JPS6225518B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a thermal head that is small in size, has high operating speed, and can be mounted at high density.

Conventionally, a thermal head equipped with a heat generating resistor element 1 and a semiconductor element such as a diode 2 is equipped with a signal line (1 to m) that should be commonly wired in order to realize a two-layer wiring implementation of the circuit as shown in Fig. 1. Two-layer wiring was performed using a two-layer wiring element 3 or a thick film element.

In FIG. 1, solid lines indicate the wiring and leads of the element, and broken lines indicate the wiring of the thermal head board. 4
is a signal line for taking out to the outside.

However, according to this mounting method, since the two-layer wiring element 3 or the thick film element is used, a large mounting space is required, and the number of wiring steps is long, resulting in high cost.

There is also a two-layer wiring technique using a tape carrier 6 as shown in FIG. 2, but both have the drawbacks mentioned above. However, when using the tape carrier 6, after inner lead bonding of semiconductor elements such as the diode 2 on the tape, outer lead bonding to the board can be automatically performed, reducing the number of man-hours, but as shown in Figure 2. The disadvantage of requiring a large amount of mounting space remained unsolved.

In FIG. 2, the solid lines indicate the wiring and leads of the elements including the tape carrier, and the broken lines indicate the wiring of the thermal head board.

The present invention eliminates these drawbacks by
Signal pads, which are electrodes of signal lines to be used as common wiring for semiconductor devices such as the above, and dummy pads, the same number as the number of terminals of the signal pads, are arranged and formed symmetrically within the semiconductor device. These are then inner lead bonded to the tape carrier, and after the individual signal pads and dummy pads are connected, the tape carrier is outer lead bonded.

This reduces bonding man-hours and realizes two-layer wiring, which reduces mounting space.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 3, a signal pad 11, which is an electrode of a signal line to be used as a common wiring for semiconductor elements such as an IC 10 mounted on a thermal head substrate,
A dummy pad 12 having the same number of electrodes as the number of terminals of the signal pad 11 and no other wiring is connected to the IC 10.
A film is formed on the surface of the semiconductor so that it is left and right symmetrical, and the film is arranged and formed by photolithography and plating. Next, as shown in FIG. 4, these are inner lead bonded to the tape carrier 6, and the individual signal pads 11 1-m and the dummy pads 12 1'-m' are connected, respectively. In FIG. 4, reference numeral 13 indicates wiring on the tape, and reference numeral 15 indicates a thin film pattern on the substrate. Thereafter, as shown in FIG. 5A, the tape carrier 6 on which IC chips and the like are inner lead bonded on the thermal head substrate is outer lead bonded to the conductive film pattern 15 on the substrate. FIG. 5B shows the state seen from the side. In FIG. 5A, broken lines indicate the wiring of the thermal head board, and thin and thick lines indicate the wiring and leads of the tape carrier.

Also, IC101 to 1, IC201 to 2, IC
Signal lines 4 from 301 to m are taken out to the outside. These signal lines can be taken out from any IC, and the order (arrangement) of the signal lines can be selected as appropriate.

With such a configuration means, signal lines of adjacent ICs 10 can be easily connected, and furthermore, two-layer wiring is possible with a small space.

To operate such a thermal head, for example, a signal from one part of the IC 101 is passed through the tape carrier 6 to the outer lead bonding section 14.
From there, it passes through the wiring on the board and enters one part of IC201. The same applies to the IC 301 below, and the signals 2 to m of the signal pad 11 also apply in the same manner.

Note that if there is no need to connect to an adjacent chip depending on the type of signal, the wiring on the board may be cut.

As explained above, according to the present invention, two-layer wiring can be realized with fewer man-hours and a smaller mounting space, making it possible to achieve high-density mounting and to obtain a thermal head that is miniaturized at low cost. It has the advantage of being able to In other words: 1. Automatic bonding is possible by using a tape carrier.

2. No space is required for multilayer wiring (most of the space can be taken up on the board below the IC chip);
A compact thermal head with high density packaging can be realized. (It can be made approximately 1/2 the size of a conventional head.)

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the two-layer wiring section of a conventional thermal head, Figure 3 is an IC chip diagram for explaining an embodiment of the present invention, and Figure 4 is an illustration of an embodiment of the present invention. FIG. 5A is a mounting diagram for explaining an embodiment of the present invention, and FIG. 5B is a side view thereof. It is. 6... Tape carrier, 10... Semiconductor element such as IC, 11... Signal pad, 12... Dummy pad, 13... Wiring on tape, 14... Bonding part.

Claims (1)

[Claims] 1. In a thermal head that mounts a heat generating resistor element and a semiconductor element such as an IC, a signal pad which is the electrode of the signal line to be used as a common wiring for each semiconductor element such as an IC, and dummy pads of the same number as the number of terminals of the signal pad. are arranged symmetrically within the semiconductor element, and are connected to the individual signal pads and dummy pads by inner lead bonding to the tape carrier, and then the tape carrier is bonded to a thin film on the substrate. A method for manufacturing a two-layer wiring part of a thermal head, characterized by bonding a pattern and an outer lead.