GB2448882A - Self-assembly microstructure with polyimide thin film elastic joint - Google Patents

Self-assembly microstructure with polyimide thin film elastic joint Download PDF

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Publication number
GB2448882A
GB2448882A GB0708350A GB0708350A GB2448882A GB 2448882 A GB2448882 A GB 2448882A GB 0708350 A GB0708350 A GB 0708350A GB 0708350 A GB0708350 A GB 0708350A GB 2448882 A GB2448882 A GB 2448882A
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Prior art keywords
microstructure
self
assembly
micro
thin film
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GB0708350D0 (en
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Alex Horng
I-Yu Huang
Chih-Hung Wang
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Sunonwealth Electric Machine Industry Co Ltd
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Sunonwealth Electric Machine Industry Co Ltd
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Priority to GB0708350A priority Critical patent/GB2448882A/en
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Publication of GB2448882A publication Critical patent/GB2448882A/en
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    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/10—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00007—Assembling automatically hinged components, i.e. self-assembly processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0018—Structures acting upon the moving or flexible element for transforming energy into mechanical movement or vice versa, i.e. actuators, sensors, generators
    • B81B3/0032—Structures for transforming energy not provided for in groups B81B3/0021 - B81B3/0029
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    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
    • B81C1/0019—Flexible or deformable structures not provided for in groups B81C1/00142 - B81C1/00182
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    • B81—MICROSTRUCTURAL TECHNOLOGY
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    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
    • B81C1/00444—Surface micromachining, i.e. structuring layers on the substrate
    • B81C1/00468—Releasing structures
    • B81C1/00476—Releasing structures removing a sacrificial layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
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    • B81C1/00539—Wet etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
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    • H—ELECTRICITY
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    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
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    • H01G9/20—Light-sensitive devices
    • H01G9/2045—Light-sensitive devices comprising a semiconductor electrode comprising elements of the fourth group of the Periodic System (C, Si, Ge, Sn, Pb) with or without impurities, e.g. doping materials
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    • H01—ELECTRIC ELEMENTS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
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    • B32B2310/04—Treatment by energy or chemical effects using liquids, gas or steam
    • B32B2310/0409—Treatment by energy or chemical effects using liquids, gas or steam using liquids
    • B32B2310/0418—Treatment by energy or chemical effects using liquids, gas or steam using liquids other than water
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    • B32B2386/00—Specific polymers obtained by polycondensation or polyaddition not provided for in a single one of index codes B32B2363/00 - B32B2383/00
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    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2603/00—Vanes, blades, propellers, rotors with blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
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    • B81B2201/01—Switches
    • B81B2201/012—Switches characterised by the shape
    • B81B2201/014—Switches characterised by the shape having a cantilever fixed on one side connected to one or more dimples
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B81B2201/03—Microengines and actuators
    • B81B2201/032—Bimorph and unimorph actuators, e.g. piezo and thermo
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
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    • B81B2201/03—Microengines and actuators
    • B81B2201/038—Microengines and actuators not provided for in B81B2201/031 - B81B2201/037
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    • B81C2201/00—Manufacture or treatment of microstructural devices or systems
    • B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
    • B81C2201/0101—Shaping material; Structuring the bulk substrate or layers on the substrate; Film patterning
    • B81C2201/0128—Processes for removing material
    • B81C2201/013—Etching
    • B81C2201/0132—Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
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    • B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
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    • B81C2201/0128—Processes for removing material
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    • B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
    • B81C2201/0174—Manufacture or treatment of microstructural devices or systems in or on a substrate for making multi-layered devices, film deposition or growing
    • B81C2201/0176—Chemical vapour Deposition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract

The self-assembly microstructure includes a photosensitive polyimide elastic joint 52 between stationary 50 and movable 51 parts. The polyimide elastic joint 52 contracts during a high temperature reflow process. The surface tension of the cured polyimide rotates and lifts-up the movable part 51 of the microstructure. The formation process is also claimed. The microstructure can be a micro-fan.

