TW512450B - Apparatus and method to dice integrated circuits from a wafer using a pressurized jet - Google Patents

Abstract

An apparatus and method to cut irregularly shaped dice from a wafer using a fluid jet cutting system. One embodiment of the invention involves a method to cut irregularly shaped dice from a wafer, such as planar light-wave circuit device. The method includes placing a wafer on a fixture; aligning the wafer in the fixture to expose the dice to a fluid jet cutting nozzle; supplying an abrasive to the fluid jet cutting nozzle; supplying a pressurized fluid to the fluid jet cutting nozzle expelling the abrasive in combination with the fluid from the fluid jet cutting nozzle at a velocity sufficient to cut through the wafer, while the fluid jet cutting nozzle moves in relation to the wafer in the fixture; and removing the dice from the fixture after the dice have been cut from the wafer. A second embodiment of the invention is directed to an apparatus to provide a wafer die cutting system to cut a wafer. The apparatus includes a fixture to align and hold the wafer a cutting nozzle to expel a fluid and an abrasive towards the wafer at a velocity sufficient to cut through the wafer, a fluid source to supply the fluid to the cutting nozzle; an abrasive source to supply the abrasive to the cutting nozzle; and a mechanism to move the cutting nozzle relative to the wafer in the fixture.

Description

512450 A7 B7 V. Description of the invention (i) [Background of the invention] [Field of the invention] The present invention generally relates to a device and method for cutting an integrated circuit with a high-pressure jet, and more specifically, an abrasive sprayer (abrasive Water jet) device and method for cutting a wafer into integrated circuits such as planar light-wave circuits. [Description of the prior art] The planar light wave circuit (PLC) has a tendency to be used in many optical and electronic optical systems (such as computer systems, programmable electronic systems, telecommunication switching systems, control systems, etc.). Planar lightwave circuits can be fabricated on a wafer in much the same way as electronic integrated circuits are fabricated on a semiconductor wafer. In some cases, planar lightwave circuits can be manufactured on wafers such as electronic integrated circuit wafers, but in order to increase the production of planar lightwave circuits for individual wafers, most of them are used to produce planar lightwaves on irregularly shaped wafers. The circuit is better. Figure 1A illustrates a portion of a wafer containing planar lightwave circuit arrays 102, 104, 106, 108, 110, 112, and 114 of the same irregular shape. Each planar lightwave circuit includes a non-rectangular structure that does not completely fit a rectangular sample after being cut from wafers 116 and 118 (indicated by dashed lines). Fig. 1B shows the conventional rectangular die cutting situation, which will lose several plane lightwave circuits. The plane lightwave circuit 110 is still intact and the plane lightwave circuits 106, 108, 112, and 114 are damaged. The cutting device and method for cutting non-rectangular wafers by cutting wafer components can greatly improve the yield and manufacturing cost of each planar lightwave circuit wafer. Figure 1C illustrates that the size of the plain paper after precision cutting from the wafer applies the Chinese national standard (CNS > A4 specification (210 X 297 male t _ ^ 1 ~~ 9Ϊ856 ") ------------ Please read the note on the back first Please fill out this page again) Order. -If ϋ 512450 V. Description of the invention (2) Surface light wave circuit 102. However, the wafer is cut into the traditional wafer dicing method and device (ie, a rotating-grinding wafer ore). Such irregular shapes have great difficulties. Traditional wafer cutting methods and devices are particularly unsuitable for cutting a die into non-rectangular edges. Laser cutting can cut irregularly shaped die from a wafer. There are many disadvantages. These disadvantages include high equipment and operating costs, and poor cutting quality due to thermal stress and different laser energy absorption of different structures and layers on the wafer. This laser crystal The bad quality of the edge of the grain cut will cause the fracture of the die and eventually spread to the center of the die, so there will be problems in operation and reliability. Therefore, in order to increase the yield of the die and reduce the individual wafers The unit cost of manufacturing a die requires a low-cost device and method for cutting irregular-shaped die from a wafer in the art of the art. There is also an urgent need for a device and method in the art of the art. The fracture will not propagate to the operating area in the center of the die and high-quality die edges can be obtained. [Summary of the Invention] In order to increase the yield of individual wafers and reduce the unit cost of manufacturing the die, the present invention provides a Low-cost device and method for cutting irregular-shaped grains from a wafer. The present invention also provides a device and method capable of cutting out high-quality grain edges without propagating fractures to the operation area of the grains. The present invention The first aspect is a method for cutting irregularly shaped grains from a wafer. This method includes placing the wafer on a holder, aligning and fixing the paper size and using the Chinese National Standard (CNS) A4 specification ( (210 x 297 male cages) 512450 A7 B7 printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (3) The wafers in the device can expose multiple die to the jet cutting nozzle, when When the flow cutting nozzle is moved to the relevant position of the wafer on the holder, the mixed liquid is discharged from the jet cutting nozzle at a flow rate sufficient to cut through the wafer, and the crystal is removed from the holder after the die is cut from the wafer. The second aspect of the present invention is a device for providing a wafer cutting system for dicing a wafer. The device includes a holder capable of calibrating and fixing the wafer, and discharging liquid toward the wafer at a flow rate sufficient to cut the wafer. And the cutting tip of the abrasive, the liquid supply source for supplying the cutting tip liquid, the abrasive supply source for supplying the cutting tip abrasive, and the mechanical device, the cutting tip can be moved to the relative position of the wafer. The advantages of the present invention can be obtained from the following The detailed description of the invention and the drawings are fully understood through the art in the art. [Simplified Description of the Drawings] Figure 1A illustrates a part of a wafer that contains the same irregularly shaped planar lightwave circuit array. Fig. 1B shows a conventional rectangular die-cutting situation, which will lose several planar lightwave circuits. One planar lightwave circuit is still intact and the other four planar lightwave circuits are damaged. Figure 1C illustrates a planar lightwave circuit after the wafer is accurately cut. FIG. 2 illustrates an embodiment of the present invention using all wafers. FIG. 3 illustrates a holder according to an embodiment of the present invention. Figure 4 illustrates another embodiment of the present invention using a jet cutting system with a visual calibration system. Figure 5 illustrates an embodiment of a wafer with a calibration mark, which is visually calibrated by one or more cameras. ^ -------- (Please read the notes on the back and then fill out this page) This paper size applies to China National Standard (CNS) A4 (210 x 297 mm) 3 91856 512450

