TW535230B - Method of forming multi-layered micro-machine structure on IC chip surface - Google Patents

Abstract

The present invention provides a kind of method for forming multi-layered micro-machine structure on IC chip surface. In the invention, the press fit process of dry-film, laser processing and nickel plating process are conducted repeatedly by deep carving of excimer laser together with the precise electroplating method. At last, the entire dry-films are removed to form a multi-layered metal micro-machine structure and complete the integrated micro-mechanical device. The manufacturing method of the present invention is simple such that it is capable of greatly decreasing the chip area for lowering the production cost and can be used in any integrated circuit process.

Description

535230 V. Description of the invention (1) Field of the invention: The present invention relates to a method for manufacturing a micromechanical structure, in particular to a method for forming a multilayer metal micromechanical structure on the surface of a wafer, for application to sensing elements and radio frequency components. Or micro-electro-mechanical components such as optical components. Background of the Invention: With the rapid development of science and technology, products continue to develop light, thin and short, resulting in micro-system technology that is required by the next generation of industry. Integrating Micromechnical Devices and related sensing or control circuits on a single chip can greatly reduce costs and increase competitiveness. In general, 'integrated integrated circuit lithography, electrochemical technology, and molecular molding technology in microsystem technology's deep electroforming mold LI ga (Lithography' Electroplating 'Micromoiding)' is the most popular method for mass-producing MEMS components One of the best methods is to fabricate a nickel metal structure on the surface of an IC chip to achieve the above objectives. Because the l I technology is a low-temperature process, it will not affect the completed 1C, and this manufacturing method is not only simple, but also can significantly reduce the wafer area to reduce costs, and at the same time, the alloy has low stress (providing large-scale components such as scanning Mirror surface), high strength and high density (providing greater quality such as inertial sensing), can be used as a variety of micro-electro-mechanical components than silicon materials. See

Patent citations such as W0 89/0 1 632, US 5,5 95,940 and US 6,290,8 ^ 8M. ’Among them, the method disclosed in the WO 89/0 1 632 patent case uses χ_ light as the exposure source of L I G Α to produce a microstructure with sub-micron accuracy, but because

Page 4 535230 V. Description of the invention (2) High cost: The procedure is complicated and the time duration is long. It is not generally available [light small / ', and the required X-ray mask is difficult to make and expensive. = And US 6,29G, 8 The method disclosed in the patent case of Figure 8 uses UV exposure and plasma etching to complete deep actions. The performance is quite complicated, and plasma etching cannot achieve a high aspect ratio. Special applications , Such as larger sensing capacitance. The above methods are not easy to provide the manufacture of multi-layer metal structures, and more ... the method of design and use flexibility. Therefore, the multi-layered micro-mechanical system of the present invention is constructed in the absence of IC, M, and λα + species. Maple ,, and mouth structure method to effectively overcome the above-mentioned object of the invention. This chip is used in IC chip technology. It is used in IC crystallization. The microcomputer is used in IC chip. It can be large enough to achieve metal and photosensitivity. To form the step and outline the main surface of the chip surface of the electrical components on the other surface of the circuit to reduce the width of the circuit and the above-mentioned welding pad and film; to connect the ladder-shaped junction to the purpose method, 'to complete or system-purpose method, wafer surface area. The purpose of protecting the system is to provide a system that integrates the system with a high level. The system provides the system with a volume and a decrease. The excimer laser of the substrate of the present invention out of the metal forms a multilayer micromechanical structure excimer laser. Processing and electroforming technology / single aspect ratio and high precision characteristics form a multilayer micro-mechanical structure. The clothing is simple in length and can increase the cost of the process bomb. It can be applied to 4 layers on a semiconductor substrate surface and the substrate. Surface formation: t remove part of the photosensitive dry film and dry the perforated area; and then deposit the electroforming starting layer on the positive surface of the photosensitive dry film and metal pad on the 535230 V. Description of the invention (3); A metal structure is grown in the perforated area; finally, the photosensitive dry film is removed to obtain a single-layer micromechanical structure. In another aspect of the present invention, the dry film lamination, laser processing, and electroforming processes are repeatedly performed until a predetermined number of metal structure layers are made, and then all the photosensitive dry films are removed to form a multilayer. Metal micromechanical structure.

