JPS63263433A - Spectrometric element - Google Patents

Abstract

PURPOSE:To eliminate the need for separate formation of an IR absorption filter so that this element is simplified and the cost thereof is reduced by previously imparting an IR absorption characteristic to a light diffusing member at the time of disposing the light diffusing member to the front face of a photodetector having color filters made of org. films. CONSTITUTION:The color filters 3, 4, 5 respectively corresponding to red light, green light and blue light are juxtaposed on the opposite surface of the light incident side of a glass substrate G. Photodetecting parts 2 formed to the photodetector 10 so as to correspond to the respective filters are pressed to said filters. The diffusion plate DF are provided to the light incident side of the substrate G. The plate DF is formed of, for example, an acrylic resin and cuprous oxide is mixed therewith to impart the IR absorption characteristic to the plate DF itself. The IR absorption filters and the diffusion plate are thus commonly formed of one member in such a manner, by which the constitution of the element is simplified and the size and cost thereof are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a spectrometry element using a light receiving element having an organic film color filter.

(Conventional technology) Conventionally, gelatin, casein, polyvinyl alcohol (P
Organic film color filters are used in which dyed substrates made of organic materials such as VA) are dyed with dyes. Furthermore, a color filter made of a polyimide resin containing a pigment has been proposed as an organic film color filter with improved heat resistance and light resistance.

Compared to color filters formed by other vapor deposition or electrodeposition methods, these organic film color filters can be patterned using photolithography, making it possible to miniaturize them and making it easier to align them with respect to the light receiving part. It has the advantage of being easy. However, organic films transmit almost all infrared wavelength light, so in most cases it is necessary to add an infrared absorption filter to obtain the desired spectral sensitivity characteristics.

This will be explained using an example of a white balance sensor for a color video camera. Figure 10 shows the spectral sensitivity characteristics of a desired white balance sensor, which has sensitivity over the entire visible light range and is insensitive to ultraviolet and infrared light. In order to obtain this, an organic film color filter having spectral transmittance characteristics as shown in FIGS. 12(a) to 12(c) is used. Each color filter 3.4.5 for detecting red light, green light, and blue light is formed in advance on a glass substrate G, as shown in FIG. 2
Align the relative positional relationship with (stacking method) or
Alternatively, as shown in FIG. 11(b), the light receiving element 10
In Fig. 6, DF is a diffusion plate and IR is an infrared absorption filter.

As can be seen from Figures 12(a) to (c), organic film color filters have blocking properties against ultraviolet light and are opaque; Figure (1,)), red filter (Figure (e))
Both have transmission characteristics for infrared light. by the way,
The spectral detection sensitivity characteristics of the light receiving section 20 of the silicon light receiving element 10 are as shown in FIG. 13, and are sufficiently sensitive to infrared light. Therefore, in order to cut the infrared light incident on each of the color filters and to make the characteristics of the red filter as shown in FIG. An absorption filter IR is placed in front of the color filter. A specific example of a structure in which the light receiving element 10 is packaged as a final product is shown in FIG. 15111 and FIG. 16.

FIG. 15 is a sectional view of a structure in which the light receiving element 10 is mounted on a chip carrier 60 for surface mounting. A light receiving element 10 having organic film color filters 3 to 5 on its light receiving surface is held by die bonding to a chip carrier 60. A bonding pad portion (not shown) made of an aluminum film is formed at the edge of the light receiving element 10, and this bonding pad portion is connected to a conductive portion (not shown) of the chip carrier 60 via a bonding wire 50. )It is connected to the. The inside of the chip carrier 60 is filled with transparent resin 20, and an infrared absorption filter IR is applied thereon.

