TWI235490B - Image sensor and fabricating method thereof - Google Patents

Abstract

An image sensor comprising an image sensing device layer, a silicon on insulator layer, a optical device array and a substrate is provided. The silicon on insulator layer has a first surface and a second surface. The image sensing device layer is formed on the first surface of the silicon on insulator layer. The optical device array is formed on the second surface of silicon on insulator layer. The substrate is configured above the second surface of the silicon on insulator layer and the optical device array is located between the substrate and the silicon on insulator layer. After emitting through the optical device array and the silicon on insulator layer, the light from environment is received by the photo sensor device forming in the image sensing device layer so as to reduce the probability of the absorption or reflection of the light and improve the photo sensing efficiency of the image sensor.

Description

1235490 13159twf.doc / 006 IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to an optical device and a manufacturing method thereof, and particularly to an image sensor and a manufacturing method thereof. [Prior art]

With the prevalence of audiovisual multimedia, Ik has successively launched digital imaging equipment, and its key core component image sensor has become increasingly important. Image sensors are mainly responsible for converting light image signals into electrical signals, and depending on the type of sensing element, they can generally be divided into charge coupled devices (Charge Coupled Device (CCD)) image sensors and complementary metal oxide Semiconductor (Complementary Metal Oxide Semiconductor, CMOS for short) image sensors and so on. Among them, the complementary metal-oxide semiconductor image sensor has the advantages of low price, low power consumption, random reading of daylight, and high integration. Therefore, it is currently used in camera phones and webcams. And other more affordable products. FIG. 1 is a simplified schematic diagram of a conventional complementary metal-oxide-semiconductor image sensor. Please refer to FIG. 1. The photosensitive element 120 of the complementary metal-oxide semiconductor image sensor 100 is disposed in the substrate 102, and the sensor 120 is divided into two parts. For example, most of the substrates 120 have a pn connection. It consists of a photo diode of a p_n junction. In more detail, the photosensitive element 120 is generally composed of an n-type doped region, a p-type doped region, and a plane naturally formed between the n-type doped region and the p-type doped region in the substrate 102. The interconnection layer 104 is disposed on the bottom 1235490 13159twf.doc / 〇〇6 102 'and contains a number of metal interconnections and a dielectric layer (not shown) located between these metal interconnections. (Shown), these metal interconnections are suitable for transmitting the signal received by the photosensitive element 120 to the circuit board 110 for post-image processing. The color filters 132 are arranged in an array on the interconnect layer 104 and correspond to the photosensitive elements 120 in the substrate 102. A microlens 130 for collecting light is covered above each color filter 132. A glass substrate 134 is disposed above the microlens 130, and is connected to the interconnect layer ιo through a support 150. The external light 140 is incident on the interconnect layer 104 through the micro lens 130 and the color filter 132, and is then received by the photosensitive element 120. Therefore, the layout of the metal interconnections in the 'interconnection layer 104' must avoid the top of the photosensitive element 120 to prevent the metal layer (not shown) as the metal interconnections from reflecting light and reducing the sensing of the photosensitive element 120. To light intensity, so the process is more complicated. In addition, the dielectric layer (not shown) in the interconnect layer 104 also blocks part of the incident light (that is, absorbs or reflects light), so that the light intensity is gradually attenuated in the interconnect layer 104, resulting in photosensitivity. Insufficient light intensity is sensed by element 120. It can be known from the above that, since the external light 140 must first penetrate the interconnect layer 104 before it can be received by the photosensitive element 120, the conventional complementary metal-oxide semiconductor shirt image sensor 100 has a low aperture ratio (fill rati). And the disadvantages of low contrast. In addition, the conventional complementary