In the following, detailed descriptions will be made with specific embodiments and accompanying drawings to make it easier to understand the purpose, technical content, features and functions of the present invention. Description of drawing number: 12 protective layer 16 nickel metal structure 20 photosensitive dry film 2 0 4 perforated area 2 4 nickel metal structure 2 6 2 stepped structure 28 electroforming starting layer 32 double-layer metal micromechanical structure 10 semiconductor substrate 14 metal welding Pad 18 Nickel metal structure 2 0 2 Stepped structure 22 Electroforming starting layer 26 Photosensitive dry film 2 6 4 Perforated area 30 Nickel metal structure

Detailed description: The first figure is a schematic diagram of forming a metal micromechanical structure on the surface of an IC wafer according to the present invention. As shown in the figure, a semiconductor substrate 10 including a sensing and control integrated circuit is usually a silicon substrate. It can also be other non-silicon substrates. 'Substrate 1 0 The exposed surface is the protective layer 12 and the metal welding pad 1 4' metal.

Page 6 535230 V. Description of the invention (4) Ή1 surface is determined by the integrated circuit manufacturing process, which is usually inscribed metal.不定 # F, Mon structures 16 and 18 are formed on the substrate by providing bare metal pads 14 and at the same time, T substrate 1 0 is also connected by metal pads 14 Integrated circuit. The advantage of this manufacturing method is that it is suitable for any integrated product: and; the metal structure is completely suspended above the wafer, and the circuit with a large floating height ',', ~ μ can be completely made under the metal structure, so it can be People's 2 large festivals, where the wafer area after completion, reduces costs. At the same time, nickel and nickel 3 gold materials can achieve low stress, which can be used to produce large-area micro-electromechanical components, such as micro-scanning mirrors of optical elements; the high strength and ductility of the metal can avoid the fracture problem of brittle materials, and the nickel The density is greater than 8 grams / cubic centimeter), which is much larger than Shixi's 2.3g / cm3. In addition to the south aspect ratio (> 丨) provided by UGA technology, the present invention is used as an inertial sensor, such as an accelerometer and a gyroscope. It can provide a large mass and a large initial capacitance value to increase the sensitivity of the stem and the q value of the system. In addition, the evening plane nickel metal structure provided by the embodiment of the present invention can also use nickel metal as a support structure. A layer of steel or gold is formed on the surface of nickel as radio frequency (Radi〇Frequency) elements, such as u inductor (miCroinductor), radio frequency switch (π SWltchL or phase array antenna), etc. Now ~ the above structure comes Illustrating the manufacturing method of the present invention, please refer to FIGS. 1A to 1I, which are cross-sectional structural views of steps in fabricating a multilayer micromechanical structure on the surface of an IC wafer according to a preferred embodiment of the present invention. As shown, the main method of the present invention includes the following system steps: A second reading wheat figure, first, there is provided a sensing and control comprising