FIG. 16 is a sectional view of a tl-type device in which the light receiving element 10 is mounted on the lead frame 30. The light receiving element 10 is die-bonded onto a tab portion 31 located at the center of the lead frame body 30 using a conductive adhesive [40]. The inner lead end portion 32 of the lead frame main body 30 includes
One end of the bonding wire 50 is connected. The other end of the bonding wire 50 is connected to a bonding pad of the light receiving element 10. The outer lead 33 of the lead frame main body 30 is electrically connected to the inner lead end 32, and serves as an external lead wire of the light receiving element IO. The light receiving element 10 is entirely molded in transparent VI4Ha 20. After that, an infrared absorption filter IR is attached externally.

In any of these cases, a diffuser plate DF as shown in FIG. 11 is separately arranged in front of the infrared absorption filter IR. Such a diffuser plate DF is
This is necessary to diffuse the incident light and make the light uniformly enter each light receiving section 2 of the light receiving element 10.

(Problems to be Solved by the Invention) As mentioned above, in the case of a light receiving element using an organic film color filter, it is necessary to add an infrared absorption filter to the optical system, which makes the optical system complicated and requires miniaturization. This poses a problem in that it hinders the process and also increases costs.

The present invention has been made in view of these points,
The purpose of this invention is to provide a spectroscopic measurement element in which other components have the infrared absorption characteristics of an infrared absorption filter, thereby eliminating the need for a separate infrared absorption filter.

(Means for Solving the Problems) In the spectrometry element according to the present invention, a light diffusing member is disposed in front of a light receiving element having an organic film color filter, and this light diffusing member has infrared absorption characteristics. It is characterized by the fact that

(Function) In the spectrometry element according to the present invention, a light diffusing member is disposed in front of a light receiving element having an organic film color filter, and this light diffusing member has infrared absorption characteristics, so that the infrared rays of the incident light can be absorbed. External light components are absorbed by the infrared absorption characteristics of the light diffusing member, and desired spectral detection characteristics are obtained, and there is no need to separately provide a filter for infrared absorption.

(Example) FIG. 1(a) is a diagram showing a schematic configuration of a spectroscopic measurement element according to an example of the present invention. In this example, red light, green light, and blue light are detected. As shown in FIG.
The relative positions of the f-systems are made to meet. A diffusion plate DF for diffusing incident light is arranged in front of the color filter 3.4.5, and this diffusion plate DF is provided with infrared absorption characteristics.

FIG. 1 (1+) is a diagram showing a schematic configuration of a spectrometry element according to another embodiment of the present invention. In this embodiment, each color filter 3, 4, 5 is a It is attached as an on-chip type so as to be in contact with the light receiving section 2.

FIG. 2 is a diagram showing a cross-sectional structure of the light receiving element 10 used in the embodiment of FIG. 1(b). This light receiving element 10 is used as a white balance sensor of a color video camera, and emits R (red light).

The light intensity of G (green light) and B (blue light) can be measured. A light receiving section 2 is formed on the surface of the silicon substrate 1 using a normal semiconductor manufacturing process, and a red filter 3 is provided on the surface of each light receiving section 2.
, a green filter 4 and a blue filter 5 are arranged to cover the light receiving surface and its vicinity. A top coat film 6 is applied to the surface of each filter 3 to 5.

A wiring section made of aluminum film 7 is exposed at the edge of silicon substrate 1 .

FIG. 3(a) shows the light receiving element 10 placed on a chip carrier 60.
1. As shown in FIG. 1, the light receiving element 10 is accommodated in the cavity 61 of the chip carrier 60. FIG. A recessed step 62 is formed at the edge of the chip carrier 60 to attach the diffuser plate DF.

FIG. 4 is a diagram showing the manufacturing process of the above-mentioned light receiving element 10. Further, FIGS. 5 to 7 [J are explanatory diagrams of each process.

Hereinafter, the manufacturing process of the light receiving element 10 will be explained with reference to these figures. It should be noted that each process in FIGS. 5 and 6 is performed on one wafer, but the drawings show only one chip. Further, in FIGS. 5 and 6, wiring is omitted.

