TW471061B - Forming method of biconvex microlens of image sensor - Google Patents

Abstract

The present method comprises: first, providing a substrate formed thereon a passivation layer, a color filter layer and a planar layer; then forming plural photoresist layers with a predetermined distance on the planar layer, proceeding etching to the planar layer by using plural photoresist layers as plural etching mask, so that the planar layer has plural arc-like concave surfaces; then forming a microlens layer on the planar layer and its arc-like concave surface; exposing the microlens layer by photolithography process and forming plural microlens layers; proceeding a thermal process and processing the microlens region, so as to form plural biconvex microlenses having biconvex shape.

Description

471061 Case No. 90100324 Amendment V. Description of the Invention (1) 5-1 Field of Invention: The present invention relates to a method for manufacturing an image sensor element, and more particularly to a method for forming a lenticular microlens. 5-2 Background of the Invention: The image sensor has a photodetector (photodetector) that can be used to detect light. It can be used in digital cameras, scanners and other devices. The response mechanism of the sensing element is to convert incident light photons into electron-electron hole pairs. As the number of absorbed photons increases, the current generated will also be proportional. Increasing. Microlenses (microcr ο 1 ens) have been widely used in related light sensing device facilities, especially in operating applications of photodiodes and charge coupled devices (CCDs) In general, the purpose of a microlens is to focus the pixel value of a ray on a semiconductor element, thereby increasing the sensitivity of the display. In other words, 'a microlens is used to focus incident light on a photoelectric element. On the polar body. The solid-state image sensor includes a plurality of photoelectric diodes formed in an element. The photoelectric diode can be replaced by an electronic signal to generate an electric charge. τ _ ~ such as the image sensor also contains

471061 --f ^, 90100324_—day correction_ V. Description of the invention (2) Sense amplifier (sense a ^ lifier; sA), color filter layer (colol f 1 11 er 1 ayer) and cover on photoelectric two With the micro lens on the polar body, the sense amplifier can sense the image signal transmitted from the charge-coupled element to generate an electronic signal. In a solid image sensor, each photodiode is assigned a microlens'. The light emitted from an object is continuously focused on the photodiode of the semiconductor element through the microlens to generate an electronic signal. As shown in FIGS. 1A to 1C, cross-sectional views of the structure of a conventional microlens manufacturing process are shown. First, a substrate 100 is provided, on which a passivation layer 110, a color filter layer 120, and a transparent layer as a transparent layer are formed in this order. 130. Then, a microlens 1 ayer 140 is formed on the planner layer 130. Secondly, the micro-lens layer (m i c r ο 1 e n s 1 a y e r) 1 4 0 is exposed through a lithography process and a micro-lens region 150 is formed. Thereafter, the microlens area 150 is processed by a thermal process so as to form a plano-convex microlens 160 having an arc shape protruding upward. As shown in the first figure C, it is obvious that the incident light 170 is focused by the plano-convex microlens 16 0, and then passes through the flat layer 1 3 0, the color filter layer 1 2 0, and the protective layer 1 1 0 until the incident light enters the substrate 100. Therefore, there is no doubt that in order to form a light sensor with high sensitivity, it is necessary to increase the projection area of the incident light 170 on the substrate 1000 as much as possible, so as to absorb the maximum light.

Page 5 471061 Case No. 90100324 _η Five. Description of the invention (3) Number of children. Regardless of poor quality, that is, the photodiode. Therefore, it is difficult for the above-mentioned micro-convex and micro-convex to contact area. One of the improved micro-minds is the guide area to increase how, due to the convergent nature of the above-mentioned plano-convex microlenses, it is difficult to focus the incident light 1 70 on the response without error, so that it causes Factors such as dispersion and resolution degradation optimize the sensitivity of this traditional image sensor. Then the contact surface between the lens 160 and the battle layer 130 is the smaller, which will cause the adhesion properties of the microlens material. In terms of the adhesion properties and focusing properties of the surface lens, its & Λ The structure of a new microlens is inferred, which makes it have a substantially adhesive property and a focusing property. Tables ^ and ^ are based on the above reasons ’we need more — a new micro-formation method. In order to improve the yield and yield of subsequent processes. 5. See the purpose and summary of the invention:

In the context, the present invention provides a method for a traditional semiconductor manufacturing process that can be used to overcome it; J In view of the above-mentioned inventions, there are many disadvantages and process problems. The object of the present invention is to provide a method for image sensing crying. The invention can form a micro lens so as to maximize the shape of the mirror in the reaction area of the substrate. Therefore, the present invention has a yield rate in the process. $ Literacy improvement system

