A gang-punch pin apparatus for punching selected hole patterns in thin sheet materials such as greensheets is provided. The gang-punch pin apparatus uses program plates in the punch apparatus which plates are positioned intermediate the non-punching end of the punch pins and a clearance plate wherein punch pins not used for punching a particular layer of the MLC are retracted into during punching. At the other punch pin locations, the punch pins, upon activation of the punch apparatus by compressing an expandable chamber, usually by application of a force on the punch apparatus, are extended through the lower portion of the punch apparatus to form vias in a greensheet. A die apparatus is also provided for use with the punch assembly to form the vias and to remove the punched material (slugs) from the die apparatus. The gang punch-pin may be shorter than conventional pins and be made at a low cost because of the thin sheet metal plates preferably used to make the component parts of the punch and die apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S) In describing the preferred embodiment of the present invention, reference will be made herein to FIGS. 1 - 6 of the drawings in which like numerals refer to like features of the invention. Features of the invention are not necessarily shown to scale in the drawings. Referring now to the figures in detail, the present invention of a method of using the punch apparatus and die apparatus of the invention to make via openings in greensheets can be demonstrated. In FIG. 1A, a gang-punch assembly shown generally as 10 is shown positioned above and apart from die assembly 11 which has a greensheet 29 thereon. As will be shown in the following figures, in operation, gang punch assembly 10 with stripper plate 12 is placed on top of greensheet 29 in registration with the vertical through-holes 24 a - 24 k of die plate 24 . The punch assembly will then be activated by exerting a force on the gang-punch assembly and the via holes punched. Referring to FIG. 1 A, punch assembly 10 comprises a stripper plate 12 having vertical through-hole openings 12 a - 12 k therein. Overlying stripper plate 12 is guide plate 13 having vertical through holes 13 a - 13 k in registration with vertical through-hole openings 12 a - 12 k of stripper plate 12 . Between guide plate 13 and stripper plate 12 is a pressure chamber shown generally as 14 bounded by stripper plate 12 and guide plate 13 . This chamber 14 as shown in FIGS. 5A and 5 B, comprising guide plate 13 above and stripper plate 12 below, allows stripper plate 12 to move up and down with respect to guide plate 13 . This is achieved as shown in FIGS. 5A and 5B by enclosing plates 12 and 13 with a surrounding pressure containment assembly consisting of outer rings 61 a and 61 b , rigidly fixed to guide plate 13 , and moveable inner rings 62 a and 62 b rigidly attached to stripper plate 12 . A flexible rubber diaphragm 60 allows inner rings 62 a and 62 b to move in relation to outer rings 61 a and 61 b while maintaining pressure within the pressure chamber 14 . Pressure in pressure chamber 14 can be controlled by utilizing gas ports 63 . FIG. 5A shows the pressure chamber 14 in an expanded, non-punching portion with low pressure (10 psi) applied through ports 63 . FIG. 5B shows the pressurized chamber 14 in a contracted, punching position. At this point after punching, high gas pressure can be applied through ports 63 to the pressure chamber 14 , to apply a holding force to the stripper plate 12 , firmly holding the greensheet 29 against the die plate 24 while retracting (stripping) the punch pins from the die assembly 11 and greensheet 24 . Following this stripping operation, high pressure is exhausted and low pressure is again applied to the pressurized chamber 14 so that the gang punch assembly 10 may be lifted to gain access for removal of the greensheet 29 . This prevents over-extension (bowing) of the stripper plate 12 which may cause the punch pins 15 to be retracted past the upper surface of the stripper plate 12 causing possible damage to the punch pins 15 upon re-entry into the stripper plate 12 . Although a pressure containment ring assembly 61 a and 61 b and 62 a and 62 b are shown, alternate methods of sealing pressure chamber 14 can be used. These may consist of O-ring seals or others to prevent the