JP6671167B2 - Processing method of laminated substrate - Google Patents

Description

  The present invention relates to a method for processing a laminated substrate.

  For example, in a package substrate including a resin package substrate or a semiconductor package substrate called a WL-CSP (wafer-level chip-scale package) substrate, a metal layer including device electrodes and metal posts protruding from the electrodes is sealed with resin. Have been. With respect to such a package substrate, a package forming method is known in which a resin is removed from a workpiece sealed with the resin to expose a metal protrusion (for example, see Patent Document 1).

JP 2013-008899 A

  The cutting tool used in the package forming method described in Patent Literature 1 is suitable for processing a ductile material containing a resin containing no metal or filler. For this reason, the cutting tool is suitable for removing the resin from the workpiece sealed with the resin containing no filler. However, when this cutting tool is used for removing resin from a workpiece sealed with a resin containing a filler, the cutting tool may be easily worn, and the life of the cutting tool may be shortened.

  Therefore, there is known a technique of removing a resin with a grinding wheel before removing the resin from a workpiece sealed with the resin, before grinding with a bite cutting tool. However, in this technique, abrasive grains such as diamonds contained in the grinding wheel may fall off the grinding wheel and remain on the resin surface after grinding. If the abrasive grains remain on the resin surface after the grinding, the tool of the cutting tool for cutting the resin surface after the grinding with the grinding wheel is chipped, and the life of the tool is shortened.

  The present invention has been made in view of the above, and an object of the present invention is to provide a method of processing a laminated substrate in which abrasive grains are prevented from remaining on a resin surface after grinding.

In order to solve the above-described problems and achieve the object, a method for processing a laminated substrate of the present invention is a method for processing a laminated substrate that flattens a resin containing a filler that is coated on the surface of the substrate, the method comprising: Holding the laminated substrate on the holding surface of the chuck table in a state where the surface is exposed, and, after performing the holding step, using a grinding wheel tool for surface grinding mounted on a spindle having a rotating shaft parallel to the holding surface. A pre-processing step of grinding and removing the surface of the resin of the laminated substrate held on the chuck table; and a resin surface of the laminated substrate ground in the pre-processing step, the surface being parallel to the holding surface. And a finishing step of forming the resin surface flat by a cutting tool that rotates in the inside.The grinding tool for surface grinding is a grinding tool in which abrasive grains are electrodeposited on a base. Characterized by .

  In the method for processing a laminated substrate, the laminated substrate is a package substrate in which a metal post projecting from an electrode of a device formed on the substrate is sealed with a resin containing a filler. Preferably, the resin is removed to such an extent that the post is not exposed, and in the finishing step, the metal post and the resin are cut to expose the metal post.

  According to the method of processing a laminated substrate of the present invention, in a preliminary processing step, a grinding wheel tool for surface grinding mounted on a spindle having a rotation axis parallel to a holding surface of a chuck table, and a method of processing the laminated substrate held by the chuck table. The surface of the resin is removed by grinding. Then, after the pre-processing step, in the finishing processing step, the resin surface of the laminated substrate ground in the pre-processing step is further cut with a cutting tool rotating in a plane parallel to the holding surface of the chuck table, and the resin surface is flattened. Formed. As described above, in the method of processing the laminated substrate, the use of the grinding tool for surface grinding in the preliminary processing step can suppress the residual abrasive grains on the resin surface after the grinding. In addition, by suppressing the residual abrasive grains on the resin surface after grinding, the method for processing a laminated substrate can extend the life of a cutting tool.

