JP3112773B2 - Semiconductor device, image reading device, and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-moisture permeable semiconductor device, and more particularly to a non-moisture permeable image reading device suitable for a facsimile apparatus, an image reader, and the like.

[0002]

2. Description of the Related Art Hitherto, improving the moisture resistance of a semiconductor device has been an important technique for maintaining stable characteristics for a long period without deteriorating its characteristics. In particular, in an image reading apparatus such as a one-dimensional line sensor used for a facsimile apparatus or the like, it is considered to improve the moisture resistance in order to prevent performance degradation.

For example, in Japanese Patent Application Laid-Open No. 63-226064, in order to improve the moisture resistance stability of an optical sensor, the optical output is stabilized by coating a polyimide resin on the optical sensor. In this case, the microsheet glass as the moisture-impermeable protective member is bonded to the polyimide resin on the sensor substrate with an epoxy resin.

[0004] In Japanese Patent Application Laid-Open No. 2-219267, the stability of moisture resistance is improved by making the width of the optical sensor seem wider.

FIG. 5 is a schematic sectional view showing the structure of such a conventional image reading apparatus. In the figure, a sensor substrate 1 on which a semiconductor element such as an optical sensor 8 coated with a polyimide resin is formed is an epoxy resin between a light-transmitting and moisture-resistant support substrate 40 and a thin glass 32. Is sealed by the protective adhesive layer 29 to maintain moisture resistance.

[0006]

However, if the width of the sensor is reduced in order to increase the number of pieces taken from one glass substrate in order to reduce the cost of the sensor, the penetration time of moisture becomes relatively short. The structure of a conventionally used polyimide resin and epoxy adhesive has a problem that sufficient moisture resistance cannot be obtained.

[0007] This is because the polyimide resin and the epoxy resin have relatively large moisture absorption and moisture permeability characteristics. Conventionally, the resin has a purity that is low in moisture absorption and moisture permeability characteristics and does not adversely affect sensor characteristics. This is because there is no material that can achieve both adhesiveness.

In the conventional method of bonding the optical sensor and the microsheet glass, the work is inferior because the lamination is performed while removing bubbles while squeezing with a rubber roller using a liquid epoxy resin. There was a problem that it was easily broken and the yield was poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a moisture-resistant semiconductor device such as an image reading device which can obtain high moisture resistance even with a narrow sensor width, has good workability, and has a good yield, and a method of manufacturing the same. To provide.

[0010]

According to the present invention, as a means for solving the above-mentioned problems, a semiconductor element region formed on a moisture-impermeable substrate and a moisture-impermeable protective member provided on the region are provided. And a non-moisture permeable semiconductor device having a non-moisture permeable outermost layer, wherein the protective member and the outermost surface layer are:
It is another object of the present invention to provide a semiconductor device characterized in that the semiconductor device is constituted by being bonded by an adhesive layer mainly composed of an amorphous fluorine resin.

Further, in the image reading apparatus having a semiconductor optical sensor formed on a moisture-impermeable substrate, a moisture-impermeable protective member provided on the optical sensor, and a moisture-impermeable outermost surface layer, An image reading apparatus, wherein the protective member and the outermost surface layer are bonded to each other with an adhesive layer mainly composed of an amorphous fluorine resin. A step of forming a semiconductor element on the moisture-impermeable substrate; a step of applying and drying an amorphous fluororesin covering the semiconductor element; and a step of applying and drying an amorphous fluororesin to the moisture-impermeable surface protection member. After the step, a step of superimposing the surface protection member on the semiconductor element with the respective amorphous fluororesin layers facing each other, and heating and pressing in a vacuum to perform heat fusion. Forming a semiconductor optical sensor on a moisture-impermeable substrate; and coating and drying an amorphous fluororesin covering the optical sensor. And a step of applying and drying an amorphous fluororesin on the microsheet glass, and after the step, on the optical sensor, the microsheet glass, Heat-sealing by heating and pressing in a vacuum, and superposing the respective amorphous fluororesin layers facing each other, and providing a method of manufacturing an image reading apparatus. is there.

