TW452988B - Method to reduce the cost of solid state image sensor module - Google Patents

Abstract

The present invention provides a method to reduce the cost of solid state image sensor module, wherein an IR-cut filter is formed by semiconductor process on the color filter after it is completed during manufacturing the image sensor IC of the solid state image sensor module, and then the subsequent process of image sensor IC is proceeded. By the process of transferring the IR-cut filter to the primary lens set of solid state image sensor module, the cost of solid state image sensor module can be reduced.

Description

4 521 V. Description of the invention d) [Field of the invention] The present invention relates to a method for manufacturing an image sensing integrated circuit (IC), and particularly to an IR-cut ii 1 ter ) A method for integrating into the image sensing IC to reduce the cost of the solid-state image sensing module. [Known technology] Generally, a photodiode in a semiconductor silicon substrate has a photodiode as a sensor area to sense different colors of light. In addition, it is above the photodiode. There will be a color filter (color fi Iter). After the incident light passes through the color filter, it will be divided into three primary colors, red (R), green (G), and blue (B), and then absorbed and sensed by the corresponding photopole. A conventional method for manufacturing an image sensing IC is shown below. FIG. 1 is a cross-sectional view showing a conventional image sensing IC. First, a photodiode 102 is formed in a semiconductor silicon substrate 100, and each photodiode 102 has a corresponding transistor 104 'for reading image data. After that, a transparent and planarized oxide layer 106 is covered over the transistor 104, and then a color filter 108 is formed on the planarized oxide layer 106. Continue to form another transparent and planarized oxide layer 11 above the color phosphor plate 108, and then form microlenses 112 on the planarized oxide layer 110. The manufacturing method of the microlens jig is based on the planarized oxidation. The layer 110 is covered with a photoresist layer, and after being patterned by a developing process, heat treatment is performed to completely melt the patterned photoresist layer and use its own surface tension to form the microlens 112.

Page 5 452 5. Description of the invention (2) However, the red pixel R portion of the color filter 108 allows not only red light in the visible region to pass, but also infrared light, so it must be in a solid state. The primary lens group (primary 1 ens set) of the lens part of the image sensor module is placed with an infrared light shielding filter, that is, to filter out incident light with a wavelength of about 62 nm or more to prevent infrared light from entering the sensor. The measurement area 'makes red light, blue light and green light have approximately the same transmittance and sensitivity. However, the cost of the infrared light shielding filter is quite high, which will increase the cost of the entire solid-state image sensing module. [Objective and Summary of the Invention] In view of the above-mentioned shortcomings of the infrared light shielding filter having a high manufacturing cost ', the present invention provides a method capable of reducing the cost of the infrared light shielding filter. In addition, the present invention provides a method capable of reducing the cost of the solid-state image sensing module. The present invention proposes improvements based on the shortcomings of the conventional technology. The method for reducing the cost of a solid-state image sensing module of the present invention includes: forming a multilayer interconnect structure on a sensing area, and then covering a dielectric layer. Then, a color filter is formed on top of it, and then an infrared light shielding filter is formed on the color filter by a semiconductor process, and then another dielectric layer is formed thereon, and then formed on the dielectric layer. The microlens corresponding to the measurement area.

According to a preferred embodiment of the present invention, wherein the material of the infrared light shielding filter comprises a negative photoresist D mainly composed of methacrylate resin and epoxy resin C.

