TWI223105B - Manufacturing method of ball microlens for image sensor - Google Patents

Abstract

The present invention relates to a manufacturing method of ball microlens for image sensor, wherein a spacer ball is used to replace the conventional polymer microlens, so as to avoid the problems of instability and overlarge curvature of the polymer material. The method of the present invention is compatible to the current semiconductor process, and can form multiple stages of microlens structure easily for increasing the capability to collect light. In addition, the present invention further provides a method to reduce the cross talk problem resulted from the stray light to the photosensitive element.

Description

1223105 V. Description of the invention (l) [Technical field to which the invention belongs] The present invention relates to a method for manufacturing a spherical micro-lens used in an image sensor, and more particularly to a CCD and its complementarity The manufacturing method of spherical microlenses on image sensing elements such as metal oxide semiconductors (CMOS) uses a spherical spacer particle to replace the original polymer microlenses, which can improve the polymer material with poor stability and high curvature. problem. [Prior art]

Image-sensing elements made of photoelectric-coupled devices (CCD) and complementary metal-oxide semiconductors (CMOS) have been widely used in digital cameras, camcorders, and surveillance cameras , PC cameras, facsimiles, scanners and other optical equipment, but only a part of the photosensitive unit (pixel) of each image sensing element is photosensitive, and can only feel light incident in a specific direction. Therefore, how to make light directly project to the photosensitive area of each photosensitive unit as much as possible is one of the very important research topics when developing image sensing elements. In order to achieve this purpose, during the production of the image sensing element, a "micro lens" can be placed in front of each photosensitive unit to control the light incident on the photosensitive area of the photosensitive unit and improve the quantum effect of several pieces of image sensing. Please refer to FIG. 1, which is a schematic diagram of a microlens structure of an image sensing element of a conventional technology. As shown in the figure, when light 14 is incident on the image sensing element, the effect of the microlens 13 can make the light After focusing, it penetrates the color filter (CF) 12 and enters the photosensitive unit 11,

Page 5 1223105 V. Description of the invention (2) ------ Greatly improve the efficiency of incident light. The traditional microlens manufacturing process uses a photoresist coating on the color phosphor layer, the photomask is exposed to money, and the special reflow process is a process that allows polymer materials to form a curved structure due to surface tension. After cooling, the desired microlens structure is formed. However, there are many shortcomings in the traditional system of forming a microlens structure. For example, the stability of polymer materials is not good, and it is easy to produce qualitative changes when strong light and high-radiation light are incident, which affects the quality of optical imaging. Due to process factors, the curvature of the lens formed by this method is too large and the curvature cannot be accurately controlled, which is likely to cause a discount in the application effect; more importantly, the light collection power of a lens is far inferior to that of a multiple microlens group, but in existing semiconductors In the manufacturing process, there are technical difficulties in manufacturing multiple microlenses. Therefore, it is the object of the present invention how to overcome the above-mentioned shortcomings and provide a new microlens manufacturing method with good effect and easy manufacturing process. [Summary of the Invention] The main purpose of the present invention is to provide a method for manufacturing a spherical micro lens applied to an image sensor, and more particularly to a method for applying a photocoupler; a device (CCD) and a complementary metal oxide semiconductor (CM0s). The method for manufacturing spherical microlenses on image sensing elements and the like uses a spherical microlens to replace the original polymer microlenses in order to improve the problems of poor material stability and excessive curvature. Another object of the present invention is to provide a method for manufacturing a spherical microlens used in an image sensor. The existing semiconductor technology is used in conjunction with the process of embedding a spherical microlens, which is more compatible with existing semiconductor processes and Easily