[0012]

According to the present invention, an optical sensor is disposed on a non-permeable sensor base, and a non-permeable protective member is disposed above the sensor base so as to cover the optical sensor. In an image reading apparatus in which an adhesive layer is provided between the protective member and the sensor substrate to bond the sensor member and the sensor base, the adhesive layer is made of amorphous fluororesin, thereby improving moisture resistance. This is to reduce the sensor width.

Amorphous fluoro resin is applied to cover the optical sensor, and after drying, micro-sheet glass treated in the same process is overlapped and heated and heat-sealed in a vacuum press to easily remove air bubbles. In addition, since there is no squeezing with a roller at the time of laminating, the microsheet glass is not broken and a simple and high-yield production is enabled.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2A is a partial plan view showing a first embodiment of the image reading apparatus of the present invention.
(B) and (C) are BB sectional views and CC, respectively.
It is sectional drawing.

In FIG. 2, 1 is a sensor substrate made of glass, 10 is a matrix wiring portion, 8 is an optical sensor portion, 1
2 is a charge storage unit, 13 is a transfer switch 13a and a discharge switch 13b for resetting the charge of the charge storage unit 12.
, A wiring connecting the signal output of the transfer switch to the signal processing unit, and 23 a transfer switch 13
This is a load capacitor for storing and reading out the charge transferred by a.

In this embodiment, an a-Si: H film is used as the photoconductive semiconductor layer 4 constituting the optical sensor section 8, the transfer switch 13a and the discharge switch 13b, and the insulating film 3 is nitrided by glow discharge. Silicon film (SiNH)
Is used.

In FIG. 2A, the photoconductive semiconductor layer 4, the insulating film 3, and the protective films 29, 30 and 32 are not shown in order to avoid complication. Further, the photoconductive semiconductor layer 4 and the insulating film 3 are formed in the photosensor section 8, the charge storage section 12, the transfer switch 13a and the discharge switch 13b, and between the upper electrode wiring and the sensor substrate 1. Is also formed. Furthermore the interface between the upper electrode wiring and the photoconductive semiconductor layer, n ⁺ a doped the a-Si: H layer 5 is formed, an ohmic junction is taken.

In the wiring pattern of this embodiment, all signal paths output from each sensor section are arranged so as not to intersect with other wirings, so that crosstalk of each signal component and induction from the gate electrode wiring are performed. The generation of noise is prevented.

In the optical sensor section 8, 16 and 17 are upper layer electrode wirings. The light enters from the entrance window 19, and the protective layer 3
2 (not shown)
The illumination light reflected by changes the electrical conductivity of the photoconductive semiconductor layer 4, which is a-Si: H, and changes the current flowing between the comb-shaped upper electrode wirings 16 and 17. Reference numeral 2 denotes a metal light-shielding layer connected to an appropriate driving unit, which prevents light from directly entering the sensor unit from the light source.

The charge storage section 12 includes a lower electrode wiring 14 and
It comprises a derivative of the insulating layer 3 and the photoconductive semiconductor layer 4 formed on the lower electrode wiring, and a wiring formed on the photoconductive semiconductor layer 4 and continuous with the upper electrode wiring 17 of the optical sensor portion. The structure of the charge storage section 12 is the same as that of a so-called MIS capacitor.

FIG. 2C shows a switch 13 having a TFT structure including a transfer switch 13a and a discharge switch 13b.
The transfer switch 13a includes a lower electrode wire 24 serving as a gate electrode, an insulating layer 3 serving as a gate insulating layer, a photoconductive semiconductor layer 4, and an upper electrode wire 25 serving as a source electrode.
And an upper layer electrode wiring 17 serving as a drain electrode.

The gate insulating film and the photoconductive semiconductor layer of the discharge switch 13b are composed of the insulating layer 3 and the photoconductive semiconductor layer 4.
The source electrode is the upper electrode wiring 17, the gate electrode is the lower electrode wiring 27, and the drain electrode is the upper electrode wiring 26. Reference numeral 33 denotes a lower wiring connected to the gate electrode of the transfer switch 13a.

