JPS61186061A - Device for driving contact type image sensor or thermal head or the like - Google Patents

Abstract

PURPOSE:To attain thin profile for a drive section and to reduce the time for bonding and test by connecting directly a bonding pad to a wiring pattern corresponding onto a board via a hot-pressed anisotropic conductive film. CONSTITUTION:Wiring patterns 22, 42 prolonged up to the corresponding position respectively to each bonding pad 31 of an IC30 are formed to the surface of an insulation board 10. Then the anisotropic conductive film 70 cut off into a size to cover each pattern tip is provided on the wiring patterns 22, 42. Then the IC30 is provided on the film 70 with its face down to align each bonding pad 31 and the tip of the wiring patterns 22, 42. Then the film 70 and the IC30 are hot-pressed onto the board by using a hot press to bond directly the bonding pad 31 and the tip of the wiring patterns 22, 42.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies to objects (in these examples, manuscripts and recording paper) of electronic devices such as the light receiving part of a contact image sensor and the heat generating part of a thermal head. The I
The present invention relates to a driving device such as a contact type image sensor or a thermal head that drives these elements arranged in a C format, and particularly relates to an improvement in the mounting structure of the IC on the substrate.

[Conventional technology]

FIG. 4 and FIG. 5 show, as an example, how the driving IC (hereinafter simply referred to as IC) is mounted in a conventional contact type image sensor. However, FIG. 4 is a partial plan view of the contact type image sensor, and FIG. 5 is a sectional view taken along line AA' in FIG. 4.

4 and 5, 10 is an insulating substrate made of glass, ceramic, etc., and 20 is a divided electrode made of a conductive thin film of Al, Cr, Au, etc. on this substrate 10, and 5e-As-Te. Alternatively, a photoconductive layer made of an amorphous semiconductor film such as a-8i or a polycrystalline semiconductor film such as CdS or CdSe, and a transparent electrode made of a transparent conductive thin film such as 5n02 or ITO are deposited in sequence. 21 is a wiring pattern drawn out from each of the above-mentioned electrodes of the light receiving section 20 onto the substrate 10 as shown in the figure, for example. Reference numeral 30 indicates a bonding pad of the IC 3Q, and 40 indicates a bonding pad of the IC 3Q for driving the light receiving section 20 through these wiring patterns 21, and a reference numeral 40 indicates a connection pad for supplying power to the IC 3Q and connecting the IC 3Q to a main device (not shown) when driving the light receiving section 20. 41 is an example of its wiring pattern; 50 is a bonding wire that electrically connects the bonding pad 31 of IC3Q- to the wiring patterns 21 and 41 described above; 60 is the wire; This is a protective film made of an appropriate resin for protecting the wire 50 and the wire 50 bonded by the wire 50.

In this way, conventionally, when mounting IC3Q on the board 10,
After the IC3Q is made into a so-called face amplifier and its back is appropriately bonded onto the substrate 10, electrical continuity is established between the IC3Q and its peripheral circuits by so-called wire bonding using a wire 50.

[Problem that the invention seeks to solve]

Connections using wire bonding have been frequently used to achieve high-density wiring, but as shown in Figure 5, this connection method
Since the height α (normal quantity) of the wire 50 naturally increases the height from the top surface of the substrate 10 to the top surface of the protective film 60, especially in a contact type image sensor as shown here, ■ Light reception This prevents the portion 20 from coming into close contact with the original.

■ It also poses a problem in making the device itself smaller and thinner.

This would lead to such inconvenience.

In addition, the connection itself using wire bonding: (1) Bonding and testing take time (normally, it takes about 30 minutes for one image sensor).

(2) When sealing with the protective film 60 described above, the wire 50 may fall down and cause a short circuit.

Due to these problems, it was difficult to mass-produce the applicable equipment, and furthermore, it was difficult to lower the price.

This situation is also common in thermal heads and the like.

〔Effect of the invention〕

As described above, according to the driving device for a contact type image sensor or a thermal head, etc., according to the present invention, the driving portion of the contact type image sensor or thermal head, etc. can be reliably made thinner, and as a result, these contact type image sensors It is possible to improve the degree of adhesion of the light-receiving section and the heat-generating section of the thermal head to the original, recording paper, etc., and to further reduce the size and thickness of the applied device.