FIG. 1 is an exploded perspective view showing the laminated substrate according to the present embodiment in an exploded manner. FIG. 2 is a perspective view showing the laminated substrate according to the present embodiment. FIG. 3 is a cross-sectional view illustrating the laminated substrate according to the present embodiment. FIG. 4 is a flowchart illustrating the method for processing the laminated substrate according to the present embodiment. FIG. 5 is a functional block diagram showing a surface grinding apparatus for a laminated substrate according to the present embodiment. FIG. 6 is a cross-sectional view showing the laminated substrate in a preliminary processing step of the method for processing a laminated substrate according to the present embodiment. FIG. 7 is a cross-sectional view illustrating the laminated substrate in a finishing step of the method for processing the laminated substrate according to the present embodiment. FIG. 8 is a cross-sectional view showing a state where the laminated substrate according to the present embodiment is divided into devices. FIG. 9 is a perspective view showing another example of the laminated substrate according to the present embodiment.

  Hereinafter, embodiments according to 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 components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Further, the configurations described below can be appropriately combined. In addition, various omissions, substitutions, or changes in the configuration can be made without departing from the spirit of the present invention.

  In the following description, an XYZ rectangular coordinate system is set, and the positional relationship between the components will be described with reference to the XYZ rectangular coordinate system. One end direction in the horizontal plane is defined as an X-axis direction, and a direction orthogonal to the X-axis direction in the horizontal plane is defined as a Y-axis direction, and a direction orthogonal to each of the X-axis direction and the Y-axis direction is defined as a Z-axis direction. The X, Y plane including the X axis and the Y axis is parallel to the horizontal plane. The Z-axis direction orthogonal to the X and Y planes is a vertical direction.

  FIG. 1 is an exploded perspective view showing the laminated substrate according to the present embodiment in an exploded manner. FIG. 2 is a perspective view showing the laminated substrate according to the present embodiment. FIG. 3 is a cross-sectional view illustrating the laminated substrate according to the present embodiment. As shown in FIGS. 1 to 3, the laminated substrate 10 has a substrate 20 and a resin layer (resin) 30. The laminated substrate 10 is a disk-shaped member, and has a front surface 10A and a back surface 10B facing the opposite direction to the front surface 10A. The front surface 10A and the back surface 10B are parallel. In the present embodiment, the diameter of the laminated substrate 10 is 8 inches (203.2 [mm]). The diameter of the laminated substrate 10 may be 12 inches (304.8 [mm]).

  The substrate 20 includes at least one of a silicon substrate, a sapphire substrate, a lithium tantalate substrate, a lithium niobate substrate, a resin substrate, and a ceramic substrate. The substrate 20 has a front surface 20A and a back surface 20B facing in a direction opposite to the front surface 20A. The substrate 20 has a functional layer 21. The functional layer 21 is a layer for forming a device, and is a low dielectric constant insulator made of an inorganic film such as SiOF or BSG (SiOB) and an organic film such as a polyimide or parylene polymer film. Includes a coating (Low-k film). The functional layer 21 is laminated on the surface 20A of the substrate 20. The surface 10A of the laminated substrate 10 includes the surface (resin surface) 30A of the resin layer 30. The back surface 10B of the laminated substrate 10 includes the back surface 20B of the substrate 20.

  The functional layer 21 is partitioned by a planned dividing line 22 formed in a lattice shape. A plurality of devices 23 each having an electrode in a region defined by the planned division line 22 are formed. The device 23 is partitioned by the dividing line 22. The devices 23 are arranged on the laminated substrate 10 in a matrix.

  The surface 20A of the substrate 20 includes a device area DA in which a plurality of devices 23 are formed, and an outer peripheral surplus area SA surrounding the device area DA. The device 23 is not formed in the outer peripheral surplus area SA. By dividing the laminated substrate 10 having the substrate 20 and the resin layer 30 along the dividing line 22, the device 23 is formed of an integrated circuit (IC) or an LSI (large scale integration) covered (molded) with a resin. Such a device chip is manufactured.

  After the resin layer 30 is ground, the device 23 is provided with bumps 26 (see FIG. 8) that connect to the electrodes 24 of the device 23 via the electrode posts 25. The bump 26 is provided on each of the devices 23. The bump 26 is provided so as to protrude from the surface 10 </ b> A of the laminated substrate 10. The bumps 26 are formed of, for example, a noble metal such as copper (Cu), gold (Au), or platinum (Pt), or an alloy such as Sn-Cu.

