TWI225221B - Capacitive fingerprint sensor against ESD damage and contamination interference and a method for manufacturing the same - Google Patents

Abstract

A capacitive fingerprint sensor against ESD damage and contamination interference includes a substrate, a plurality of plate electrodes, a metal mesh, a plurality of ESD units, a plurality of bonding pads, and a protection layer. The plate electrodes, bonding pads and metal mesh are positioned on the substrate at the same level, and are composed of the same material. The ESD units are connected to the metal mesh that is conducted to the ground, and are exposed via a plurality of first openings. Thus, electrostatic charges from a finger may be discharged through this path to the ground. The metal mesh is covered by the protection layer and is not exposed. The number of the ESD units is far less than that of the plate electrodes so as to reduce the contamination interference on the captured fingerprint image.

Description

1225221 V. Description of the invention (1) [Cross-reference materials] The invention of the invention is related to the Republic of China patent application assigned to the assignee of this case: |: J〇911_6 'The application is April 3, 2002, The name of the invention is: "Shicai read pattern read chip", the disclosure of which is incorporated herein by reference. [Technical Field to which Ming belongs] The present invention relates to a capacitive fingerprint sensor and a straight method, and more particularly, to a device capable of resisting electrostatic damage and preventing electricity and a method for manufacturing the same. Ding Zhizhi's electric valley-style sunburst feeling [Prior technology] The known fingerprint reading method can be used on paper, and then optically y ^ 3 earth and water fingers are pressed into the brain, and then the paper is described with the information to mark the paper. The biggest disadvantage of fingerprint input is the inability to compare text and graphics. However, the above methods have more and more real-time authentication parameters and processing purposes, so they cannot meet the needs of the more secure electronic products, while the two-network authentication 'e-commerce, and the instant fingerprint reader t: t identity authentication' security System and more. Surgery. Traditionally, Dou and J can be used as the key technology in the biometrics market. However, it has the disadvantage that the volume sensor is large enough to read fingerprints in real time. For this reason, the use of the silicon chip to overcome the above-mentioned two-chip fingerprint sensor of the optical type, the test, the capacitive fingerprint point is considered. Based on the structure of the Shixi integrated circuit manufacturing process, the capacitor Two ^ becomes the most direct and simple method. Arranging the array in an array manner 12 = When the sensor contains a plurality of capacitive sensing elements, the hand can be sensed; = the surface of the sensing element exposed to the outside is on the button pattern peak The capacitance curve left. Because the sensor

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Most of the area needs to cause the short circuit of the circuit, and the electrical processing appears to be exceptional image quality. Exposed to the outside world, any damage caused by or permanent damage. For this reason, it is important. In addition, it is necessary to take into account the antistatic effect on the surface of the sensor that may be near the charged body, to prevent residue interference, and to prevent the electrostatic damage of the fingerprint sensor. Please refer to "U.S. Patent No. 6,114,862" Announcement and Thomas in U.S. Patent No. 6, 5 1 5, 488, the disclosure of which is incorporated herein by reference. Please refer to Figures 1 to 3. The above-mentioned method for preventing electrostatic damage is to use enveloping ^ an electric f-type The sensing element is exposed to the tungsten metal mesh and connected to the ground terminal, which conducts the static electricity of objects close to it to the ground terminal. This design can effectively solve the electrostatic damage. However, this tungsten metal mesh The formation method and design department will lead to other problems. The plate electrode 丨 丨 2 and the tungsten metal mesh 丨 丨 3 are located above the substrate 110, but they are located at different heights, and are made of different materials in different manufacturing steps. Formation. During the deposition of tungsten metal and subsequent etch-back steps, many small holes 1 08 are formed on the protective layer of the sensor surface, causing defects and causing problems such as stress concentration. When the finger nails are not careful Impact sensing When the outer surface is 1.09, the sensor will be damaged. In addition, the structure of the tiny holes 108 will make the surface of the protective layer hydrophilic, so when the moisture of the finger contacts the outer surface 109, it will spread. This further deteriorates the image quality. To this end, Thomas proposed to fill the aforementioned small holes 108 with the oxide stone 107 by the deposition of silicon oxide and the subsequent chemical mechanical polishing (CMP) process. The flat outer surface is 109. However, this makes the manufacturing process too complicated and is not suitable for general commercial wafer foundry manufacturing. In addition, the above-mentioned technology has caused the problem of finger stains that disturb the image quality.