1223105

A multi-level micro-lens structure is formed to increase the light collecting ability. Another object of the present invention is to provide a microlens manufacturing method applied to an image sensor to improve the effect of adjacent pixels (pixe0 cross-talk). In order to achieve the above object, The invention provides a method for manufacturing a spherical microlens applied to an imager, which includes the following steps: ~ (a) providing a substrate, the substrate comprising a plurality of basic photosensitive elements, and covering the plurality of A thin film layer of a basic photosensitive element; (b) forming a color filter layer over the thin film layer; 'testing (c) forming an etch stop layer over the color filter layer; (d) over the etch stop layer Forming a ball spacer layer having a plurality of grooves, the bottom of the groove is penetrated to the etch stop layer; and tooth pass (e) a ball-shaped spacer particle is built into the groove ( spacer bau); (f) forming a flat protective layer to fix the spherical spacer particles in the groove. In order to achieve the above-mentioned object, the present invention provides another method for manufacturing a microlens in an image sensor. Implementation, tied to steps After f), the method further includes the following steps: U) forming an etch stop layer over the protective layer; (h) repeating steps (d) to (f) above the etch stop layer to form a laminated ball Micro lens structure. In order to achieve the above-mentioned object, another embodiment of a method for manufacturing a spherical microlens applied to an image sensor of the present invention is to form a total reflection layer on

1223105

The side walls of the grooves form a light pipe effect to reduce crosstalk caused by stray light, which includes the following steps: (a) for a substrate, the substrate includes a plurality of basic photosensitive elements, and covers the A thin film layer of a plurality of basic photosensitive elements; (b ') forming a color filter layer over the thin film layer; (c) forming a engraved stop layer over the color filter layer; (d') in the etching A ball spacer Uyer having a plurality of grooves is formed above the stop layer, and the outer edge of the groove has a side wall and the bottom thereof penetrates to the etch stop layer; (e ') in the groove A spacer wall is formed around the side wall; (Γ) a spacer ball is built into the groove; (g ') forms a protective layer through a planarization process to seal the spherical spacer particle Fixed in the groove. [Embodiment] Hereinafter, a preferred embodiment will be listed to describe in detail the detailed method, operation mode, achieving effect, and other technical features of the present invention applied to a method for manufacturing a spherical microlens of an image sensing element. First Embodiment FIGS. 2A to 2D are schematic diagrams of a first embodiment of a method for manufacturing a lens of an image sensor according to the present invention. As shown in the figure, a substrate 21 is provided, and the substrate 21 includes A plurality of basic sensing elements 22, and a thin film layer covering the plurality of basic photosensitive elements 22

Page 8 1223105 V. Description of the invention (5) 2rn, where the plurality of basic photosensitive elements 22 can be optoelectronic / composite element layer supplementary oxidized metal semiconductors ("〇5". Next, a thin film is formed on the side of the film. A color filter layer 24, and an etching stop layer 25 is etched on top of the color filter layer 24. The etch stop layer 25 is mainly used as a rear: on: the particle stop layer can also be used as an etching stop layer when the card groove is formed. As a spacer layer between the ^ -shaped microlens and the color filter layer 24, a spherical particle spacer layer 26 having a plurality of grooves is formed above the etching stop layer 5, and its manufacturing method is preceded by etching. The stop layer is deposited on top of the plasma-assisted chemical vapor deposition method (PECVD), spin-on-glass method (s0g), or sub-atmospheric chemical vapor deposition system (SACVD). The material of the spherical particle spacer layer 26 may be silicon dioxide (SiO2), silicon nitride, or fluorine glass (FSG), and then a complex number is formed on the spherical particle spacer layer 26 through steps of exposure, development, and etching. Grooves 261, which are used to provide a spherical shape The depth of the groove required for the microlens is about 0.5um ~ 11um and the shape can be arbitrary. The principle is to accommodate spherical microlenses inside. The stop layer of the etching step is the etching stop layer 25, so the The bottom of the groove 261 penetrates to the etch stop layer 25. Next, a spherical spacer particle (262) is built into the groove. This spherical spacer particle 262 has been widely used in the process of liquid crystal display. It is used to evenly spread between two glass substrates to support it. A material is provided to facilitate the subsequent liquid crystal infusion process. The material may be silicon dioxide, resin or polymer, and the diameter of the sphere is between 0.5um and 10um. Finally, a flat protective layer 27 is formed to fix the spherical spacer particles 262 in the groove. The formation method can be a spin-on glass method.

