JP2008012633A - Water jet machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with the frequent replacement of a buffer tank by preventing deterioration of the buffer tank installed in a water jet machining device. <P>SOLUTION: In this water jet machining device 1, a workpiece 8 is held in a holding means 2, and machining water 30a mixed with abrasive grains and water is injected from an injection nozzle 30 to machine the workpiece 8. The buffer tank 4 constituted of a water storage tank 40 for storing the machining water 30a passing through the workpiece 8, a basket 41 stored in the water storage tank 40, and a plurality of buffer balls 42 stored in the basket 41 is provided just under the injection nozzle 30. By agitating the buffer balls 42, force of the machining water can be weakened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water jet processing apparatus that processes a workpiece by high-pressure jetting of processing water in which abrasive grains and water are mixed.

  A wafer on which a plurality of devices such as an IC and an LSI are formed is divided into individual devices using a dividing device such as a dicing device or a laser processing device, packaged, and used for various electronic devices.

  For example, when manufacturing a package of almost the same size as a semiconductor chip called a CSP (Chip Size Package), the chip is arranged and arranged in each partitioned region in a lead frame partitioned in a matrix by streets. After all chips are sealed with resin and a CSP substrate is formed, the street is cut and divided into individual CSPs.

  However, when the lead frame is cut with a cutting blade, there is a problem that burrs are generated and the lead terminals are short-circuited. The same problem occurs when cutting other workpieces. In view of this, the present applicant has developed a water jet machining apparatus that performs cutting by jetting processing water, which is a mixture of abrasive grains and water, from an injection nozzle at a high pressure of about 50 to 100 MPa. In this water jet processing apparatus, since the injected processing water penetrates the workpiece, a buffer tank for weakening the momentum of the processing water is installed in the penetrating direction of the processing water (for example, a patent) Reference 1).

JP 2005-230994 A

  However, since the buffer tank deteriorates with time due to the pressure of the processing water, there is a problem that the buffer tank must be frequently replaced.

  Therefore, the problem to be solved by the present invention is to prevent deterioration of the buffer tank installed in the water jet machining apparatus and eliminate frequent replacement.

  The present invention relates to holding means for holding a workpiece, and processing water for processing a workpiece by injecting, from an injection nozzle, processing water in which abrasive grains and water are mixed into the workpiece held by the holding means. The present invention relates to a water jet machining apparatus comprising at least a jetting means and a buffer tank that is disposed immediately below the jet nozzle and receives the machining water penetrating the workpiece to weaken the momentum of the machining water. It is comprised from the water storage tank which stores the processed water which penetrated the thing, the basket accommodated in a water storage tank, and the some buffer ball accommodated in a basket.

  In the water jet machining apparatus, the buffer ball preferably has a diameter of 3 mm to 8 mm.

  Moreover, it is desirable that the material constituting the buffer ball includes the same material as that constituting the abrasive grains contained in the processed water. In this case, the buffer sphere is made of alumina ceramics, for example.

  In the present invention, since a plurality of buffer balls are accommodated in the basket to constitute the buffer tank, the processing water penetrating the workpiece collides with the plurality of buffer balls, and the plurality of buffer balls are agitated to process the processing water. Momentum is weakened. In particular, by setting the diameter of the buffer ball to 3 mm to 8 mm, the momentum of the processing water is more effectively reduced.

  In addition, if the material that makes up the buffer ball contains the same material as the material that makes up the abrasive grains contained in the processed water, even if the buffer ball is damaged by impact from the processed water, the processed water is circulated. There is no obstacle to reuse.

  A water jet machining apparatus 1 shown in FIG. 1 includes a holding unit 2 that holds a workpiece, and a machining water injection unit 3 that processes the workpiece by injecting the machining water onto the workpiece held by the holding unit 2. And at least a buffer tank 4 that receives the injected processing water and weakens the momentum of the processing water.

  The holding means 2 includes a plate-like member 20 on which a workpiece is placed, a penetrating portion 21 formed in a shape corresponding to the shape of the workpiece and penetrating in the vertical direction, and when the workpiece is placed. And a plurality of positioning pins 22 serving as a positioning reference.