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V. Description of the invention (3) < It is worth noting that 'the infrared light shielding filter is not limited to a certain position, it is set above the color filter, it can also be set elsewhere,' only = 忐 at the incident Before the light enters the sensing area, the incident light in the infrared light range is filtered to make the above-mentioned objects, features, and advantages of the present invention more comprehensible. The following describes a preferred embodiment and combines the drawings. The detailed description is as follows:-[Schematic description] Figure 1 is a cross-sectional view showing the conventional image sensing J c. FIGS. 2A to 2B are cross-sectional views showing the flow of manufacturing an image sensing IC according to a preferred embodiment of the present invention. [Symbol description] Semiconductor silicon substrate: 100 substrate: 200 photodiode: 102, 202 transistor: 104, 204 oxide layer: 1 0 6, 11 0 dielectric layer: 206, 216, 226, 236 color filter: 108, 208 Microlenses: 112, 240 Leads: 207a '207b Infrared light shielding filter: 21 0 [Example] The infrared light shielding filter is in the main lens group of the solid-state image sensing module

452988 V. Description of the invention (4) An indispensable component, but the cost of traditionally manufacturing infrared light shielding filters is quite high, so the present invention integrates the infrared light shielding filters into the color filter manufacturing process. Through the low-cost semiconductor manufacturing process, the cost of the solid-state image sensing module is reduced. A detailed description will be given below with reference to the cross-sectional views of the manufacturing process of the image sensing IC in FIGS. 2A to 2B. First, referring to FIG. 2A, a photodiode 202 is formed in a substrate 200, and the photodiode 202 is a sensing area. Each photodiode 202 has its corresponding transistor 2 0 4 'to read the charge data generated in the sensing area, and then convert it into an image through a series of circuit designs. After that, a transparent and planarized dielectric layer 206 is covered over the transistor 204, and the material is, for example, silicon oxide. Due to the increase in pixel density, the number of interconnects has also increased. 'Traditional single-layer interconnect structures can no longer meet the requirements of circuit design.' Therefore, multi-layer interconnect structures must be used to complete the connection between components. . The multilayer interconnect structure is fabricated over the dielectric layer 206. In Figure 2A, the two-layer interconnect structure is taken as an example. The reference numerals 207a and 207 in the figure indicate the wires of the first layer and the second layer, respectively, and the wires 207 & A transparent dielectric layer 216 is used for electrical isolation. The material of the dielectric layer 216 is, for example, oxidized. Then, a transparent and planarized dielectric layer 226 is formed on the third layer of the conductive wire 20b. The material is, for example, an oxide ty. A light sheet 2 ^ 8 is formed on the planarized dielectric layer 226 to form red, green, and blue. The color data is then formed over the color filter 208 using a semiconductor process.

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452 98 S V. Description of the invention (5) Infrared light shielding filter 21 0, the material of this infrared light shielding filter 21 0 must have the following characteristics: transmittance (transmittance) higher than 95%; high heat resistance ( At least need to be able to withstand heat to 270 oC); preferably a negative photoresist to be compatible with the existing color filter 208 process. The material is, for example, a negative photoresist mainly composed of a methacrylate resin and an epoxy resin (epoxy r e s i η). The above-mentioned manufacturing method of the infrared light shielding filter 21 0 is, for example, using a spin coating method to cover the color filter with a layer of negative photoresist that can shield infrared light. After the exposure and development process, it is hardened. The thickness of the light-shielding filter 210 is between about 1 micrometer and about 2 micrometers. It is worth noting that in this embodiment, it is mainly considered that the manufacturing process of the infrared light shielding filter 21 0 is compatible with the manufacturing process of the color filter 208, so the infrared light shielding filter 210 is configured in the color filter. Above the sheet 208. However, the present invention is not limited to this, as long as the infrared light shielding filter 21 0 is set in the image sensing IC by using a semiconductor process, and it is at least located above the photodiode 2 2 used for light sensing, To achieve the purpose of the present invention, before the incident light enters the photodiode 202 in the substrate 200, the incident light in the infrared light range has been filtered out. Therefore, the infrared light shielding filter 210 can also be disposed below the color filter 208 or elsewhere. Next, please refer to FIG. 2B, and continue to form another transparent and flattened dielectric layer 236 on the infrared light shielding filter 2 1 0. The material is, for example, silicon oxide. This dielectric layer 236 can not only sense the entire image In addition to flattening the surface of 1C, its thickness can also be controlled to adjust the focal length of incident light.

