JPH0281465A - Construction for grounding static breakdown protective layer in electronic device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to electronic components such as hybrid ICs having an electrostatic breakdown prevention layer on the surface, and in particular, to electronic components such as thermal \\nand, 1x type image sensors, etc. This invention relates to an electrostatic breakdown prevention layer grounding structure for a long electronic device having an electrostatic breakdown prevention layer on its surface.

[Conventional technology]

During actual use, long electronic devices such as thermal heads and 1-magnification image sensors move while in direct contact with thermal recording paper, thermal transfer ribbons, objects to be read, etc. , static electricity is generated on the surface of the device, and sometimes electrostatic damage occurs in the functional circuit portion of the device, resulting in device destruction.

For this reason, a semi-insulating layer for electrostatic charge dispersion (
ρ-■06 to 109ΩC=11). It is known that the effect can be dramatically improved by connecting this semi-insulating layer for dispersion to the ground potential.

FIG. 7 is an example of a conventional electronic device in which a semi-insulating layer for electrostatic charge dispersion is formed.

In FIG. 7, ``■'' is an electrostatic breakdown prevention layer as a semi-insulating layer for electrostatic charge dispersion, and disperses electrostatic charges accumulated in the functional film 7 provided below. When the electronic device is a thermal head, the functional film 7 serves as a heating resistor and an electrode 115 for power supply to the resistor! Alternatively, it is a wear-resistant protective film. Usually, the electrostatic breakdown prevention layer 1 is made of cermet or semi-insulating semiconductor.

6 is a substrate, and in the case of a thermal heave, a glazed ceramic substrate is usually used.

An IO is a structure of an electronic device, for example a human sink. 8 is a circuit wiring board on which a drive circuit for driving the thermal head and the like are formed.

Reference numeral 9 denotes a ground potential wiring section provided on the circuit wiring board.

In this conventional example, in order to ground the electrostatic breakdown prevention layer, the electrostatic breakdown prevention layer l and the ground potential wiring section 9 are connected by a connecting metal piece I2. Reference numeral 11 denotes a conductive adhesive for connecting the metal piece 12, the electrostatic breakdown prevention layer l, and the ground potential wiring section 9.

Thereby, the electrostatic damage prevention layer 1 can be completely grounded, and electrostatic damage development due to accumulated static charges can be minimized.

[Problem to be solved by the invention]

However, cermet or semi-insulating semiconductor is generally used for the electrostatic breakdown prevention IF layer I, and these films cannot be connected by soldering or wire bonding using AP, Au, or Cu wires. It was not possible to use the method.

For this reason, the ground wire has been formed by using a hardening type conductive paste, for example, a conductive epoxy resin, or by crimping or pressing a member made of a metal piece.

Therefore, in the former case, (1) the mechanical adhesion strength between the paste and the dispersion semi-insulating layer is weak, (2) protrusions will be formed on the surface, and (3) connecting lines in mm units are required. , the area required for the fixation becomes large, and (4) processes other than the formation and mounting process of ICs and electric circuits are required.

In the latter case, (1) crimping and press-welding will damage the ground, and as in the former case, (2) protrusions will be formed on the surface, and (3) connections in mm units. This method has the following problems: wires are required and the area for fixing them becomes large; and f4) steps other than the formation and mounting process of ICs and electric circuits are required.

This invention was made in view of the above points, and the connection is reliable and easy, does not require a special process for connecting the grounding wire, and moreover, the area for connecting the grounding wire is small. The purpose of this invention is to provide a connection structure for grounding wires that is easy to use.

[Means and effects for solving the problem] In order to solve the above-mentioned problem, the present invention provides the following features: ! To prevent electrostatic damage, a bonding film is provided near the layer, and when wire bonding is performed to this film, the bonding wire near the ball bond part or tellurium bond part is connected to the electrostatic damage prevention layer. The electrostatic breakdown prevention layer is grounded.

This makes it possible to provide a connection structure that solves the above problems.

(Example) The present invention will be explained with reference to actual examples shown in FIGS. 1 to 6. In FIGS. 1 to 6, the same parts as the conventional example shown in FIG. Since they are given the same number,
In the following description of the embodiment, detailed description of these parts will be omitted.

(1) First Embodiment FIG. 1 is a first embodiment of the present invention, and shows a cross-sectional 1+i diagram of a portion where an antistatic layer of an electronic device is grounded. In the figure, 1 is an electrostatic breakdown prevention layer, 7 is an anodic film, and 6
9 is the S board, E is the circuit wiring board, 9 is the ground potential wiring section,
Reference numeral 10 denotes a structure, and these members are the same as those in the conventional example explained in conjunction with FIG.

In the case of this first embodiment, on the substrate 6, adjacent to the electrostatic breakdown prevention layer l, A! A wire bonding film 2 such as a film is provided, and the bonding wire 5 is ball-bonded so that the ball bond portion 3 is placed on the wire bonding film 2 and the electrostatic breakdown prevention layer 1.

Since the wire bonding film 2 is made of a film capable of ordinary wire bonding, such as /1, the ball bond portion 3 is reliably bonded onto the wire bonding film 2. The ball bond portion 3 on the electrostatic breakdown prevention layer 1 is not integrally bonded to the electrostatic breakdown prevention layer l, but as shown in the figure, it is in contact with the surface thereof and is electrically well connected. That will happen. Arrow A in the figure is a contact point between the electrostatic breakdown prevention layer 1 and the ball bond part 3.

The other end of the bonding wire 5 is tail-bonded onto the ground potential wiring section 9. In this case, it is desirable that 1/2 or more of the ball bond part 3 be located on the wire bonding film 2, and the distance between the wire bonding film 2 and the electrostatic breakdown prevention layer I should be within 40 μm. It is desirable to do so.