pressurized air from escaping the pressure chamber. Referring back to FIG. 1 A, the punch pins 15 a - 15 k have a spherical head 16 a - 16 k at the upper end of each punch pin with said spherical heads slightly larger than the diameter of the punch pin. The punch pins may be made of any suitable material with tungsten being preferred. A head plate 17 is positioned on the upper surface of guide plate 13 and has a plurality of corresponding vertical through-holes 17 a - 17 k corresponding to the vertical through-holes of guide plate 13 . The pins 15 a - 15 k are shown disposed in the guide and stripper plates and the head plate 17 . The vertical through openings of head plate 17 are slightly larger than the vertical through-hole openings of stripper plate 12 and guide plate 13 to accommodate the larger punch pin head. The heads 16 a - 16 k of punch pins 15 a - 15 k , therefore, rest on the upper surface of guide plate 13 and are restricted when the punch assembly is at rest from moving downwardly through the guide and stripper plates by the heads 16 a - 16 k of the punch pins. A program plate 18 is shown on top of head plate 17 and comprises a plurality of vertical through-hole openings 18 a , 18 b , 18 e , 18 g , 18 h , 18 i , 18 j and 18 k . The size of the vertical through-hole openings are approximately the same size as the vertical through-hole openings of head plate 17 to accommodate movement of the punch pins 15 a - 15 k therethrough. The program plate 18 has openings only where punching of the greensheet is not desired. Where punching of the greensheet is desired as, for example, punch pins 15 c , 15 d and 15 f , there are no vertical through-hole openings in the program plate 18 . On top of program plate 18 is a clearance plate assembly shown generally as 19 . The clearance plate assembly comprises a lower clearance plate 20 , an intermediate clearance plate 21 and an upper clearance plate 22 . A force plate 23 is disposed on top of upper clearance plate 22 . Each clearance plate has vertical through-hole openings therein corresponding to the vertical through-hole openings of stripper plate 12 , guide plate 13 and head plate 17 . Thus, clearance plate 20 has vertical through openings 20 a - 20 k , clearance plate 21 has vertical through-hole openings 21 a - 21 k and upper clearance plate 22 has vertical through-hole openings 22 a - 22 k . As will be more fully described hereinbelow, for punch pin 15 a , which is a non-punching pin for the particular greensheet to be punched, during the punching operation, punch pin 15 a will be forced upward through vertical through-hole openings 18 a , 20 a , 21 a and 22 a . This is to be contrasted with punch pin 15 c , which is a punching pin, which during the punching operation will be forced downward through the lower surface of stripper plate 12 forming a via in greensheet 29 . Referring now to the die assembly 11 of FIG. 1A, a groove plate 28 has a series of channels 28 a , 28 b and 28 c extending to an opening (not shown) for removing punched material (commonly termed slugs). Disposed on the surface of groove plate 28 is a window plate assembly shown generally as 25 . The window plate assembly 25 comprises a lower window plate 26 and an upper window plate 27 . Each window plate has corresponding openings 26 a - 26 f and 27 a - 27 f forming vertical through-hole openings in the window plate. It will be noticed that the diameter of the window plate openings are larger than the via openings 24 a - 24 k of die plate 24 . The die plate 24 is disposed on top of the window plate assembly 25 and comprises a series of via openings 24 a - 24 k which correspond to vertical through-hole openings 12 a - 12 k of stripper plate 12 . A greensheet 29 is disposed on the top of die plate 24 . Referring now to FIG. 1 B, the punch assembly 10 has been placed on the surface of greensheet 29 and has been activated for the punching operation. Thus, a force as shown by arrow A is applied to force plate 23 to force pressure chamber 14 to contract. The chamber 14 will typically be vented allowing gas in the chamber to be expelled. As chamber 14 contracts, punch pins 15 c , 15 d and 15 f will be forced through the lower surface of stripper plate 12 and into greensheet 29 at corresponding die plate openings 24 c , 24 d and 24 f . The non-punching punch pins 15 a , 15 b , 15 e and 