Further, as shown in FIGS. 2B and 2C, the protective layers 29, 30, 3
2 are formed.

As the first protective layer 30, the light sensor section 8
As a high-purity material capable of stabilizing the surface of the optical sensor unit 8 and improving the moisture resistance, it is an inorganic film such as a SiO ₂ film or a SiNH film, An organic film such as a polyimide resin, a polyamide resin, a silicon resin, or a fluorine resin which can be formed and has little influence on the sensor is used.

As the second protective layer 29, an amorphous fluorine resin having low moisture permeability and low moisture absorption is used. The amorphous fluoro resin can be bonded by heat fusion.

As the third protective layer 32, a microsheet glass such as borosilicate glass is used as a material that is moisture-impermeable and has high wear resistance and high light transmittance.

The second protective layer has a function as an adhesive layer in the present invention, and the third protective layer 32 has a function as a protective member in the present invention.

When the protective layer 30 is made of a fluorine resin, the protective layers 29 and 30 are formed integrally.

In this embodiment, compared to the prior art shown in FIG. 5, since the material used is superior in moisture resistance, it is possible to prevent moisture in the outside air from entering the optical sensor 8. it can.

An essential new point in the present invention is that an amorphous fluoro resin is used in place of the epoxy resin conventionally used as the adhesive layer. Epoxy resin is a material having an extremely strong adhesive force and is excellent as an adhesive, but has a problem in moisture resistance.

The point of the present invention lies in that the moisture resistance is improved by using an amorphous fluororesin and the anti-wear layer 32 and the sensor substrate 1 are bonded together.

That is, conventional fluororesins (PTFE, PF
A, FEP, ETFE, PCTTE) and the like have low moisture absorption and low moisture permeability, but could not be used as an adhesive. This is because these fluorine resins are non-polar and extremely crystalline materials, and thus could not be used as an adhesive. Further, such a highly crystalline material is opaque and cannot be used particularly in a field requiring light transmittance such as an image reading apparatus according to the present invention.

As an example of an attempt to improve the adhesiveness, introduction of a Si group, an acrylic group, a hydroxyl group, or the like into the molecular structure is performed. However, although the adhesive property is improved, the moisture resistance is reduced.

CYTOP (trade name of Asahi Glass Co., Ltd.) used in the present invention is a fluorine resin having an amorphous structure different from a conventional fluorine resin. Since this can be dissolved in a special solvent, it can be applied as a coating material. Further, since the transparency is excellent, it is suitable for an image reading apparatus as in the present invention.

In terms of characteristics, it has low moisture absorption and low moisture permeability.
It is suitable as a passivation film for semiconductors.

FIG. 3 is a diagram showing the change over time in characteristics between the present embodiment and the conventional example shown in FIG. In FIG. 3, the sensor was manufactured in exactly the same width direction L = 6 mm, and the first protective layer 30 and the adhesive layer 29 on the sensor were made of polyimide resin or epoxy resin in the conventional example. 1 is different in that it is formed of a single-layer film of amorphous fluorine resin (trade name: CYTOP manufactured by Asahi Glass Co., Ltd.).

To examine the change in dark current characteristics under high temperature and high humidity, the dark current characteristics of the sensor are a good indicator of moisture penetration. As shown in FIG. It can be seen that the examples are overwhelmingly improved in moisture resistance.

In this embodiment, a sensor having a sensor substrate with a width of L = 3 mm, which is about half the width of the conventional sensor substrate, was manufactured, and an equivalent experiment was performed. FIG. 3 shows an example in which the width L is 3 mm. As can be seen from the results, the configuration of the present invention shows that the sensor width has sufficient moisture resistance even when the sensor width is reduced to half of the conventional width.

Although not particularly limited, the protective layer 29 may be used in combination with the inorganic protective layer 30.

