Sealed stacked arrangement of semiconductor devices

Abstract

A pair of DRAM chips 1A and 1B are mounted opposedly to each other with wiring means such as lead frames put therebetween, the lead frames being substantially integral with external terminals 3B. Then, these DRAM chips and lead frames are connected together by the conventional wire bonding method. Plural pairs of the thus-connected DRAM chips and lead frames are stacked and corresponding leads of the lead frames are connected in common to form a laminate. The plural DRAM chips thus mounted are activated selectively in accordance with a predetermined chip selection signal. Additionally, partial DRAM chips capable of partially functioning normally are combined together by utilizing the above chip mounting method to constitute a single DRAM package.

Description

BACKGROUND OF THE INVENTIONThe present invention relates to a semiconductor device and a method for manufacturing the same. For example, the present invention is concerned with a DRAM package (a semiconductor device with one or plural DRAM chips mounted thereon will hereinafter be referred to herein as "DRAM package") comprising plural DRAM (Dynamic Random Access Memory) chips (a semiconductor chip capable of functioning as DRAM will hereinafter be referred to herein as "DRAM chip"), as well as a technique which is particularly useful in producing such DRAM package.A DRAM chip having as a basic configuration a memory array comprising lattice-like arranged dynamic memory cells as well as a DRAM package having such DRAM chip as a basic configuration are known. In the conventional DRAM package, usually, one DRAM chip is mounted thereon and bonding pads used therein are connected to corresponding leads of a lead frame integral with external terminals.As to the DRAM package carrying a si...

AI Technical Summary

Benefits of technology

It is the first object of the present invention to provide an effective chip mounting method capable of mounting plural sub chips of the same size without sacrificing the heat radiation characteristic of a package and the product yield.

It is the third object of the present invention to realize a DRAM package having a memory capacity plural times that of a package of about the same size and comprising a single DRAM chip and thereby expand the limit of memory capacity of DRAM chips, etc.

According to the above means it is possible to provide an effective chip mounting method capable of mounting plural sub chips of the same size without sacrificing the heat radiation characteristic of the package and the product yield. Besides, it is possible to attain large memory capacity and low power consumption of the DRAM package and simplify the manufacturing process for the package. Moreover, it is possible to realize a DRAM package having a memory capacity plural times that of a package comprising a single DRAM chip and thereby expand the limit of memory capacity of DRAM chips; at the same time it is possible to enhance the packaging efficiency of a memory system having a DRAM package as a basic configuration and reduce the cost thereof. Further, it is possible to utilize partial DRAM chips without waste and enhance a substantial product yield of DRAM chips, etc.

Problems solved by technology

However, with progress of higher integration density and larger capacity of semiconductor chips, the present inventors found out that the following problems were involved in the foregoing chip mounting methods.

Therefore, it is impossible to constitute a package using the same size of sub chips formed in the same manufacturing process, like a DRAM chip for example.

In all of these methods, moreover, the manufacturing process is complicated and the product yield is deteriorated in comparison with, for example, the conventional packaging method involving direct wire bonding to a lead frame.

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