1225221 V. Description of the invention (3) As shown in Figure Λ, U finger 1 (considered as a virtual ground terminal) touches the sensor = 1 # 2 /, 1 疒, the induced capacitance formed by the ripple 11 and the plate electrode 112 and The induced capacitance value formed by the plate electrode 112. Finger 1]: 1 ^ can be penetrated through the tungsten metal mesh 113 and put 1, this completely exposed tungsten gold capacity 115 and more than L are grounded from the residue 114 of the finger, which indirectly forms the residue valley 115 and interferes Image quality, as shown in Figure 3. [Summary of the Invention] One purpose of anti-residue: 2 、, t is to provide a capacitive fingerprint sensor capable of resisting electrostatic damage and residual π interference, and a manufacturing method thereof. The present invention provides an electric valley-type fingerprint sensor capable of resisting static electricity damage and preventing interference from residual electricity. The fingerprint sensor includes a substrate including a stone substrate, a plurality of flat mines, and a, -The element of the circuit, a plurality of pads and a protection sound: ㈡: two or more electrostatic discharge sheets are formed on the substrate. ; All genus are arranged in an array between the electrodes and are flush with these flat electrodes ::: 海 4 千 板 Smoke, fish :: cake. The electrostatic discharge cells are connected to the metal grid and formed between the pre-metal plate electrodes in the plate electrodes. The number of the electrostatic discharge cells is less than the flat

Head: A plurality of welding pads are used as the capacitive fingerprint sensing J output knife. The protective layer is completely covered on the flat screens and partially covers the electrostatic discharge sheets S and the two gold 2 to form a plurality of first-patterns on the electrostatic discharge cells, which are formed on the solder pads. The plurality of second openings are annihilated in the size of each of the second openings. Brother-the size of the opening is less than page 9 1225221

In order to prevent residue, the following layers are included: pole-shifting, metal laminated resisting layer; mouth to discharge the second power-on to the exposed window at each of these [implementing the interference steps: except part of the network, and the light based on the light to make the The number of openings is guaranteed, and the unit is opened by the second method.] The purpose of the capacitor is to deposit a resistive layer-shaped protective layer on a plurality of metal plates in one from the protective layer into the first opening to make these first openings. 'The fingerprint of this hair contains a stacked body, electrostatic discharge is a guarantee of a plurality of these first-line dry mouths, and Ming also provides an antistatic method, the silicon base of the circuit of the basic tester to form the above electrical unit and A protective layer; forming a plurality of flat welding joints on the first window, a window, and the damaged and metal-clad laminate on the second window plate of Jinchengguangguang; the upper layer of the protective layer and a plurality of welding pads Wait for the second window to be exposed; Surname carved, corresponding to the pads to be exposed from the second opening, each inch; and Remove the light so that the mouth corresponding to the second window is exposed, so that the first Plural The isostatic small size of the opening of the first resist layer. Fig. 4 shows the unintended use of the capacitive fingerprint sensor of the present invention to read finger prints. As shown in FIG. 4, the fingerprint sensor 2 includes a plurality of capacitive sensing elements 20 arranged in a two-dimensional (2D) array. When the finger 1 contacts the sensor 2, the irregularly shaped Ridge 11 on the surface of the finger 1 will contact a part of the capacitive sensor 20, and a capacitance value curve 11a will be left on the sensor 2. By reading the capacitance value curve Ua; f-shaped V, the shape of the original ripple peak 11 can be identified. FIG. 5 is a schematic partial plan view of a capacitive fingerprint sensor according to a first embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the capacitive fingerprint sensor taken along line 6-6 of FIG. 5. As shown in Figures 5 and 6, the capacitive fingerprint of the present invention