  The holding means 2 is driven by the first feeding means 5 and is movable in the Y-axis direction (the direction of the arrow Y in FIG. 1). The first feeding means 5 includes a ball screw 50 disposed in the Y-axis direction, a pulse motor 51 connected to one end of the ball screw 50 and rotating the ball screw 50, and a guide rail 52 disposed in parallel to the ball screw 50. And a holding means supporting portion 53 that supports the holding means 2 and is slidably contacted with the guide rail 52 and has an internal nut screwed into the ball screw 50, and a base portion 54 that supports the ball screw 50, the pulse motor 51, and the guide rail 52. As the ball screw 50 is rotated by being driven by the pulse motor 51, the holding means support portion 53 is moved in the Y-axis direction while being guided by the guide rail 52.

  The holding means 2 is driven by the second feeding means 6 and is movable in the Z-axis direction (the direction of the arrow Z in FIG. 1). The second feeding means 6 is arranged in the Z direction and is parallel to the ball screw 60 that is screwed into a nut inside the base portion 54, a pulse motor 61 that is connected to one end of the ball screw 60 and rotates the ball screw 60, and the ball screw 60. The guide rail 62 is slidably in contact with the base 54 and the ball screw 6, the pulse motor 61, and the base 63 that supports the guide rail 62. The ball screw 60 is driven by the pulse motor 61 to rotate. Accordingly, the first feeding means 5 and the holding means 2 are guided by the guide rail 62 and moved in the Z-axis direction.

  The holding means 2 is driven by the third feeding means 7 and is movable in the X-axis direction (the direction of the arrow X in FIG. 1). The third feeding means 7 includes a ball screw 70 disposed in the X-axis direction and screwed into a nut inside the base 63, a pulse motor 71 connected to one end of the ball screw 70 and rotating the ball screw 70, and a ball screw 70. A guide rail 72 that is arranged in parallel and is in sliding contact with the base 63, and a base 73 that supports the ball screw 70, the pulse motor 61, and the guide rail 62, and is driven by the pulse motor 71 to rotate the ball screw 70. Accordingly, the second feeding means 6, the first feeding means 5 and the holding means 2 are guided by the guide rail 72 and moved in the X-axis direction.

The processing water injection means 3 includes an injection nozzle 30 that injects downward processing water in which abrasive grains made of alumina ceramics (Al ₂ O ₃ ) having a particle size of ¢ 30 μm to ¢ 50 μm and water are mixed. A processing water tank 32 for storing processing water is connected to 30 via a pump 31, and the processing water is supplied from the processing water tank 32 to the injection nozzle 30 by the pump 31. Further, in the illustrated example, a circulation path 46 for circulating and reusing the used machining water is connected to the machining water tank 32, and the machining water passing through the circulation path 46 flows into the machining water tank 32. .

  The buffer tank 4 is disposed immediately below the injection nozzle 30. As shown in FIG. 2, the buffer tank 4 includes a water storage tank 40 that stores the processing water sprayed from the spray nozzle 30, a net-like basket 41 that is stored in the water storage tank 40, and a plurality of containers that are stored in the basket 41. And a buffer ball 42. The water storage tank 40 is formed of, for example, stainless steel, and in the illustrated example, the water storage tank 40 is accommodated in the drainage tank 43, and the processing water overflowing from the water storage tank 40 is transferred to the drainage tank 43. Can be drained.

  The water storage tank 40 is provided with an outlet 44 through which processing water flows into the circulation path 46. The outlet 44 is preferably provided with a valve. As shown in FIG. 1, the processing water refining unit 50 is interposed in the circulation path 46, and the used processing water is made available again and flows into the processing water tank 32. On the other hand, the drainage tank 43 is provided with an outlet 45 that flows out into the drainage passage 47.

The buffer spheres 42 are balls formed of alumina ceramics (Al ₂ O ₃ ) having the same type of wear resistance as the alumina ceramics constituting the abrasive grains contained in the processing water. As the buffer ball 42, for example, an “alumina ball” provided by AS ONE Corporation can be used. The diameter of the buffer ball is, for example, 3 mm to 8 mm.

  The CSP substrate 8 shown in FIG. 3 is an example of a workpiece, and includes three blocks 8a, 8b, and 8c. Each block is partitioned by a horizontal street S1 and a vertical street S2 to form a plurality of CSPs 80. The street S is divided into individual CSPs 80 by cutting the street S vertically and horizontally.

