JPS63263434A - 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 sealing resin at the time of subjecting a photodetector having color filters made of org. films to resin sealing. CONSTITUTION:The photodetector 10 is housed in the surface recess provided to a chip carrier 60 for surface packaging and the color filters 3-5 and a top coat 6 are laminated and provided on the photodetecting surface on the front face thereof. The terminals respectively provided to the detector 10 and the carrier 60 are connected by using bonding wires 50 and the surfaces including these are coated by the transparent resin 20. For example, cuprous oxide having the IR absorption characteristic is incorporated into the resin 20 at this time, by which the need for separated formation of the IR absorption filters is eliminated and the size of the element is 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 a multicolor filter.

(Conventional technology) Conventionally, gelatin, casein, polyvinyl alcohol (P
Organic membrane color filters dyed with a dye substrate dye made of an organic substance such as VA) are used. 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 make them finer and easier to align them with the light receiving area. It has the advantage of being However, organic films transmit almost all infrared wavelength light, so in most cases it is necessary to add an infrared absorption filter to obtain 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 (e) 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 Figure 0, 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; Both the red filter (FIG. (b)) and the red filter (FIG. (c)) have transmission characteristics for infrared light. Incidentally, the spectral detection sensitivity characteristics of the light receiving section 2 itself 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 red filter characteristics as shown in FIG. 10, infrared absorption with spectral sensitivity characteristics as shown in FIG. The filter IR is placed in front of the color filter. A specific example of the configuration in which the light receiving element 10 is packaged as a final product is shown in FIGS. 15 and 16. The light receiving element 10 is mounted on the chip carrier 60 in FIG. 15 and on the lead frame 30 in FIG. 16, but in both cases, it is necessary to add an infrared absorption filter IR.

(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 spectroscopic measurement element according to the present invention, a light receiving element having an organic film color filter is sealed with a resin, and the sealing resin is given infrared absorption characteristics. This is a characteristic feature.

(Function) In the spectrometry element according to the present invention, the light-receiving element having an organic film color filter is sealed with a resin, and the sealing resin is given infrared absorption characteristics, so that the infrared light component of the incident light is sealed. The infrared rays are absorbed by the infrared absorbing property of the stopper resin, and the desired spectral detection properties are obtained, and there is no need to separately provide an infrared absorbing filter.

(Embodiment) FIG. 1 is a sectional view of one embodiment of the present invention. In this embodiment, a light receiving element 10 is mounted on a chip carrier 60 for surface mounting. A light receiving element 10 having color filters 3 to 5 and a top coat 6 on its light receiving surface is held by being firmly bonded to a chip carrier 60. A bonding pad portion made of aluminum is formed at the edge of the light receiving element 10 (see FIG. 3), and this bonding pad portion is connected to a conductive portion of the chip carrier 60 (not shown) via a bonding wire 50. ). The inside of the chip carrier 60 is filled with transparent resin 20 (
For example, a silicone resin is used as the transparent resin 20 that has been subjected to botting.

This silicone resin includes, for example, cuprous oxide (CuzO
) to give it infrared absorption properties.

FIG. 2 is a sectional view of another embodiment of the invention.

In this embodiment, the light receiving element 10 is attached to the lead frame 3.
It is installed on 0. 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 layer 40 . One end of a bonding wire 50 is connected to the inner lead end portion 32 of the lead frame main body 30. 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 10. The light receiving element 10 is entirely molded (transfer molded) in a transparent resin 20. As the transparent resin 20, for example, epoxy resin is used. This epoxy resin includes, for example, cuprous oxide (Cu,
O) is mixed to give it infrared absorption properties.

FIG. 3 is a diagram showing a cross-sectional structure of the light receiving element 10 used in each of the above embodiments. This light receiving element 10 is used as a white balance sensor of a color video camera, and is used for R (red light), G (green light), and B (blue light).
The light intensity 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, a green filter 4, and a blue filter 5 are provided on the light receiving surface and on the surface of each light receiving section 2, respectively. It is provided to cover the vicinity. A top coat M6 is applied to the surface of each filter 3 to 5. At the edge of the silicon substrate 1,
A wiring portion made of aluminum film 7 is exposed.