1225221 V. Description of the invention (5) — The sensor 2 basically includes a silicon substrate 21 containing integrated circuits, a plurality of plate electrodes 22, a metal mesh 23, a plurality of electrostatic discharge cells 24, and a plurality of solder pads 25 , And a protective layer 26. The plate electrodes 22 are formed on the substrate 21 in an array. The metal mesh 23 is formed between the flat electrodes 22 and is flush with the flat electrodes 22 and surrounds each of the flat electrodes 22. In detail, the metal mesh 2 3 is arranged vertically and horizontally in the gap between the flat electrodes 22. The plate electrodes 22 and the metal meshes 23 are separated by a predetermined distance. The pads 25 are used as input and output portions of the capacitive fingerprint sensor 2. The metal net 23 is connected to a ground terminal GND, which is mainly to introduce static electricity to the ground terminal GND to avoid the sensor from being damaged by static electricity. The electrostatic discharge units 24 are connected to the metal net 23 and further connected to the ground terminal. The distance D between the adjacent electrostatic discharge cells 24 is much larger than the distance between the adjacent plate electrodes 22, so the number of the electrostatic discharge cells 24 is much smaller than the number of the plate electrodes 22. The protective layer 26 completely covers the flat electrodes 22 and the metal mesh 23, and partially covers the electrostatic discharge cells 24 and the pad supports. The protective layer 26 is formed on the electrostatic discharge cells 24, and forms a plurality of first layers on the pads 25.

It is worth noting that the size of each of the first openings 27 is much smaller than the size of each of the second openings 28. The J-compliant layer 26 is typically a protective dielectric layer for a CMOS process. The conventional material can be a stack of silicon oxide and silicon nitride, and its thickness varies depending on the selected process, usually between micrometers. However, in order to increase the lifetime of the fingerprint sensor and anti-static damage, a high hardness can also be added.

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Layer (in this embodiment, it is diamond-like carbon film (diamond-like carbc) nfi 1 m) and slavery; Mayan film, may also be barium titanate film, titanium titanate film and oxide button film, etc. ) On the protective layer 26, and its thickness may be between 0.3 and 2 microns. It is clear from Fig. 5 that in order to make the electrostatic discharge unit 24, the present invention sacrifices the sensing area of some flat electrodes without affecting the sensing effect. Therefore, the plate electrodes 22 include a plurality of sacrificial electrodes 22s and a plurality of standard electrodes 22N. The sacrificial electrodes 2 2S are adjacent to the electrostatic discharge cells 24 and the size of each of the sacrificial electrodes 2 2 S is smaller than that of each. Size of standard electrode 22N. In this embodiment, each of the electrostatic discharge units 24 is connected to only one

The two sacrificial electrodes 2 2 S are adjacent. Therefore, among the nine plate electrodes 22, there is only one sacrificial electrode 2 2 S. The plate electrode 22 and the metal mesh 23 may be made of the same material. For example, the plate electrode 22 and the metal mesh 23 may be an aluminum metal laminate 30 or a copper metal laminate. The aluminum metal stack 30 is the topmost metal film in the integrated circuit manufacturing process. In this embodiment, the area of the flat electrode 22 is about 40 microns * 40 microns, the area of the capacitive sensing element 20 is 50 microns * 50 microns, and a sensing capacitance is formed between the flat electrode 22 and the finger 1. The metal nets 2 and 3 are used for electrostatic protection.

When a finger approaches the sensor, static electricity can flow from the first opening 27 to the ground terminal GND through the metal net 23. In this embodiment, the optimization distance D between two adjacent electrostatic discharge cells 24 is 500 to 100 μ. FIG. 7 shows an enlarged schematic view of the bonding pad of FIG. 6. FIG. 8 shows an enlarged schematic view of the discharge cell of FIG. 6. As shown in FIGS. 7 and 8, the aluminum metal stack 30 includes a titanium layer 51 on the substrate 21 and an aluminum alloy layer on the titanium layer 51.