(i) Color paste application, semi-curing process (fifth
(See Figures (, )) First, a heat-resistant color paste 8 for color filters is applied to the surface of the silicon substrate 1 on which the light receiving section is formed.

At this stage, the silicon substrate 1 is being processed not in units of individual chips but in units of wafers. The heat-resistant color paste 8 includes a solvent, an organic pigment insoluble in the solvent,
It consists of a polyimide precursor. When applying, in advance,
After drying the silicon substrate 1 on which the light receiving part is formed in N2 gas at 200° C. for 10 minutes, a small amount of the first color color paste 8 is dropped onto the silicon substrate 1, and a spinner (for example, Mikasa ¥1 JIH-DS type) is applied. ) using 500 r
A coating film is formed under the conditions of 5 seconds at a rotation speed of pm and then 30 seconds at a rotation speed of 3000 rpm. This coated film is semi-cured for 30 minutes in air at 140° C. using a ventilation dryer. The first color paste 8 is red,
Any color from green or blue may be used.

FIG. 8 is a diagram showing how the color paste 8 is applied using a spinner. A color paste 8 is obtained by mixing an organic pigment with a mixture of a solvent and a polymer, and this color paste 8 is poured onto the surface of the silicon substrate 1 from, for example, a beaker (see Fig. 8 (a)). The color paste 8 poured onto the surface of the silicon substrate 1 is uniformly dispersed over the surface of the silicon substrate 1 by centrifugal force (see Fig. 8).
b)), No. 9 [2I is a factor showing the relationship between the rotation speed of the spinner and the coating film thickness. As is clear from this figure, by increasing the number of rotations of the spinner, the thickness of the coating film can be reduced. In FIG. 9, each line indicates the characteristics when applying color paste (red mark 0, green mark Δ, blue mark).

Examples of the components of the heat-resistant color paste used in the color paste application process are as follows.

^ -One paste general formula -1-QCC0-NH-Q-SO2-Q-NH-)-R
z OOCCOORa However, R6: aromatic hydrocarbon ring or heterocycle R2: polymer 10 represented by hydrogen or a hydrocarbon group having 1 to 10 carbon atoms
0g, for organic pigment, as red pigment, color index No. 7390
Quinacridone pigments such as No. 5 Pigment Red 209 and No. 46500 Pigment Viole L19; or as a green pigment, Color Index No. 7416
0 Pigment Green 36, No. 7426
A phthalocyanine green pigment represented by Pigment Green 7% of 0: or.

As a blue pigment, Color Index N017416
0 Big Men)-Blue15 3, same No. 7416
A heat-resistant color paste for color filters comprising a phthalocyanine blue pigment represented by Pigment Blue 15, 4, etc. of 0.

H-Paste general formula However, R1: aromatic hydrocarbon ring or heterocycle R2: polymer 10 represented by hydrogen or a hydrocarbon group having 1 to 10 carbon atoms
For 0g of organic pigment, the color paste (
A heat-resistant color paste for color filters, which is made by mixing 10 to 300 g of the same red raw material, green pigment, or 1¥ color pigment as used for I).

H - Paste ■ General formula However, R1: aromatic hydrocarbon ring or polychoric ring R2: hydrogen or carbon'l! For 100 g of a polymer represented by a number of 1 to 10 hydrocarbon groups, add either the same red pigment, green pigment, or blue pigment as used for the color base)-(1) for the organic pigment, A heat-resistant color paste for color filters that is mixed in a proportion of 10 to 300 g.

As the color paste 8 applied to the silicon substrate 1, any of the color pastes (1) to (III) above may be used.Before applying the color paste, the unevenness of the light-receiving surface should be smoothed. A transparent polyimide layer may be coated on the light-receiving surface in order to lower the surface.

i) Resist coating and prebake process (Fig. 5(b)
(See) The silicon substrate 1 coated with the color paste 8 and semi-cured is taken out from the ventilation dryer, waits for it to cool down, and then coats the photoresist. In this embodiment,
A positive resist "Microposit Photoresist 1400-31" (trade name) manufactured by Sibley was used.