Furthermore, since the time required for IC mounting is significantly shortened and the electrical reliability is improved, so-called good products can be provided at low cost.

〔Example〕

FIG. 1 and FIG. 2 show an embodiment of a drive device according to the present invention. However, this implementation example also takes the drive device of a contact type image sensor, and of these Figures 1 and 2, Figure 1 shows the partial planar configuration of the same contact type image sensor, and Figure 2 is BB' in Figure 1.
The cross-sectional configuration at each line portion is shown. In addition, in these Figures 1 and 2 ζ, parts that are the same as those shown in Figures 4 and 5 are given the same numbers, and there are no overlaps. Explanation will be omitted.

In this embodiment, 70 is an anisotropic conductive film, and as shown in FIGS. 1 and 2, in this embodiment, the face-down C30 is It is mounted on the board 10. That is, the wiring pattern drawn out from the light receiving section 20 (this is called 22 because the pattern is different from the previous wiring pattern 21), and the wiring pattern drawn out from the control wiring section 40 (this is also different from the previous wiring pattern 41). 42) are metal particles in the anisotropic conductive film 70 that are stretched and arranged to the positions of the bonding pads 31 corresponding to each circuit configuration of the IC 30 and fixed by heat. The IC3Q is electrically connected to these corresponding bonding pads 31 through these. Here, this anisotropic conductive film refers to the item name "anisotropic conductive film" in the magazine "Electronic Technology" Vol. .16 No. 1
As is well-known in the item title ``Conductive rubber connector for collectively connecting LSI chips and packages by thermocompression bonding'' on pages 02 to 104, there is metal in a thermoplastic or thermosetting resin film or rubber film. The anisotropically conductive film 70 has a structure in which fine particles of
When the film 70 is heated to a predetermined temperature (temperature at which only the film material or both the film material and metal particles melt) while applying pressure in the sandwiching direction, each bonding of the electrode part, that is, IC3Q Between the pad 31 and each tip of the wiring pattern 22.42 facing thereto, the metal particles or molten metal particles between these pads 31 and the wiring patterns 22.42
Since it is pressurized by the tip of the metal part and commonly interposed between these metal parts, electrical continuity is established between these opposing electrodes, and the other part, that is, the part between each of the bonding pads 31, With respect to the opposing surface portion of the substrate 10 on which no printed wiring is formed, the packing density of the metal particles in the film is reduced due to the level difference between the tip portion of the wiring pattern 22° 42 and the surface of the substrate, and the film material It is electrically isolated by its own insulating properties. As is clear from FIG. 2, the height of the drive unit of this contact type image sensor including the IC3Q mounted in this way from the surface of the substrate 10 is determined approximately by the thickness of the IC30 itself. Even including the thickness of the protection J[60, the drive section of the conventional image sensor shown in FIG. 5 is significantly thinner.

Hereinafter, with reference to FIG. 3, a method for mounting the IC 30 on such a contact type image sensor using the anisotropic conductive film 70 will be explained in detail.

1) The wiring patterns 22 and 42 are formed on the surface of the insulating substrate 10. At this time, these wiring patterns 22
and 42 are extended to positions corresponding to the respective bonding pads 31 of the IC3Q, as shown in FIG. Suppose that it is done.

2) The wiring patterns 22 and 42 thus formed
The above-mentioned anisotropic conductive film 70 cut into a size that can cover each tip portion is placed on top of the anisotropic conductive film 70.

Note that at this time, a method of simply attaching the anisotropically conductive film 70 may be used.

3) I on this laid anisotropic conductive film 70
C3Q is disposed face down and aligned so that each bonding pad 31 and the electrically corresponding tips of the wiring patterns 22 and 42 are accurately opposed to each other. When arranging this IC3Q, it is also possible to simply attach it in the same manner as described above.

4) Finally, the anisotropically conductive film 70 and IC3Q stacked in this way are heated and pressed onto the substrate 10i using a hot press. At this time, heating is performed from below the substrate 10 in order to protect the IC3Q.

