JP2009172723A - Cutting work device and cutting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting work device and a cutting method capable of detecting the thickness of a lamination part even in a central part of a wafer. <P>SOLUTION: The cutting work device includes a chuck table with a retaining surface for retaining a plate material composed of a substrate part and a lamination part formed on an upper surface of the substrate part with a prescribed thickness; a cutting work means having a cutting blade for cutting the lamination part by being moved in parallel to the upper surface of the lamination part of the plate material retained by the chuck table, with this cutting blade retained rotatably; a contact type first height measuring means for measuring a height of the chuck table and a height of the upper surface of the lamination part of the plate material retained by the chuck table; and a non-contact type second height measuring means for detecting the height of the upper surface of the substrate part and the height of the upper surface of the lamination part of the plate material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting apparatus and a cutting method for cutting the thickness of a laminated portion of a semiconductor wafer having a laminated portion made of resin, metal, or the like on a surface thereof to a desired thickness.

  There are various techniques for realizing light and thin semiconductor devices. As an example, a plurality of metal protrusions called bumps having a height of about 10 to 100 μm are formed on the surface of a device formed on a semiconductor wafer, and these bumps are directly bonded to the electrodes formed on the wiring board. A technique called flip chip bonding has been put into practical use.

  The bump formed on the device surface of the semiconductor wafer is formed by a method such as plating or stud bump. For this reason, the heights of the individual bumps are non-uniform, and it is difficult to uniformly bond the plurality of bumps to the electrodes of the wiring board as they are.

  In order to realize high-density wiring, there is an integrated circuit mounting technique in which an anisotropic conductive film (ACF) is sandwiched and bonded between a bump and a wiring board. In the case of this mounting technique, if the height of the bump is insufficient, a bonding failure is caused, so that a certain bump height is required. Therefore, it is desired to cut a plurality of bumps formed on the surface of the semiconductor wafer to a desired thickness.

As a method of cutting the bump to a desired thickness, a method of scraping the bump with a cemented carbide tool (cutting blade) is proposed in, for example, Japanese Patent Application Laid-Open No. 2007-59523. In this method, the thickness of the bump where the bump is not formed on the surface of the semiconductor wafer and the height of the upper surface of the bump are measured with a contact gauge, and the thickness of the bump is calculated as the difference between the heights of the two points. Yes.
JP 2007-59523 A

  However, in general, the portion of the semiconductor wafer where the bumps are not formed is outside the device region and becomes the outer peripheral surplus portion of the semiconductor wafer. Further, the excess portion of the outer periphery of the semiconductor wafer is a portion that is held at the time of conveyance in a pattern forming process or the like, and is easily damaged or dented.

  When the height of the semiconductor wafer is measured at a portion having a scratch or a dent, the bump thickness is calculated to be thicker than the actual thickness, so that a problem arises that a larger amount than the desired cutting amount is cut.

  In addition, when the semiconductor wafer is warped, for example, has a concave shape, the thickness of the bump is calculated to be thinner than the actual thickness, which causes a problem of cutting less than a desired cutting amount.

  On the other hand, by using a non-contact type thickness measuring device, the thickness of the laminated portion can be detected even in the center of the wafer. However, the surface of the wafer before cutting has minute irregularities, and there is an adverse effect that the minute irregularities are also measured when measuring the thickness of the wafer.

  Therefore, an object of the present invention is to provide a cutting apparatus and a cutting method capable of accurately detecting the thickness of the laminated portion even in the center of the wafer.

  Another object of the present invention is to provide a cutting device and a cutting method that do not include minute irregularities on the wafer surface and can accurately detect the thickness of the laminated portion even in the center of the wafer.

  According to the first aspect of the present invention, a chuck table having a holding surface for holding a plate-like object composed of a substrate portion and a laminated portion formed with a predetermined thickness on the upper surface of the substrate portion, and the chuck table A cutting tool having a cutting blade that is moved in parallel to the upper surface of the laminated portion of the plate-like material held by the blade and cuts the laminated portion, and the cutting blade is rotatably held by the cutting blade. A processing apparatus, a contact-type first height measuring means for measuring a height of the chuck table and a height of the upper surface of the stacked portion of the plate-like object held by the chuck table, and the plate-like object And a non-contact type second height measuring means for detecting the height of the upper surface of the substrate portion and the height of the upper surface of the laminated portion.

  As a modification, the first height measuring unit may be omitted, and the second height measuring unit may also function as the first height measuring unit. Preferably, the cutting apparatus further includes alignment means for moving the second height measuring means to a desired position.

  According to the fourth aspect of the present invention, the cutting device according to any one of the first to third aspects is used to form a substrate portion and a laminated portion formed with a predetermined thickness on the upper surface of the substrate portion. A plate-like material cutting method for cutting an upper surface of a plate-like material to form the laminated portion in a desired thickness, wherein the plate-like material held on the chuck table by the first height measuring means Measuring the upper surface height of the object, measuring the upper surface height of the chuck table and calculating the thickness of the plate-like object, and calculating the thickness of the plate-like object A first cutting step of flattening the upper surface of the plate-like object held by the chuck table by the cutting means based on the thickness of the plate-like object; and the second height measuring means. To detect the height of the upper surface of the substrate portion and to detect the height of the upper surface of the laminated portion. A laminated portion thickness calculating step for calculating a thickness of the portion, and a second portion for cutting the laminated portion to a predetermined thickness by the cutting means based on the thickness of the laminated portion calculated in the laminated portion thickness calculating step. And a cutting step. A method for cutting a plate-like object is provided.

  According to the fifth aspect of the present invention, the upper surface of the plate-like object composed of the substrate portion and the laminated portion formed with a predetermined thickness on the upper surface of the substrate portion using the cutting device according to the third aspect. Is a cutting method of a plate-like object in which the laminated portion is formed to a desired thickness, and the upper surface height of the plate-like object held on the chuck table by the first height measuring means is determined. And measuring the thickness of the plate-like material by measuring the upper surface height of the chuck table and calculating the thickness of the plate-like material, and calculating the thickness of the plate-like material calculated in the plate-like material thickness calculating step. First, a first cutting step of flattening the upper surface of the plate-like object held on the chuck table by the cutting means, and the second height measuring means using the alignment means Alignment process for moving to a desired position, and the alignment In the moved position, the stack height unit measures the height of the upper surface of the substrate portion by the second height measuring means and calculates the thickness of the stack portion by measuring the height of the upper surface of the stack portion. A thickness calculating step, and a second cutting step of cutting the laminated portion to a predetermined thickness by the cutting means based on the thickness of the laminated portion calculated in the laminated portion thickness calculating step. A plate-like material cutting method characterized by the above is provided.

  According to the present invention, it is possible to accurately detect the thickness of the stacked portion even in the device region of the semiconductor wafer, and the thickness of the stacked portion can be uniformly cut to a desired thickness with higher accuracy.

  Hereinafter, a cutting apparatus according to an embodiment of the present invention and a cutting method using the cutting apparatus will be described in detail. FIG. 1 shows a perspective view of a cutting apparatus according to an embodiment of the present invention.

  The housing 4 of the cutting device 2 includes a horizontal housing part 6 and a vertical housing part 8. A pair of guide rails (only one is shown) 10 extending in the vertical direction are fixed to the vertical housing portion 8.

  A cutting unit 12 is mounted along the pair of guide rails 10 so as to be movable in the vertical direction. The cutting unit 12 is attached to a moving base 14 whose housing 22 moves up and down along the pair of guide rails 10.

  The cutting unit 12 includes a housing 22, a spindle (not shown) rotatably accommodated in the housing 22, a servo motor 24 that rotationally drives the spindle, a bite wheel 26 fixed to the tip of the spindle, and a bite wheel 26. A cutting tool (cutting blade) 28 is detachably attached to the tool.