45298 8 V. Description of the invention (6) Then a microlens 240 is formed on the planarized dielectric layer 236. The method for forming this microlens 240 is, for example, covering a layer of resin after grinding, 'patterning this resin layer through a development process, and then performing heat treatment' to completely melt the patterned resin layer and use its own surface tension 'to form a figure. The illustrated microlens 240 corresponds to the photodiode 202. [Features and Effects of the Invention] In summary, the present invention has at least the following advantages: 1. The present invention reduces infrared light shielding by moving the infrared light shielding filter from the autonomous lens group to the color filter manufacturing process. Manufacturing costs of filters.

2 · The present invention uses a semiconductor process to manufacture an infrared light shielding filter and integrate it with the image sensing IC, so it can save its manufacturing cost, and then reduce the overall manufacturing cost of the solid-state image sensing module D 3. The present invention The manufacturing process of the infrared light shielding filter is quite simple, and it is easily compatible with the current manufacturing process. Although the present invention has been disclosed in the preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make changes and retouches without departing from the spirit and scope of the present invention. The scope of protection shall be defined by the scope of the patent application.

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Claims (1)

4 5298 VI. Scope of Patent Application 1. A method for reducing the cost of a solid-state image sensing module, comprising: providing a substrate, the substrate having a sensing area, and the substrate having an electric body B for controlling The sensing region; covering the transistor with a first dielectric layer; forming an interconnect structure on the first dielectric layer to control the transistor; forming a first interconnect structure on the interconnect structure Two dielectric layers; forming a color phosphor on the first dielectric layer; forming a bismuth external light shielding filter on the color filter; forming a first on the infrared light shielding filter Three dielectric layers; and forming a micro lens on the third dielectric layer. 2. The method for reducing the cost of a solid-state image sensing module according to item 1 of the scope of patent application, wherein the materials of the first dielectric layer, the second dielectric layer, and the third dielectric layer include silicon oxide . 3. The method of reducing the cost of the solid-state image sensing module as described in item 丨 of the patent application range, wherein the infrared light blocking filter is a negative photoresist. 4. The method for reducing the cost of the solid-state image sensing module as described in item 1 of the scope of the patent application, wherein the infrared light shielding filter is a negative photoresist mainly composed of methacrylic resin and epoxy resin. 5. The method for reducing the cost of the solid-state image sensing module according to item 4 of the scope of the patent application, wherein the thickness of the infrared light shielding filter is between 1 micrometer and 2 micrometers. 6. —A method for reducing the cost of a solid-state image sensing module, wherein the solid-state image sensing module includes a main lens group and an image sensing κ, 'this = Page 11 4 52 98 6. Patent application scope Image sensing IC includes a sensing area in a substrate, a first dielectric layer is covered on the sensing area, and a first dielectric layer is formed on the first dielectric layer. An interconnect structure, forming a second dielectric layer on the interconnect structure, forming a color filter on the second dielectric layer, and forming a third dielectric layer on the color filter; And forming a microlens on the third dielectric layer, wherein the present invention is characterized in that: an infrared light shielding filter is disposed in the image sensing 1C using a semiconductor process, and at least above the substrate, so that The incident light has filtered out incident light in the infrared light range before entering the sensing area in the substrate. 7. The method for reducing the cost of the solid-state image sensing module as described in item 6 of the scope of patent application, wherein the infrared light shielding filter is a negative photoresist. 8. The method for reducing the cost of a solid-state image sensing module as described in item 6 of the scope of patent application, wherein the infrared light shielding filter is a negative light mainly composed of a fluorene-based acrylic resin and an epoxy resin. Resistance. 9. The method for reducing the cost of the solid-state image sensing module according to item 8 of the scope of the patent application, wherein the thickness of the infrared light shielding filter is between 1 μm and 2 μm.