The application of the photoresist 9 is also carried out using a spinner, with a rotation speed of 500 rpm for 5 seconds, and then a rotation speed of 2000 rpm.
A coating film is formed at a rotation speed of rp- for 30 seconds. Pre-baking is performed using nitrogen gas (N
i gas) for 30 minutes.

(iii) Exposure process (see Figure 5 (6)) Next, after adjusting the exposure position on the silicon substrate l using a mask aligner, exposure of 70 mJ is performed, and the photo is exposed only on and near the light receiving surface. Photomask 1 so that resist 9 remains
Exposure to ultraviolet light is performed through 1.

(iv) Resist development and etching process (Fig. 5(d)
)9) Next, the photoresist 9 of the silicon substrate 1 that has been exposed is
Develop. As the developer, we used a 1:1 mixture of Microposite "MP-312 Developer 7 Bar" (trade name) manufactured by Gyplay and water at a solution temperature of 22°C for 60 seconds. Develop the resist, then process and sotch the excess color paste layer, rinse the etched silicon substrate 1 with water, and blow N2 gas.
Let dry in one rack.

(v) Resist peeling, rinsing, and curing process (Fig. 5)
e) 9) Next, in order to peel off the photoresist 9 remaining on the color paste layer, the silicon substrate 1 was immersed and stirred in ethyl acetate, taken out after 5 minutes, and rinsed with isopropyl alcohol. , dried by blowing N2 gas, and then dried in N2 gas at 300℃ in a ventilation dryer for 30 minutes.
Cure for 0 minutes.

In the embodiment, an example is shown in which a positive resist is used as the photoresist, but a negative resist (for example, a negative resist "RU-IlooN" (trade name) manufactured by Hitachi Chemical Co., Ltd.) may also be used.

(vi) Step of creating the second color filter Next,
Starting with the creation of the second color filter, the same processes (i) to (v) as for the first color are applied until the color paste 8 is applied and cured. Again, the second color can be any of red, green, or blue, excluding the first color.For example, if the first color is green,
The second color may be red.

(vii) Process of creating a third color filter Repeat the same processes (i) to (v) as for the first color, and the third color is the remaining one of red, green, and blue, excluding the first and second colors.
Becomes a color. For example, if the first color is green and the second color is red, the third color is blue.

In this way, in the case of a light-receiving element with multiple light-receiving surfaces, by repeating the photophosphorography method as described above using a color paste containing organic pigments of different colors,
Color filters of different colors can be attached to each light-receiving surface, and a spectral detection light-receiving element having spectral characteristics determined mainly by the type of organic pigment contained in each color filter can be formed.

(vii)) Coating process of whirlpool coating film (Fig. 6(a) 9
(See) After completing the creation of the three color filters 3, 4, and 5 on the same silicon substrate 1, the top coat film 6 is finally formed. In order to form the top coat film 6, for example, JSR polyimide “JIA-1-2” manufactured by Japan Jikai Rubber Co., Ltd.
(trade name) to a thickness of 0.5μ- and baked.

The baking conditions were 1 hour in an atmosphere of 150°C.

In addition to this, the top coat film 6 may be formed using, for example, a surface flattening agent "JSS-17" (trade name) manufactured by Japan Synthetic Rubber Co., Ltd.

The purpose of applying this top coat film 6 is to
On the surface of the colored polyimide color filter formed in step i), so-called orange beer-like roughness occurs, which often leads to a decrease in light transmittance due to diffuse reflection on the surface. Therefore, the surface is coated with top coat Jll16. This is to flatten the surface to prevent diffused reflection and improve light transmittance.