Description

SELF-ASSEMBLY MJCROSTRUCTURE WITH POLYDvIIDE
THIN-FILM ELASTIC JOINT
E00011 The invention presents a self-assembly microstructure with pçlyimide thin film as elastic joint, which utilizes an integrated miniaturized planar technology with simple, fast and economical characteristics so as to solve shortcomings of conventional self-assembly technology.
2] The development and application of miniaturization technology is a major trend of modem science, and self-assembly technology, in particular, is a rudimentary method of the microscopic world in recent years.
[00031 Referring to a micro rotary fan manufactured by microelectromechanical systems (MEMS) technology, as shown in Figure 1, a portion between a Scratch Drive Actuator (SDA) of the micro rotary fan and the micro blades structure must be implemented by virtue of a self-assembly technology and multi-user MEMS processes (MUMPs).
[0004J The so-called self-assembly technology means that the microstructure will self-align after the completion of the final release process.
As shown in Figures 2-4, conventional microstructures fabricated using of self-assembly technology have the following three types.
[00051 Type 1 uses residual stress from the manufacturing process to generate a deformation resulting in displacement of microstructure as shown in Figure 2, which illustrates a 3D micro-optic switch developed by Lucent Technology.
6] Type 2 uses surface acoustic waves generated by ultrasonic waves to move the microstructure to a preset position by vibration as shown in Figure 3.
7] Type 3 uses a solder ball, photoresist or other polymer to form an elastic joint on a micro-hinge. A molten state of the elastic joint presents under a high temperature reflow type I process a surface tension force pulling up the microstructure as shown in Figure 4.
[00081 However, type 1 and type 2 of the traditional self-assembly technology are only applicable to a static application or a fixed microstructure, but are not suitable for dynamic or rotatable microstructure such as a micro-fan application.
[0009J In regard to type 3 self-assembly technology, there are a host of materials suitable for elastic joint fabrication. However, different materials feature respective disadvantages. Take the solder ball as an example: [001OJ Lead contamination: the solder ball is composed of tin and lead (63Sn/3TPb). During the reflow process, facilities and environment will be contaminated by lead.
[0011J High cost: most of the surface micromachined microstructures are usually constructed by polycrystalline silicon (Poly-Si), where a layer of gold pad must be coated as an interconnection between a solder ball and Poly-Si. This additional process will inevitably result in production difficulty and increased cost.
2] Poor precision: to calculate the raised angle or displacement of microstructure, the dimension of solder ball must be accurately controlled.
However, traditional solder ball usually has a volume deviation up to 25%, which makes the precision of a raised angle or displacement uncontrollable.
3] Manual processing: so far, attaching the solder ball on the gold pad still adopts manual alignment processing.
4] Miniaturizing infeasibility: currently, a smallest diameter of solder ball is no less than 100 pm, which limits a minimum size of the solder-based devices.
5] Taking the elastic joint* formed by photoresist as another
example:
100161 The manufacturing process of the elastic joint formed by photoresist is not as complicated as that of the solder ball, and the cost thereof is also lower. However, the release of the microstructure must be processed by dry or wet etching.
[00171 The dry etching utilizes liquid carbon dioxide to release the microstructure and replace the water molecule so as to avoid the stick effect of the microstructure. Whereas, super critical CO2 dry release equipment used for the method is quite expensive, and thus the cost of this process is relatively high.
[0018J The wet etching requires no additional manufacturing equipment, making it a solution with less cost. However, after etching the sacrificial layer with the solution of diluted hydrofluoric acid (HF) or buffered oxide etch (BOE), further apply the isopropyl alcohol (IPA) to quickly vaporize the water molecules. The IPA is characterized by dissolving the photoresist so that it will damage the photoresist-based elastic joint fabricated originally.
[00191 In sum, considering production cost, process integration and miniaturization capability, a brand new manufacturing process is urgently required to resolve various shortcomings arising from the elastic joint formed by the solder ball or the photoresist.
[0020J In view of this, the present invention provides a polyimide-based thin film self-assembly technology, including five process steps described as follows: (1) deposits a sacrificial layer and a low-stress microstructure layer on a silicon substrate; (2) patterns and etches the low-stress microstructure layer to provide a stationary part and a movable part of the microstructure; (3) coats a photosensitive polyimide thin film as elastic joint of the microstructure layer and defines its shape by using photolithography technique; (4) releases the sacrificial layer beneath the movable part of microstructure layer by wet etching; (5) lastly proceeds the reflow process of polyimide to result in the contraction of the elastic joint further to rotate and hR the movable part in completion of the self-assembly of the microstructure.