1223105 V. Description of the invention (6) (S0G) Direct and uniform coating to form a flat chemical vapor deposition (CVD) deposition of a protective layer, two back two) or chemical mechanical polishing (CMp) c ing In addition to the lens manufacturing method = m = r lens structure, such as EE tmm; many easy-to-finish micro-transmittance: money engraved stop layer 25, and then repeat the foregoing: J27, shaped particle spacer layer 26 '' etched to form Concave, = spaced particles 262, and covering protective layer 27, layer 2 type microlenses, this material is even expected to be made into a triple pair and a layered microlens structure to increase its light collection effect. The second embodiment:-: ί: When the light collected by the microlens is opposite, each light-sensitive element is hardly more sensitive than the 70-piece stray light, which has an increasing degree of convergence. Zujin will not receive scattering from other micro-lenses. "Therefore, the phenomenon of cr0ss talk, which is the phenomenon of breaking light in the present invention. It is designed to greatly reduce the figure 2 due to stray light. To FIG. 3D, the manufacturing method in the first embodiment of the spherical micro-transmitting device of the second embodiment of the method for manufacturing a 3 / a mirror of the present invention is the “Baisen Lizi spacer layer 31. Auxiliary Concavities: Spherical particles of 311 ^ ^ ^ Slightly assist in chemical disordered phase deposition (PECVD), bismuth-coated glass method (SOG) or sub-atmospheric chemical vapor deposition system (sacvd) Page 10 1223105

V. Description of the invention (7) The refractive index of a p bow Ks station deposited by other methods must be larger than the refractive index of the film layer 32 'The material of the spacer film layer 32 is the refractive index of the material of the spacer layer 31 of the Jiang Mi second sub-layer, and then carved Stop the upper f particle spacer layer 31 above and the bottom of the groove 311 (that is, the gap between the etch ^ _ gap wall 3 1 2 and finally put the protective layer of the spherical spacer particle inspection early W ^ 4+ 绖 flattening process) 33. The spherical spacer particles 313 are sealed and fixed in the groove 311.

For example, the method in the first embodiment, the second embodiment can also form a f: and layer micro-lens structure, as shown in Figure 3, which is based on protection, and then an etch stop layer 3 is formed. Then, repeat the method described above to sequentially form a spherical particle spacer layer 31, etch the groove holder 311, and form a spacer wall 312 on the side wall of the groove, insert spherical spacer particles 313, and cover the protective layer 33. In this way, a double laminated spherical microlens can be formed, and even a laminated microlens structure with more than two layers can be fabricated to increase its light collection. Third Embodiment In addition, the method for manufacturing a spherical microlens of the present invention particularly provides a Method, which can increase the effect of blocking stray light to avoid crosstalk. FIGS. 4A to 4D are schematic diagrams of a second embodiment of a method for manufacturing a spherical microlens of an image sensor according to the present invention. As shown in the figure, first, the manufacturing method in the first embodiment is used on the etching stop layer 40. A ball with a groove 411 = a particle spacer layer 41 is formed above, and then an anti-reflection layer 42 is formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) to form an anti-reflection layer 42.