Page 12 I22522l 5. Description of the invention (7) 52 'and a titanium nitride layer 53 on the aluminum alloy layer 52. The aluminum alloy layer 52 is exposed through each of the first openings 27. Each pad 25 includes a titanium layer 51 located on the substrate 21, a bonding gold layer 52 located on the titanium layer 51 and exposed through each of the second openings 28, and located on the aluminum alloy layer 52 and surrounding Each of the second openings 28 is a titanium nitride layer 53. It is worth noting that due to the characteristics of the etching process described below, the intermediate thickness T1 of one of the titanium nitride layers 5 3 in each of the first openings 27 is smaller than the peripheral thickness T2 of one of the titanium nitride layers 53. The titanium nitride layer 53 in each of the second openings 28 is substantially completely removed. FIG. 9 is a schematic top view of a capacitive fingerprint sensor according to a second embodiment of the present invention. The sensor of FIG. 9 is similar to that of FIG. 5 except that each of the electrostatic discharge cells 24 of FIG. 9 is adjacent to only two sacrificial electrodes 22S. That is, two adjacent plate electrodes 22 each sacrifice one area for use by the electrostatic discharge unit 24. FIG. 10 shows a top view of a capacitive fingerprint sensor according to a third embodiment of the present invention. The sensor of FIG. 10 is similar to that of FIG. 5 except that each of the electrostatic discharge cells 24 of FIG. 10 is adjacent to only four sacrificial electrodes 22s. That is, each of the four adjacent plate electrodes 22 sacrifice one area discharge cell 24 for use. Figures 11 A and 1 1 B show the lightning crosses of the present invention, respectively. This "a. ,, ^ β < Otani-type fingerprint sensor before and after the application of static electricity. Results of this" ... ,, the test conditions for this product are all applied 10 times in air mode + ay rate is W. As shown in Figures m and 11B, the damage of the two-frequency interval display indicates that the sensor can still operate normally. Therefore, the electrostatic discharge (ESD) protection of the wooden invention well pattern sensor can reach six p ^^^, and this force can already reach more than 20k.

1225221 V. Description of the invention (8) And the internal circuit sensed will not be damaged. Figures 12A to 12E show the manufacturing steps of the capacitive fingerprint sensor of the present invention, respectively. Referring to Fig. 12A ', a metal stack 50 is first formed on a silicon substrate 21 containing integrated circuits. ... Next, please refer to FIG. 2β, a part of the metal stack 50 is removed to form a plurality of plate electrodes 2 2, a metal mesh 2 3, a plurality of electrostatic discharge cells 24, and a plurality of pads 25. The structure of the above components and their relationships have been described above, and will not be described in detail here. However, referring to FIG. 12C, a metal retaining layer 26 is deposited on the metal stack 50 and the substrate 21. In this embodiment, the structure of the protective layer 26 includes an oxide layer and a stack of a silicon nitride layer. Therefore, a silicon oxide layer can be deposited on the metal stack 50 and the substrate 21, and then a nitride layer can be deposited on the silicon oxide layer. Then, please refer to FIG. 12D, a photoresist layer 40 is formed on the protective layer 26, and then a plurality of first windows 41 and a plurality of second windows 42 are formed on the photoresist layer 40. The protective layer 26 is exposed from the first windows 41 and the second windows 42. Then, referring to FIG. 12E, the exposed protective layer 26 is dry-etched to form a plurality of first openings 27 corresponding to the first windows 41 and a plurality of second openings corresponding to the second windows 42 28, and the pads 25 are exposed through the second openings 28, and the electrostatic discharge cells 24 are exposed through the first openings 27. The size of each of the first openings 27 is much smaller than that of each of the second openings 28. Of the size. In this dry etching process, the complete removal position =