5. Description of the Invention (4) FIG. 6 illustrates an embodiment of the cutting head assembly. Figure 7 shows a flow chart for aligning and cutting a wafer on a jet cutting system according to an embodiment of the present invention. FIG. 8 shows a flowchart of dicing a die from a wafer according to another embodiment of the present invention. [Description of Component Symbols] ------------- Installation · — (Please read the precautions on the back before filling this page) Order: • Intellectual Property of the Ministry of Economic Affairs-Bureaux · Printed by X Consumer Cooperative 102, 104, 106, 108, 110, 112, 11 4 Planar light wave circuit 116, 11 8 Non-rectangular structure 200 Wafer slicing 202 Grain 204 ^ 206, 208 Cutting line 3 00 Holder 304 '' 306, 308 Positioning stopper 310, 312 Holder bottom half 314 Surface groove 316 Groove 402 Jet cutting system 404 Crosshair generator 406 Computer hardware / software 408 Camera 410 Monitor 412 , 414, 416, 418, 420 > 422 signal 500, 614 wafer 502 irregular die 504, 506 calibration mark 600 cutting head assembly 602 °? P barrel 606 abrasive inlet 608 cutting head body 610 mixing tube 612 nozzle [ Detailed description of the present invention] The present invention provides an apparatus and method for cutting irregular or regular-shaped crystal grains from a substrate (such as a wafer or a crystal plate) by a curve cutting method. In one embodiment of the present invention, the curved edge is cut from the wafer (non-straight, non-paper size applies to National Standard (CNS) A4 specification ⑵ × 297 public love) 4 91856 512450 A7 B7 intellectual property of the Ministry of Economic Affairs Printed by the Consumer Cooperative of the Bureau of the People's Republic of China. 5. The invention's description (rectangular) of plane light wave circuit grains. In many embodiments, the constituent materials of the substrate are, for example, various compositions of polymers, ceramics, glass (such as borosilicate glass and other low coefficient thermal expansion glass), pure or doped silicon, germanium, gallium arsenide, Or other semiconductor compounds of III-v or II-VI elements. This system is preferred to use relatively non-compressible fluids such as water, with pressures ranging from 36,000 pounds per square inch (36,000 PSI or 2,400 bar) to 100.000 PSI (7,000 bar). In other embodiments, the pressure of the water is from 40.000 PSI (2,700 bar) to 60,000 PSI (4,100 bar). The kinetic energy required to cut the material comes from the ultra-high force provided by pressurized water or other liquids, and borrows This high-speed liquid magma is gathered to form a tight cutting water flow through the cutting nozzle with a very small inner diameter. The main component of this jet cutting system is a grinding pump. To achieve this pressure, water is introduced into the device by means of a booster pump and a filter. The filter filters water before it reaches ultra-high pressure to protect the high-pressure pump and provide a continuous stream of cutting water. After filtering the water into a high pressure cylinder, the water is pressurized to the desired strength. Then water is sent to the abrasive water to cut

