Moulding apparatus with compensation element

Abstract: The invention relates to a moulding apparatus for moulding a chip on a flat carrier (4), comprising a mould formed by two mould parts (2,3) which are movable relative to each other and between which the carrier (4) can be received, the one mould part (3) of which is provided with a mould cavity against the peripheral edges of which the carrier (4) can be pressed, and means for exerting pressure in at least one cavity for moulding material arranged in the mould and connected to the mould cavity by means of a runner, wherein at least one compensation element (11) is arranged whereby in the closed position of the mould parts one side of the carrier (4) is held sealingly against the peripheral edge of the mould cavity.

Description: The invention relates to a moulding apparatus as disclosed in the preamble of claim 1. Such a moulding apparatus is known from the Japanese patent JP 05 218508. The moulding apparatus according this patent is provided with pressing parts that are pressed floatable to the wiring pattern on a substrate carrying a semiconductor device. The pressing parts are urged to the substrate by springs. Pressing parts and springs are integrated in a die of the moulding apparatus. Although substrates with a thickness that is not precisely known can be processed with such a device this processing is not fully controlled as the clamping force of the pressing parts is dependent on the thickness. The present invention has for its object to provide a moulding apparatus for moulding a chip on a flat carrier which variations in the thickness of the carrier can controlled be compensated. The present invention provides for this purpose a moulding apparatus as disclosed in claim 1. Use of this moulding apparatus enables controlled processing of carriers of varying thickness; by displacement of the beam the force exerted on the carrier can be regulated independent of the thickness. It hereby becomes possible not only to use less expensive carriers but also to use carriers of a material with a relative great thickness toleration. This makes it possible for example to use printed circuit board material as carriers. The present invention will further elucidated with reference to the non-limitative embodiments shown in the following figures. Herein: figure 1 shows, only as an example useful for understanding the invention, a partly cut away perspective view of a moulding apparatus with a segment supported by springs, and figure 2 shows a partly cut away perspective view of a moulding apparatus with clamping device. Figure 1 shows a prior art moulding apparatus 13 in which a lower mould part 14 is provided with a mould cavity 15 and, communicating therewith, a runner 16 which is then connected to a supply device 17 for moulding material. An upper mould part 18 comprises two segments 19, 20 moveable relative to each other. The segments 19, 20 are mutually connected with interposing of springs 21. The mould parts 14, 18 close precisely onto each other close to the supply device 17 irrespective of the thickness of a carrier 22. The force exerted on the carrier 22 by the segment 20 as according to arrows P depends on the spring constants of the spring 21. The springs 21 thus determine with what force the carrier 22 is pressed against the lower mould part 14, without this having to depend on the thickness of the carrier 22, wherein the thickness of the carrier 22 also has no influence on the connection of the mould parts 14, 18 close to the supply device 17 for moulding material. Figure 2 shows a moulding apparatus 35 in which a carrier 22 is received between two mould parts 14, 18 on which carrier 22 is arranged a chip for moulding (not shown in this figure). In a surface (x) of the lower mould part 14 is arranged a mould cavity 15 in which a covering element can be arranged through a runner 16 by exerting pressure on moulding material 7 using a plunger 17. In order to prevent moulding material leaking to the outside at a parting between the mould parts 14, 18, the mould halves 14, 18 must connect together precisely. For this purpose the mould halves 14, 18 are pressed against each other with a predetermined force. To now ensure that the carrier 22 is enclosed non-movably between the mould parts 14, 18, i.e. irrespective of differences in the thickness of the carrier 22 a compensation element 37 in the form of a clamping device is arranged in the upper mould part 18. This compensation element 37 presses the carrier against a peripheral edge 24 of the surface (x) of the lower mould part 14. A segment 36 of the mould part 18 is connected to a holding plate 34 with interposing of a clamping device 37. The segment 36 is urged further downward relative to holding plate 34 by displacing a beam 38 as according to arrow T. Depending on the force exerted in the direction of arrow T, it is possible to vary the force which a surface (y) of the segment 36 exerts on carrier 22. The embodiment of the beam 38 shown here has of course many alternatives. Wedge-shaped elements (z) are envisaged here as an example. With this preferred embodiment it is also possible to move mould part 14 and segment 19 to within a short distance of each other in order to effect the definitive connection of segment 19. to mould part 14 after the segment 36 has already been brought into contact with carrier 26.

Claims: Moulding apparatus (35) for moulding a chip on a flat carrier (22), comprising: a mould comprising a first mould part (14) and a second mould part (18), said first and second mould parts (14, 18) being movable relative to each other and between which the carrier (22) can be received; a mould cavity (15) provided at a surface (x) of said first mould part (14), said mould cavity (15) having peripheral edges (24) to which the carrier (22) can be pressed; a supply device (17) for exerting pressure to moulding material (7), said supply device (17) being provided in one of the first and second mould parts (14, 18); a runner (16) provided at said surface (x) of said first mould part (14), said runner (16) interconnecting said supply device (17) and said mould cavity (15); the second mould part (18) comprises a first segment (36), a second segment (19) and a holding plate (34), said first segment (36) being interposed between said surface (x) of said first mould part (14) and said holding plate (34), said first segment (36) being movable relative to said second segment (19) and having a segment surface (y) opposed to said surface (x) of said first mould part (14); a clamping device (37) interposed between said first segment (35) and said holding plate (34), said clamping device (37) being adapted for holding, in a closed position of the mould parts (14, 18), the carrier (22) sealingly against said peripheral edge (24) and said segment surface (y); characterised in that , said clamping device (37) comprises, a displaceable beam (38) having a surface comprising a wedge shaped protrusion (z), said displaceable beam (38) being interposed between said holding plate (34) and said first segment (36) such that displacement of said displaceable beam (38) varies a force which said first segment (36) exerts upon the carrier (22).

Inventors: PETERS GERARDUS F W, PETERS HENDRIKUS J B, PETERS, GERARDUS F.W., PETERS, HENDRIKUS J.B.
Applicants: FICO BV, FICO B.V.
Application year: 1996
Main classification: H01L21
IPC codes: B29C45, B22D17, H01L21, B29C33