  The resin layer 30 covers and seals the surface 20A of the substrate 20. The resin layer 30 is, for example, a resin such as an epoxy resin containing a filler containing SiC or silica. The surface 30A of the resin layer 30 is a plane parallel to the surface 20A of the substrate 20. The resin layer 30 has a thickness of t1 at the position of the electrode post 25 of the substrate 20.

  Next, a method for processing the laminated substrate 10 according to the present embodiment will be described. FIG. 4 is a flowchart illustrating the method for processing the laminated substrate according to the present embodiment. As shown in FIG. 4, the processing method of the laminated substrate 10 includes a holding step S1, a preliminary processing step S2, and a finishing processing step S3.

  First, the holding step S1 is executed. The holding step S1 is a step of holding the laminated substrate 10 on the holding surface 50Ta of the chuck table 50T (see FIG. 6) of the surface grinding device 50 with the surface 30A of the resin layer 30 exposed.

  First, the surface grinding device 50 will be described with reference to FIG. FIG. 5 is a functional block diagram showing a surface grinding apparatus for a laminated substrate according to the present embodiment. As shown in FIG. 5, the surface grinding device 50 includes a control device 100, a table rotation drive device 111, a table drive device 112, a table position detection device 113, a grinding blade rotation drive device 121, and a grinding blade. A driving device 122 and a grinding blade position detecting device 123 are provided.

  As shown in FIG. 5, the control device 100 includes an arithmetic processing device 101 having a microprocessor such as a CPU (central processing unit), and a memory such as a ROM (read only memory) or a RAM (random access memory). It has a storage device 102 and an input / output interface device 103. The arithmetic processing device 101 performs arithmetic processing according to a computer program stored in the storage device 102, and outputs a control signal for controlling the surface grinding device 50 via the input / output interface device 103.

  The chuck table 50T of the surface grinding device 50 holds the laminated substrate 10 detachably. The chuck table 50T holds the surface 10A of the laminated substrate 10 so as to be parallel to the XY plane. In the chuck table 50T, a plurality of suction ports connected to a vacuum suction source including a vacuum pump via a flow path are provided on the holding surface 50Ta. The chuck table 50T sucks and holds the multilayer substrate 10 by operating the vacuum suction source while the multilayer substrate 10 is placed on the holding surface 50Ta of the chuck table 50T. When the operation of the vacuum suction source is stopped, the chuck table 50T releases and releases the suction of the laminated substrate 10.

  The chuck table 50T is controlled by the control device 100. More specifically, chuck table 50T is rotatable around a central axis parallel to the Z-axis direction by table rotation driving device 111 including an actuator. The chuck table 50T holds the laminated substrate 10 so that the central axis thereof coincides with the central axis of the surface 10A of the laminated substrate 10. The chuck table 50T is movable in the X-axis direction by a table driving device 112 including an actuator. The position of chuck table 50T in the X-axis direction is detected by table position detection device 113.

  After executing the holding step S1, the preliminary machining step S2 is executed. In the preliminary machining step S2, after the holding step S1 is performed, as shown in FIG. 6, the grinding means 52 for surface grinding mounted on the spindle 51 of the central axis AY50 parallel to the holding surface 50Ta of the chuck table 50T, This is a step of grinding and removing the surface 30A of the resin layer 30 of the laminated substrate 10 held on the chuck table 50T. FIG. 6 is a cross-sectional view showing the laminated substrate in a preliminary processing step of the method for processing a laminated substrate according to the present embodiment.

  The surface grinding device 50 has a grinding means 52. The grinding means 52 includes a spindle housing 53, a spindle 51 rotatably supported by the spindle housing 53, a fixed flange 54 provided at the tip of the spindle 51, and a detachable flange detachably fixed to the fixed flange 54. 55, a fixing member 56 for fixing the detachable flange 55 to the fixed flange 54, a grinding blade 57 that is a grinding tool for surface grinding, which is sandwiched and fixed between the fixed flange 54 and the detachable flange 55, And a nozzle 58 for injecting the grinding fluid R toward the grinding blade 57.