Page 7 535230 V. Description of the invention (5) Semiconductor substrate 10 including integrated circuits, the semiconductor substrate 10 is shown on the table ^ metal pads 14 and the protective layer 12 protecting the substrate 10, metal welding ^ ^ 5 It is determined that the integrated circuit manufacturing process is usually a junction metal; tightly "by 4 = printed circuit board manufacturing method" is formed on the surface of the semiconductor substrate 丨 0 _ dry film 20 (such as Hitachi Chemical Co. HN650 series products) In order to cover the metal pad 14 and the protective layer 12; the photosensitive dry film 20 series 3σ is formed by the two-dimensional material on the semiconductor substrate 10 by hot pressing method, and requires the traditional photoresist coating to quickly It is simple and convenient. Furthermore, the hot pressing method provides two planarization processes, and the subsequent requirements for the flatness of the microstructure manufacturing are easy. The thickness of the photosensitive dry film 20 is between 20 and 5. Micrometers make the microstructure formed: between the substrates. The distance is large, the microstructure will not adhere to the wafer due to the liquid surface tension (in the final dry film process), and the capacitance effect between the microstructure and the substrate is also greatly reduced, λ (this will affect the sensing And RF component design are important As shown in the second figure I, excimer laser (wavelength 248-) is used to process :: the feeling of wounding * dry film 20 ′ to form a stepped structure 202 and expose the Ϊ f: Τ 田 4 ff 孔 区 204 ′ and the step-like structure 202 is formed after processing :: using the energy of the branch: or less time. Its *, the quasi-sensitive dry film 20 is directly removed: m spoon method, The polymer (including photoresist coating, soft baking :: "the above-mentioned second-stage photosensitivity during the complicated steps of exposure and development of the resist; film = shadow, fixing, and hard baking) can be used in the same two photomask processes, and this m: -The general exposure process requires two graphics. The addition method only needs to be covered with a private mask on the same mask (the mask is moved and the workpiece is moved 535230. 5. Description of the invention (6) Functions are all excimers The basic function of a laser processing machine), and the processed dry film 20 can achieve a relatively high aspect ratio (greater than 10), that is, the aspect ratio of the perforated area 2 0 4 to fully meet the design of the microstructure And application, please refer to the attached document Bruce C · S. Chou (周正 三) et al. Study of PMMA on Microstruct uring as a KrF excimer laser LIGA mater ia 1 o Please refer to Figure 2C, using physical vapor deposition method to form an electroforming starting layer (Seed Layer) 22 on the top surface of the semiconductor substrate 10 Part of it is formed on the front surface of the bare metal pad 14, partly formed on the front surface of the stepped structure 202, and partly formed on the outermost surface of the photosensitive dry film 20. The material of the electroforming starting layer 22 is a nickel / titanium or nickel / chromium two-layer metal. Among them, titanium, and chromium are used as an adhesion layer. Next, an electroforming process is performed, and the substrate is placed in an electroforming solution with an amino group: metal is passed through the electrode 14 to give a current, so that the nickel metal structure 2 4 begins to grow in the inner hole, as shown in the second figure. As shown, wait until the three-layer metal contacts the stepped structure 002 of the electroformed starting layer 22 '. The plane of the temple continues to grow, and the ancient remains of Dingxian & As far as the problem is concerned, this nickel metal structure 24 series 1 is a suspended ocean micromechanical structure. Can be done. After the above-mentioned manufacturing process, if the photosensitive dry film 20 is removed, it is even more: no — :: metal micromechanical structure. However, according to the manufacturing method of the present invention, "Γ" shown in the second diagrams A to D can be repeated to form a multilayer nickel metal micromechanical structure. This multilayer mechanical structure is used for conventional use. X-ray or uv_ light exposure is equivalent, V is due to the completion of the second photoresist coating, soft baking, exposure

Page 9 535230 V. Description of the invention (7) Light, development, fixing and hard roasting, but not the scene {the photoresist structure left over from the previous time is not easy '' so the conventional technology only emphasizes the production of a single layer structure . After the first layer of nickel metal structure 24 is completed in the present invention, the first layer of metal structure can be fabricated thereon. Please refer to the second figure E, and then form another photosensitive dry film 26 on the surface of the photosensitive dry film 20 and the nickel metal structure 24 by hot pressing. The manufacturing method is the same as the method of forming the photosensitive dry film 20 above. I will not repeat them here. The area of the connection part 2 6 4 Although the positive metal junction of the substrate is shaped and the solution begins to grow to growth, it is isomorphic 30 / body 0. Please refer to the figure below, using excimer laser plus-▼ Μ, ν- The photosensitive dry film 26 is removed to form a stepped structure 262, and the perforated region 1 exposes a part of the nickel metal structure 24. Then, an electroforming starting layer 28 is formed on the semiconductor by a vapor deposition method, as shown in the second G diagram, which is partially formed on the exposed structure 24 and partially formed on the stepped structure 262 ^ It is formed on the outermost surface of the photosensitive dry film 26. On the surface and after, the semiconductor substrate was placed on the amino group, and a current was passed through the metal pad 14 so that the electric power of f was grown, and a two-layer nickel metal structure 30 ′ was grown in the tooth hole area 2R4. For example, the second record of the order belongs to the temple. The I Φ that touches the stepped structure 262 grows up to a defined height as a floating micromechanical surname hibiscus. This nickel metal knot卞 ... Combined with the nickel metal structure 24