471061 __Case No. 90100324 Rev. ___ V. Description of the invention (4) Another object of the present invention is to provide a method for forming a microlens of an image sensor. The invention can form a biconvex microlens to replace the traditional plano-convex microlens. The lenticular microlens of the present invention can increase the focusing property to improve the image intensity (i m a g e i n t e n s i t y). In addition, the present invention can also increase the flat area by the lenticular appearance of the microlenses, so as to improve the lenticular microlenses. Another object of the present invention is to improve the lens forming method. In the present invention, the flat layer has an arc-shaped concave mirror during the engraving process. Therefore, the simple method of the present invention can be applied to the technique of deep sub-micron. According to the above-mentioned purpose, the method of forming the lenticular microlens of the present invention. A substrate is sequentially formed with protection thereon. Then, a plurality of contacts are defined on the flat layer, and the photoresist layer is mistakenly formed when the layer enters the rest, so that the flat layer is removing the photoresist. After the layer, the arc-shaped depressions on the surface. Subsequently, a plurality of microlens areas are borrowed and formed. Finally, the mirror area is used to form a plurality of adhesive properties with a contact surface between the lamella and the microlens. For a biconvex micro of an image sensor, before forming a microlens layer, a worm-contaminated surface is used to form a biconvex micro-transmission, which is in line with economic benefits. The invention discloses an image sensor. In an embodiment of the present invention, a layer, a color filter layer and a flat layer are first provided. The photoresist layers separated by a predetermined distance form a plurality of etching masks and flatten a surface having a plurality of arc-shaped depressions. A micro-lens layer is formed on a flat layer and the micro-lithography process is used to expose the micro-lens layer, and a thermal process is performed to process the micro-transparent bi-convex micro-lens.

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471061 --j number 90100324_ ^-year month day _ amendment V. Description of invention (5) 5-4 Detailed description of invention:

The present invention is directed to a method for forming a lenticular lens of an image sensor. In order to fully understand the present invention, detailed steps will be proposed in the following description. Obviously, the practice of the present invention is not limited to the specific details familiar to those skilled in the art of half-body elements. On the other hand, well-known process steps have not been described in detail to avoid unnecessary limitations of the present invention. The more specific embodiments of the present invention will be described in detail as follows. However, in addition to these detailed descriptions, the present invention can also be widely implemented in other embodiments, and the scope of the present invention is not limited. The later patent scope shall prevail. . Referring to FIG. 2A and FIG. 2B, in an embodiment of the present invention, a substrate 2 0 with a plurality of light sensing elements is first provided, and a protective layer 2 1 0, a A color filter layer 2 2 0 and a flat layer 2 3 0, where 'the flat layer 2 3 0 uses a transparent material', for example, Ethylenglycolmonoethylether acetate (ECA) 'Methacryl resin ^ Multifunctional aery 1 monomer ° and then 'A plurality of photoresist layers 2 4 0 separated by a predetermined distance are defined on the flat layer 2 3 0. Next, the plurality of photoresist layers 2 4 0 are used as a plurality of etching masks and the flat layer 2 3 is etched to form a plurality of remaining carved areas whose outer shapes are concave surfaces, and the plurality of last carved areas are located at A plurality of light sensing elements

471061 __Case No. 90100324_year__ monthg_____ V. Description of the invention (6) In the position, the etching process of the above-mentioned flat layer 2 3 0 can use a wet etching method or a dry etching method to make the flat layer 2 3 The surface of 0 is recessed downward, as shown in the second B figure. Referring to FIG. 2C and FIG. 2D, in this embodiment, after removing a plurality of photoresist layers 240, a photosensitive material (spinning materia 1) is spin-coated on the planar layer 2 3 0 and its insects. A photosensitive layer 250 is formed on the engraved area. The thickness of the photosensitive layer 250 described above is less than about 5 microns. Then, the lithographic process is used to expose the photosensitive layer 2 50 and form a plurality of photosensitive areas 2 60, wherein the above-mentioned plurality of photosensitive areas 2 6 0 are located on the concave surface of the #etched area of the flat layer 2 3 0 on. Finally, a thermal process is performed to process the photosensitive area 2 60 and a plurality of biconvex microlenses 2 7 0 are formed, as shown in the second E diagram.