The grinding blade 57 is a whetstone tool in which abrasive grains are electrodeposited and fixed on the outer peripheral surface of a disk-shaped or drum-shaped base having a through hole at the center with a width of several [mm] in the Y-axis direction. . In other words, the grinding blade 57 is a grindstone tool in which abrasive grains are electrodeposited on a base. The grinding blade 57 is rotatable around a central axis AY50 of the grinding means 52 in a direction indicated by an arrow R50 when the spindle 51 is rotated by a grinding blade rotation driving device 121 including an actuator. When the rotating grinding blade 57 comes into contact with the surface 30A of the resin layer 30, the grinding blade 57 grinds the surface 30A of the resin layer 30. The central axis AY50 is parallel to the Y-axis direction. The grinding blade 57 is movable in the Y-axis direction and the Z-axis direction by a grinding blade driving device 122 including an actuator. The positions of the grinding blade 57 in the Y-axis direction and the Z-axis direction are detected by the grinding blade position detection device 123.

  The control device 100 drives the grinding blade rotation driving device 121 to rotate the grinding blade 57 in the direction indicated by the arrow R50 to a position in the Z-axis direction where the cutting blade 57 is cut into the resin layer 30. The chuck table 50T is driven and processed in the X-axis direction to form a grinding groove in the X-axis direction from one end to the other end of the laminated substrate 10. Thereafter, the grinding blade driving device 122 is driven to index and feed the grinding blade 57 in the Y-axis direction. The control device 100 is based on the detection value of the table position detection device 113 and the detection value of the grinding blade position detection device 123 so that the grinding blade 57 contacts the surface 30A of the resin layer 30 held on the chuck table 50T. By driving the table driving device 112 and the grinding blade driving device 122, the relative position between the surface 30A of the resin layer 30 and the grinding blade 57 is adjusted. In this embodiment, the control device 100 detects the detection value of the table position detection device 113 and the position of the grinding blade so that the surface 30A of the resin layer 30 is removed from the surface 25A of the electrode post 25 except for the thickness t3. The table driving device 112 and the grinding blade driving device 122 are driven based on the detection value of the device 123, and the grinding blade 57 is cut into the surface 30A of the resin layer 30. In the present embodiment, t3 is not less than 2 [μm] and not more than 50 [μm], preferably not less than 5 [μm] and not more than 20 [μm].

  More specifically, the control device 100 sets the amount of grinding of the resin layer 30 (the dimension in the Z-axis direction at which the resin layer 30 is ground) to 100 [μm] or less, preferably 30 [μm] or less with respect to the resin layer 30. Then, the grinding blade 57 is cut. The controller 100 feeds the chuck table 50T while the grinding blade 57 is cut into the surface 30A of the resin layer 30 held on the chuck table 50T.

  In this way, the entire surface 30A of the resin layer 30 is ground, and the thickness t2 of the surface 30A of the resin layer 30 is removed from the surface 25A of the electrode post 25 while leaving the thickness t3.

  In the preliminary processing step S2, the grinding blade 57 rotates about the central axis AY50 in the direction indicated by the arrow R50, and the chuck table 50T holding the surface 30A of the resin layer 30 is processed and fed in the X-axis direction. For example, as compared with the case where the resin layer 30 is ground with a grinding device having a rotation axis orthogonal to the holding surface 50Ta of the chuck table 50T as disclosed in JP-A-2013-093338, the resin layer 30 of the grinding blade 57 is The contact time with the surface 30A is short. Thereby, when the grinding blade 57 grinds the surface 30 </ b> A of the resin layer 30, the abrasive grains hardly remain in the resin layer 30.