1223105 V. Description of the invention (8) ------ Qi Ning (TiN), gasification stone (SiN), complex (Cr) or silicon oxynitride connected to [absorb stray light to avoid ^ necessary reflection And scattering. In the manner of the first embodiment, a gap wall 412 is formed around the side wall of the groove 411. Similarly, the refractive index of the material of the gap wall 412 must be greater than the refractive index of the material of the spherical particle spacer layer 41. Finally, the anti-reflection film at the bottom of the groove (above the 12 stop layer) is removed, and then spherical spacer particles 413 are placed, and a protective layer 43 is formed through a planarization process to form the spherical spacer particles 41 3 Sealed and fixed in the groove 411. Preferably, after the anti-reflection layer 42 is formed, the anti-reflection film layer above the spherical particle spacer layer 41 and above the etch stop layer 40 can be removed by etch back. As shown in FIG. 4F, only a part of the side wall of the groove 411 is left to form an anti-reflective film wall 421. Then, a gap wall 412 is formed, and spherical spacer particles 413 are inserted, and finally a protective layer 43 is formed after the planarization process. The spherical spacer particles 413 are sealed and fixed in the groove 411, as shown in FIG. 40. In addition, as in the method of the first and second embodiments, the third embodiment can also form a multilayer As shown in FIG. 4E, the laminated micro-lens structure is further formed on the protective layer 43 by an etching stop layer 40. Then, the method described above is repeated to sequentially form a spherical particle spacer layer 4 and the etching is performed. Forming a groove holder 411, depositing to form a resistance The reflective layer 42 forms a gap 412 'on the side wall of the groove, removes the anti-reflection layer at the bottom of the groove, and inserts spherical spacer particles 413' and covers the protective layer 43 ', so as to form a double laminated spherical shape. The micro-lens structure can even make three or more laminated micro-lens structures to increase its light-collecting effect.

1223105 V. Description of the invention (9) In summary, the above is only a preferred embodiment of the present invention, and it cannot be used to limit the scope of the present invention. Any equal changes and modifications made in accordance with the scope of the patent application for the present invention should still fall within the scope of the patent for the present invention. I ask your reviewing committee to make a clear note and pray for your approval.

Page 1212105 Brief description of the drawings [Simplified description of the drawing system] The first series is a shadow map of the conventional technology; "The microlens structure of the sensory residual element is shown schematically. The second A to the second D are the manufacturing methods of the lens of the present invention. The first embodiment of the invention is a ball-type micro-transmitting ring of the shirt-type sensor. The second E series is the first tone of the present invention; A schematic diagram of the first embodiment of a method for manufacturing a spherical microlens of an image sensor according to the present invention; FIG. 3E is a schematic structural diagram of a laminated spherical microlens according to the second embodiment of the present invention. FIG. 4 is a schematic diagram of a third embodiment of a method for manufacturing a spherical microlens of an image sensor according to the present invention; FIG. 4E is a schematic diagram of a structure of a laminated spherical microlens according to the third embodiment of the present invention; Figure 4G is a schematic diagram of another embodiment of the third embodiment of the present invention to change the anti-reflection layer. Figure number description: 11-photosensitive unit 13-microlens 2 1-substrate 23-thin film layer 25-etching stop Layer 1 2-color light layer 1 4-incident light 22-basic sense 24- element color filter layer 26-- spacer layer of spherical particles

ISBS P.14 1223105 262 ~ Spherical spacer particle pattern brief description 261-Groove 27_Protective layer 25'_Etched stop layer for laminated micro lens 26 '-Spherical particle spacer layer for laminated micro lens 26Γ -Laminated Micro-lens groove 2 6 2 '-Spherical spacer particles of laminated micro-lens 27 _ Protective layer of laminated micro-lens 31-Spherical particle spacer layer 33-Protective layer 31 2-Spacer wall 3 0 _ Time-stop layer 32-spacer film layer 311-groove 31 3 -spherical spacer particle 3 〇-etch stop layer of laminated microlens 31 spherical particle spacer layer of laminated microlens 33 '-protective layer of laminated microlens 31Γ- Laminated microlens groove 31 2-Laminated microlens gap wall 4 0-Epistop layer 4 2- Antireflection layer 411-Groove 413-Spherical spacer particle 3 1 3-Laminated 2 microlens ball Spacer particles 4 1 a spherical particle spacer layer 43-a protective layer 4 1 2-a gap wall 42 丨 ~ an antireflection film wall 4 〇, an etch stop layer of a laminated micro lens 41 a spherical particle spacer layer 42 of a laminated micro lens '-Laminated microlens anti-reflective layer, page 15 1223105 Schematic illustration 43'-Protection of laminated microlens Layer 411 ’-grooves of laminated microlenses 41 2 ′-spacers of laminated microlenses 41 3 ′-spherical spacer particles of laminated microlenses

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Claims (1)