  The cutting unit 12 includes a cutting unit moving mechanism 20 including a ball screw 16 and a pulse motor 18 that move the cutting unit 12 in the vertical direction along the pair of guide rails 10. When the pulse motor 18 is pulse-driven, the ball screw 16 rotates and the moving base 14 is moved in the vertical direction.

  A chuck table unit 30 is disposed in the horizontal housing portion 6. The chuck table unit 30 includes a chuck table base 32 and a chuck table 34 mounted on the chuck table base 32. The chuck table 34 is moved in the Y-axis direction by a chuck table moving mechanism (Y-axis direction feed mechanism) (not shown).

  Reference numeral 36 denotes a height measuring device assembly for measuring the height of the chuck table 34, the height of the wafer 11 (see FIG. 2) held on the chuck table 34, and the like, and a gate shape fixed to the horizontal housing portion 6 of the housing 4. The support member 38 is included. The support member 38 is attached with a pair of linear gauges 40 and 42 that measure the height in a contact manner.

  A rectangular attachment member 44 is further fixed to the support member 38. The mounting member 44 is provided with an X-axis drive mechanism including a ball screw 48 and a pulse motor 50. When the pulse motor 50 is driven in pulses, the slider 46 is moved in the X-axis direction.

  The slider 46 is equipped with a Z-axis drive mechanism including a ball screw 54 and a pulse motor 56. When the pulse motor 56 is driven in a pulsed manner, the non-contact type height measuring device 52 is moved in the vertical direction (Z-axis direction). Moved.

  The non-contact type height measuring device 52 includes, for example, a non-contact type height measuring unit 58 such as a scanning white interferometer SWLI (manufactured by Toray Engineering Co., Ltd.) and an alignment unit 60 having an imaging unit such as a CCD camera. It is attached. Instead of the scanning white interferometer, ultrasonic measurement means, laser beam measurement means, or the like may be employed as non-contact type height measurement means.

  The horizontal housing portion 6 of the housing 4 includes a first wafer cassette 62, a second wafer cassette 64, a wafer transport mechanism 66, a positioning table 68 having a plurality of positioning pins 70, a wafer carry-in mechanism 72, A wafer carry-out mechanism 74 and a spinner unit 76 are provided.

  Further, a cleaning water spray nozzle 78 for cleaning the chuck table 34 is provided at a substantially central portion of the horizontal housing portion 6. The cleaning water jet nozzle 78 ejects cleaning water toward the chuck table 34 in a state where the chuck table 34 is positioned in the wafer carry-in / out area.

  Referring to FIG. 2, a plan view of the semiconductor wafer 11 is shown. The semiconductor wafer 11 is made of, for example, a silicon wafer having a thickness of 600 μm, and a plurality of streets 13 are formed in a lattice shape on the surface 11a, and an IC is formed in each of a plurality of regions partitioned by the plurality of streets 13. A device 15 such as an LSI is formed.

  The semiconductor wafer 11 configured as described above includes a device region 17 in which the device 15 is formed, and an outer peripheral surplus region 19 that surrounds the device region 17. Further, a notch 21 is formed on the outer periphery of the semiconductor wafer 11 as a mark indicating the crystal surrounding of the silicon wafer.

  FIG. 3 is a cross-sectional view of the device 15 portion of the semiconductor wafer 11. A device 15 is formed on a silicon substrate 23 by a well-known semiconductor manufacturing process, and a laminated portion 25 including a plurality of bumps 27 and a resin layer 29 is formed on the device 15. The bumps 27 are made of a metal such as copper, for example, and are connected to the electrodes of the device 15.

  The cutting operation of the cutting apparatus 2 configured as described above will be described below. The semiconductor wafer 11 accommodated in the first wafer cassette 62 is conveyed by the vertical movement and forward / backward movement of the wafer conveyance mechanism 66 and placed on the wafer positioning table 68.