  After performing the preliminary processing step S2, the finishing processing step S3 is performed. In the finishing processing step S3, as shown in FIG. 7, the resin layer 30 of the laminated substrate 10 ground in the preliminary processing step S2 is rotated in a plane parallel to the holding surface 60Ta of the chuck table 60T of the cutting tool 60. In this step, the surface 30A of the resin layer 30 is formed flat by further cutting with the cutting tool 61. FIG. 7 is a cross-sectional view illustrating the laminated substrate in a finishing step of the method for processing the laminated substrate according to the present embodiment.

  The cutting tool 60 includes a control device, a table driving device, a table position detecting device, a cutting tool rotating driving device, a cutting tool driving device, and a cutting position detecting device.

  The cutting tool 60 cuts and flattens the surface 30A of the resin layer 30 of the laminated substrate 10 held on the chuck table 60T. The cutting tool 60 has a cutting tool 61. The cutting tool 61 includes a spindle housing 62, a spindle 63 rotatably supported by the spindle housing 62, and a cutting wheel 64 provided at a tip end of the spindle 63.

  The tool bit 61 is rotatable around the center axis AZ60 of the tool bit 61 in the direction indicated by the arrow R60 when the spindle 63 is rotated by a tool rotary drive device including an actuator. The central axis AZ60 is parallel to the Z-axis direction. The tool 61 can be moved in the Z-axis direction by a tool driving device including an actuator. The position of the tool 61 in the Z-axis direction is detected by a tool position detecting device. When the rotating cutting tool 61 contacts the surface 30A of the resin layer 30, the cutting tool 61 cuts the surface 30A of the resin layer 30.

  The control device drives the table driving device to cut and feed the chuck table 60T in the X-axis direction, while driving the bite rotation driving device to rotate the bite tool 61 in the direction indicated by the arrow R60. The control device controls the table driving device and the cutting tool based on the detected value of the table position detecting device and the detected value of the cutting tool position detecting device so that the cutting tool 61 contacts the surface 30A of the resin layer 30 held on the chuck table 60T. The driving device is driven to adjust the relative position between the surface 30A of the resin layer 30 and the cutting tool 61.

  In the present embodiment, the control device adjusts the table position so that the surface 30A of the resin layer 30 cuts the laminated substrate 10 by the thickness t3 or more and the surface 25A of the electrode post 25 disposed on the functional layer 21 is exposed. The table driving device and the bite driving device are driven based on the detection value of the detection device and the detection value of the bite position detection device, and the bite tool 61 is cut into the surface 30 </ b> A of the resin layer 30.

  More specifically, in the control device, the cutting amount of the resin layer 30 (the dimension in the Z-axis direction in which the resin layer 30 is cut) is 20 μm or less, preferably 10 μm or less with respect to the resin layer 30. The cutting tool 61 is cut as described above. The control device cuts and feeds the chuck table 60T in the X-axis direction with the rotating cutting tool 61 cut into the surface 30A of the resin layer 30 held by the chuck table 60T by a predetermined amount. When the surface 25A of the electrode post 25 is not exposed from the surface 30A of the resin layer 30 by one cut, the control device moves the tool 61 in the Z-axis direction, and further cuts the tool 61 into the resin layer 30. Not cut. The control device repeats such an operation until the surface 25A of the electrode post 25 is exposed from the surface 30A of the resin layer 30.

  In this way, the entire surface 30A of the resin layer 30 is cut, and the surface 30A of the resin layer 30 is removed to a level where the surface 25A of the electrode post 25 is exposed, and the surface is flattened.

  After performing the finishing step S3, the bumps 26 are formed on the surface 25A of the electrode posts 25 exposed on the surface 30A of the resin layer 30 by, for example, soldering. Then, as shown in FIG. 8, the laminated substrate 10 is divided along the dividing lines 22 to manufacture the devices 23. FIG. 8 is a cross-sectional view showing a state where the laminated substrate according to the present embodiment is divided into devices.

