JP5254733B2 - Water jet machining method - Google Patents

Description

  The present invention relates to a water jet machining method for cutting a plate-like workpiece such as a semiconductor wafer with a water jet jetted at a high pressure.

  In the semiconductor device manufacturing process, circuits such as ICs and LSIs are formed in a large number of regions arranged in a lattice pattern on the surface of a substantially disc-shaped semiconductor wafer, and each region where such a circuit is formed is predetermined. Individual semiconductor chips are manufactured by dicing along cutting lines called streets. The semiconductor chip thus divided is packaged and widely used in electronic devices such as mobile phones and personal computers.

  Electronic devices such as mobile phones and personal computers are required to be lighter and smaller, and a package technology capable of reducing the size of a semiconductor chip package called a chip size package (CSP) has been developed. As one of the CSP technologies, a package technology called Quad Flat Non-lead Package (QFN) has been put into practical use. This package technology called QFN is a method in which a plurality of connection terminals corresponding to connection terminals of a semiconductor chip are formed and a plurality of metal plates such as a copper plate in which streets divided for each semiconductor chip are formed in a lattice shape. Semiconductor chips are arranged in a matrix, and a CSP substrate is formed by integrating a metal plate and a semiconductor chip by a resin portion obtained by molding resin from the back side of the semiconductor chip. The CSP substrate is cut along the streets to be divided into individually packaged CSPs.

  Such cutting of the CSP substrate is generally performed by a precision cutting device. The cutting apparatus includes a cutting blade having an annular abrasive layer, and the CSP substrate is cut along the street by rotating the cutting blade and moving relative to the street of the CSP substrate. Divide into CSPs. However, when the CSP substrate is cut with a cutting blade, there is a problem that burrs are generated in the connection terminals, and the adjacent connection terminals are short-circuited to deteriorate the quality and reliability of the CSP.

  Further, when a workpiece such as a semiconductor wafer is cut by a cutting blade, not only the CSP substrate, there is a problem that fine cutting waste adheres to the surface of the workpiece and is contaminated.

  As a cutting technique for solving such problems in cutting with a cutting blade, high pressure processing water mixed with abrasive grains such as silica, garnet, diamond, etc. is sprayed from a nozzle onto the work held by the work holding means. A water jet cutting process for cutting has been proposed (see, for example, Patent Documents 1 and 2).

JP 2005-231000 A JP 2004-136427 A

  The water jet machining method shown in Patent Documents 1 and 2 is processed by injecting the processing water from the nozzle tip toward the workpiece, but the processing water is injected with a certain spread, There is a problem that it is difficult to sufficiently reduce the processing width.

  The present invention has been made in view of the above, and an object of the present invention is to provide a water jet machining method capable of sufficiently narrowing the machining width.

  In order to solve the above-described problems and achieve the object, a water jet machining method according to the present invention is a water jet machining method in which a workpiece having a machining scheduled line is cut by spraying machining water containing abrasive grains from a nozzle. A mask mounting method in which a mask member is mounted on the processing side surface of the workpiece, and an opening having a predetermined width formed in the mask member for each processing line to be processed corresponds to the processing line. An alignment step of aligning the alignment pattern set on the workpiece with respect to the workpiece on which the mask member is mounted, and the opening of the mask member with respect to the workpiece aligned in the alignment step By injecting the processing water from the nozzle along the planned processing line via Characterized in that it comprises a processing step of performing processing to over click, the.

  Further, in the water jet machining method according to the present invention, in the above invention, the mask mounting step includes a mask installation step of installing the mask member in a state before the opening is formed on the processing side surface of the workpiece. And an opening forming step of performing removal processing along the planned processing line for each of the planned processing lines to form the opening having a predetermined width with respect to the mask member installed on the workpiece. It is characterized by.

  The water jet machining method according to the present invention is characterized in that, in the above invention, the mask member is made of a transparent material with respect to alignment light for detecting the alignment pattern in the alignment step.