  After the wafer placed on the wafer positioning table 68 is centered by a plurality of positioning pins 70, the wafer loading mechanism 72 pivots to the chuck table 34 positioned in the wafer loading / unloading area. It is placed and sucked and held by the chuck table 34.

  When the chuck table 34 sucks and holds the wafer 11 as described above, the chuck table moving mechanism is operated to position the chuck table 34 at the height measurement position shown in FIG.

  At the height measurement position, the height of the upper surface of the chuck table 34 is measured with the first linear gauge 40, and the height of the wafer 11 is measured by bringing the second linear gauge 42 into contact with the stacked portion 25 of the semiconductor wafer 11. To do. The thickness of the wafer 11 is calculated from the difference between the readings of the two linear gauges 40 and 42.

  As shown in FIG. 3, since the thickness of the laminated portion 25 composed of the bumps 27 and the resin layer 29 is uneven, it is held on the chuck table 34 based on the thickness of the wafer 11 calculated from the above-described thickness calculation step. Then, a first cutting step of flattening the upper surface of the wafer 11 with the cutting unit 12 is performed.

  As shown in FIG. 5, the first cutting process is performed by feeding the chuck table 34 in the arrow Y direction at, for example, 0.66 mm / second while rotating the cutting tool 28 in the arrow A direction at, for example, 2000 rpm. Thereby, the lamination | stacking part 25 can be planarized.

  When the flattening process is performed in this way, the chuck table 34 is returned to the height measurement position again, and the alignment process is performed. In this alignment process, the imaging unit of the alignment unit 60 images the alignment target laminate 25 and detects the position of the laminate 25 where the height is to be measured by performing image processing such as pattern matching. As shown in FIG. 6, the non-contact height measuring means 58 is moved to the above position.

  At the position moved in the alignment step, the height of the upper surface of the substrate 23 is measured by the non-contact type height measuring means 58 and the height of the upper surface of the stacked portion 25 is measured to calculate the thickness of the stacked portion 25. To do.

  Since the white light of the scanning white interferometer constituting the non-contact type height measuring means 58 passes through the resin layer 29, not only the height of the upper surface of the laminated portion 25 but also the substrate portion (substrate 23 + device 15) is measured. The measurement of the upper surface height can also be performed without contact.

  When the thickness of the laminated portion 25 is calculated by the non-contact type height detecting means 58, the second portion of cutting the laminated portion 25 with the cutting tool 28 so that the laminated portion 25 has a desired thickness as shown in FIG. Perform cutting.

  In the second cutting step, similarly to the first cutting step, while rotating the cutting tool 28 in the direction of arrow A at 2000 rpm, the stacking section 25 is moved while feeding the chuck table 34 in the direction of arrow Y at, for example, 0.66 mm / second. To cut.

  When the laminated portion 25 is cut to a desired thickness, a chuck table moving mechanism (not shown) is driven to position the chuck table 34 in the wafer loading / unloading area on the front side of the apparatus. When the chuck table 34 is positioned in the wafer carry-in / out area, the washing water is ejected from the washing water jet nozzle 78 to wash the wafer 11 held on the chuck table 34.

  After the suction and holding of the wafer 11 held on the chuck table 34 is released, the wafer 11 is conveyed to the spinner unit 76 by the wafer carry-out mechanism 74. The wafer conveyed to the spinner unit 76 is cleaned here and spin-dried. Next, the wafer 11 is stored in a predetermined position of the second wafer cassette 64 by the wafer transport mechanism 66.

  As a modification of the above-described embodiment, the linear gauges 40 and 42 which are contact-type height measuring means are omitted, and the non-contact-type height measuring means 58 is also used as the function of the linear gauges 40 and 42. good.

  According to the embodiment described above, it is possible to detect the thickness of the stacked portion 25 by measuring the upper surface height of the stacked portion 25 and the upper surface height of the substrate portion in the device region 17 of the semiconductor wafer 11. The laminated part can be uniformly cut to a desired thickness with higher accuracy.

It is an external appearance perspective view of a cutting device. It is a top view of a semiconductor wafer. It is sectional drawing of a semiconductor wafer. It is explanatory drawing of a wafer thickness calculation process. It is explanatory drawing of a laminated part planarization process (1st cutting process). It is explanatory drawing of a laminated part thickness calculation process. It is explanatory drawing of a 2nd cutting process.

Explanation of symbols

2 Cutting device 11 Semiconductor wafer 12 Cutting unit 15 Device 17 Device region 19 Peripheral surplus region 23 Substrate 25 Laminating portion 27 Bump 28 Cutting tool 29 Resin layer 34 Chuck table 36 Height measuring device assembly 40, 42 Linear gauge 58 Non-contact Type height measuring means 60 alignment means

Claims (5)

A chuck table having a holding surface for holding a plate-like object composed of a substrate part and a laminated part formed with a predetermined thickness on the upper surface of the substrate part; and the plate-like object held on the chuck table A cutting device having a cutting blade that is moved parallel to the upper surface of the laminated portion and cuts the laminated portion, and a cutting means that is rotatably held by the cutting blade,
Contact-type first height measurement means for measuring the height of the chuck table and the height of the upper surface of the laminated portion of the plate-like object held by the chuck table;
Non-contact type second height measuring means for detecting the height of the upper surface of the substrate portion and the height of the upper surface of the laminated portion of the plate-like object;
A cutting apparatus characterized by comprising:   2. The cutting apparatus according to claim 1, wherein the first height measuring unit is omitted, and the second height measuring unit also serves as the function of the first height measuring unit.   3. The cutting apparatus according to claim 1, further comprising an alignment unit that moves the second height measuring unit to a desired position. Using the cutting apparatus according to any one of claims 1 to 3, the upper surface of a plate-like object composed of a substrate portion and a laminated portion formed with a predetermined thickness on the upper surface of the substrate portion is cut. , A cutting method of a plate-like material for forming the laminated portion to a desired thickness,
A plate that measures the upper surface height of the plate-like object held on the chuck table by the first height measuring means and calculates the thickness of the plate-like object by measuring the upper surface height of the chuck table. A thickness calculation step,
Based on the thickness of the plate-like object calculated in the plate-like object thickness calculating step, the upper surface of the plate-like object held by the chuck table is cut and flattened by the cutting means. Cutting process;
A laminated part thickness calculating step of detecting the height of the upper surface of the substrate part by the second height measuring means and calculating the thickness of the laminated part by detecting the height of the upper surface of the laminated part;
Based on the thickness of the laminated part calculated in the laminated part thickness calculating step, a second cutting step of cutting the laminated part to a predetermined thickness by the cutting means;
A cutting method for a plate-like object comprising: Using the cutting apparatus according to claim 3, the upper surface of a plate-like object composed of a substrate portion and a laminated portion formed with a predetermined thickness on the upper surface of the substrate portion is cut, and the laminated portion is desired. It is a cutting method of a plate-like object to be formed to a thickness of
A plate that measures the upper surface height of the plate-like object held on the chuck table by the first height measuring means and calculates the thickness of the plate-like object by measuring the upper surface height of the chuck table. A thickness calculation step,
Based on the thickness of the plate-like object calculated in the plate-like object thickness calculating step, the first surface of the plate-like object held by the chuck table is cut and flattened by the cutting means. Cutting process;
An alignment step of moving the second height measuring means to a desired position using the alignment means;
At the position moved in the alignment step, the height of the upper surface of the substrate unit is measured by the second height measuring unit, and the thickness of the upper surface of the stacked unit is measured to calculate the thickness of the stacked unit. Laminate thickness calculation step,
Based on the thickness of the laminated part calculated in the laminated part thickness calculating step, a second cutting step of cutting the laminated part to a predetermined thickness by the cutting means;
A cutting method for a plate-like object comprising:

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