^ ifcK nozzle 〇 In one embodiment of the present invention, the grinding device supplies a fine mesh abrasive to the cutting water stream. A typical grinding unit includes an abrasive hopper, an abrasive feed system, a pneumatically controlled on / off valve, and a grinding cutting nozzle. This abrasive is first stored in a pressurized abrasive hopper and then delivered to a metering unit, which controls the amount of particles fed to the cutting nozzle. The abrasive is then introduced into the cutting water flow in the special mixing chamber inside the abrasive cutting head. The harder k paper size is applicable to the national standard (CNS) A4 specification (210 X 297 public love) -------- 3 91856 ▼ I ^ -------- ^ ----- ---. (Please read the note on the back? Matters before filling out this page) 6 512450 V. Description of the invention (6) | The material can accelerate its wear process and cut and grind at a faster rate. After cutting, the energy remaining from the cutting water flow is distributed to the collecting cylinder, which can store the slit material (that is, the washed substrate material) and waste abrasive. Repeated use of harder but more expensive waste abrasives is more economical and improves cutting and machine efficiency. For example, silicon carbide can be used to replace lower cost garnets in cutting operations. In some embodiments, the abrasive is used at a concentration of about 5 to about 60% by weight. A variety of abrasive powders can be used, such as ovine, stone, corundum, alumina, diamond, silica, tungsten carbide, silicon carbide, various ceramic powders, and the like Hard powder (such as compounds of metal oxides). In some embodiments, the average diameter of the abrasive particles is from about 0.1 microns to 2,000 microns. In other embodiments, the average diameter is from about 0.1 microns to 200 microns. In one embodiment, the average particle diameter does not exceed about I20% of the nozzle diameter, and in other embodiments, the average particle diameter does not exceed 10% of the nozzle diameter. If the average particle diameter is large, the nozzle may be blocked due to "bridging". The diameter of the cutting nozzle is usually determined by other parameters. In particular, the diameter of the nozzle of the cutting nozzle is determined by the following parameters : First, the larger the mouth width 'the mouth flow width is larger' and the slit is larger. The accuracy of cutting is usually inversely proportional to the diameter of the nozzle of the cutting mouth. Generally, when cutting thinner materials, The smaller the nozzle, the higher the accuracy and meticulousness of other parameters. Use less cutting medium per unit of cutting length. Second, the larger the nozzle width, the greater the mass flow of splatter 'and the faster the cutting rate. Therefore, the 91856 ^ ^ --------- line (please read the precautions on the back before filling this page) A7 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