As another embodiment, when an organic material such as polyimide, polyamide, or silicon is used for the protective layer 30, these materials have a higher moisture absorption than the amorphous fluororesin (Cytop) 29. It is preferable to adopt a structure (shown in FIG. 4) in which the periphery is surrounded by an amorphous fluorine resin (trade name: Cytop) 29.

[Manufacturing Method] Next, the manufacturing method of the first embodiment will be described below.

As described above, although it is an excellent amorphous fluororesin (trade name: Cytop), there are the following problems in using this as an adhesive for bonding in a large area. That is, 1. 1. The solvent must be dried because it is dissolved in the solvent; After the solvent is dried, it becomes solid as a film, so that no adhesive force is generated with a new contact member.

The present inventors have paid attention to the fact that the material of an amorphous fluororesin becomes soft and becomes tacky when heated, and after being formed as a film, the film is heat-fused by reheating and pressing an adhesive to form an adhesive. Could function as. It was also found that the image reading device having the adhesive structure exhibited excellent moisture resistance stability as described above. The present invention has been made based on these findings.

The amorphous fluororesin can be applied as a thin film because it is dissolved in a special solvent. Therefore, it is necessary to heat after coating to remove the solvent and form a film. The thus formed amorphous fluororesin is softened by reheating and can be re-adhered.
Therefore, when the thin glass is adhered by the manufacturing procedure of the present invention as shown in FIG. 1, the yield decreases due to the residual bubbles compared to the case where the thin glass is adhered by ironing using a liquid epoxy adhesive. It was found that the method was excellent in workability without cracking of the thin glass and had a good yield.

FIG. 1 is a view showing a manufacturing process of the present invention.

(Explanation of FIGS. 1A and 1B) First, a sensor substrate 1 having a semiconductor layer 50 on which a semiconductor element such as an optical sensor element is formed is prepared, and the sensor substrate 1 is set on a spinner to form an amorphous layer. Fluoro resin (trade name: Cytop) is dropped and spin-coated for a specified number of times and for a specified time.

Next, a thin glass substrate (microsheet glass) 32 is prepared, and similarly, the thin glass substrate 32 is set on a spinner, and an amorphous fluorine resin (trade name: Cytop) 29 'is dropped, and the specified number of times and the specified time are set. Spin-apply.

(Explanation of FIG. 1 (c)) Next, the sensor substrate 1 coated with the amorphous fluorine resin (trade name: Cytop) is put into a drying furnace and dried for a specified time. Similarly, a thin glass substrate 32 coated with an amorphous fluororesin (trade name: Cytop) is also put into a drying furnace and dried for a specified time.

(Explanation of FIGS. 1D and 1E) Next, the thin glass substrate 32 is placed on the sensor substrate 1 and put into a hot press. Take this out after the specified time.

A better result can be obtained by using a vacuum press to remove air bubbles in the amorphous fluorine resin (trade name: Cytop). When a vacuum press is used, the number of sensor substrates that can be simultaneously bonded can be increased, and air bubbles are easily released because pressurization and heating proceed simultaneously in a vacuum. In the vacuum press, since heating can be performed in a furnace, work efficiency and yield are improved.

As an example of the vacuum press, “Electronic material 19
October 1984, "Laminated Vacuum Press for Multilayer Printed Boards" by Nagata may be used.

The present inventors experimentally placed the sensor substrate and the microsheet glass in a glass bell jar, placed a weight for pressurization, and then placed the same in a heating furnace to heat it. While evacuating the bell jar, a sample was made.

In this embodiment, although the thin glass substrate is also coated with amorphous fluororesin (trade name: Cytop), only one of them may be coated. To improve the familiarity of the amorphous fluoro resin (Cytop), it is better to apply it on both sides.

The protective film 30 is made of SiO ₂ , SiNH
In the case of using an inorganic film such as that described above, if the amorphous fluoro resin (Cytop) is applied in advance, the impact force of laminating when the microsheet glass is laminated can be reduced, There is also an effect that occurrence of cracks and damage can be suppressed.

