MULTI-FUNCTIONAL MOULD

Abstract: A multi-functional mould which is used for encapsulating chips placed on lead frames is characterized by a chamber (15) arranged in one of the mould halves (5, 6) in which an aggregate can be replaceably arranged. Depending on the use of the mould in the context of the so-called transfer method or in an injection moulding method a different aggregate (16, 19) is placed in the chamber (15). In the application as transfer mould the aggregate consists of an elongate member (16) with a bore (17) for guiding a plunger (7), which makes encapsulating material liquid due to the pressure applied thereto and the increase in temperature. In the application as injection mould the aggregate contains a member (19) with a through-channel (22) for a plasticized encapsulating material coming from the nozzle (13) of the injection moulding device.

Description: MULTI-FUNCTIONAL MOULD The invention relates to a multi-functional mould particularly for encapsulating chips placed on lead frames, comprising mutually movable mould halves on the mutually facing surfaces of which cavities are arranged for receiving 5 chips for encapsulating, means for ejecting finished product out of the mould, runners for the passage of encapsulating material to the cavities and a feed opening in one of the mould halves for admitting encapsulating material. Chips arranged on lead frames are normally 10 encapsulated with material by means of the so-called transfer method. An example of such a method and device suitable therefor is described inter alia in the European patent application 89.203003.2. With this known method and device a pellet-like piece of encapsulating material is 15 placed in a space suitable for this purpose, pressure is applied on the pellet by means of a plunger and a temperature increase effected such that it becomes liquid and moves through runners suitable therefor to the mould cavities. Materials with a ther osetting character are used 20 as encapsulating material. In addition to the transfer method, encapsulating material can also be processed as is usual in injection moulding devices. Materials used herein have a thermoplastic character. 25 It is the object of the invention to provide a mould which can be used with both transfer devices and injection moulding devices. This is achieved according to the invention in a multi-functional mould as described in the preamble by a chamber connecting to the feed opening and 30 extending to the cavities for replaceably receiving an aggregate. The invention makes it possible by exchanging only the aggregate for the mould to be used as desired in a method for encapsulating according to the transfer method or in an injection moulding device. A mould for use as a transfer mould has an aggregate with a bore for the passage of a plunger in addition to a mounting plate holding the member fixedly on the mould. A mould for use as injection mould for connection to an injection moulding device has a member with a through- channel and a mounting plate holding the member fixedly on the mould. The invention will be elucidated with reference to the drawing. In the drawing: Fig. 1 shows schematically the arrangement of a mould during application of the transfer method, Fig. 2 shows the arrangement of a mould during application of the injection moulding method, Fig. 3 shows the multi-functional mould according to the invention with dismantled parts, Fig. 4 is a view on a larger scale along the arrow IV in fig. 1, Fig. 5 shows a sectional view of the multi-functional mould according to the invention during use as transfer mould, and Fig. 6 shows a sectional view of the multi-functional mould during use as injection mould. The arrangement according to fig. 1 shows guides 2, 3, 4 placed on a base 1 in the usual manner and control means for mutually displacing mould halves 5 and 6. In the closed situation the plunger 7 (fig. 4) is displaced in the transfer method whereby due to the pressure exerted and the increase in temperature the pellet-like encapsulating material becomes liquid, moves through runners 9 arranged for this purpose to the chips for encapsulating on the lead frames 10, 11. This is the usual transfer method. Shown schematically in fig. 2 is the use of the multi-functional mould according to the invention in an injection moulding device. Encapsulating material is fed from a storage holder 12 to an injection moulding device, heated and plasticized therein and fed via a spray nozzle 13 to the feed opening of the mould 14. Since injection moulding devices and the operation thereof are generally known, no further mention will be made thereof in this context. The multi-functional mould according to the invention is shown in fig. 3. The mould consists of both parts 5 and 6 and has a chamber 15 for receiving an aggregate. The latter can be assembled on the one hand from a member 16 with a bore 17 for passage of the plunger. In addition the aggregate comprises a mounting plate 18. When the member 16 and the mounting plate 18 have been mounted on the mould half 5, the mould is suitable as transfer mould. To make the mould suitable for use as injection mould the parts 16 and 18 are removed and replaced by the member 19 and the mounting plate 21. The member 19 has a through- channel 22 for transport of plasticized encapsulating material to the interior of the mould. The debouchment of the channel 22 has a shape adapted to the injection mould nozzle 13. As seen from the debouchment the channel 22 is divergent to allow break-off of the solidified material to take place at the desired location. Fig. 5 and 6 are sectional views respectively of a mould provided with an aggregate consisting of the parts 16 and 18 and a mould provided with an aggregate consisting of the parts 19, 20 and 21. The moulds are otherwise of normal construction. The mould halves are provided with cavities, for instance 23, 24, for encapsulating chips placed on lead frames. *****

Claims: CLAIMS 1. Multi-functional mould particularly for encapsulating chips placed on lead frames, comprising mutually movable mould halves on the mutually facing surfaces of which cavities are arranged for receiving chips for encapsulating, means for ejecting finished product out of the mould, runners for the passage of encapsulating material to the cavities and a feed opening in one of the mould halves for admitting encapsulating material, characterized by a chamber connecting onto the feed opening and extending to the cavities for replaceably receiving an aggregate. 2. Mould as claimed in claim 1, characterized in that the aggregate is a member having a bore for passage of a plunger and a mounting plate holding the member fixedly on the mould. 3. Mould as claimed in claim 1, characterized in that the aggregate is a member having a through-channel and a mounting plate holding the member fixedly on the mould. 4. Mould with aggregate as claimed in claim 2, characterized in that the mould is used as transfer mould. 5. Mould with aggregate as claimed in claim 3, characterized in that the mould is used as injection mould for connection onto an injection moulding device. *****

Inventors: GIESEN HENRICUS BERNARDUS ANTO, GIESEN, HENRICUS, BERNARDUS, ANTONIUS
Applicants: ASM FICO TOOLING, ASM-FICO TOOLING B.V.
Application year: 1992
Main classification: B29C45
IPC codes: B29C45, B29L31, H01L21