15 g - 15 k are forced upward through the vertical through-holes in the program plate and the clearance plates and do not punch the greensheet. Referring now to FIG. 1 C, the punching operation has been completed and the pressure chamber 14 is completely contracted so that the punch pins 15 c , 15 d and 15 f extend completely through the respective die openings and window plate openings forming slugs 30 c , 30 d and 30 f which are shown falling toward the bottom of channel 28 b . As shown in FIG. 1 D, after the punching operation, high pressure air is supplied to chamber 14 expanding the chamber and retracting guide plate 13 from stripper plate 12 and retracting punch pins 15 c , 15 d and 15 f from the die assembly 11 and greensheet 29 . In its final position, the punch pins 15 c , 15 d and 15 f will be completely removed from greensheet 29 and the apparatus ready for the punching of another greensheet. The slugs 30 c , 30 d and 30 f may be removed by vacuum or air pressure in the channel. An important feature of the invention is that pressure chamber 14 acts to maintain lower stripper plate 12 in contact with the greensheet 29 surface thus holding the greensheet firmly in place against the die plate 24 during both punching and stripping to ensure positional accuracy while minimizing tearing or other deformation of the formed via. Another important feature of the current invention is the utilization of a Universal Groove plate. FIG. 6 shows a cut-away plan view of the die portion of the present invention. A portion of a die plate 24 with closely spaced holes 24 x depicting a typical punch pin density of 0.004″ diameter on a 0.008″ grid. A cut-away view of the window plate 25 is shown below the die plate 24 with open cells 25 x providing clearance for the punch pins 15 and slugs 30 as they penetrate the die 24 . Webs 25 y in the window plate 25 span the grooves 28 a , 28 b , and 28 c in the groove plate 28 and rest on the top surface of webs 70 of the groove plate 28 shown as webs 70 a , 70 b , 70 c and 70 d to transfer the punching force on the die plate 24 caused by the punch pins 15 , to the groove plate 28 . The webs 25 y of the window plate are sufficiently narrow (approximately 0.002″) as to enable their placement between the holes 24 x in the die 24 so as not to interfere with the punch pins 15 and slugs 30 as they pass through the die plate 24 . Placement of the groove plate webs 70 a - 70 d is not dependent on the location of the holes 24 b in the die plate 24 because the window webs 25 y provide sufficient rigidity to span any open area (i.e., 28 a , 28 b or 28 c ) in the channel plate 28 . This allows for a universal groove plate design independent upon the location of punch locations in the plates above, allowing the groove plate to be re-used for any pattern, reducing cost. For areas where punch pin density does not dictate the use of the open window area 25 x such as single isolated punches, or small clusters of punches, small clearance areas can be used that are centered on the localized areas. A single punch area 71 is indicated by die location 24 a with corresponding window plate clearance hole 25 z . A cluster of punches 72 is shown with die locations 24 e and 24 f with corresponding window plate clearance holes 25 s and 25 t . The clearance holes form a continuous area surrounding the die holes without substantially decreasing the load transfer capability of the window plate to the groove plate 28 . With reference to the punch assembly 10 as shown in FIG. 1A for example, clearance plates 20 , 21 and 22 , program plate 18 , head plate 17 , guide plate 13 and stripper plate 12 may be formed from thin sheet material using, e.g., lasers, photoetching, mechanical drilling, electro-discharge machining, etc. Materials such as stainless steel, steel alloys, tungsten carbide and molybdenum may be used with stainless steel and molybdenum being preferred. This significantly reduces the cost of the assembly and the time needed for fabrication of the punch assembly. Likewise, die plate 24 and window plates 26 and 27 of die assembly 11 may also be made from thin sheet material. The thin sheet material may likewise be any suitable material such as stainless steel, steel alloys, tungsten carbide and molybdenum, preferably stainless steel and molybdenum. The thickness of the material is generally about 0.002 to 0.040 inch. In yet another aspect of the invention, stripper plate 12 , grid plate 13 , and die plate 24 , for example, as shown in FIG. 4 , can be composed of an assembly of separate plates bonded together to form a single unit. This allows the outer plates such as 13 a and 13 c to be formed by photoetch processes well-known in the art to produce extremely uniform, accurately placed holes 72 compared to larger holes 73 in plates 12 b , 13 b and 24 b , while the entire assembly overcomes the limitations of a one-to-one aspect ratio limit for such etching processes. Spacer plates 12 b , 13 b and 24 b as shown in FIG. 4 can be fabricated using alternate and less accurate means such as laser drilling, mechanical drilling, EDM machining, as well as photoetch techniques. This allows a looser tolerance on the hole locations and diameter. The holes in plates 12 b , 13 b and 24 b may be oversized as it serves only to separate the plates 13 a and 13 c , 12 a and 12 c and 24 a , and provides the necessary clearance for the punch shank as well as providing increased rigidity to the assemblies 12 , 13 and 24 . For die plate 24 , plate 24 b provides the necessary rigidity without the requirement of having another thin plate on the opposite side from plate 24 a. Additionally, the photoetch process allows the generation of tapered holes as shown as 72 a in FIG. 4 to facilitate punch loading, proper punch to hole clearance, slug removal, etc. Bonding of the assemblies 12 , 13 , and 24 can be accomplished by using adhesives including epoxies, urethanes, silicon rubbers, etc. The assemblies can also be soldered, welded, riveted or otherwise fastened. Referring now to FIGS. 2 A- 2 E and 3 A- 3 D, it can be seen how a gang-punch apparatus of the invention is constructed depending on the via-layout of the multilayer ceramic substrate to be built and also how the program plates are designed for use in the apparatus to make the multilayer ceramic substrate electronic component product. The layers of the multilayer ceramic are shown as 31 , 32 , 33 and 34 . Each layer has via holes therein. Thus, layer 31 has via holes 35 a , 35 c , 35 e , 35 g and 35 i . Layer 32 has via holes 35 a , 35 b , 35 d , 35 e , 35 f and 35 h . Layer 33 has via holes 35 d and 35 h . Layer 34 has via hole 35 i . Based on the via holes of the MLC, gang apparatus data plate 35 shows the location of all the via holes which have to be punched to form the MLC comprising substrate layers 31 - 34 . Using this data, a gang-punch apparatus is formed having a 3×3 array of via holes 35 a - 35 i . Thus, there would be a total of 9 punch pins in the gang-punch apparatus with some of the punch pins being non-punch pins depending on the layer being punched. As shown in FIGS. 3 A- 3 D, to form program plate 31 a for use in the apparatus of the invention to make MLC greensheet substrate layer 31 , program plate 31 a would have through hole openings 35 b , 35 d , 35 f and 35 h therein. As discussed hereinabove, these openings in program plate 31 a would be non-punch pin locations which would not be punched in the greensheet since the respective punch pins 15 b , 15 d , 15 f and 15 h would be retracted into the clearance plate through-holes. Similarly, program plate 32 a has through-hole openings 35 c , 35 g and 35 i . When program plate 32 a is used in the apparatus of the invention, via holes will be formed in via locations 35 a , 35 b , 35 d , 35 e , 35 f and 35 h . With regard to program plate 33 a , via openings would only be formed in MLC layer 33 at via locations 35 d and 35 h . Likewise, using program plate 34 a to make MLC layer 34 , a via will only be punched in layer 34 at via location 35 i. It is apparent that this program feature enables this single gang-punch apparatus to manufacture up to all of the layers in a MLC ceramic substrate. Additionally, it is possible to create a gang-punch apparatus which has incorporated therein all the possible punch locations on a closely spaced grid (i.e. 0.004 inch diameter on 0.008 inch centers). This gang-punch could therefore punch any pattern, utilizing only different program plates so long as said pattern was designed so that the punches fall on the closely spaced grid. While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention. Thus, having described the invention, what is claimed is: