JPS5845974A - Thermal head - Google Patents

Abstract

PURPOSE:To simplify the multiple wirings in a thermal head by forming the wiring of the output unit side in a semiconductor device in a structure for leading from an input unit side, extending the conductor unit of a film carrier to a through hole bump formed in the vicinity of the wirings of the output unit side and utilizing the conductor unit as wirings. CONSTITUTION:An integrated circuit which is composed of an output transistor 32, an output drive unit 33, a logic circuit 34 including a latch and a shift register, etc. and an input circuit 35 is formed on the upper surface of a semiconductor device 7. Bumps 51'', 53'', 25'' are respectively provided at the transistor 32, the unit 33 and an input terminal 25, and the bumps are electrically connected therebetween via the conductors of the film carrier. Since the conductors are raised upward by the projected bumps, they are not contacted with the integrated circuit on the semiconductor device 7 at the part except the bumps, and no shortcircuit occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal head, and more particularly to an improvement in the wiring of a semiconductor device incorporated in the thermal head.

As is well known, the thermal head consists of minute resistive heating elements arranged in a line or in a matrix, and the heating elements are selectively energized (1) to generate heat, and (4) thermal paper brought into contact with the heating resistors is colored to generate electrical information. This is a device that converts electricity into i-electronics.

FIG. 1 is a plan view of a conventional thermal head, and FIG. 2 is a sectional view taken along line X-X of the same thermal head. In these figures, 1 is a heat dissipation base, and 2 is a heat-resistant substrate made of ceramic or the like with a glazed surface, which is placed on the heat dissipation base 1. 3 is a heating resistor formed on the heat-resistant insulating substrate 2, and usually there are 8 heating resistors per 1 m (8 dots/
m) is formed as a fine pattern. The heat generating resistors 3 are divided into groups, and one end of the heat generating resistors 3 divided into each group is electrically connected to each group as a common electrode 4, and the other end of the heat generating resistors 3 is electrically connected to each group. A separation electrode 6 is formed on the side.

Reference numeral 6 denotes a heat radiating plate placed on the heat radiating base 1, and a semiconductor device 7 is fixed on the heat radiating plate 6. Reference numeral 8 indicates a coating film for the semiconductor device 7, and reference numeral 9 indicates a sintering film that covers the entire head wiring mounting portion. - 10 is a conductor portion of a film carrier that electrically connects the circuit formed on the semiconductor device 7 and the separation electrode 6 on the heat-resistant insulating substrate 2; 10' is the signal line 12 on the multilayer wiring board 11;
This is a conductor portion of the film carrier that electrically connects the circuit on the semiconductor device T and the circuit on the semiconductor device T.

In the conventional thermal head, as facsimiles have become two-speed, it has become necessary to use the thermal head for high-speed recording, and a method has been adopted in which a large number of heating resistors 3 are driven simultaneously. The semiconductor device 7 used at this time needs to be a special high-density integrated circuit in which shift registers, latches, and drivers are integrated into a multi-bit cluster.

On the other hand, such semiconductor devices must be arranged in large numbers in a narrow area to accommodate the heating resistor, which is usually formed with a fine pattern of 8 bits per square inch. There was a need for miniaturization. Therefore, the integrated circuits of semiconductor devices were made with multilayer wiring structures to increase the density, but the manufacturing process of integrated circuits with multilayer wiring was complicated and yields were poor. It is necessary to take out the integrated circuit wiring from both sides of the semiconductor device 7 (the heating resistor 3 side and the multilayer wiring board 11 side), making the wiring complicated. .

Hereinafter, the integrated circuit of the semiconductor device 7 and its peripheral wiring in a conventional thermal head will be explained in detail, and its drawbacks will be discussed.

3- is a basic circuit diagram of the thermal head, and FIG. 4 is an actual diagram of the same part. In FIG. 3, this is an output side terminal that connects the output transistor 22 and the heating resistor 3 in the 21μ semiconductor device 7 on a one-to-one basis. Therefore, a convex conductor (Φ) is formed.

23 is a common ground line for the output transistor 22; 24 is a driving power line connected to the base of the output transistor 22 to drive the transistor; 23' and 24' are the common ground line 23 and the driving power line 24, respectively. and electrical 1
31 is an integrated circuit formed on the semiconductor device 7 and includes a latch, a register, etc., 26 is an input terminal of the semiconductor device 7, and 26 is a conductor part of the film carrier and multilayer wiring. The connection point with the signal line 12 formed on the plate 11 is shown.

FIG. 4 is a plan view of essential parts of a conventional thermal head having the wiring shown in FIG. 3. In the same figure, the semiconductor device 7 includes an output transistor section 32 . in which a large number of transistors are arranged. Output drive section 33; logic circuit section 34 and input circuit section 36 composed of latches, shift registers, etc.
It has an integrated circuit on its top surface.

6. A bump is formed on the output side terminal 21 of this integrated circuit for connection to the heating resistor 3 side. This output side terminal 21 is electrically connected to a large number of heating resistors 3 arranged on the heat-resistant insulated rice 2 through a film carrier 1o made of a resin film 41 and a conductive foil 42.

On the other hand, multilayer wiring board 1 placed on the other side of semiconductor device 7
A large number of signal lines 12 are formed in parallel on the signal line 1, and a film carrier 10' made of a resin film 41' and a conductive foil 42' is arranged on the signal line 12. The conductive foil 42' has an L-shape, and one end thereof is electrically connected to the signal line 12 at the connection portion 26, and the other end is electrically connected to the input side terminal 26 of the semiconductor device 7.

In a thermal head that connects the input and output parts of a semiconductor device using a film carrier, in the conventional case, the common ground line 23 and driving power supply line 24 of the output transistor located in the output part are connected without complicated wiring. Logic circuit section 34
Since it is configured to be taken out to the input side through the wire, it is necessary to create a multilayer wiring structure on the semiconductor device. That is, the common ground line 23 is passed through the through hole 32', and the drive power supply line 24 is passed through the through hole 33'. Multilayer wiring section 2
Terminals are taken out from 3224# on the input side, and a multilayer wiring structure is used to take out these wirings. Here, since the common ground line and the drive power supply line require a large current capacity, the wiring width must be increased, which causes current leakage at the intersections in the multilayer wiring.

The present invention has been made in view of the above-mentioned conventional drawbacks in order to reduce the number of multilayer wiring in an integrated circuit of a semiconductor device. The conductor portion of the carrier is extended to the bump and used as part of a multilayer wiring circuit, and the integrated circuit of the semiconductor device can be simplified.

Detailed explanation of the present invention 1 below based on the drawings do.

FIG. 6 is a plan view showing the structure of a semiconductor device of a thermal head and its surroundings in an embodiment of the present invention, and FIG. 6 is a YY/cross-sectional view of FIG. In these figures, the same parts as in FIG. 4 showing the conventional example are designated by the same numbers.

In these figures, the upper surface of the semiconductor device 7 has an output transistor section 32. as in the conventional case. Output drive section 3
3. An integrated circuit is formed from a logic circuit section 34 and an input circuit section 36, which are composed of latches, shift registers, etc. The feature of this embodiment is that the output transistor section 32
．． Output drive section 33. The input terminal 25 is provided with bumps 61z53' and 25', respectively, and these bumps are electrically connected by conductor portions C of the film carrier hereinafter referred to as fingers. in particular,
Grounding bump 61′ in the output transistor section 32
and the bump 26' of the input terminal 26 are electrically connected by a finger 62 extending from the input terminal 25,
Further, the bump 63' for applying the signal voltage vcc in the output drive section 33 and the bump 25' of the input terminal 26 are electrically connected by a finger 64.

Here, the fingers that electrically connect each bump are lifted upward by the protruding bumps, so
There is no contact with the integrated circuit on the semiconductor device at any part other than the bumps, and defects such as short circuits do not occur.

Incidentally, as shown in FIG. 6, the bangs 51' and 25' are formed on the grounding terminal 61 and the input side terminal 26 through diffusion prevention layers 61' and 25', respectively, and these terminals 61 and 26 are connected to each other. They are electrically connected to each other.

On the other hand, the bump 21' formed on the output side terminal 21 via the diffusion prevention layer 21' is electrically connected to the separation electrode 6 on the heating resistor side by the film carrier conductor part 1o. It is the same as the conventional one.

Note that 61 is an interlayer insulating layer of the multilayer wiring section, 62 is a protective insulating layer, and 23' and 24' are second conductor layers.

The thermal head of the above embodiment has the following advantages.

0) In a configuration in which the wiring on the output side of the semiconductor device 7 is inserted and taken out from the tip side, the conductor part of the film carrier is extended to the through-hole bump provided near the wiring part on the output side, and this conductor part is connected to the wiring. Since it is used as a semiconductor device, multilayer wiring within a semiconductor device can be simplified, and the yield of semiconductor devices can be greatly improved.

@) The conductor portion of the film carrier that bridges between bumps has a large width and thickness, so it can be effectively used as power system wiring such as grounding wires. Therefore, conventionally, wide conductor wiring was used in semiconductor integrated circuits. Failures caused by current leakage between the first layer and the second layer can be prevented.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional thermal head, Figure 2 is a sectional view taken along line xx' of the same thermal head, Figure 3 is a diagram showing the electrical wiring of the thermal head, and Figure 4 is a semiconductor in a conventional thermal head. FIG. 6 is a diagram showing the wiring state around the semiconductor device in an embodiment of the present invention, and the sixth side is a Y-Y/cross-sectional view of FIG. 6. 1-...Base for heat dissipation, 2...Heat-resistant insulating substrate, 3...Heating resistor, 7...Semiconductor device, 10°10'...・・・Film carrier,”
11...Multilayer wiring board, 21126161', 6
3'... Bump, 52° 54... Extended conductor part of the film carrier. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (3)

[Claims] (1) A heat-resistant i-edge substrate on which a row of heating resistors is formed;
A semiconductor device and a multilayer wiring board are arranged on a heat dissipation base,
Electrical connections are made between the heating resistor and the semiconductor device and between the heating resistor and the multilayer wiring board using a film carrier, and through-hole bumps are provided at predetermined portions of the integrated circuit of the semiconductor device, and the film A thermal head characterized in that a conductor portion of the carrier extends to the bump and becomes part of the circuit wiring of the semiconductor device. (2) The semiconductor device has a multi-bit output terminal at one end thereof and input terminals for a signal system and a power system at the other end, and at least the input terminal for the power system is provided. The thermal bed according to claim 1, characterized in that a conductor portion of the film carrier is extended and electrically connected to the bump. 2 ・ (3) The thermal head according to claim 2, wherein the input terminal of the power system is a ground terminal into which the head current flows.