Therefore, the I
Complete C3Q implementation. Ho IU [60 will be adjusted accordingly from now on]
This film should be formed.

Although illustrations and detailed explanations are omitted, the basic structure on the substrate is similar to the above-mentioned image sensor in the thermal head used in thermal printers, magnetography, etc., and the present invention By applying this, the same effect as described above can be obtained.

By the way, the above-mentioned anisotropic conductive film 70 preferably has the following main characteristics in practical terms.

First, regarding film materials, 0 The melting point is 150°C or less.

o Must have electrical insulation of 1010Ω or more.

0 500g/C7+1 (25℃) or more +7)m adhesion strength.

0 High solvent resistance to organic solvents such as xylene, toluene, acetone, ether, and alcohol, and inorganic solvents such as acids and alkalis.

is desired. In this sense, preferred materials for the film material include vinyl resins (for example, styrene-butadiene-rubber (SBR), etc.), polyamides, polyester polycarbonates, polyacetals, ionomer resins, polyether sulfones, fluorinated resins, and cellulose resins. thermosetting resins such as resins, phenolic resins, eria resins, melamine resins, allyl resins, furan resins, unsaturated polyester resins, epoxy resins, silicone resins,
There are thermosetting resins such as polyimide polyurethane.

Regarding the metal particles dispersed in this film material, the melting point must be 150°C or lower.

0 High conductivity.

etc., so fine particles of low melting point solder are suitable as this material, but fine particles of metals such as nickel, gold, platinum, copper, silver, aluminum, etc. are also effective (in these cases , the melting point may be 150°C or higher)
. In particular, if the particle size is set to 25 μm or less (20/Jm±5 μm or less), the wiring resolution of the IC that drives the above-mentioned contact-type image sensor or thermal head can be increased to 20 wires/order or more, and the same drive This makes it possible to downsize the unit.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view showing an embodiment of a driving device for a contact type image sensor according to the present invention, and FIG.
3 is a sectional view showing the cross-sectional structure of the device taken along the line -B', FIG. 3 is a perspective view showing the manufacturing method of the embodiment device shown in FIGS. 1 and 2, and FIG. 4 is a conventional close-contact type A partial plan view showing the structure of the drive device of the image sensor, FIG.
FIG. 2 is a cross-sectional view showing the cross-sectional structure of the device taken along line A-A' in the figure. 10... Insulating substrate, -20... Light receiving section, 21, 22° 41.42... Wiring pattern, 30... rc, 31
...Bonding pad, 40...Control wiring section, 5
0... Bonding wire, 60... Protective film, 70
...Anisotropic conductive film Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (5)

[Claims] (1) A contact image that is arranged as an IC on the same substrate as the light receiving part of the contact image sensor or the heat generating part of the thermal head and drives the contact image sensor or thermal head. In a driving device such as a sensor or a thermal head, a wiring pattern of a portion of the substrate electrically connected to the IC is made to correspond to a bonding pad pattern of the same IC, and the bonding pad of the IC is anisotropically conductive. A driving device for a contact image sensor, a thermal head, or the like, characterized in that the drive device is mounted so as to be directly connected to the corresponding printed pattern on the substrate through a film. (2) The anisotropically conductive film is a thermoplastic or thermosetting resin film in which metal particles having a particle size of 25 μm or less are evenly dispersed.
) A driving device for a contact type image sensor or a thermal head, etc., as described in item 2. (3) The thermoplastic resin film is made of vinyl resin such as styrene-butadiene-rubber, polyamide, polyester, polycarbonate, polyacetal, ionomer resin, polyether sulfone, fluorinated resin, or cellulose. A driving device for a contact type image sensor or a thermal head, etc., according to claim (2), which is made of a resin. (4) The thermosetting resin film includes a phenol resin,
or an area resin, or a melamine resin, or an allyl resin, or a furan resin, or an unsaturated polyester resin, or an epoxy resin, or a silicone resin, or a polyimide, or a polyurethane, and the adhesive type according to claim (2). Drive device for image sensor or thermal head, etc. (5) The contact image sensor according to claim (2), wherein the metal particles are made of a metal or a metal compound such as solder, nickel, gold, platinum, copper, silver, or aluminum. Or a driving device such as a thermal head.