1225221 V. Description of the invention (9) At the same time as the titanium nitride layer 5 3 in the second openings 28, one part of the titanium nitride layer 5 3 in the first openings 27 can be removed. So that the intermediate thickness T 1 of one of the titanium nitride layers 5 3 in each of the first openings 27 is smaller than the peripheral thickness T 2 ′ of one of the nitride layers 5 3 as shown in FIG. 8. It is worth noting that the protective layer 26 may further include the above-mentioned high hardness layer, which is located on the titanium nitride layer 53. In this case, the high-hardness layer can be regarded as a part of the protective layer 26. Then, the photoresist layer 40 is removed to form a structure as shown in FIG. 6. With the above structure and method, since the metal mesh 23 is designed under the protective layer 26, the protective layer 26 will not be exposed to the etching environment after the deposition is completed. Even in the process of forming the openings 27 and 28, the protective layer 26 is protected by the photoresist layer 40, so there is no damage. As a result, the surface of the protective layer 26 does not have tiny holes like the conventional technology, which may easily cause stress concentration, surface hydrophilicity, ESD damage, improper use, and residual interference with the image. In addition, the first opening 27 for the electrostatic discharge unit 24 is designed in the same mask as the second opening 28 for the pad 25, but the size is quite different. For example, the size of the first opening 27 is usually 5 to 10 microns, and the size of the second opening 28 is usually 100 to 150 microns. Therefore, in the process of opening formation, not only the protective layer 2 6 can be completely removed to form a second opening 2 8, but the uppermost titanium nitride layer 5 3 can also be completely removed so that the aluminum alloy layer 5 2 is completely exposed. , In order to facilitate subsequent threading actions. ‘The artisan should easily understand that the dry etching method used to form the openings has a loading effect (10ading ef f ect), that is, the opening

1225221 V. Description of the invention (10) The smaller one, the slower the etch rate is, the lower the retention rate is about 0.1 micron). From the long-term use, suitable for violent static electricity, it can be connected to the ground through the 52 connection. The above-mentioned process design know-how, and the process and materials can be used to make not only a few electrostatic discharge cell contamination of the advantages of the present invention. Most of the residues are also a lot of residue capacitors in the preferred embodiment to facilitate the description of the present invention to the above embodiment, and in the case where it is not the case, it is done. The present invention makes use of this characteristic, because the titanium nitride layer 5 3 (thicker than the titanium nitride layer 5 3) in a part of the first opening 27 is not easy to be oxidized, is resistant to corrosion, and is suitable for exposure to the air. The first opening 27 near the sensor, the titanium nitride layer 5 3, and the aluminum alloy layer are used to avoid electrostatic damage. The heart does not need to use the standard lumens of the aforementioned all-utilized commercial integrated circuit factory with high complexity The sensor lies in the ESD protection ability. At the same time, ESD protection can be completed only by using a long distance. Even if there is residual independence after use, it is not connected to the metal mesh 2 3 to reduce the interference caused by the image. The specific embodiments proposed in the present invention are only used for technical content, rather than narrowly limiting the present invention beyond the spirit of the present invention and implementing the following application variants, which are all within the scope of the present invention.

Page 16 1225221 Brief Description of Drawings Figure 1 shows a schematic diagram of the upper surface of a conventional fingerprint sensor. FIG. 2 shows a schematic diagram of a conventional fingerprint sensor in contact with a finger. FIG. 3 is a schematic diagram showing a stain remaining on the fingerprint sensor of FIG. 2. FIG. 4 shows a schematic diagram of reading a finger print using the capacitive fingerprint sensor of the present invention. FIG. 5 shows a partial plan view of the capacitive fingerprint sensor according to the first embodiment of the present invention.

FIG. 6 shows a schematic cross-sectional view of the capacitive fingerprint sensor along line 6-6 of FIG. 5. FIG. 7 shows an enlarged schematic view of the bonding pad of FIG. 6. FIG. 8 shows an enlarged schematic view of the discharge cell of FIG. 6. FIG. 9 shows a plan view of a capacitive fingerprint sensor according to a second embodiment of the present invention. FIG. 10 shows a schematic top view of a capacitive fingerprint sensor according to a third embodiment of the present invention. 11A and 11B show the sensing results of the capacitive fingerprint sensor of the present invention before and after being subjected to static electricity, respectively.