metal-oxide-semiconductor image sensor also has high defects in the testing process and the packaging process. [Summary of the Invention] l2354m-6 Therefore, the object of the present invention is to provide a method for manufacturing an image sensor, which can improve the contrast of the image sensor and improve the yield of the back-end process. Another object of the present invention is to provide an image sensor having a relatively low contrast and a small element size (thickness). The invention provides a method for manufacturing an image sensor. This method firstly forms a silicon-clad insulation layer on a substrate, and the silicon-clad insulation layer has a first surface and a second surface in contact with the substrate. Then, an image sensing element layer is formed on the first surface of the silicon-clad insulating layer, and then a first substrate is disposed on the image sensing element layer. Then, the first substrate, the image sensing element layer, and the silicon-clad insulating layer are separated from the substrate to expose the second surface of the silicon-clad insulating layer. An optical element array is then formed on the second surface of the silicon-clad insulating layer. According to the embodiment of the present invention, after the optical element array is formed, a second substrate may be disposed above the optical element array. The material of the first substrate and the second substrate is, for example, glass. In another embodiment, before disposing the second substrate, for example, a support is formed on the second surface of the insulating layer, and then the second substrate is disposed on the support, so as to support the object. The second substrate is fixed above the optical element array. According to an embodiment of the present invention, after the formation of the optical element array ', the first substrate is removed to expose the image-forming element layer. In another embodiment, after removing the first substrate, the method further includes electrically connecting the image sensing element layer to the circuit board. The method for electrically connecting the image sensing element layer to the circuit board is, for example, forming a redistribution layer on the image sensing element layer, and then electrically connecting the redistribution layer to the circuit board. The method for electrically connecting the redistribution layer to the circuit board is, for example, firstly forming an additional 12,354 bumps on the redistribution layer, each of which is electrically connected to the redistribution layer. Then, the bumps are electrically connected. To the circuit board. / According to an embodiment of the present invention, the step of forming an optical element array on the second surface of the silicon-clad insulating layer includes firstly forming a plurality of arrays on the second surface of the silicon-clad insulating layer. The filter films are arranged, and then light-concentrating elements are arranged on each of the light-emitting elements. The light-concentrating elements are, for example, microlenses 0. According to the embodiment of the present invention, a method for forming an image sensing element layer is, for example, An active layer is first formed on the first surface of the silicon-clad insulating layer, and a photosensitive element is already formed in the active layer. Then an interconnect layer is formed on the active layer, and the interconnect layer is electrically connected to the photosensitive element. Then Then, a plurality of solder pads are formed on the interconnecting layer. Each of the soldering pads is electrically connected to the interconnecting layer. In one embodiment, the photosensitive element is, for example, a photodiode. According to an embodiment of the present invention, Recount After the optical element array, it further includes a cutting process to form a plurality of image sensor units. The present invention provides an image sensor, which mainly includes an image sensor element 2, a silicon-coated insulating layer, an optical element array, and a substrate. Among them, the silicon-clad insulating layer has a first surface and a second surface, and the image sensing element layer system is equal to the surface of the insulating layer of the stone layer. The optical element is arranged on the second surface of the insulating layer of the stone layer. The substrate is disposed above the surface of the silicon-clad insulating layer, and the optical element array is located between the substrate and the silicon-clad insulation. ^ According to the embodiment of the present invention, the