V. Description of Invention (8) Example. When cutting 204, 206, and 208, the die 202 of the optical etching method must be aligned, so that the slice wafer 200 can be correctly positioned and stopped on the holder to facilitate cutting on the jet cutting system, although the die There is a positional deviation when performing the optical engraving method on the dicing wafer 200. In one embodiment, 204 and 206 are parallel cut lines perpendicular to 208. All of these cutting lines are cut by a cutting machine with a precision calibration system, such as a vision calibration system with one or more cameras that can inspect the die on each wafer Calibration marks produced by the same optical etching method. In another embodiment, these cutting lines 204, 206, and 208 are cut by any cutting system capable of accurately aligning the cutting lines 204, 206, and 208 on each segmented wafer 200 toward the wafer 202. FIG. 3 shows a holder 300 according to an embodiment of the present invention. The holder 300 has positioning stops 304, 306, and 308 (for example, a post or pin having a rectangular or other polygonal cross section, or a fence). ), The X-axis, Y-axis, and Θ (bevel) directions of the jet cutting system can be calibrated. In another embodiment, the slicing wafer 200 has a plurality of cutting lines passing through each wafer (as shown in FIG. 2), which precisely match the positions of the positioning stops 304, 306 and 308 corresponding to the die 202. . In another embodiment, the positioning stop is a diameter from 60 mils (0.15 cm) to 500 mils (1.25 cm) and a height of about 20 mils (0.05 cm) to 100 mils (0.25 cm) pin. Three pins are sufficient to correctly align a wafer slice in the holder 300; however, in another embodiment, more than three pins and a fence (such as a rectangular protrusion) can be used. 5. Description of the invention (9 ) And a pin or two fences to align a wafer in the holder 300. The pins and bars are usually made of the same material as the holder, but the pins and the bars can be different. Made of materials. In one embodiment, the thickness of the holder 300 is from 2 inches (51 cm) to 10 inches (25.4 cm). The preferred method is to include a surface groove 314 under the die as a grip. The vacuum concave surface of the die after the wafer is cut and the groove under the die cutting path can be filled with water to absorb the jet flow energy and reduce the cutting. In another embodiment, the vacuum The depth of the concave surface is 50 mils (0125 cm) and the width is 50 mils (0.125 cm), the depth of the grooves is 5 inches (3.75 cm) and the width is 200 mils (50 cm). This vacuum concave surface is connected to a pipe network (not shown) inside the holder, and the outside of the channel is connected to a vacuum pump via a valve and hose (not shown). In other embodiments, the special position and size of the appropriate die can be used as the vacuum concave surface and groove, or the vacuum concave surface and groove are not used. In another embodiment, the ' holder 300 is made of stainless steel (e.g., 44 ° C hardened stainless steel or 303 stainless steel). The holders of some embodiments are selected from low replacement costs (such as Ming, Ming alloy, glass, or equivalent) or have greater resistance to jet cutting (such as steel alloys, various non-scale steels, Jinjin, ceramics , And the like). In another embodiment, the anchor 300 has a bolt bottom half 31 and the positioning stoppers 304, 306, and 308 pass through its movable upper half 312 so that the direction of the upper half 312 of the anchor 300 can be accurate. Corresponds to the jet cutting system. In another embodiment, the holder 300 does not have an upper half or a bottom half, 512450 K 'n Α7

Μ -------- ^ --------- line f Jing first read the sound on the back? (Fill in this page again) 512 450 A7 B7

^ -------- ^ -------- AWI (Please read the notes on the back before filling this page) M2450 1 r A7

Install -------- Order --------- Line—— (Please read the precautions on the back before filling out this page) V. Description of the invention (13) = or more sales and- Fence, or two fences. (In operation) Order to form the cutting operation of the die. The method ends at operation 820, where the holder is removed from the jet stream system and the wafer is removed from the holder for inspection and cleaning. If the fixture has an upper half and a lower half, the upper half of the fixture and the die are removed from the system, and the lower half of the fixture with the positioning stop is still sandwiched between the fixtures In the system. If it is necessary to continue cutting other wafers, the process returns to step 810. FIG. 8 shows a flowchart 900 of cutting a die from a wafer according to another embodiment of the present invention. The operation of this method starts at 902. Then in operation 904, the holder is aligned with the χ-axis and γ-axis of the jet cutting system to accurately cut the die from the wafer. Then in operation 906, the 0 of the holder is aligned with the 0 of the jet cutting system to accurately cut the die from the wafer. Then, in operation 908, the linear velocity and path of the cut are stylized into the jet cutting system. Next is operation 910, which places the wafer into a holder on a jet cutting system. Then in operation 912, the camera in the visual calibration system of the jet cutting system is moved to the first calibration mark on the wafer. The coordinates of the first calibration mark are then transmitted to the computer in operation 914 '. Then in operation 916, the camera is moved to the second calibration mark ^ and then in operation 918 ', the coordinates of the second calibration mark are transmitted to the computer. Then, in operation 920, the electrons calculate the deviations of χ, γ, and $ from the rated coordinates. Then, the operation of cutting the crystal grains is officially performed in operation 922. The method ends