1223105 • A method for manufacturing a ball-shaped microlens of a shirt-like sensor, which is a series of steps. · Dan you include the following (a) to provide a substrate, which includes a plurality of basic sensing elements, And a thin film covering one of the plurality of basic photosensitive elements is formed on the film layer to form a color phosphor layer; 4 film layers; (c) an etch stop layer is formed on the color filter layer; (d) A ball spacer layer having a plurality of grooves is formed over the etch stop layer, and the grooves are two spherical particle spacer layers; (e) a spherical spacer particle (叩 ^^ bau) is built into the groove; (f) a flat protective layer is formed on the spherical particle spacer layer to fix the spherical spacer particle to the groove; Inside. 2. The method for manufacturing a spherical micro-lens of an image sensor as described in item 1 of the scope of the patent application, wherein after step (f), the method further includes the following steps: (g) forming a stop for a while on the protective layer Layer; (h) repeating steps (d) to (f) above the etch stop layer. 3 · The method for manufacturing a spherical microlens as described in item 2 of the scope of patent application, wherein after step (h), it further includes a step (i): repeating step (g) to step (h) at least once above the protective layer ). 4 · The method for manufacturing a spherical microlens of an image sensor as described in item 1 of the scope of the patent application, wherein the plurality of basic photosensitive elements in step (a) are photoelectric light-emitting elements (CCD) and complementary oxidation One of metal semiconductors (CM0S). 5 · Spherical micro lens of image sensor as described in item 丨 of Shenjing patent scope Page 17 1223105 6. Method for making a patent application, wherein the material of the spherical particle spacer layer in step (d) may be one of materials such as silicon dioxide, silicon nitride, and fluorine glass (FSG). The spherical microlens method of the image sensor described in item 1 of the application, wherein the spherical particle spacer layer in step (d) is electro-assisted chemical vapor deposition (PECVD), spin coating It is deposited by one of the methods such as glass method (SOG) and sub-atmospheric pressure chemical vapor deposition system (SACVD). 7. ΐI request the spherical microlens of the image sensor described in item 1 of the patent scope, wherein the depth of the groove in step (d) is between 0.5 rhyme and • = 1. The spherical micro-lens handle method of the image sensor described above, wherein the spherical shape of the spherical spacer particles in step (e) is slightly smaller than the depth of the groove. H ΐ The spherical micro-lens method of the image sensor according to item 1 in the scope of the item, wherein the spherical spacer in step (e) is specialized. The spherical micro-lens of the tester ::::: where the flat protective layer in step 可 can be applied with a π Μ μ μ protective layer followed by etching back and chemical mechanical polishing (CMP). —Square) and 1.—Spherical micro-transmission of an image sensor comes / ° into the following steps: · The method of making a clothing micro lens, which includes page 1223105 on page 18 (a) providing a substrate comprising a plurality of basic photosensitive elements and a thin film layer covering the plurality of basic photosensitive elements; (b) forming a color filter layer over the thin film layer; ( c) forming a engraved stop layer over the color filter layer; (d) forming a ball spacer layer having a plurality of square grooves above the etch stop layer, the groove having a sidewall And a bottom, and the bottom is in communication with the spherical particle spacer; (e) forming a gap wall around the side wall of the groove; (f) a spherical spacer particle is built into the groove (g) forming a flat protective layer over the spherical particle spacer layer to fix the spherical spacer particle in the groove. 1 2 · The method for manufacturing a spherical micro-lens of an image sensor according to item 11 of the scope of patent application, wherein after the steps, the method further comprises the following steps ... (h) forming an etch stop layer over the protective layer; (0) Repeat steps (d) to (g) above the last stop layer. 1 3 · The method for making a spherical microlens as described in item 12 of the patent application scope, wherein after step (i), it further includes There is a step (j): repeating the steps (h) to (i) at least once over the protective layer. 1 4 · The method for manufacturing a spherical micro-lens of an image sensor as described in item 11 of the patent application scope, wherein After step (d), a step (d 1) is further included. An anti-reflection film layer is formed on the spherical particle spacer layer. 