After removing all the photosensitive dry film 20, take a picture of 〆Τ-^ ung Wu 朕 ζ υ, zb, you can π w 丄 iridium 1 and other examples & 丨 J to Rudi Suo; 9 belong to政 机械 结构 3 2 ， This 钍 椹 你 # Figure is not the structure. In addition, the structure of 々% is the same as that of the first "， 3, with multiple layers (greater than or equal to "

Page 10 535230 V. Description of the invention (8) The manufacturing steps are designed to be re-produced so that it can be shaped. Therefore, the lack of laser processing and hot pressing with high-precision special films is simple and large. This is the above point. 'Its purpose is based on the fact that according to the present invention, the dry film lamination, laser processing, and nickel electroforming are covered in the present invention, and after the number of layers of the micromechanical structure is removed, all the photosensitive dry films are removed to form ~ Multi-layer recording metal micromechanical structure. The greatest spirit of the manufacturing method of the present invention is to integrate the excimer electro-detection technology on the surface of the IC wafer to complete a single-crystallized micro-electro-mechanical device or system with high aspect ratio. Removal can not only effectively overcome, increase process flexibility, reduce costs, but also has a process two = 1, the area of the positive film, and is applicable to any integrated circuit manufacturing process, which cannot be achieved by conventional technologies. The consistent examples described are only passed on today and every day to make 孰 羽 + the 5 brothers to understand the technical ideas of the present invention and the special technology will be used by people who do n’t know enough about this technology. The invention of Uchida Tsukuba limited the invention's patented target range, which is disclosed in the present invention, which is within the scope of the patent made by the moon god. J Temple is justified or modified, still should be covered

535230 Brief description of the drawings: The first drawing is a schematic view of forming a metal micromechanical structure on the surface of an IC wafer according to the present invention. Figures 2A to 2I are cross-sectional views of the structure of each step of manufacturing the multilayer micromechanical structure on the surface of the IC wafer according to the present invention.

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Claims (1)