This paper size applies _ National Standard (CNS) A4 size (Gx 297 public love) Clean. If the holder has an upper half and a lower half, the upper half of the holder and the die are removed from the system, and there is a solid deformation of the positioning stop M2450

V. Description of the invention (14 The lower half of the device is still clamped and fixed in the system. If it is necessary to continue cutting other wafers, return to the step of operation 910. The crystal grains are cleaned with one or more cleaning liquids, and the cleaning liquid It is preferred to contain isopropyl alcohol. Commercial grade isopropyl alcohol and acetone for cleaning the residues of the cut crystal grains can be purchased from any chemical supplier. Another embodiment utilizes other cleaning liquids (eg, toothed hydrocarbons) Type, olefin type, or soap and water). The examples of the embodiments described here are for illustrative purposes only, and the present invention is not limited to this. Therefore, the techniques known in the art can also be applied to other embodiments. Without departing from the scope and spirit of the patent application of the present invention described below. ^ -------- Order --------- Line (Please read the precautions on the back before filling this page} Ministry of Economy Wisdom Cai 1- Bureau employee consumer cooperative prints moderate ruler one paper one book standard A4 5) N (C quasi-standard house ¥! Public 1297 1857

Claims (1)

H3 No. 90124783 Patent Application Amendment to Patent Scope (October 14, 91) 1. A method for cutting multiple dies from a k-wafer, including the following steps: placing the wafer on a holder; aligning The wafer in the holder exposes the plurality of dies to a jet cutting nozzle; supplies abrasive to the jet cutting nozzle; supplies pressurized liquid to the jet cutting nozzle; when the jet cutting nozzle moves to The relative position of the wafer on the holder is to discharge the abrasive mixed with the liquid from the jet cutting nozzle at a flow rate sufficient to cut through the wafer; and after cutting a plurality of dies from the wafer, the wafer is removed from the holder. The device takes multiple grains. ~ 2. The method according to item i in the patent application range, wherein the plurality of crystal grains include a plurality of non-rectangular planar lightwave circuits. 3. The method according to item i of the patent application, wherein the liquid is water and the jet cutting nozzle is a water jet cutting nozzle. Printed by the Staff Welfare Committee of the Central Standards Bureau of the Ministry of Economic Affairs 4. If the method of claiming the scope of the patent is declared, the abrasive includes at least one of the following materials: , Tungsten carbide, silicon carbide, and gold steel drills. 5. The method according to item 1 of the patent application range, wherein the abrasive is a particle selected from an average diameter from a minimum diameter of 0.1 micron to a maximum diameter of 200 micron. 6. The method according to item 丨 of the patent application range, wherein the liquid is pressurized to a minimum pressure of 2,000 pounds per square inch (no bar) to a maximum pressure of 91S56 512450 square inches per square inch (7, _ ba. 7 · If the patent application scope item 1 Xigu, method, where the wafer is placed in the holder before slicing, and pull the fixed position of the holder to align with the holder 8 · 如The method of applying patent No. 丨 of the scope of this article, the method of ^ ^ 0, wherein the wafer is optically aligned with the jet cutting nozzle by a visual calibration system. 9. If the method of the patent No. 1 application, the jet The moving speed of the cutting nozzle with respect to the wafer is the lowest per minute and the highest 100 British pairs per minute. 10 · —A method for cutting a circuit die from a wafer, including the following steps: The wafer is placed in a water spray On the holder in the cutting system; aligning and positioning the wafer corresponding to the water jet cutting system; supplying abrasive from the abrasive storage tank to the water jet cutting nozzle; supplying water from the opening coupled to the water tank to the water jet cutting nozzle; when The water jet cutting tip moves When the relative position of the wafer is reached, the abrasive mixed with the water is discharged from the water jet cutting nozzle at a flow rate sufficient to cut through the wafer; After placing multiple dies, take out from the fixed cry = multiple dies. Λ 11 · The method of item 10 of the scope of patent application, wherein the wafer within the aligning ^ § § includes the use of the wafer The plurality of physical structures on the holder 1 __ identify the wafer in the holder. 12. The method according to item 10 of the patent application scope, further comprising: performing one time before the wafer is placed in the holder. Or use the above ^ paper size to comply with national standards (CNSTT4 specifications (210 x 297 mm-cutting step ^ 1 ^ 56 512450) 13. If the patent application for the wafer contains a visual inspection of the-mouth ... Multiple calibration standards on the Japanese yen 14. The method of item 10 of the patent application scope, further comprising: the step of cutting the plurality of dies from the wafer ^ The silly cleaning of the plurality of dies粒 15. Party 1 () in the scope of patent application The further steps include: the step of moving the first χ-axis and γ-axis parameters of the water jet cutting nozzle to correspond to the second X-axis reference coordinates of the wafer. The method further includes: a step of moving a first reference coordinate of the water jet cutting nozzle to correspond to a second zero reference coordinate of the Japanese yen. 17. The method of claim 10 in the patent application scope further includes: A step of determining the linear velocity and path of the water jet cutting nozzle relative to the movement of the wafer 18. 18. A holder for aligning a wafer slice having two or more straight edges in a jet cutting system, Includes: The Staff Welfare Committee of the Central Standards Bureau of the Ministry of Economic Affairs prints a number of structures that engage the two or more straight edges to align the wafer slices in the holder. 19. The holder of claim 18, wherein the material of the holder is selected from the group consisting of aluminum, aluminum alloy, steel alloy, titanium alloy, ceramic, and glass. 20. The holder of claim 18, further comprising a plurality of vacuum concave surfaces capable of holding the wafer slice and a pipe connected to the plurality of vacuum concave surfaces, wherein the pipe can be connected to an external vacuum source. 'Zhang scale applies Chinese National Standard (CNS) A4 specification (210 x 297 mm)-91856 1' If you apply for the patent scope No. 18 of 15] A, groove, where the groove is located in the crystal 'in- The steps include multiple grooves for cutting under the sn + y blade and can hold a liquid that can absorb the spraying energy of 22 pieces such as ... • Such as the application for the patent scope TF Η η ^, a holder, and further including a movable Member 4U contains the iris grains cut from the wafer slice, and the bottom part still bolted to the jet cutting system. 23: =:]? The holder around item 22, -The step includes at the bottom stop = stop, the plurality of wafer slices are positioned through a plurality of openings in the movable top to align the wafer slices. The system includes: a holder for aligning and fixing the wafer; a nozzle ejecting liquid and abrasive material toward the wafer at a flow rate sufficient to incisive the wafer; a liquid supply source for supplying the liquid to the cutting nozzle; abrasive material, Ying Yuan, supplying the abrasive to the cutting nozzle; and mechanical devices, Move the cutting nozzle to the relative position of the wafer. Printed by the Staff Welfare Committee of the Central Standards Bureau of the Ministry of Economic Affairs. 25. If the patent application scope of the wafer die cutting system is 24, it further includes a calibration system to make the cutting nozzle Move the alignment position of the wafer die aligned on the wafer. 26. For example, the wafer die cutting system with the scope of patent application No. 25, further includes one or more cameras to find The multiple calibration marks on the wafer align the movement of the cutting nozzle with the calibration position of the wafer die on the wafer. 37. The wafer die cutting system such as the 25th in the scope of patent application , Further making the paper size applicable to the Chinese National Standard (CNS) A4 Regulation (210 X 297 mm) 91856 512450 including: one or more cameras to find multiple calibration standards on the wafer; A crosshair generator to produce a crosshair to cover one of the calibration marks; one or more television monitors to align the crosshair of the crosshair generator to cover the multiple School One of the marks is a calibration mark; and a device for moving the cutting nozzle, which starts operation after calibrating multiple coordinates of the wafer die cutting system to multiple coordinates of the wafer die on the wafer. 28. If applying The wafer dicing system of item 24 of the patent scope, wherein the abrasive is a particle selected from an average diameter from a minimum diameter of 100 microns to a maximum diameter of 100 microns. The grain cutting system, wherein the abrasive material is selected from the group consisting of garnet, mullite, gangue, alumina, silica, stone-reversing crane, carbonization & diamond, and diamond. Printed by a member of the Central Standards Bureau of the Ministry of Economic Affairs and the Welfare Committee. 30. For example, the wafer die cutting system for patent application No. 24, where the liquid is water and pressurized to a minimum pressure of 2,000 pieces per square inch ( 130 bar) to a maximum pressure of 10,000 pounds per square inch (7,000 bar). This paper size is applicable to China (CNS) A4 size (210 X 297 cm 7 91856