(2) Second Embodiment FIG. 2 shows a second embodiment of the present invention. This embodiment has the same structure as the first embodiment except that the wire bonding layer 2 is extended below the electrostatic breakdown prevention layer 1. In the case of this embodiment, the distance between the wire bonding film 2 and the electrostatic breakdown prevention layer 1 can be made sufficiently small, contributing to miniaturization.

(3) Third Embodiment FIG. 3 shows a third embodiment of the present invention. In FIG. 3, 1 is an electrostatic breakdown prevention layer, 7 is a functional film, 6 is a substrate, and 8
1 is a circuit wiring board, 9 is a ground potential wiring section, and 10 is a structure, and these members are the same as the conventional example explained with FIG. 7 and the embodiment shown in FIGS. 1 and 2.

In this embodiment, a hole is made in the electrostatic breakdown prevention layer l, a wire bonding film 2 is provided in the hole, a bonding wire 5 is tail-bonded on the wire bonding layer 1 pattern 2 in this hole, and , bonding wire 5
The other end is ball-bonded onto the ground potential wiring section 9.

As a result, the bonding wire 5 comes into contact with the electrostatic breakdown prevention layer 1 at point A, and electrical grounding is achieved. In this case, the wire bonding film 2 and the electrostatic breakdown prevention layer 1
It is desirable that the distance is 300 μm or less.

(4) Fourth Embodiment FIG. 4 shows a fourth embodiment of the present invention. In this example, wire bonding IG! The other structure is the same as that of the third embodiment except that the end portion of the electrostatic breakdown prevention layer 1 is extended to the lower part of the electrostatic breakdown prevention layer 1. In this embodiment, since the distance between the end of the electrostatic breakdown prevention layer 1 and the wire bonding film 2 can be shortened, further miniaturization is possible.

(5) Fifth Embodiment FIG. 5 shows a fifth embodiment of the present invention. In this embodiment, the circuit wiring board 8 is not used, but the board 6 is provided as an extension, and the wire bonding film 2 is provided thereon. A bonding wire 5 is tail-bonded to this +1ff2 for wire bonding, and further ball-bonded is applied to the end of the film 2 for wire bonding so as to cover the electrostatic breakdown prevention layer 1.

(6) Sixth Embodiment FIG. 6 shows the sixth actual AI example of the present invention. In this embodiment, similarly to the third embodiment, an opening is provided in the electrostatic breakdown prevention layer 1, a wire bonding film 2 is provided in this opening, and a bonding wire 5 is tail-bonded to this part. However, without providing the circuit wiring board 8, the base Fi
, 6 are extended, and a ground potential wiring section 9 is directly placed on this board 6.
is formed.

In the first to sixth embodiments described above, the contact point with the electrostatic breakdown prevention layer l is at one location, but it goes without saying that it may be provided at multiple locations in the longitudinal direction of the elongated electronic device. Mona (
, in this case the connection establishment is even higher and grounding within the device is ensured.

Further, the wire bonding described above is not only used for this grounding, but is also the same as the mounting method for bare chips such as ICs mounted on electronic devices, and can be performed in the same process.

〔Effect of the invention〕

As described above, according to the present invention, (1) The area required for the connection can be narrowed compared to the conventional connection method. That is, the length of the required area, which was conventionally on the order of mm, can be reduced to about 100 μm, resulting in space savings.

In addition, the appearance of protrusions can be prevented. (2) Connections are made by wire bonding, which is the same method used for hair chips such as ICs that are mounted as control elements of electronic devices, so connections can be made in the same process. (3) The connection method is wire bonding, which is used for ICs, etc., and a highly reliable connection is possible. (4) ) No new membrane configuration is required to make the connection (
It has the following excellent effects: it can be realized by simply changing the pattern or by applying a conventional pattern.

[Brief explanation of the drawing]

1 to 6 are diagrams showing an embodiment of the present invention, and FIG. 7 is a diagram showing a conventional example. 1 - Electrostatic breakdown prevention layer (semi-insulating layer) 2 - 1 piece for wire bonding 3 - Ball bond part 4 Tail bond part 5 - Bonding wire 6 - Substrate 7 Mechanical film 8 - Circuit wiring board 9 - Ground potential Wiring section 10 Structure Figure 1 Figure 5 Figure 2 Figure 6 Figure 7 Figure 4 Procedural amendment (method) Contents of amendment January 18, 1999 Commissioner of the Japan Patent Office Yoshi 1) Moon Takeshi 1, Display of case 1988 Patent Application No. 232835 2
, Title of the invention: Electrostatic breakdown prevention layer grounding structure in electronic devices 3, Relationship with the case of the person making the amendment Patent applicant address: 3-1 Nihonbashi-chome, Chuo-ku, Tokyo Name: Jf.
(306) T.D.K. Co., Ltd. Representative Hiroshi Sae 1, Statement 1, line 13 [Electric breakdown prevention layer grounding side construction,
1 and line 14 “[Industrial application field] I, [3
, insert Detailed Description of the Invention J. 4. Agent address: 1-19-8 Kanda-Awaji-cho, Chiyoda-ku, Tokyo Shipping mortar December 20, 1988

Claims (1)

[Claims] (1) In an electronic device having a functional film on which an electrostatic breakdown prevention layer made of a semi-insulating layer is formed, a bonding film is provided near the electrostatic breakdown prevention layer, and a wiring portion whose one end is at ground potential Electrostatic discharge in an electronic device, characterized in that a bonding wire is provided, the other end of which is connected to the bonding film, and which is electrically connected to the electrostatic breakdown prevention layer. Destruction prevention layer grounding structure.