(ix) Resist coating process (see 6th IN (b)) Next, the aluminum film 7 covered with the top tool l-film 6
In order to expose the wiring made of aluminum and form a bonding pad part, a photoresist 12 is applied, and aluminum fl! A wiring (ponding pad portion) made of aluminum film 7 is formed on the edge of silicon substrate 1, and is exposed to ultraviolet light through a photomask 13 so that only the photoresist 12 in the portion I7 is removed. Therefore, for example, FIG. 5(,) is slightly exaggerated as shown in FIG. 7.

(x) Etching process of top coat film (Fig. 6(e)
(See) Next, the exposed silicon substrate 1 is developed and etched to form a top coat 1E16 on the aluminum film 7.
remove.

(xi) Resist stripping process (see 6th [2I(d))]
Furthermore, the photoresist 12 covering the Totubuko film 6 is removed using ethyl acetate or acetone.
Through the above steps (ix) to (xi), the top coat lll6 in the portion corresponding to the bonding pad portion is removed. In other words, the electrode made of aluminum film 7 is exposed.

(xi) Assembly process (see FIG. 3) Next, a wafer test is performed to determine whether the wafer is good or bad, and after gluing each chip, only the good chips are die-bonded into the cavity 61 of the chip carrier 60. Die bonding is performed using an adhesive made of conductive epoxy resin.

After die bonding is completed, the wire is cured at 1100° C. for 1 hour, and then wire bonding is performed to connect the wires. The substrate heating temperature during wire bonding is 100 to 150°C. When wire bonding is completed, the light receiving element 10
The whole is molded with transparent resin 20. Finally, the diffusion plate DF is attached so as to fit into the recessed step 62 of the chip carrier 60. Here, the diffusion plate DF is made of, for example, acrylic resin, and the acrylic resin contains cuprous oxide (
CuzO) to give it infrared absorption properties. The white balance sensor constructed in this manner has spectral response characteristics as shown in FIG.

Note that the spectrometry element may be configured as an integrated circuit chip having a treatment heel circuit and a light receiving element on a common chip.

(Effect of the invention) As described above, the spectrometry element according to the present invention has the following features:
A light diffusing member is placed in front of the light receiving element having an organic film color filter, and this light diffusing member has infrared absorption characteristics, so that the infrared absorbing filter and the diffusing plate, which were conventionally provided independently, can be combined into one. It is possible to use multiple members, simplify the structure, reduce the size, and reduce costs accordingly.

[Brief explanation of the drawing]

FIG. 1(a) is a schematic configuration diagram of an embodiment of the present invention;
b) is a schematic configuration diagram of another embodiment of the present invention, FIG. 2 is a sectional view of a light receiving element used in the above, and FIG. 3(a) is a sectional view showing a structure in which the above light receiving element is mounted on a chip carrier. , FIG. 4 is a process diagram showing the manufacturing process of the above light-receiving element, and FIGS. 5 to 7 are explanatory diagrams for explaining each of the manufacturing processes of the above. , FIG. 8(a),
(b) is an explanatory diagram showing the color paste application process, No. 9
The figure shows the relationship between spinner rotation speed and coating film thickness.
Fig. 10 is a characteristic diagram showing the spectral bad path of the same light receiving element as above, Fig. 11 (a), (b) is a block diagram showing the schematic structure of the conventional light receiving element, Fig. 12 (a), (b), (c) is a diagram showing the spectral transmittance characteristics of the color filter, FIG. 13 is a characteristic diagram showing the spectral detection sensitivity of the silicon semiconductor light receiving part,
FIG. 14 is a diagram showing spectral transmittance characteristics of an infrared cut filter used in a light receiving element, and FIGS. 15 and 16 are sectional views of different conventional examples. 3 to 5 are color filters, 10 is a light receiving element, and DF is a diffuser plate.

Claims (1)

[Claims] (1) A spectrometry element characterized in that a light diffusing member is disposed in front of a light receiving element having an organic film color filter, and the light diffusing member has infrared absorption characteristics.