In an embodiment of the present invention, a new method of forming a microlens of an image sensor is provided. The invention can form a micro-lens so as to effectively maximize the incident light in the reaction area of the substrate. Therefore, the present invention can effectively improve the yield in the process. In addition, the present invention can replace the conventional plano-convex microlens by the formation of a biconvex microlens, and the biconvex microlens of the present invention can add focusing properties to improve image intensity. Furthermore, the present invention can also increase the contact surface area between the flat layer and the microlenses by using the lenticular appearance of the microlenses, so as to improve the adhesion properties of the lenticular microlenses. … Surface, the present invention is to form a micro-lens.

Page 9 471061 Case No. 90100324 Amendment V. Description of the invention (7) Lens. Therefore, the method of the present invention is simple and economical, and can be applied to deep sub-micron technology. For deep sub-micron processes, this method is a better and feasible microlens process for image sensors. Obviously, according to the description in the above embodiments, the present invention may have many modifications and differences. Therefore, it needs to be understood within the scope of the appended claims. In addition to the above detailed description, the present invention can be widely implemented in other embodiments. The above are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included in the following application patents Within range.

Page 10 471061 _Case No. 901Q0324_ 年月 日 _iMz_ The drawings briefly explain the first A to C are the cross-sectional schematic diagrams of the traditional plano-convex micro lens process; and the second A to E A schematic cross-sectional view illustrating a process of manufacturing a lenticular microlens in one embodiment of the present invention. The number symbol represents the difference β! J5: the main point is οοοοοοοοοοοοοοο 012345670--2 3 4 5 6 7 layers. . Mirror layer. . Mirror. mirror. Layer through. . mirror. . Layer through. The straddle layer mirror is dim. Layer filter layer mirror micro bottom color protection transparent transparent convex bottom color protection transparent transparent convex base

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Claims (1)

