Semiconductor device having an improved connection arrangement between a semiconductor pellet and base substrate electrodes and a method of manufacture thereof

Abstract

A semiconductor device comprising a semiconductor pellet mounted on a pellet mounting area of the main surface of a base substrate, in which first electrode pads arranged on the back of the base substrate are electrically connected to bonding pads arranged on the main surface of the semiconductor pellet. The base substrate is formed of a rigid substrate, and its first electrode pads are electrically connected to the second electrode pads arranged on its reverse side. The semiconductor pellet is mounted on the pellet mounting area of the main surface of the base substrate, with its main surface downward, and its bonding pads are connected electrically with the second electrode pads of the base substrate through bonding wires passing through slits formed in the base substrate.

Description

[0001]This is a continuation of reissue application Ser. No. 09 / 613,541, filed Jul. 7, 2000, the subject matter of which is incorporated by reference herein.[0002]More than one reissue application has been filed for the reissue of U.S. Pat. No. 5,777,391. These reissue applications are: (1) Ser. No. 09 / 613,541, filed Jul. 7, 2000; (2) the present application, Ser. No. 10 / 105,236, filed Mar. 26, 2002; (3) Ser. No. 11 / 182,039, filed Jul. 15, 2005; (4) Ser. No. 11 / 182,040, filed Jul. 15, 2005; (5) Ser. No. 11 / 256,620, filed on Oct. 24, 2005; (6) Ser. No. 11 / 256,621 filed on Oct. 24, 2005; (7) Ser. No. 11 / 285,729, filed on Nov. 23, 2005; and (8) Ser. No. 11 / 285,730, filed on Nov. 23, 2005. [0003]The present reissue application also claims the benefit under 35 USC §120 of the filing date of Dec. 11, 1995 of Ser. No. 08 / 570,646, now U.S. Pat. No. 5,777,391, and benefit under 35 USC §119 of Japanese Application No. 6-316,444, filed on Dec. 20, 1994 and Japanese Application No. 7-126405, fi...

AI Technical Summary

Benefits of technology

[0015]The circuit systems framed on the typical semiconductor pellets 2 have tended to grow in their level of integration and the number of functions they perform. With enhanced integration and more diversified functions of the circuit system, the number of bonding pads 2A of the semiconductor pellet 2 and the number of second electrode pads 1A of the base substrate 1 increase. That is, the number of through-hole conductors 1C electrically connecting the second electrode pads 1A and the first electrode pads 1B increases as the integration and function of the circuit system are enhanced. Hence, there has been a problem that the external size of the base substrate 1 increase with the increasing number of the through-hole conductors 1C, which in turn increases the size of the semiconductor device as a whole.

[0035]Furthermore, the base substrate used is formed of a rigid substrate having a small planar thermal expansion coefficient and a high Young's modulus compared with those of a flexible substrate, which means the rigid substrate is harder to bend. As a result, the rigid base substrate is free from deformations (warping or twisting) due to reflow heat during the process of mounting the semiconductor device on the mounting surface of the mounting board. As a result, a sufficient degree of flatness of the back of the base substrate with respect to the mounting surface of the mounting board can be secured, which in turn allows the manufacture of semiconductor devices with high mounting precision.

Problems solved by technology

Hence, there has been a problem that the external size of the base substrate 1 increase with the increasing number of the through-hole conductors 1C, which in turn increases the size of the semiconductor device as a whole.

There is also another problem which the inventors have considered.

This, in turn, increases inductance and reduces the operating speed of the semiconductor device.

This gives rise to an apprehension that the connection strength between the bonding wires and the second electrode pads may decrease, leading to connection failures of bonding wires and reduced electric reliability of the semiconductor device.

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