode embedded from the device electrode toward the back surface of the semiconductor substrate, and a chamfered portion in an outer peripheral surplus region surrounding the device region A wafer processing method for dividing a wafer provided with a wafer into individual devices,
A chamfered portion removing step of positioning a cutting blade in the outer peripheral surplus area and cutting a predetermined depth to remove the chamfered portion;
A carrier plate disposing step of disposing a carrier plate on the surface of the wafer via a resin;
A Via electrode detection step of detecting the depth of the Via electrode from the back surface of the wafer;
A back grinding process for grinding and thinning the back surface of the wafer to such an extent that the Via electrode is not exposed on the back surface;
An etching step of etching the semiconductor substrate from the back surface of the wafer to project the Via electrode;
An insulating film coating process for coating the back surface of the wafer with an insulating film;
A finishing step in which the via electrode protruding from the back surface is scraped to be exposed from the insulating film and the head of the via electrode is finished on the same plane as the insulating film;
A bump disposing step of disposing a bump on the head of the Via electrode;
A transfer step of attaching a dicing tape to the back surface of the wafer, removing the carrier plate from the front surface of the wafer, and transferring the wafer to the dicing tape;
Including at least
After the back grinding step and before the etching step, a part of the resin used in the carrier plate arranging step protrudes from the outer periphery of the chamfered wafer, supports the outer periphery of the wafer, A wafer processing method for removing at least the protruding resin in a cleaning step of cleaning the back surface of the carrier plate.

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