  As described above, the method of processing the laminated substrate according to the present embodiment includes, in the preliminary processing step S2, the surface grinding mounted on the spindle 51 of the center axis AY50 parallel to the holding surface 50Ta of the chuck table 50T of the surface grinding device 50. Grinding means 52 for grinding removes surface 30A of resin layer 30 of laminated substrate 10 held on chuck table 50T. Then, in the finishing step S3 after the preliminary processing step S2, the surface 30A of the resin layer 30 ground in the preliminary processing step S2 is rotated in a plane parallel to the holding surface 60Ta of the chuck table 60T of the cutting tool 60. The cutting is further performed with a cutting tool 61 to form a flat surface 10A of the laminated substrate 10. As described above, in the method of processing the laminated substrate, in the preliminary processing step S <b> 2, by using the grinding means 52 for surface grinding, the amount of the filler contained in the resin layer 30 to be cut by the cutting tool 61 is reduced, and the grinding is performed. The remaining abrasive particles on the surface 30A of the resin layer 30 later can be suppressed, and chipping of the cutting tool 61 by the abrasive particles can be suppressed.

  More specifically, in the method of processing the laminated substrate, the grinding blade 57 rotates in the direction indicated by the arrow R50, and the chuck table 50T is processed and fed in the X-axis direction. For this reason, the contact time of the grinding blade 57 with the surface 30A of the resin layer 30 can be shortened as compared with the case where the resin layer 30 is ground by a grinding device having a rotation axis orthogonal to the holding surface 50Ta of the chuck table 50T. it can. Accordingly, abrasive grains generated when the grinding blade 57 grinds the surface 30 </ b> A of the resin layer 30 can be less likely to remain in the resin layer 30.

  As described above, according to the method of processing a laminated substrate, it is possible to suppress the abrasive grains from remaining on the surface 30A of the resin layer 30 after the grinding. Accordingly, in the method of processing the laminated substrate, it is possible to suppress the abrasive tool from being damaged by the abrasive grains coming into contact with the tool bit 61 of the tool cutting device 60. For this reason, the processing method of the laminated substrate can extend the life of the cutting tool 61 of the cutting tool 60.

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

  In the above embodiment, the laminated substrate 10 is described as sealing the devices 23 arranged in a matrix on the substrate 20 with one resin layer 30, but the present invention is not limited to this. For example, as shown in FIG. 9, the laminated substrate 210 may be one in which devices formed on the substrate 220 are each sealed with a resin layer 230. FIG. 9 is a perspective view showing another example of the laminated substrate according to the present embodiment.

Reference Signs List 10 laminated substrate 20 substrate 20A surface 21 functional layer 22 scheduled division line 23 device 30 resin layer (resin)
30A surface (resin surface)
Reference Signs List 50 surface grinding device 50T chuck table 50Ta holding surface 51 spindle 52 grinding means for surface grinding 57 grinding blade (grinding wheel tool for surface grinding)
60 byte cutting machine 60T chuck table 60Ta holding surface 61 byte tool AY50 center axis AZ60 center axis

Claims (2)

A method for processing a laminated substrate that flattens a resin containing a filler that is coated on the surface of the substrate,
Holding step of holding the laminated substrate on the holding surface of the chuck table with the resin exposed,
After performing the holding step, the surface of the resin of the laminated substrate held on the chuck table is removed by grinding using a grinding tool for surface grinding mounted on a spindle having a rotating shaft parallel to the holding surface. Pre-processing steps
A finishing step of further cutting the resin surface of the laminated substrate ground in the preliminary processing step with a bite tool rotating in a plane parallel to the holding surface to form the resin surface flat ;
Grinding tool for the plane grinding, machining method of the laminated substrate abrasive grains to the base is characterized grindstone tool der Rukoto electrodeposited. The laminated substrate is a package substrate in which metal posts protruding from electrodes of a device formed on the substrate are sealed with a resin containing filler,
In the pre-processing step, the resin is removed to such an extent that the metal post is not exposed,
The method according to claim 1, wherein in the finishing step, the metal post and the resin are cut to expose the metal post.

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