471061 6. Application scope 1. A method for forming a microlens, the method includes at least the following steps: providing a substrate; forming a flat layer on the substrate; defining a photoresist layer on the flat layer; and using the light The resist layer is used as an etching mask to etch the flat layer and form an etched area on the flat layer; remove the photoresist layer; form a micro lens layer on the etched area of the flat layer; and form the micro layer The lens is on the etched area of the flat layer. 2. The method for forming a microlens as described in item 1 of the scope of patent application, wherein the above-mentioned substrate includes at least one light sensing element. 3. The method for forming a microlens as described in item 1 of the scope of patent application, wherein the flat layer includes at least one light-transmitting material. 4. The method for forming a microlens as described in item 1 of the scope of the patent application, wherein the method of engraving the flat layer mentioned above includes at least a wet-type I engraving method. 5. The method for forming a microlens as described in item 1 of the scope of the patent application, wherein the method of engraving the flat layer described above includes at least a dry money engraving method. 6. The method for forming a microlens according to item 1 of the scope of the patent application, wherein the above-mentioned engraved area includes at least a concave surface of the flat layer. Page 12 471061 7. The method for forming a microlens as described in item 1 of the scope of the patent application, and the microlens layer described above includes at least one photosensitive material. "Of which 8 · The method for forming a microlens as described in item 1 of the scope of patent application The method for forming the microlens layer described above includes at least a spin coating method. Forming method The above-mentioned forming method of the M lens includes at least a thermal process. A micro lens forming method includes at least 10. An image sensor includes the following steps: providing a substrate having a light sensing element; A flat layer is on the substrate;-a photoresist layer is formed on the flat layer; 卞 umbrella f ^ Α photoresist layer as-# 刻 罩 幕 以 # 刻 The flat layer, and π formed on the Qiantan layer -㈣ The surface is formed into a ㈣ region; the photoresist layer is removed; and a thermal process is formed on the etched area of the flat layer by spin coating to form a thermal process to process the sensitized area on the etched area. Layer to form a micro lens. 11. The method for forming a micro lens as described in item 10 of the patent application scope, which Page 13 471061 6. The above-mentioned flat layer in the scope of patent application includes at least one light-transmitting material. 12. The method for forming a microlens as described in item No. 0 of the patent application range, wherein the method for etching the flat layer includes at least a wet etching method. 13. The method for forming a microlens as described in item I of the flat layer described above in the scope of the patent application, which includes a dry etching method. The method is as described in y i 14. The method of forming a microlens on the substrate as described above in item No. 丨 0 of the patent application scope, and the position of the light sensing element. 1 5. As described in the patent application, the thickness of the above-mentioned photosensitive layer is less than about 5 ^, the method of forming a microlens, which is described in 10 of the microlens16. A microlens is formed to provide a substrate; a protective layer is formed on Forming a color filter layer to form a flat layer, defining a photoresist layer at the fault, and using the photoresist layer as a money engraved area to remove the photoresist layer in the flat layer; method > method i less The following steps: Prepare the substrate; · On the protective filter color filter layer! = To etch the flat layer; and form a micro lens layer on the flat layer ' No. 14 Yin 471061 6. The scope of the patent application forms a micro lens area on the etched area of the flat layer; and processes the micro lens area on the etched area to form a micro lens on the etched area of the flat layer on. 17. The method for forming a microlens as described in item 16 of the scope of the patent application, wherein the above substrate includes at least one light sensing element. 18. The method for forming a microlens as described in item 16 of the scope of patent application, wherein the above-mentioned flat layer includes at least one light-transmitting material. 19. The method for forming a microlens as described in item 16 of the scope of the patent application, wherein the method for engraving the flat layer includes at least a wet touch engraving method. 20. The method for forming a microlens as described in item 16 of the scope of the patent application, wherein the method of flattening the flat layer at least includes a dry #etching method. 21. The method for forming a microlens according to item 16 of the scope of the patent application, wherein the above-mentioned touch-engraved area includes at least a concave surface of the flat layer. 2 2. The method for forming a microlens as described in item 16 of the scope of the patent application, wherein the above-mentioned microlens layer includes at least one photosensitive material. 2 3. The method for forming a microlens as described in item 16 of the scope of patent application, wherein the method for forming the microlens layer described above includes at least a spin coating method. Page 15 471061 6. Scope of patent application 24. The method for forming a microlens as described in item 16 of the scope of patent application, wherein the method for forming the microlens area described above includes at least one lithography process. 25. The method for forming a microlens as described in item 16 of the scope of the patent application, wherein the method for forming the microlens described above includes at least one thermal process. 26. A method for forming a microlens of an image sensor, the method comprising at least the following steps: providing a substrate having a light sensing element; forming a protective layer on the substrate; forming a color filter layer on the substrate On the protective layer; forming a flat layer on the color filter layer; defining a photoresist layer on the flat layer; using the photoresist layer as a food mask to etch the flat layer, and on the flat Forming a etched area with a concave surface on the layer; removing the photoresist layer; forming a photosensitive layer on the flat layer by a spin coating method; forming a photosensitive area on the etched area of the flat layer; and A thermal process is performed to process the photosensitive area on the etched area and form the microlens. 27. The method for forming a microlens as described in item 26 of the scope of patent application, wherein the above-mentioned flat layer includes at least one light-transmitting material. Page 16 471061 6. Scope of patent application 28. The method for forming a bismuth lens according to item 26 of the scope of patent application, wherein the above-mentioned method for etching the flat layer at least includes a wet etching method. 29. The method for forming a microlens as described in item 26 of the scope of the patent application, wherein the method for etching the flat layer at least includes a dry etching method. 30. The method for forming a microlens according to item 26 of the scope of the patent application, wherein the above-mentioned etching area is located at the position of the light sensing element of the substrate. 31. The method for forming a microlens as described in item 26 of the scope of the patent application, wherein the thickness of the photosensitive layer is less than about 5 microns. 32. The method for forming a microlens as described in item 26 of the scope of the patent application, wherein the method for forming the above-mentioned photosensitive area includes at least one lithography process. A method for forming a plurality of lenticular microlenses of an image sensor, the method includes at least the following steps: providing a substrate having a plurality of light sensing elements; Forming a protective layer on the substrate; forming a color filter layer on the protective layer; forming a flat layer on the color filter layer; meaning a plurality of photoresist layers on the flat layer; by the plurality Photoresist layers as a plurality of etching masks to etch the plane Page 17 471061 A layer is formed, and an etching area is formed on a concave surface of the plurality of light-sensing elements; a plurality of photoresist layers are removed on the first layer; A spin coating method is used to apply a photosensitive material to a photosensitive layer having a thickness of less than about 5 microns; a photolithographic process is used to expose the photosensitive layer on the plurality of etched areas of the flat layer; and a thermal process is performed. A process is performed to process the plurality of photosensitive regions, and a lenticular microlens is opened on the remaining region of the flat layer. Λ 复 3 4 _ The method for forming a lenticular microlens as described in item 33 of the scope of patent application, wherein the above-mentioned flat layer includes at least a light-transmitting material. 35. The method for forming a lenticular microlens as described in item 33 of the scope of patent application, wherein the method for etching the flat layer includes at least a wet etching method. 36. The method described in item 33 of the scope of patent application A method for forming a lenticular microlens, wherein the above method for etching the flat layer includes at least a dry-etching method ----