Further, an amorphous fluoro resin (trade name)
The method of applying CYTOP is not limited to spin coating, but may be dipping or printing.

[Embodiment 2] The semiconductor device of the present invention using an amorphous fluororesin as an adhesive layer is not limited to an image reading device, but may be applied to any semiconductor device requiring moisture resistance. Yes, it is clear that a similar effect can be obtained.

[0058]

As described above, according to the present invention,
In a semiconductor device such as an image reading device that requires moisture resistance, by using an amorphous fluororesin as an adhesive layer, higher moisture resistance can be provided, and moisture in the outside air does not easily enter an element region such as a sensor unit. Therefore, the stability of the element characteristics is increased, and the optical sensor can have the same or higher environmental resistance as that of the conventional optical sensor even if the sensor width is reduced. As a result, the sensor can be manufactured at low cost, and the performance has been improved.

As an example of the manufacturing method, in the case of an image reading device, an amorphous fluororesin is coated over an optical sensor and dried, and then microsheet glass subjected to a similar process is overlaid, and the glass sheet is placed in a vacuum press. By adopting the method of heating and heat-sealing, since the thin glass sheets can be bonded uniformly without cracks and without bubbles, the effect of improving the yield and reducing the cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for manufacturing an image reading apparatus embodying the present invention.

FIGS. 2A and 2B are diagrams illustrating the structure of an image reading apparatus embodying the present invention, wherein FIG. 2A is a plan view of an optical sensor embodying the present invention, and FIG. 2B is an optical sensor embodying the present invention; BB
FIG. 4C is a sectional view of the optical sensor (A) embodying the present invention.
-C sectional drawing.

FIG. 3 is a diagram showing moisture resistance characteristics of the optical sensor of the present invention and a conventional example.

FIG. 4 is a schematic sectional view showing another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor board 2 Optical sensor part (semiconductor element part) 29 2nd protective film (adhesive layer) 30 1st protective layer 32 3rd protective layer (microsheet glass) 40 Support substrate

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-291169 (JP, A) JP-A-3-150872 (JP, A) JP-A-4-355096 (JP, A) JP-A-5-205 40357 (JP, A) Japanese Utility Model Hei 4-40547 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01L 23/29 H01L 23/31 H01L 27/14 H04N 1/028

Claims (5)

(57) [Claims] 1. A moisture-impermeable semiconductor device having a semiconductor element region formed on a moisture-impermeable substrate, a moisture-impermeable protective member provided on the region, and a moisture-impermeable outermost layer. A semiconductor device, wherein the protective member and the outermost surface layer are adhered by an adhesive layer mainly composed of an amorphous fluorine resin. 2. An image reading apparatus comprising: a semiconductor optical sensor formed on a non-permeable substrate; a non-permeable protective member provided on the optical sensor; and a non-permeable top surface layer. An image reading apparatus, wherein the protective member and the outermost surface layer are bonded by an adhesive layer mainly composed of an amorphous fluorine resin. 3. The image reading apparatus according to claim 2, wherein said optical sensor section is mainly composed of amorphous silicon. 4. A step of forming a semiconductor element on a moisture-impermeable substrate, a step of applying and drying an amorphous fluororesin covering the semiconductor element, and a step of applying and drying an amorphous fluororesin on a moisture-impermeable surface protection member And after the step, on the semiconductor element, the surface protection member, the respective amorphous fluorine resin layer facing each other, and superimposed, heated in a vacuum, the step of heat fusion by pressing, A method for manufacturing a semiconductor device, comprising: 5. A step of forming a semiconductor optical sensor on a moisture-impermeable substrate, a step of applying an amorphous fluororesin to cover the optical sensor and drying, and a step of applying and drying an amorphous fluororesin to microsheet glass And after the step, a step of heat-fusing the microsheet glass on the optical sensor by superposing the respective amorphous fluororesin layers facing each other, heating and pressing in vacuum. A method for manufacturing an image reading apparatus, comprising: