JPH03296234A - Wire-bonding method of semiconductor device - Google Patents

Abstract

PURPOSE:To achieve bonding without any mark on a wire and that for a chip with a narrow pitch between pads by performing bonding of a short wire initially from a film lead side to a pad side and then that of a long wire from the pad side to the film lead side. CONSTITUTION:First, a short wire 5 is used for bonding from a film lead side to a chip side between a lower stage side film lead 2a and a pad 4 at a side of a chip 3, wire bonding of all lower stage film lead 2a is completed, and then an upper stage side film lead 2b and the pad 4 at a side of the chip 3 are bonded from the pad side to the chip side using a long wire 6, thus achieving bonding to all internal film leads. Therefore, the bonded wire has a peak near the film lead side and the pad side is in wire shape with a low loop, thus preventing contact with an adjacent short wire when a tool moves to the pad side and from the pad side to the film lead side when bonding a longer wire.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for assembling a semiconductor device, and more particularly to a method for wire bonding a semiconductor device using a ceramic case.

[Conventional technology]

Conventionally, the bonding method connects the semiconductor chip die-bonded to the ceramic case and the internal film lead of the ceramic case using two different lengths of Au wire (hereinafter referred to as wire). , □
Bonding is performed from the chip electrode (hereinafter referred to as pad) side to the membrane lead side.

FIG. 3(a) is a plan view for explaining the above conventional method;
FIG. 5B is a cross-sectional view, and in these figures, a short wire 5 and a long wire 6 are connected from the pad 4 of the semiconductor chip 3 die-bonded to the ceramic case 1 to the lower film lead 2a and the upper film lead 2b, respectively. When wire bonding is performed using the wire, a wire loop having peaks 5a and 6a near the pad 5 side is formed. Here, the short wires 5 and the long wires 6 are normally arranged alternately for wire bonding.

[Problem to be solved by the invention]

In such a conventional wire bonding method, when bonding a long wire after bonding a short wire, the tool 8 comes into contact with the adjacent wire, as shown in the perspective view of FIG. It happens that the wire breaks at the same time.

In particular, when the loop height of the short wire 5 increases, the long wire 6
When the tool 8 moves to the pad side for bonding, and in the process of moving from the pad side to the film lead side, the tool and the adjacent wire come into contact. This means that when the die bond position of the chip is misaligned, the wire spacing becomes narrower, increasing the risk of damage. In addition, wire deformation (bending) of short wires is added, and there is a problem in that chips with short distances between pads cannot be bonded.

[Means to solve the problem]

In order to solve the above problems, the wire bonding method of the present invention first performs bonding of short wires from the membrane lead side to the pad side, and then bonds long wires from the pad side to the membrane lead side.

〔Example〕 Next, the present invention will be explained with reference to the drawings.

FIG. 1(a) is a plan view for explaining a first embodiment of the present invention, and FIG. 1(b) is a sectional view. Figure 1(a), (
In b), the pads 4 of the chip 3 bonded to the ceramic case 1 and the internal film leads 2 of the case
a and 2b are connected by a short wire 5 and a long wire 6, respectively. The ceramic case 1 in this example is
The internal membrane lead is composed of 1 and 2 lower tiers, and the lower tier membrane lead is 2.
a. Upper membrane! J-F' 2 b are alternately connected to pads on the chip side by wires. In this wire bonding method, first, a short wire 5 is connected between the lower membrane lead 2a and the pad 4 on the chip 3 side from the membrane lead side to the chip side.
After completing the wire bonding of all the lower film leads 2a, next connect the upper film leads 2b and the pad 4 on the chip 3 side with a long wire 6 from the pad side to the chip side.
Bonding is performed to all internal film leads.

FIGS. 2(a) and 2(b) are a plan view and a sectional view, respectively, for explaining a second embodiment of the present invention. In these figures, the internal membrane leads 7a, 7 of the ceramic case 11
b is formed in a staggered arrangement. In the wire bonding here, as in the previous embodiment, the short wires 5 are first bonded to the pads 4 from the inner film lead 7a side, and after all the short wires 5 are bonded, the short wires 5 are bonded to the pads 4 on the chip 3 side. Bonding of the long wire 6 to the outer membrane lead 7b is performed.

〔Effect of the invention〕

As explained above, in the present invention, the shorter wire is bonded from the internal film lead side to the pad side. As a result, the bonded wire has a peak near the membrane lead side, and the pad side has a wire shape with a low loop, so when bonding the longer wire next, the tool will move from the pad side and the membrane lead side. There is no possibility of contact with adjacent short wires when moving toward the lead side. Therefore, bonding can be performed without damaging the wire.

Furthermore, bonding is possible even for chips with a narrow pitch between pads.

[Brief explanation of drawings]

FIG. 1(a) is a plan view showing a bonding state for explaining the first embodiment of the present invention, FIG. 1(b) is a sectional view, and FIG. 3(b) is a plan view showing the bonding state in the example, FIG. 3(b) is a sectional view, FIG. 3(a) is a plan view showing the bonding state in the conventional wire bonding method, FIG. 4 is a perspective view for explaining a conventional wire bonding method. ■, 11...Ceramic case, 2a...
...Lower membrane lead, 2b... Upper membrane lead, 3
... Semiconductor chip, 4 ... Electrode pad, 5 ... Short wire, 6 ... Long wire,
7a...Inner membrane lead, 7b...Outer membrane lead, 8...Tool.

Claims (1)

[Claims] In a wire bonding method in which the electrodes of a semiconductor chip die-bonded to a ceramic case and the internal film leads of the case are connected using wires of two different lengths, the shorter wire connects the chip from the film lead to A wire bonding method for a semiconductor device, characterized in that bonding is performed to an electrode, and the longer wire is bonded from the chip electrode side to the film lead.