  When the CSP substrate 8 is divided into individual CSPs 80, the CSP substrate 8 is supported by the first jig 9a shown in FIG. 4 and the second jig 9b shown in FIG. Each jig has a structure in which a support plate 90 and a lid member 91 are connected to each other by a hinge 92 so that the support plate 90 can be opened and closed. A positioning pin formed on the holding means 2 shown in FIG. The same number of fitting holes 93 as the positioning pins 22 are formed. Further, the cover member 91 is formed with a through window 94 for passing the processed water. An engagement hole 95 is formed on the side surface of the support plate 90, and an engagement piece 96 is formed on the lid member 91 by engaging with the engagement hole 95. The CSP substrate 8 is placed on the support plate 90. When the engagement piece 96 is engaged with the engagement hole 95 in the state where the support plate 90 is engaged, the support plate 90 and the lid member 91 are locked in the closed state, and the CSP substrate 8 is held between the support plate 90 and the cover member 91.

  The first jig 9a shown in FIG. 4 is a jig used when cutting the lateral street S1 shown in FIG. 3, and all the lateral streets in the state in which the CSP substrate 8 is held in the support plate 90. Under S1, a through groove 97 for passing the processing water is formed in the same direction as the lateral street S1. The through groove 97 in the illustrated example is formed continuously.

  On the other hand, 9b shown in FIG. 5 is a jig used when cutting the vertical street S2 shown in FIG. 3, and below the all vertical streets S2 in the state in which the CSP substrate 8 is held in the support plate 90. The through-groove 98 for letting process water pass is formed in the same direction as the vertical street S2. The through groove 98 in the illustrated example is formed continuously.

  Referring to FIG. 1, the first jig 9 a holding the CSP substrate 8 is held by the holding means 2 with the fitting hole 93 fitted to the positioning pin 22. Then, either one of both ends of the lateral street S1 formed on the CSP substrate 8 is positioned directly below the injection nozzle by driving by the first feeding unit 5 and the third feeding unit 7.

  Then, the processing water in which the abrasive grains and water are mixed is jetted from the jet nozzle 30 at a high pressure downward, and the CSP substrate 8 is moved in the X-axis direction by the third feeding means 7 while the horizontal direction corresponding to the X-axis direction. Cut the street S1 in the direction. After cutting one horizontal street S1, the CSP substrate 8 is slightly moved in the Y-axis direction by the first feeding means 5, and then the CSP substrate 8 is again moved in the X-axis direction by the third feeding means 7. Move and cut the adjacent horizontal street S1. Such operation is continuously repeated so that the processing water is sprayed along the through groove 97 formed in the support plate 90 of the first jig 9a. As a result, all the horizontal streets S1 are cut.

  Next, while removing the 1st jig | tool 9a from the holding means 2, the CSP board | substrate 8 is removed from the 1st jig | tool 9a, The CSP board | substrate 8 from which the 1st street S1 was cut | disconnected is used as the 2nd jig | tool 9b. To hold. Then, the second jig 9 b is held by the holding means 2.

  Next, either one of both ends of the longitudinal streets S2 formed on the CSP substrate 8 is positioned directly below the injection nozzle by driving by the first feeding unit 5 and the third feeding unit 7. Then, working water in which abrasive grains and water are mixed is jetted downward from the jet nozzle 30 at a high pressure, and the CSP substrate 8 is moved in the Y-axis direction by the first feeding means 5 while the vertical direction corresponding to the Y-axis direction. Cut the direction street S2. After cutting one longitudinal street S2, the CSP substrate 8 is slightly moved in the X-axis direction by the third feeding means 7, and then the CSP substrate 8 is moved again in the Y-axis direction by the first feeding means 5. Next, the adjacent vertical street S2 is cut. Such operation is continuously repeated so that the processing water is sprayed along the through groove 98 formed in the support plate 90 of the second jig 9b. As a result, all the vertical streets S2 are cut and divided into individual CSPs.