15. The spherical micro-transmission of the image sensor according to item 14 of the scope of patent application Page 19 1223105 VI. Scope of patent application The method for making a mirror, wherein after step (e), it further includes a step (e 1) ·· removing the anti-reflection film at the bottom of the groove. 16 · The method for manufacturing a spherical microlens of an image sensor according to item 5 of the patent application scope, wherein after step (g), the method further includes the following steps: (h) forming an etch above the protective layer Stop layer; (i) Repeating steps (d) to (g) above the etch stop layer to form a laminated spherical microlens structure. 17 · The method for manufacturing a spherical microlens as described in item 6 of the patent application scope, wherein after step (i), it further includes a step (j): repeating step (h) to step at least once above the protective layer (I). 18 · The method for manufacturing a spherical microlens of an image sensor as described in item 4 of the patent application scope, wherein after step (dl), it further includes a step (d2): the spherical particle spacer layer and the etching The anti-reflection film on the upper surface of the stop layer is removed, and only the anti-reflection film on the side wall remains. 19. The method for manufacturing a spherical microlens of an image sensor as described in item 18 of the scope of patent application, wherein after step (g), the method further includes the following steps: (h) forming an etch above the protective layer Stop layer; (i) Repeat steps (d) to (g) above the etch stop layer. 20. The method for manufacturing a spherical microlens as described in item 19 of the scope of patent application, wherein after step (i), it further includes a step (j): repeating steps (h) to step (i) above the protective layer at least once ). 21 · The method for manufacturing a spherical micro-lens of an image sensor according to item 11 of the scope of patent application, wherein the plurality of basic photosensitive elements in step (a) are a photo-coupled element (CCD) and a complementary metal oxide semiconductor Page 20, one of the patent application scope U (CMOS). The spherical micro-transmittance of the image sensor described in item 11 of the patent scope, wherein the material of the spherical particle spacer layer in step (d) is silicon dioxide, silicon nitride and fluorine glass (FSG) and other materials, among which ^ 3 · = ^ please apply the method of spherical micro-transmission of the image sensor described in item 11 of the patent scope, wherein the spherical particles in step (d) are acoustically spaced by electric waves. It is formed by 24-methods such as auxiliary chemical vapor deposition (PECVD), spin-on glass (SOG) and sub-atmospheric chemical vapor deposition systems (SACVD). 7. The method for manufacturing a spherical microlens of an image sensor as described in item 11 of the patent application, wherein the depth of the groove in step (d) is between 0.511111 and " um. 25. • The method for manufacturing a spherical micro-lens for an image sensor as described in item 22 of the scope of patent application, wherein the sphere 26 of the spherical spacer particle in step (f) is pinched slightly smaller than the depth of the groove. • The manufacturing method of the spherical micro lens of the image sensor according to item 11 of the patent application scope, wherein the refractive index of the spacer material in step (e) is greater than the refractive index of the spherical particle spacer layer material. • The method for manufacturing a spherical microlens of an image sensor as described in item 11 of the scope of patent application, wherein the material of the spherical spacer particles in step (f) is silicon dioxide, resin, polymer, etc. Among them ~ 〇 2 8 »• Spherical Micro Penetration of Image Sensor as described in Item 11 of Patent Application Scope 1223105 VI. Application for patent scope 29 Mirror manufacturing method, wherein the flat protective layer in step (g) can be uniformly coated by using the spin-on glass method (S0G), or by chemical vapor phase / child product method (CVD) After depositing a protective layer, it is completed by one of methods such as etching back and chemical mechanical polishing (CMP). According to the spherical micro-transmission of the image sensor described in item 14 of the patent application scope, a method for manufacturing the anti-reflection film layer may be titanium nitride (TiN), silicon nitride (SiN), chromium (Cr) And silicon oxynitride (SiON) and other materials. 30. The method for manufacturing a spherical microlens of an image sensor as described in item 14 of the patent application, wherein the antireflection film layer is formed by chemical vapor deposition. CVD and physical vapor deposition (pvD). , Page 22