  The water jet machining method according to the present invention is a water jet machining method for cutting a workpiece having a machining scheduled line by spraying machining water containing abrasive grains from a nozzle, and a mask is formed for each machining scheduled line. An alignment pattern set for the workpiece is set on the workpiece on which the mask member is mounted on the processing side surface so that openings of a predetermined width formed in the member correspond to the planned processing lines. An alignment step for performing alignment, and the work water that is aligned in the alignment step by spraying the processing water from the nozzle along the planned processing line through the opening of the mask member. And a processing step for performing processing.

  According to the water jet machining method of the present invention, a mask member having an opening with a predetermined width for each machining scheduled line is mounted on the workpiece, and the workpiece is aligned with the nozzle through the opening. Since the processing water is sprayed from the nozzle along the scheduled processing line, even if the processing water sprayed from the nozzle spreads, it is sufficiently regulated by the opening with a predetermined width in an appropriate state ensuring alignment It is possible to perform water jet machining with a narrow and uniform width on the workpiece.

  Hereinafter, a water jet machining method which is the best mode for carrying out the present invention will be described with reference to the drawings.

  First, the removal processing apparatus 100 and the water jet processing apparatus 200 used in the water jet processing method of the present embodiment will be described. FIG. 1 is an external perspective view showing the configuration of the main part of the removal processing apparatus 100. The removal processing apparatus 100 is for forming an opening having a predetermined width by performing a removal process on a mask member placed on a workpiece in a mask mounting process described later. In the present embodiment, A cutting device is used.

  The removal processing apparatus 100 includes a holding unit 101 that holds the workpiece 1, a cutting unit 103 that cuts the workpiece 1 held on the holding unit 101 as a removal process with a cutting blade 102 that rotates at high speed, and a holding unit 101. Imaging means 104 for imaging the held workpiece 1 is provided. The holding means 101 sucks and holds the workpiece 1 and is rotatably connected to a motor (not shown) in the cylindrical portion 105.

  The holding means 101 is mounted on two stages of sliding blocks 106 and 107. The holding means 101 is provided and mounted on the sliding block 106 so as to be movable in the X-axis direction, which is the horizontal direction, by a processing feed means 110 constituted by a ball screw 108, a nut (not shown), a pulse motor 109, and the like. The workpiece 1 is processed and fed relative to the cutting blade 102 of the cutting means 103. Similarly, the holding means 101 is provided so as to be movable in the Y-axis direction, which is the horizontal direction, by an index feeding means 113 constituted by a ball screw 111, a nut (not shown), a pulse motor 112, etc. The mounted work 1 is indexed and fed relative to the cutting blade 102 of the cutting means 103.

  The cutting means 103 includes a housing 114 arranged substantially horizontally, and incorporates a motor, a spindle, and the like that rotate the cutting blade 102. The housing 114 is provided so as to be movable in the Z-axis direction, which is a vertical direction, by a lifting / lowering feeding means 118 constituted by a ball screw 116, a nut (not shown), a pulse motor 117 and the like with respect to the support block 115. On the other hand, the cutting blade 102 of the cutting means 103 is relatively lowered.

  Further, the imaging means 104 mounted on the front end of the housing 114 images the upper surface of the work 1 held on the holding means 101 and is a processing scheduled line that is an area to be cut by the cutting blade 102 of the cutting means 103. For alignment. The imaging means 104 includes a light source that emits visible light for alignment, an imaging device (CCD) that images the workpiece 1 illuminated by the light source, and the like.

  FIG. 2 is an external perspective view showing the configuration of the main part of the water jet machining apparatus 200. The water jet machining apparatus 200 generally includes a holding unit 201 that holds the workpiece 1, and a nozzle 202 that performs cutting processing by injecting machining water containing abrasive grains onto the workpiece 1 held by the holding unit 201. And a catch tank 204 that is disposed immediately below the nozzle 202 and receives the machining water penetrating the workpiece 1, and an imaging unit 205 that images the workpiece 1 held on the holding unit 201. ing.

  The holding means 201 is formed of a hard metal such as stainless steel, and the work 1 is passed through a predetermined jig (not shown) (for example, see the jig shown in FIG. 8 or FIG. 9 in Japanese Patent Laid-Open No. 2008-188695). Positioning and holding a plate-like member 206 placed in a row, a rectangular opening 207 formed in a shape corresponding to the shape of the workpiece 1 and penetrating in the vertical direction, and a predetermined jig on which the workpiece 1 is mounted. And a clamp mechanism 208.

  The holding unit 201 can be moved in the X-axis direction by a first feeding unit 211 including a ball screw 209, a pulse motor 210, and the like. Therefore, the work 1 held by the holding unit 201 can be moved relative to the nozzle 202 in the X-axis direction by the first feeding unit 211. The movable base 212 on which the first feeding means 211 is mounted can be moved in the Z-axis direction by the second feeding means 215 including a ball screw 213, a pulse motor 214, and the like. Therefore, the workpiece 1 held by the holding unit 201 can be moved relative to the nozzle 202 in the Z-axis direction by the movable base 212 and the second feeding unit 215. Further, the movable base 216 on which the second feeding means 215 is mounted is movable in the Y-axis direction with respect to the support body 220 by the third feeding means 219 including a ball screw 217, a pulse motor 218, and the like. Yes. Therefore, the work held by the holding means 201 can be moved relative to the nozzle 202 in the Y-axis direction by the movable base 216, the third feeding means 219, and the movable base 212.

  In addition, the imaging unit 205 attached to the tip of the housing 221 for the nozzle 202 images the upper surface of the work 1 held on the holding unit 201 and is an area to be processed by the nozzle 202 of the processed water ejecting unit 203. It is for alignment to detect a certain processing scheduled line. The imaging unit 205 includes a light source that emits visible light for alignment, an imaging element (CCD) that images the workpiece 1 illuminated by the light source, and the like.

  Further, the processing water injection means 203 includes a nozzle 202 that injects downward processing water in which an abrasive material made of alumina ceramic abrasive grains having a particle size of about 30 to 50 μm and the like and water are mixed, and a high pressure to the nozzle 202. The processing water supply means (not shown) including a high-pressure pump for supplying the processed water from the water storage tank 222 or the like. The nozzle 202 includes an injection port having a diameter of about 200 μm, for example.

  Next, the water jet machining method of the present embodiment will be described. FIG. 3 is a schematic perspective view showing a mask installation process for the workpiece 1 to be processed, FIG. 4 is a perspective view showing an opening forming process, and FIG. 5 is a perspective view showing a processing process. FIG. 6 is a longitudinal side view showing the processing step. In this embodiment, a CSP substrate is used as a work 1. As shown in FIG. 3A, the workpiece 1 is divided by vertical and horizontal processing scheduled lines 2 and 3 to form a plurality of CSPs 4. Further, in the present embodiment, the planned processing lines 2 and 3 are the alignment patterns set on the workpiece 1.

  First, a mask mounting process is performed on such a workpiece 1. In this embodiment, the mask mounting process includes a mask installation process and an opening forming process. In the mask installation step, as shown in FIG. 3A, a mask member 10 is prepared together with the workpiece 1 to be processed, and the mask member 10 is formed on the processing side surface of the workpiece 1 as shown in FIG. Install by pasting. Here, as the mask member 10, a material made of a transparent material having transparency to the alignment light from the imaging means 104 and 205, for example, a dicing tape is used. In addition, the mask member 10 may be made of quartz, sapphire, or the like.

  Next, in the opening forming step, first, the work 1 to which the mask member 10 is attached is held by the holding means 101 of the removal processing apparatus 100 as shown in FIG. At this time, as shown in FIG. 1, the work 1 is sucked and held on the holding means 101 in a state of being stuck on the dicing tape 6 attached to the annular frame 5. Then, after performing the alignment process, as shown in FIG. 4, the mask member 10 is removed along the scheduled processing lines 2 and 3 by the cutting blade 102, thereby opening the opening 11 having a predetermined width. To form.

  Here, in such an opening forming step, first, the holding means 101 holding the workpiece 1 is positioned immediately below the imaging means 104 by the processing feeding means 110 for alignment. Then, an alignment operation for detecting a region in which the opening 11 is to be formed by the cutting blade 102 is performed by detecting the processing planned lines 2 and 3 of the workpiece 1 by the imaging unit 104. In other words, the imaging unit 104 aligns the planned machining line 2 formed in a predetermined direction of the workpiece 1 with the cutting blade 102 that performs a cutting process as a removal process along the planned machining line 2. Image processing such as pattern matching is executed, and alignment of the cutting position associated with the planned processing line 2 is performed on the mask member 10. Similarly, with respect to the planned machining line 3 formed on the workpiece 1, the mask member 10 is aligned with the cutting position corresponding to the planned machining line 3. In such an alignment operation, the mask member 10 exists on the workpiece 1, but the mask member 10 is made of a transparent material that transmits the alignment light, so that the processing scheduled lines 2 and 3 can be recognized without any trouble. . That is, alignment equivalent to the state in which the mask member 10 does not exist is possible.

  After execution of the alignment operation, the cutting blade 102 that rotates at high speed is positioned on the mask member 10 of the desired processing scheduled line 2 in accordance with the alignment information, and the holding means 101 is processed and fed by the processing feeding means 110, whereby the mask is obtained. The member 10 is formed with an opening 11 having a predetermined width along the planned processing line 2. By repeating such processing for all the scheduled processing lines 2 and 3 using the index feeding means 113, the processing feeding means 110, etc., a predetermined width along all the planned processing lines 2 and 3 is obtained. An opening 11 is formed. In this way, the mask member 10 is mounted on the processing side surface of the workpiece 1, and the opening 11 having a predetermined width formed in the mask member 10 for each processing line 2, 3 corresponds to the processing line 2, 3. It becomes a state to do. Note that the width of the opening 11 to be formed is determined by the blade thickness of the cutting blade 102, but can be regulated to a predetermined width narrower than the spread of the processing water sprayed from the nozzle 202.

  Next, the workpiece 1 on which the mask member 10 having the opening 11 is mounted is positioned and held by the holding means 201 of the water jet machining apparatus 200 as shown in FIG. 2 via a predetermined jig. And after performing an alignment process, as shown in FIG.5 and FIG.6, the process process which cuts the workpiece | work 1 along the process planned lines 2 and 3 with a water jet is performed.

  Here, in the alignment step, the holding unit 201 holding the workpiece 1 is positioned directly below the imaging unit 205 by the feeding units 211 and 219. Then, an alignment operation for detecting a region to be cut by the processing water sprayed from the nozzle 202 is performed by detecting the planned processing lines 2 and 3 of the workpiece 1 by the imaging unit 205. That is, the imaging unit 205 is an image such as pattern matching for aligning the planned processing line 2 formed in a predetermined direction of the workpiece 1 and the nozzle 202 that performs cutting along the planned processing line 2. The process is executed, and the alignment of the cutting position with respect to the workpiece 1 is performed. Similarly, the alignment of the cutting processing position with respect to the workpiece 1 is performed for the planned processing line 3 formed on the workpiece 1. In such an alignment operation, the mask member 10 exists on the workpiece 1, but the mask member 10 is made of a transparent material that transmits the alignment light, so that the processing scheduled lines 2 and 3 can be recognized without any trouble. . That is, alignment equivalent to the state in which the mask member 10 does not exist is possible.

  After such an alignment operation is performed, the nozzle 202 is positioned on the opening 11 of the mask member 10 corresponding to the desired processing line 2 or 3 according to the alignment information, and the processing water 230 containing abrasive grains from the nozzle 202. The holding means 201 is processed and fed in the direction of the planned processing line 2 or 3 by the feeding means 211 or 219. As shown in FIG. 6 (a), the machining water 230 sprayed from the nozzle 202 toward the workpiece 10 is, as shown in FIG. 6 (b), the planned machining line 2 or 2 of the workpiece 10 through the opening 11. The through-hole 7 is formed by cutting the three portions, and reaches the catch tank 204 through the opening 207 while maintaining a high pressure, and the momentum of the processing water 230 is weakened. By repeating such processing for all the planned processing lines 2 and 3 using the feeding means 211 or 219, etc., cutting along all the planned processing lines 2 and 3 is performed.

  When the workpiece 1 is cut by the machining water 230 sprayed from the nozzle 202, the machining water 230 has a spread as shown in FIG. However, the mask member 10 exists on the workpiece 1, and the machining water 230 is sprayed onto the workpiece 1 through the opening 11 formed to have a predetermined width in the planned machining lines 2 and 3. Therefore, it is possible to subject the workpiece 1 to water jet machining such that the workpiece 1 is cut by the sufficiently narrow and uniform through-hole 7 that is regulated by the opening 11 having a predetermined width. Further, when the machining water 230 is sprayed onto the workpiece 1, the directivity of the machining water 230 is improved by the opening 11 of the mask member 10, so that chipping of each chip to be cut can be suppressed. Furthermore, since the cut portion of the workpiece 1 is pressed by the mask member 10, film peeling on the workpiece 1 can be suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the cutting blade 102 is used for the removal process for forming the opening 11 in the mask member 10, but instead of the cutting means 103, as indicated by a virtual line in FIG. The laser beam irradiation means 120 that forms the opening 11 by irradiating a laser beam from the condenser 121 may be used. In the case of the laser beam irradiation means 120, it is possible to cope with the case where the processing scheduled line is a curve. In any case, by installing the mask member 10 in a state before the opening 11 is formed on the processing-side surface of the work 1 and then performing removal processing for forming the opening 11 on the mask member 10, the work 1 And the mask member 10 (opening 11) can be made unnecessary in alignment.

  However, by preparing a mask member in which an opening for each processing line is formed in advance, aligning each opening to correspond to each processing line, and mounting the mask member on the work, A mask member may be mounted on the processing side surface, and an opening having a predetermined width formed in the mask member for each planned processing line may be in a state corresponding to the planned processing line.

  Further, in the present embodiment, the processing planned lines 2 and 3 themselves in the workpiece 1 are used as the alignment pattern. However, the present invention is similarly applied even when the alignment pattern has a predetermined shape set in advance on the workpiece 1. can do.

  In particular, the mask member does not necessarily have to be a transparent material if the alignment pattern is set in a place that does not interfere with the package or device such as CSP4 or if it can be set. For example, as shown in FIG. 7A, in the work 1a, an alignment pattern 8 that defines the position of each of the planned processing lines 2a and 3a is formed on the peripheral ear of the work 1a. As shown in FIG. 7B, the mask member 10a may be installed only in a necessary portion on the work 1a in a state where the alignment pattern 8 is visible from the outside. According to this, since the imaging units 104 and 205 can perform alignment using the surrounding alignment pattern 8 even if the processing planned lines 2a and 3a themselves are not visible, the mask member 10a can perform the alignment with respect to the alignment light. An opaque material can be used, and the choice of materials is expanded. In this case, the opening may be formed in advance or after the installation.

  The workpiece 1 has been described with reference to the example of the CSP substrate, but is not particularly limited. For example, wafers such as semiconductor wafers, adhesive members such as DAF (Die Attach Film) provided on the back side of the wafer for chip mounting, semiconductor product packages, ceramic, glass, sapphire, or silicon substrates, various electronic components , Various drivers, and various processed materials that require accuracy of the order of μm. In particular, burrs such as CSP substrates that cause burrs, or those that contain various materials such as multi-layer work of resin and metal, carbon fiber materials, and the like are anisotropic. The material of the present embodiment is relatively hard and brittle, has a low thermal conductivity such as titanium, and easily accumulates heat at the processing point, as compared to cutting blade processing or laser processing. It can be said that it is suitable for such water jet processing. Also, the shape of the work is not limited to the rectangular shape as in the present embodiment, and may be a general circular shape or the like in a semiconductor wafer or the like.

  Further, in the present embodiment, the example in which the workpiece 1 is fully cut with the processing water 230 has been described, but the present invention can be similarly applied to the case of half cut. Here, in the case of half-cutting, by interposing the mask member 10 on the work 1, it is useful to protect the work 1 and the nozzle 202 from rebounding when the machining water 230 is jetted (in addition, full cut) Even at times, until the through hole 7 is opened, it similarly helps to protect the workpiece 1 and the nozzle 202 from rebounding). However, the harder the material of the mask member 10 is, the higher the strength as a mask is. However, the rebound of the abrasive grains is large and the nozzle 202 is not protected. On the other hand, if the material of the mask member 10 is too soft, the strength as the mask is lowered. However, the rebound of the abrasive grains is reduced, and the nozzle 202 is effectively protected. Therefore, since the processing water 230 is set to a processing strength commensurate with the strength of the workpiece 1, it is desirable to select a mask member 10 having a strength that can withstand it and a small rebound.

It is an external appearance perspective view which shows the structure of the principal part of the removal processing apparatus used for this Embodiment. It is an external appearance perspective view which shows the structure of the principal part of the water jet processing apparatus used for this Embodiment. It is a schematic perspective view which shows the mask installation process regarding the workpiece | work used as a process target. It is a perspective view which shows an opening part formation process. It is a perspective view which shows a process process. It is a vertical side view which shows a process process. It is a perspective view which shows the modification of a mask installation process.

Explanation of symbols

1 Workpiece 2, 3 Planned processing line 8 Alignment pattern 10 Mask member 11 Opening 202 Nozzle 230 Processing water

Claims (4)

A water jet machining method for cutting a workpiece having a machining scheduled line by spraying machining water containing abrasive grains from a nozzle,
A mask mounting step in which a mask member is mounted on the processing side surface of the workpiece, and an opening having a predetermined width formed in the mask member for each processing line to be processed corresponds to the processing line.
An alignment step of performing alignment of an alignment pattern set on the workpiece with respect to the workpiece on which the mask member is mounted;
A processing step of processing the workpiece by injecting the processing water from the nozzle along the planned processing line through the opening of the mask member with respect to the workpiece aligned in the alignment step;
A water jet machining method comprising: The mask mounting process includes
A mask installation step of installing the mask member in a state before the opening is formed on the processing side surface of the workpiece;
An opening forming step of forming the opening of a predetermined width by performing removal processing along the planned processing line for each of the planned processing lines with respect to the mask member installed on the workpiece;
The water jet machining method according to claim 1, comprising:   The water jet machining method according to claim 1, wherein the mask member is made of a transparent material with respect to alignment light for detecting the alignment pattern in the alignment step. A water jet machining method for cutting a workpiece having a machining scheduled line by spraying machining water containing abrasive grains from a nozzle,
With respect to the workpiece on which the mask member is mounted on the surface on the processing side so that the openings of a predetermined width formed in the mask member for each processing line are in a state corresponding to the processing line, the workpiece An alignment process for aligning the alignment pattern set in
A processing step of processing the workpiece by injecting the processing water from the nozzle along the planned processing line through the opening of the mask member with respect to the workpiece aligned in the alignment step;
A water jet machining method comprising:

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