  As shown in FIG. 6, during the cutting, the injected processing water 30 a penetrates the CSP substrate 8 and reaches the buffer tank 4 while maintaining a high pressure. Since the water storage tank 40 constituting the buffer tank 4 located immediately below the injection nozzle 30 stores a net-like basket 41, and the basket 41 stores a plurality of buffer balls 42, high-pressure processed water is buffered. Collides with sphere 42. And since the buffer ball 42 which process water collided rotates and the some buffer ball 42 is stirred including the thing which the process water did not collide, the momentum of process water will be weakened. Further, the processed water whose momentum has weakened falls through the mesh basket 41 and accumulates in the water storage tank 40. In this way, since the processing water is accumulated in the water storage tank 40 after the momentum at the time of injection is weakened by the buffer balls 42, the water storage tank 40 is not deteriorated.

  In addition, when the diameter of the buffer ball | bowl 42 became 10 mm or more, stirring stagnated and the hole was opened in the buffer ball | bowl 42 directly under the injection nozzle 30, and it confirmed that the function as the buffer tank 4 was impaired. On the other hand, it was confirmed that when the diameter of the buffer ball 42 was 2 mm or less, the stirring became so intense that the momentum of the processing water could not be absorbed and the basket 41 and the water storage tank 40 were damaged. By setting the diameter of the buffer ball 42 to 3 mm to 8 mm, preferably 6 mm, the buffer ball 42 is stirred by the momentum of the processing water, and the momentum of the processing water can be reduced more effectively.

  The used processing water collected in the water storage tank 40 is drained from the drainage path 47 or purified by the processing water refining unit 50 in the circulation path 46 and returned to the processing water tank 32 for reuse. If the material constituting the buffer ball 42 includes the same material as the material constituting the abrasive grains contained in the processed water, even if the buffer ball is damaged due to an impact from the processed water, It can be circulated and reused. For example, if the buffer balls 42 are formed of alumina ceramics and the abrasive grains contain alumina ceramics, even if the buffer balls 42 are damaged, there is no problem in circulating and reusing the processing water.

It is a perspective view which shows an example of a water jet processing apparatus. It is a disassembled perspective view which shows an example of a buffer tank. It is a top view which shows an example of a to-be-processed object. It is a perspective view which shows the 1st example of a jig | tool. It is a perspective view which shows the 2nd example of a jig | tool. It is explanatory drawing which shows the state which cut | disconnects a workpiece.

Explanation of symbols

1: Water jet processing device 2: Holding means 20: Plate-like member 21: Penetration part 22: Positioning pin 3: Processing water injection means 30: Injection nozzle 31: Pump 32: Processing water tank 4: Buffer tank 40: Water storage tank 41 : Basket 42: Buffer ball 43: Drainage tank 44, 45: Outlet 46: Circulation path 47: Drainage path 5: First feeding means 50: Ball screw 51: Pulse motor 52: Guide rail 53: Holding member support 54: Base 6: Second feeding means 60: Ball screw 61: Pulse motor 62: Guide rail 63: Base 7: Third feeding means 70: Ball screw 71: Pulse motor 72: Guide rail 73: Base 8: CSP substrate 80: CSP S: Street 9a: First jig 9b: Second jig 90: Support plate 91: Lid member 92: Hinge 93: Fitting hole 94 Through window 95: engaging hole 96: the engaging pieces 97 and 98: the through-groove

Claims (4)

Holding means for holding the workpiece, and processing water injection means for processing the workpiece by injecting the processing water in which abrasive grains and water are mixed into the workpiece held by the holding means from the injection nozzle And a water jet machining apparatus comprising at least a buffer tank that is disposed immediately below the injection nozzle and receives the machining water penetrating the workpiece to weaken the momentum of the machining water,
The buffer tank is a water jet processing device that includes a water storage tank that stores processing water that has penetrated the workpiece, a basket that is stored in the water storage tank, and a plurality of buffer balls that are stored in the basket. .   The water jet machining apparatus according to claim 1, wherein the buffer ball has a diameter of 3 mm to 8 mm.   The water jet machining apparatus according to claim 1 or 2, wherein the material constituting the buffer ball includes the same material as that constituting the abrasive grains contained in the processed water.   The water jet machining apparatus according to claim 3, wherein the buffer ball is formed of alumina ceramics.

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