image sensing element layer is insulated by the silicon. The layers sequentially include an active layer, an interconnect layer, and a plurality of pads. Among them, 1235490 13159twf.doc / 006 interconnect layers are arranged on the active layer, and these pads are arranged on the interconnect layer According to the embodiment of the present invention, the active layer of the image sensing element layer includes a photosensitive element, which is, for example, a p-type doped region, an n-type in the active layer. Doped region and P A photodiode formed by a p_n junction formed naturally between a doped region and an n-type doped region. According to an embodiment of the present invention, an optical element array includes a plurality of filter films arranged in an array and a filter film thereon. Condensing elements. Each of the condensing elements is disposed on a filter film. In one embodiment, the condensing elements are, for example, microlenses. According to the embodiment of the present invention, the image sensor The device further includes a branch, configured on the second surface of the tree-covered insulating layer, and connected to the substrate so that the substrate is fixed above the optical element array. According to the embodiment of the present invention, the image sensor further includes a weight The wiring layer is disposed on the image plane component layer, and is electrically connected to the pads in the shadow test component layer. In the embodiment, the redistribution layer further includes a plurality of bumps. Both are electrically connected to the bonding pads through the redistribution layer. The image sensor of the present invention can allow light to pass through Shi Xi and cover the insulating layer, and then be received by the photosensitive elements in the scene J image, the layer, And converted into telecommunications =, and the precision is output from the welding pad and the bump to Circuit board. Therefore, the present invention can solve the problem that the light can be arranged in the receiving or reflecting image area such as the dielectric layer or the metal layer, and all areas of the image_element layer belong to the wire layer, and it is not necessary to avoid the transmission of light to the photosensitive element I2354m-6. Path, which can reduce the complexity of the process. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, preferred embodiments are described below in detail with reference to the accompanying drawings, as follows. [Embodiment] The present invention uses a special process to make a shirt image sensor with a short internal light transmission path 'to improve the light sensing performance of the image sensor. The complementary metal-oxide-semiconductor image sensor will be described below as an example, but it is not intended to limit the application scope of the present invention. 2A to 2E are schematic cross-sectional views illustrating a manufacturing process of a complementary metal-oxide semiconductor image sensing method according to a preferred embodiment of the present invention. Please refer to FIG. 2A. First, a silicon-on insulator layer (SOI layer) 202 is formed on the substrate 200. The silicon-clad insulating layer 200 has a first surface 202a and a second surface 202b in contact with the substrate 200, and the substrate 200 is, for example, a wafer. Here, the process for forming the insulating layer 202 is, for example, a commonly used SOI process. Those skilled in the art should understand the detailed steps of this process, and the details will not be repeated here. Referring to FIG. 2B, an image sensing element layer 204 is formed on the first surface 202 a of the silicon-clad insulating layer 202. The image sensing element layer 204 includes, for example, an active layer 204a, an interconnect layer 204b, and a pad 204c (see an enlarged image sensing element layer 204 as shown in FIG. 2B). Among them, the interconnect layer 204b has a plurality of metal layers (as shown by the oblique line in the interconnect layer 204b shown in FIG. 2B), and the solder pad 204c is electrically connected to these metal layers. Therefore, the image sensing element layer 204 can transmit signals through these metal layers from 12354¾¾twf.doc / 006. In addition, the photosensitive element 220 in the complementary metal-oxide semiconductor image sensor of the present invention is, for example, an n-type doped region (not shown) and a p-type doped region (not shown) located in the active layer 204a. And a photodiode formed by a p_n junction formed naturally between the n-type doped region and the p-type doped region.

Please refer to FIG. 2C and FIG. 2D at the same time. Firstly, a first substrate 206a is disposed on the image sensing element layer 204, and then a silicon-clad insulating layer 202 together with the image sensing element layer 204 and the first substrate 206a and the substrate disposed thereon 200 is separated and turned 180 degrees along the arrow 233 indicated in FIG. 2C to expose the second surface 202b of the silicon-clad insulating layer 202, as shown in FIG. 2D. The material of the first substrate 206a is, for example, glass. Referring to FIG. 2E, an optical element array 230 is disposed on the second surface 202b of the silicon-clad insulating layer 202, and then a second substrate 206b is disposed above the optical element array 230 to complete the complementary metal-oxide-semiconductor image sensor 260. Making. The material of the second substrate 206b is, for example, the same as that of the first substrate 206a.

An optical element array 230 is constituted by, for example, a plurality of light film 232 and a light collecting element arranged in an array. The light-emitting film M2 series should reach the photosensitive element in the active layer 2G4a, and a light-concentrating element 234 is arranged on each of the aerial films 22. When the level is shot by an outside person, the light is focused; the piece 234 can focus the light so that it is shot through the county film 232, and then; the light receiving element 22 in the active layer 2Q4a under the light-thin film 232 is received by FIG. 2B) . Among them, the phosphor film is, for example, a color film, to allow light of a certain wavelength to pass through. The condensing element 23 11 1235490 13159twf.doc / 006 is, for example, a micro lens. In addition, Taiyin + ^ ^ ^ ^ ^ ^ In this conventional example, the second substrate 206b is configured to be 'J'. You can first form a silicon-coated insulating layer π on the second surface 202b of the layer ^) ^) ' Then, a second substrate 2 嶋 is disposed on the support 25o. • It can be fixed on the optical element array 230 by the support 250 in one second. Heart you π dry τυι dry

According to the above description, the fabrication of the image sensor of the present invention can be completed, and the skilled person should know that if the substrate 2 is used. . It is a wafer. Then, after the structure shown in FIG. 2E is completed, a dicing process must be performed to form a single image sensor. Since the structure of the video system is the same as that of the complementary metal-oxide semiconductor image shown in Figure 2E, it will not be shown here in other figures. After Yuancheng's complementary metal-oxide-semiconductor image sensor 26 shown in Figure 2E, the next step is to configure this complementary metal-oxide-semiconductor image sensor on the circuit board. The following will continue with the diagram The following describes the process of disposing the image sensor on the circuit board.

Referring to FIG. 2F, the first substrate 206a is removed to expose the image sensing element layer 204. In particular, after removing the first substrate 206a, the structure can be turned 180 degrees to facilitate the bump process to form a bump 214 electrically connected to the pad 204c. The complementary metal-oxide-semiconductor image sensor 260 is then electrically connected to the circuit board through the bump 214. Therefore, after the optical signal received by the photosensitive element 220 is converted into an electrical signal, it can pass through the interconnect layer 204b. The metal layer, the solder pad 204c, and the bump 214 are output to the circuit board 210. In addition, in this embodiment, before the bumps 214 are formed, 12 I2354? 3Q9twfd0 — firstly, a redistribution layer layer 216 is formed on the image sensing element layer 204 to facilitate resetting the positions of the bumps 214. Furthermore, the problem that it is difficult to form the bumps 214 due to the small pitch of the pads 204c in the bump manufacturing process is further solved. The bumps 214 are disposed on the contacts in the redistribution layer 216, and are electrically connected to the bonding pads 204c through wires (not shown) in the redistribution layer 216. From the above, it can be known that the image sensor manufactured according to the process of the present invention can reduce the film layer that the light needs to penetrate during the process of transmitting light from the outside to the photosensitive element, thereby increasing the photosensitive performance of the image sensor. In the following, a complementary metal-oxide-semiconductor image sensor is taken as an example, and the image sensor of the present invention will be described in detail in conjunction with the drawings. Referring to FIG. 2F, the complementary metal-oxide-semiconductor image sensor mainly includes an image sensing element layer 204, a silicon-coated insulating layer 202, an optical element array 230, and a second substrate 206b. The silicon-clad insulating layer 202 has a first surface 202a and a second surface 202b. The image sensing element layer 204 is disposed on the first surface 202a of the silicon-clad insulating layer 202. The image sensing element layer 204 includes, for example, an active layer 204a, an interconnect layer 204b, and an interconnect. The layer 204b is electrically connected to the solder pad 204c. The photosensitive metal element 220 sensing the image of the complementary metal-oxide semiconductor shirt as 260 is, for example, a photodiode located in the active layer 204a. The optical element array 230 is disposed on the second surface 202b of the silicon-clad insulating layer 202. The optical element array 23 is composed of, for example, a plurality of filter films 232 and light collecting elements 234 arranged in an array. In addition, the filter and light films 232 correspond to the photosensitive elements 220, 13 9twf.doc / 006 in the active layer 204a, and a light condensing element 234 is disposed on each of the filter films 232. When the light 24 is incident from the outside, the light-concentrating element 234 can concentrate the light and make it incident through the filter film 232, and then be received by the photosensitive element 220 in the active layer 204a located below the filter film 232. In addition, the second substrate 206b is disposed above the optical element array 230, and is fixed above the optical element array 230 by a support 250 disposed on the second surface 202b of the silicon-clad insulating layer 202. In addition, the complementary metal-oxide-semiconductor image sensor is electrically connected to the circuit board 21 through, for example, a redistribution layer 216 on the image sensing element layer 204 and a bump 214 disposed on the redistribution layer 216. As shown in Figure 2F. From the above, it can be known that the complementary metal-oxide-semiconductor image sensor of the present invention can allow light to pass through the Wei hiding layer, and then be received by the light-sensitive element in the silk towel, and be converted into an electrical signal. Output to the board. Therefore, the present invention can solve the problem that conventional light is reflected by a dielectric layer or a metal layer, etc., thereby reducing the complementary metal-oxide-semiconductor image sensing. And the sense of image 丨 the complexity of the manufacturing process on the company's work. The thickness of the substrate of the metal oxide semiconductor image sensor is about "micro = gold == 14: wf.doc / 0〇6 1235490 13159t. The manufacturing process of the oxygen semiconductor image sensor is compatible with the known process, so the mother must In addition, new process equipment is developed. In addition, manufacturing complementary metal oxide semiconductor films according to the process of the present invention can also improve the yield in the process of the complementary metal oxide semiconductor image sensing terminal. Although the present invention has been described with preferred embodiments, The disclosure is as above, but it is not intended to limit it; the present invention 'any skilled artist, without compiling the spirit and scope of the present invention', should make some changes and retouching, so the scope of the present invention should be regarded as _ Full-time _ definer is fresh.… Only [schematic explanation] —The edge of the figure i is shown as f. The cross section of the complementary metal-oxide semiconductor image sensor is not intended. Figures 2A to 2E are not based on this. A schematic sectional view of the manufacturing process of a complementary metal-oxide-semiconductor image sensor according to a preferred embodiment of the present invention. FIG. 2F is a schematic diagram of the complementary metal-oxide-semiconductor image sensor shown in FIG. 2E disposed on a circuit board. Description of main component symbols] 100 、 260: complementary metal-oxide-semiconductor image sensors 102, 200: substrates 104, 204b: interconnect layers 110, 210: circuit boards 120, 220: photosensitive elements 130: microlenses 132: color filters 15 1235, 134 : Glass substrate 140, 240: light 150, 250: support 202 · silicon-coated insulating layer 202a: first surface of silicon-coated insulation layer 202b: second surface of silicon-coated insulation layer 204: image sensing element layer

204a: Active layer 204c: Solder pad 206a: First substrate 206b: Second substrate 214: Bump 216: Redistribution layer 230: Optical element array 232: Filter film 234: Condensing element

16

Claims (1)

12354¾¾ 59twf.doc / 006 10. Scope of patent application: 1. A method for manufacturing an image sensor, comprising: forming a stone-clad insulating layer on a substrate, wherein the silicon-clad insulating layer has a first surface and is in contact with the A substrate contacts a second surface; an image sensing element layer is formed on the first surface of the silicon-clad insulating layer; a first substrate is disposed on the image sensing element layer; the first substrate and the image The sensing element layer and the silicon-clad insulation layer are separated from the substrate to expose the second surface of the silicon-clad insulation layer; and an optical element array is formed on the second surface of the silicon-clad insulation layer. 2. The method for manufacturing an image sensor according to item 1 of the scope of patent application, further comprising disposing a second substrate above the optical element array. 3. The method for manufacturing an image sensor according to item 1 of the patent application scope, wherein after forming the optical element array on the second surface of the silicon-clad insulation layer, the method further comprises: A support is formed on the second surface; and a second substrate is disposed on the support. 4. The method for manufacturing an image sensor according to item 1 of the patent application scope, wherein after forming the optical element array, the method further includes removing the first substrate to expose the image sensing element layer. 5. The method for manufacturing an image sensor as described in item 4 of the scope of patent application, wherein after removing the first substrate, the method further includes electrically connecting the image sensing element 12354¾ 9twf.doc / 006 layer to a Circuit board. 6. The method of manufacturing an image sensor according to item 5 of the scope of patent application, wherein the step of electrically connecting the image sensing element layer to the circuit board includes: on the scene > image sensing element layer Forming a redistribution layer; and electrically connecting the redistribution layer to the circuit board. 7. The method for manufacturing an image sensor as described in item 6 of the scope of the patent application, wherein the steps of electrically connecting the rewiring layer to the circuit board include the following steps: A bump process is performed for the rewiring process. A plurality of bumps are formed on the wiring layer, and each of the bumps is electrically connected to the redistribution layer; and the bumps are electrically connected to the circuit board. 8. The method for manufacturing an image sensor according to item 丨 of the patent application, wherein the material of the first substrate and the second substrate includes glass. 9. The method for manufacturing an image sensor according to item 1 of the scope of the patent application, wherein the step of forming the optical element array on the second surface of the silicon-clad insulating layer includes: Forming a plurality of filter films on the second surface; and forming a plurality of light collecting elements, wherein each of the light collecting elements is disposed on one of the filter films. 10. The method for manufacturing an image sensor according to item 9 of the scope of the patent application, wherein the light-concentrating elements include a plurality of microlenses. U • The method of manufacturing an image sensor as described in item 1 of the patent application 18 12354¾ 59twf.doc / 006 method, wherein the step of forming the image sensor element layer includes: on the first surface of the silicon-clad insulation layer An active layer is formed thereon, and a photosensitive element has been formed in the active layer; an interconnect layer has been formed on the active layer, and the interconnect layer is electrically connected to the photosensitive element; and the interconnect A plurality of pads are formed on the layer, and each of the pads is electrically connected to the interconnect layer. 12. The method for manufacturing an image sensor according to item 11 of the scope of patent application, wherein the photosensitive element comprises a photodiode. 13. The method for manufacturing an image sensor according to item 1 of the scope of patent application, wherein after forming the optical element array, it further comprises performing a cutting process to form a plurality of single image sensors. 14. An image sensor comprising: a silicon-clad insulation layer having a first surface and a second surface; an image-sensing element layer disposed on the first surface of the silicon-clad insulation layer; an optical An element array is disposed on the second surface of the silicon-clad insulating layer; and a substrate is disposed above the second surface of the silicon-clad insulating layer, and the optical element array is located between the substrate and the silicon-clad insulating layer between. 15. The image sensor according to item 14 of the scope of the patent application, wherein the image sensing element layer sequentially includes the silicon-clad insulating layer: an active layer disposed on the first layer of the silicon-clad insulating layer On the surface; an interconnect layer is arranged on the active layer; and 19 I2354gQ9 twf.doc / 006 I2354gQ9 twf.doc / 006 Several pads are arranged on the interconnect layer, five females and one brighter The pad is electrically connected to the interconnect layer. The 15-layer image device is included, in which "the active layer that senses the 7C component layer includes a light-sensitive element." 如 7. If the scope of patent application is the 16th The image described in the item, the photosensitive element includes a photodiode. /, Τ The image sense described in item 14 of the patent scope ―, # The first learning 7L element array includes: a plurality of filter films; and 遽 光 ί = =: And each of these light-concentrating elements is arranged in the image sensing 11 described in item 18 of the scope of this application patent, in which the far-t optical element includes a plurality of microlenses. Including -2 ^ 2 Please paste Gu Di M rhyme-shaped miscellaneous devices, including ^ a building is arranged on the second surface of the wealth and wealth margin layer, It is connected to the substrate so that the substrate is fixed above the optical element array. The image sensor described in item M of the patent scope, including the heavy wiring layer, is arranged on the God-covered insulating layer. Above the first surface, and located above the image-forming device layer, it is f-connected to the pad. The image sensor described in item 21 of the scope of interest includes a plurality of bumps, which are arranged in the The redistribution layer is electrically connected to the redistribution layer.