FIG. 4 is a diagram showing the manufacturing process of the above-mentioned light receiving element 10. Moreover, FIG. 5 to FIG. 7 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
Figure (a) @Sho) First, a heat-resistant color paste 8 for a color filter is applied to the surface of the silicon substrate 1 on which a 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 color paste 8 of the first color is dropped onto the silicon substrate 1, and then a spinner (for example, Mikasa IH-DS type) using 500 r9M
5 seconds at a rotation speed of 3000 rpm, and 3 seconds at a rotation speed of 3000 rpm.
A coating film is formed under conditions of 0 seconds. This coated film is semi-cured for 30 minutes in air at 140° C. using a ventilation dryer. As the first color paste 8, any color among red, green, and 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, for example, from a beaker onto the surface of a silicon substrate 1 (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)).
), and FIG. 9 is a diagram 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 addition, 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.

m-paste l General formula, where R1: 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 V 1olet 19; or as a green pigment, Color Index No. 7416
Phthalocyanine green pigments such as No. 0 Pigment Green 36, Pigment No. 74260, Pigment Green 7, etc.; Or, as a blue pigment, Color Index No. 67416
0 Pigment Blue15 3, same N0071116
A heat-resistant color paste for a color filter, comprising a phthalocyanine blue pigment such as Pigment Blue 15 or 4 mixed at a ratio of 10 to 3008.

Bar-1 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 pigment, green pigment, or blue pigment as used in 1).

9-1 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 made by mixing the same red pigment, green pigment, or blue pigment as used in 1) in a proportion of 10 to 300 g.
.

As the color paste 8 applied to the silicon substrate 1, any color paste among the above (1) to (I[[) may be used. Note that before applying the color paste, a transparent polyimide layer may be applied to the light-receiving surface in order to flatten the unevenness of the light-receiving surface.

(ii) Resist coating and prebake process (Fig. 5(b)
) 9) Color paste 8 has been applied and semi-cured silicon substrate 1 is taken out from the ventilation dryer, waited for it to cool down, and then photoresist)-9 is applied. A certain "Microposit Photoresist 1400-31'' (trade name) made by Sibley Tsuji was used. The photoresist was applied using a spinner, and the rotation speed was 500 rpm for 5 seconds, and then 2 seconds.
A coating film is formed at a rotation speed of 00 Orpm for 30 seconds. Prebaking is performed for 30 minutes in nitrogen gas (N2 gas) at 90° C. using a ventilation dryer.

(iii> Exposure process (see 9 in Fig. 5(c)) Next, after adjusting the exposure position on the silicon substrate 1 using a mask aligner, 70-J exposure is carried out on and near the light-receiving surface. Apply photomask 1 so that the photoregistry remains only on Ami.
Exposure to ultraviolet light is performed through 1.

(iv) Resist development and etching process (Fig. 5(d)
) Next, the photoresist on the exposed silicon substrate 1 is developed. As the developer, a mixture of Microposit "MF-312 Developer" (trade name) manufactured by Gibley and water at a ratio of 1:1 was used.
Develop the resist for 0 seconds, then etch the excess color paste layer, rinse the etched silicon substrate 1 with water, and spray it with N2 gas.
2. Dry.

(V) Resist stripping, rinsing, and curing process (Figure 5 (
(See e)) Next, in order to peel off the photoresist 9 remaining on the color paste layer, the silicon substrate 1 is immersed and stirred in ethyl acetate, taken out after 5 minutes, and rinsed with isopropyl alcohol. Dry by blowing N2 gas, and then dry in N2 gas at 300°C in a ventilation dryer.
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, such as this type resist "RU-1100N" (trade name) manufactured by Hitachi Chemical Co., Ltd., may also be used.

(vi) In the process of creating the second color filter,
Now we will start creating the second color filter.In creating the second color filter, we repeat the same processes (i) to (v) as for the first color until we apply color paste 8 and cure it. , the second color may be any of red, green, and blue, excluding the first color. For example, if the first color is green,
The second color may be red.

(vii) Creation process of the third color filter The creation of the third color filter begins on the garment, but also in the creation of the third color color filter, color paste 8 is applied and the color paste 8 is applied until it is cured. 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, by using a color paste containing organic pigments of different colors in the case of a light-receiving element having multiple light-receiving surfaces, and by reversing the photolithography method as described above,
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 the tube coat film (see FIG. 6(a)) After completing the creation of the three color filters 3.4.5 on the same gyricon substrate 1, the top coat ll1 is finally applied.
form 6. To form the top coat film 6, for example, IQ J S R polyimide “JIA
-1-2'' (trade name) is applied to a thickness of 0.5 μmI and baked. The baking conditions are 1 hour in an atmosphere of 150°C. In addition to this, as the top coat film 6,
For example, the surface flattening agent "JSS-17" manufactured by Japan Synthetic Rubber Co., Ltd.
” (trade name) may be used.

The purpose of applying this top coat film 6 is the above-mentioned (1) to (
On the surface of the colored polyimide color filter formed in step vii), so-called orange beer-like roughness occurs, which often leads to a decrease in light transmittance due to diffuse reflection on the surface. This is to flatten the surface to prevent diffuse reflection on the surface and improve light transmittance.

(ix) Resist coating process (see FIG. 6(b)) Next, in order to expose the wiring made of the aluminum film 7 covered with the top coat film 6 and form a bonding pad part, a photoresist is applied. 12 is applied and exposed to ultraviolet light through a photomask 13 so that only the photoresist 12 on the aluminum film 7 is removed.
The wiring (ponding pad portion) made of the aluminium-11 film 7 is formed on the edge of the silicon substrate 1. Therefore, for example, FIG. 5(a) may be slightly exaggerated as shown in FIG. 7. It has become.

(x)) Etching process of the tube coat film (Fig. 6(c))
(See) Next, the exposed silicon substrate 1 is developed, and the top coat film 6 on the aluminum film 7 is removed by etching.

(xi) Resist stripping step (see No. 6111 (d)) Furthermore, the photoresist 12 covering the top coat rfA6 is stripped off using ethyl acetate or acetone. A portion of the top coat film 6 corresponding to the padding pad portion is removed. In other words, the electrode made of aluminum film 7 is exposed.

(xi) Assembly process (see Figures 1 to 3) Next,
After conducting a wafer test, determining whether the chips are good or bad, and guising each chip, only the good chips are transferred to the chip carrier 60 (see Figure 1) or the lead frame 30 (see Figure 1).
(see figure). Die bonding is performed using an adhesive layer 40 made of conductive epoxy resin. After die bonding is completed, it is cured at 100° C. for one hour, and then wire bonding is performed to connect the wires. The substrate heating temperature during wire bonding is 100-150℃
It is. When wire bonding is completed, the entire light receiving element is sealed with transparent resin 20. In the structure shown in FIG. 2, silicone resin is used for potting, and in the structure shown in FIG. 3, transfer molding is performed, in which a transparent resin 20 such as epoxy resin or acrylic resin is cast. The white balance sensor constructed in this manner has the spectral sensitivity characteristics shown in FIG.

Note that the spectrometry element may be configured as an integrated circuit chip having a processing circuit and a light receiving element on a common chip.
Moreover, if a resin having light diffusing properties, such as a milky white resin, is used instead of a transparent resin as the sealing resin, the sealing resin can also have light diffusing properties.

(Effect of the invention) As described above, the spectrometry element according to the present invention has the following features:
A light receiving element with an organic film color filter is sealed with a resin, and the sealing resin absorbs infrared ↑,? Because I gave it sex,
There is no need to separately provide an infrared absorption filter, which simplifies the configuration, reduces the size, and reduces costs accordingly.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an embodiment of the present invention, No. 211 is a cross-sectional view of an embodiment of the pond of the present invention, Fig. 3 is a cross-sectional view of a light-receiving element used in the above, and Fig. 4 is a cross-sectional view of the light-receiving element used in the same. A process diagram showing the manufacturing process, FIGS. 5 to 7 are explanatory diagrams for explaining each of the above manufacturing processes, 8 U; 1 (a), (b)
is an explanatory diagram showing the coating process of color base [・], the ninth factor is a diagram showing the relationship between spinner rotation speed and coating film thickness, and the first
Figure 0 is a characteristic diagram showing the spectral intensity of the light receiving element as above, No. 11
Figures (a) and (b) are block diagrams showing the schematic structure of a conventional light-receiving element, Figure 12 (a), (b), and (c) are diagrams showing the spectral transmittance characteristics of a color filter, and Figure 13. Figure 14 is a characteristic diagram showing the spectral detection sensitivity of a silicon semiconductor light receiving element, Figure 14 is a diagram showing spectral transmittance characteristics of an infrared cut filter used in the light receiving element, and Figures 15 and 16 are diagrams of different conventional examples. FIG. 3 to 5 are color filters, 10 is a light receiving element, and 20 is a transparent resin.

Claims (1)

[Claims] (1) A spectrometry element characterized in that a light-receiving element having an organic film color filter is sealed with a resin, and the sealing resin has infrared absorption characteristics.