535230 VI. The scope of the patent application The following steps suddenly open the method of forming a multi-layered micromechanical structure on the surface of an IC chip, including A. Long: Supply ~ ^ Semiconductor return to its j path, where the semiconductor office = soil counter ' A sensing and control integrated electric protection layer has been provided; a metal pad is formed on the reverse surface of the soil and the substrate B is protected. The semiconductor pad is provided with a semiconductor pad and the protection 'T, surface formation-photosensitive stem Film to cover the metal junction =, film to form a stepped D · deposition area with jealous holes and surfaces; a starting layer on the photosensitive dry film and the metal surface A metal structure grows in the perforated area, and is then secreted on the surface of the photosensitive dry film and the metal structure to form another suspended micromechanical structure. Obtaining the above steps β to G · removing the photosensitive dry film, you can 12. Form as described in the scope of application for patent; mechanical structure. In the method of sheet surface, in this step F, the coin structure is from I C to step E, until a predetermined micromechanical structure is produced: = continue to repeat this step B step G. After the number of layers, the method of forming a multi-layer surface as described in item i of the patent application scope is performed step by step, wherein the multilayer micromechanical junction I: the mechanical structure is in the IC element, radio frequency element and optical element, etc. Electromechanical ^ is applied to sensing i, as described in item 3 of the scope of the patent application, forming a $ 22: layer structure of the mechanical structure on I c 535230 6. The method of applying a patent to the surface of a wafer, wherein the sensing element is Micro inertia ^ 3. The formation of a unit or unit as described in item 3 of the scope of patent application. , Chip surface method, where the RF element is two = mechanical structure in iC or phased array antenna. ′, For inductors, radio frequency switches, as described in the third aspect of the scope of the patent application, said method of forming a film surface, and the micro-mechanical structure at 1C V, as in the scope of the patent scope of the application. = Surface method, in which the photosensitive mechanical structure is formed on K f and formed on the plutonium conductor substrate. The cutting material is hot-pressed as described in item i of the scope of the patent application. The method of "if; surface", wherein the thickness of the photosensitive dry film; the mechanical structure is between the ic wood. From the system of 20 ~ 50 micron's, such as the method of patent application, the surface of the wafer, in A, ^ = forming a multilayer micromechanical structure in 1C / chrome two-layer metal. In the structure, the electric = the starting layer The material is nickel / titanium or 10, as applied, patent: two structure, and the titanium and chromium are used as the adhesion layer. τ Γ The method reported by the patented target area No. 1 Xi Kun / Method of wafer surface 1 y Xi Shi puts the mechanical structure in place. The metal structure is composed of nickel or a nickel alloy. 11. The method for forming a surface of an IC wafer as described in the patent application, item ^ / forming a multilayer micromechanical structure on steel or gold. / 、 A layer can be formed on the surface of the metal structure 12. One method of forming multiple steps is as follows: P, a method of forming a structure on the surface of a 1 c wafer, including a soil reactor, which has been provided with sensing and control integrated power Page 14A · Providing half guide installation _ ^ 535230 VI. Application scope of patents --- On the surface of the / semi-substrate substrate, a metal pad and a protective layer protecting the substrate are formed; B · On the surface of the semiconductor substrate A photosensitive dry film is formed to cover the solder pad and the protective layer; the farmer ’s and bracelets: remove a part of the photosensitive dry film to form a stepped shape, an opening structure, and a perforation of the metal pad. Area; D · deposit an electroforming starting layer on the photosensitive dry film and surface; perform the electroforming process on the surface of the stem pad to make the perforated area be a suspended micromechanical structure; and grow a metal structure F. Remove the photosensitive dry film, you can get a single 13, as described in application 4 丨 — „and the field of hibiscus. The method of forming the surface of 偁 1 C wafer as described in the item 2 of the patent of the dry circle of Ge Tming patent. Wherein, after the step E: after the money machine structure is performed in the steps B to E, a predetermined micromechanical device can be manufactured and can be repeated. Then step F is performed to remove the photosensitive dry film, and then the number of layers is formed. 。Xi layer micromechanical junction 14 、 As in the patent application scope No. 12 A method for forming a multi-layered 1C wafer surface, wherein the micromechanical structure and the micromechanical structure are used in a micro-electromechanical element such as a radio frequency element and an optical element, and j is used as a sensing element. The method for forming the surface of a multi-IC wafer as described in item 4, wherein the sensing element is: the micro-mechanical structure is formed in 16 as described in item 14 of the scope of patent application = sexy element. Method, wherein the radio frequency element is a two-way micro-mechanical structure on-off or phase array antenna. Page 15 535230 VI. Application scope of patents 17. If applying for ΪC wafer surface 18, if applying for IC wafer surface Compression method is formed between 19 and if applying for 1 C wafer surface micron. 2 0. If applying for IC surface or Ni / Cr _ 21, for applying ΪC wafer surface. 22. If the surface of the IC chip is applied for copper or gold. ----- The method for forming a multilayer n as described in item 14 of the patent scope, wherein the optical element is: a method of "multi-layer micro method" in the form described in item 12 of the patent specification, wherein the photosensitive dry film It consists of a polymer structured on the semiconductor substrate. '. The method for forming a multilayer micro-capsule according to item 12 of the thermal patent range, wherein the thickness of the photosensitive dry film is the method for forming a multilayer micro-computer as described in item 12 of the patent range, wherein the electroforming is initiated The material of the layer is: structured in a -layer metal structure, and the titanium and chromium are used as an adhesion layer. The method for forming a multi-layer microcomputer W according to item 12 of the patent scope, wherein the metal structure is a method for forming a multi-layer microcomputer according to item 12 of a patent scope consisting of nickel or a snail alloy, wherein the metal structure is The surface is even more: a layer is formed on the ruler Page 16