Figures 12A to 12E show the manufacturing steps of the capacitive fingerprint sensor of the present invention, respectively. [Explanation of Symbols of Components] 1 ~ finger 2 ~ capacitive fingerprint sensor 1 1 ~ ripple 11 a ~ capacitance curve

1225221 on page 17 Brief description of the drawing 12 ~ Moniya 20-, capacitive sensing element 2 substrate 22 ~, flat electrode 22N ~ standard electrode 22S ~ 'sacrificial electrode 23 ~ metal mesh 24 ~ electrostatic discharge port — early 25 ~ pad 26 ~ protective layer 27 ~ first opening 28 ~ second opening V 30 ~ aluminum metal laminate 40 ~ photoresist layer 4 first window 42 ~ second window 50 ~ metal laminate 51- titanium layer 52 ~ Aluminum alloy layer 53 ~ Titanium nitride layer 107 ~ Silicon oxide 108 ~ Hole 109 ~ Outer surface 110 ~ Substrate 111 ~ Protective layer 112 ~ Plate electrode 113 ~ Tungsten metal mesh 114 ~ Residue 115 ~ Residual capacitor

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Claims (1)

1225221 Capacitive fingerprint sensing of dirt interference 1 · An anti-static damage and anti-resistance device, including: a silicon substrate containing integrated circuits; a plurality of flat electrodes arranged in an array; The substrate metal mesh is arranged horizontally and horizontally between the flat planes and flat planes. It is located between the ten plate electrodes and is flush with the ten plate electrodes, and surrounds each of the flat plate ground ends. Θ Connect to one 2 electrostatic discharge cells are connected to the metal mesh and are formed in the thunder ::? Between a predetermined number of adjacent plate electrodes in the electrode, the number of the static double electric early cells is less than the number of the plate electrodes; a plurality of pads are used as the input spot output portion of the capacitive fingerprint sensor; And ^ a protective layer completely covering the flat electrodes and the metal mesh, and partially covering the electrostatic discharge cells and the pads, thereby forming a plurality of first openings on the special electrostatic discharge cell And a plurality of second openings are formed on the pads, and the size of each of the first openings is smaller than the size of each of the second openings. 2 · The capacitive fingerprint sensor capable of resisting static electricity damage and preventing interference from interference as described in item 1 of the scope of patent application, wherein the flat electrodes and the metal mesh include the same material. 3. The capacitive fingerprint sensor capable of resisting electrostatic damage and preventing interference from interference as described in item 2 of the scope of the patent application, wherein each of the flat electrodes includes a fresh metal stack. Page 19, 1225221 6. Scope of patent application 4. As described in item 3 of the scope of patent application, a capacitive fingerprint sensor that can interfere with γ ^ pollution, electrical damage and anti-residue-a titanium layer is located on the substrate 〃 ... The Lu metal stack includes: an aluminum alloy layer on the titanium layer; and a titanium nitride layer on the aluminum alloy layer to be exposed. 〇 At the ceremony, and each of the first openings 5 · As described in the second item of the patent scope of Shenyan, κ + fouling interference can be checked, rV ,,, T antistatic damage and anti-residue metal ΐί sensor, where each of the plate electrodes contains-copper fouling 6 can prevent anti-static damage and prevent sacrificing electric sacrifice and ί f sensors' where the plate electrodes contain a plurality of electric standards , The dimensions of the sacrificial electrodes are the same as those of the l electrodes, and the size of each of the sacrificial electrodes is smaller than each of the standard electricity. In the capacitive fingerprint sensor, each of the electrostatic discharge cells is adjacent to only one sacrificial electrode. 8. A capacitive fingerprint sensor capable of resisting electrostatic damage and preventing interference as described in item e of the scope of patent application, wherein each of the electrostatic discharge cells is adjacent to only two sacrificial electrodes. A 9 • As described in Item 6 of the declared patent scope, an electric valley-type fingerprint sensor capable of resisting static electricity damage and preventing residual interference, wherein each of the electrostatic discharge cells is adjacent to only four sacrificial electrodes. / 1〇 · Anti-static damage and anti-residue as described in item 6 of the scope of patent application 20th tribute 1225221 6. Scope of patent application > Interference-capable capacitive fingerprint sensor, where the protective layer is a stack of _ silicon oxide layer and a silicon nitride layer: as in the patent application scope item 6 In the capacitive fingerprint sensor capable of resisting static electricity damage and preventing residual π interference, a distance between two adjacent cells is substantially between 500 μm. East Discharge Early, -12. The capacitive fingerprint sensor capable of resisting electrostatic damage and preventing residual / defective interference as described in item 1 of the scope of patent application, further comprising: ^ m Ίhardness layer on the protective layer The high-hardness layer includes one selected from the group consisting of a carbon film, a silicon carbide film, a barium titanate film, a gill titanate film, and an oxide button film. One device U ·: A capacitive fingerprint sensing & method capable of resisting static electricity damage and anti-fouling interference, including the following steps: = forming a metal stack on a silicon substrate containing integrated circuits; removing Part of the metal stack is formed to form: "upper hard plate electrodes" are formed on the substrate plate array in an array arrangement. Ϊ ::: = interposed between the plate electrodes and static electricity with the plural ; = Each ::: pole; the predetermined I of the plate electrode is connected to the metal mesh and formed between adjacent plate electrodes of the discharge cell m 3?, The static electricity: less than the plates The number of electrodes, and several pads, as the number and part; hinder the input and output of the electric valley fingerprint sensor from depositing a protective layer on the metal stack and the μ substrate; 1 Page 21 1225221 Sixth, the scope of the application for a patent forms a photoresist layer on the protective layer; a plurality of first windows and a plurality of second windows are formed on the photoresist layer so that the protective layer is separated from the first windows And expose the second windows; dry-etch the exposed protective layer to form a plurality of first openings corresponding to the first windows and a plurality of second openings corresponding to the second windows, so that The pads are exposed through the second openings, so that the electrostatic discharge cells are exposed through the first openings, and the size of each of the first openings is smaller than the size of each of the second openings; 14. The method for manufacturing a capacitive fingerprint sensor capable of resisting static electricity damage and preventing residue interference as described in item 13 of the scope of the patent application, wherein the step of forming the metal stack on the substrate includes the following steps: A titanium layer is formed on the substrate; a Shao alloy layer is formed on the titanium layer; and a titanium nitride layer is formed on the alloy layer. 1 5. The method for manufacturing a capacitive fingerprint sensor capable of resisting static electricity damage and preventing interference from interference as described in Item 13 of the scope of patent application, wherein the step of dry etching the exposed protective layer includes the following steps : Substantially completely removing the titanium nitride layer in the second openings; and removing a portion of the titanium nitride layer in the first openings so that in each of the first openings An intermediate thickness of one of the titanium nitride layers is smaller than a peripheral thickness of one of the titanium nitride layers. 1 6. Anti-static damage and anti-residue as described in item 13 of the scope of patent application Page 22 1225221 6. A method for manufacturing a capacitive fingerprint sensor with pollution interference in the scope of patent application, wherein the step of depositing a protective layer on the metal stack and the substrate includes: depositing on the metal stack and the substrate A silicon oxide layer; and depositing a silicon nitride layer on the silicon oxide layer. 1 7. The method for manufacturing a capacitive fingerprint sensor capable of resisting electrostatic damage and preventing interference from interference as described in item 16 of the scope of patent application, wherein the step of depositing a protective layer on the metal stack and the substrate The method further includes: depositing a high-hardness layer on the nitrided layer. 18. The method for manufacturing a capacitive fingerprint sensor capable of resisting static electricity damage and preventing interference from interference as described in item 17 of the scope of patent application, wherein the high-hardness layer comprises a diamond-like carbon film or a silicon carbide film , A barium titanate film, a strontium titanate film, and a tantalum oxide film. Page 23