As the invention can be extensively applied to a myriad of miniaturizing industries, it can at least mitigate the drawbacks of the prior art and satisfy the requirements of low cost, simple manufacturing process and miniaturization.
[00211 The invention will now be described, by way of example, with reference to the accompanying drawings in which: [0022] Figure 1 is a micrograph of a known micro rotary fan manufactured by microelectromechanical systems (MEMS) technology; [0023] Figure 2 is a micrograph of a known 3D micro-optic switch developed by Lucent Technology; [0024J Figure 3 is schematic diagram of cross-sections of a known microstructure using surface acoustic wave generated by ultrasonic wave to move the microstructure to a preset position by vibration; [00251 Figure 4 is a micrograph of using a solder ball, photoresist or other polymer to form an elastic joint on a known micro-hinge [0026] Figure 5 is a micrograph of a photolithography process to define the shape of a polyimide elastic joint according to the present invention; [0027] Figure 6 is a micrograph of a reflow process of the present invention; [0028] Figure 7 is a schematic diagram showing a lift-up microstructure on silicon substrate of the present invention; [0029] Figure 8 is a schematic diagram showing the manufacturing processes of the present invention; [0030] Figure 9 is a schematic diagram (1) showing the application of present invention for the self-assembly unreleased micro-fan; and [0031] Figure 10 is a schematic diagram (II) showing the application of present invention for the self-assembly released micro-fan; 100321 The invention relates to a polyimide thin film self-assembly microstructure as shown in Figure 7, which contains at least one stationary part 53 of the microstructure and at least one movable part 54 of the microstructure. An elastic joint 52 located between the stationary part 53 and the movable part 54 is a photosensitive polyimide thin film material.
The polyimide elastic joint 52 is contracted after high-temperature reflow it) process. The surface tension force of cured polyimide can rotate and lift-up the movable part 54 of the microstructure in completion of the self-assembly of the microstructure.
3] As shown in Figure 8, the manufacturing processes of the self-assembly microstructure of the present invention are described as follows: [0034] process 1: depositing a phosphosilicate glass (PSG) on a silicon substrate 10 as a sacrificial layer 20 by means of the Plasma Enhanced Chemical Vapor Deposition (PECVD) system and further depositing a low-stress Poly-Si on the sacrificial layer 20 as the microstructure layer 30 by means of the Low Pressure Chemical Vapor Deposition (LPCVD) system; [0035] process 2: carrying out a first photolithography process and etching the microstructure layer 30 to define the entire contour by using an Inductively Coupled Plasma (ICP) etching system; [0036] process 3: using a spin coater to deposit a photosensitive polyimide thin film 40 on the microstructure layer 30; [0037J process 4: carrying out a second photolithography process to define a shape of the polyimide elastic joint 41; [00381 process 5: immersing the wafer in BOB to carry out wet etching of the pre-defined portion of the sacrificial layer 20 then releasing the microstructure layer; and 100391 process 6: carrying out a reflow process of polyimide thin film by using high temperature oven, results in a molten state of the elastic joint 41 under a high temperature of 380 C-.405 C. The heated polyimide elastic joint 41 generates a contracted deformation to rotate and lift the pre-defined portion of the Poly-Si microstructure layer 30 as shown in Figure 6.
(00401 First of all, compare the pros and cons of the polyimide elastic joint formed by the present invention and the solder ball respectively.
(0041] The present invention has no lead pollution.
2] The present invention requires no additional gold pad coated for the connection interface so as to address a simple and inexpensive manufacturing process.
3] The invention can conduct the alignment with rather high precision by virtue of the photolithography technique so as to provide a better precision.
[0044J The invention can perform an integrated miniaturized planar self-assembly processing.
(0045] The miniaturized size of the present invention has no limitation.
6] Furthermore, compare the pros and cons of the polyimide elastic joint formed by the present invention and photoresist.
[0047) Although photosensitive polyimide and photoresist are categorized as polymer materials, polyimide has a greater surface tension force which raises the same microstructure layer by a larger angle.
Consequently, the present invention is free of the concern that the elastic joint is damaged by being dissolved in IPA.
8] As the photosensitive polyimide thin film is better in withstanding the organic solution, it can be developed as an inexpensive wet etching process. Therefore, the fabrication cost of the invention is relatively low.
[0049J In summary, the invention can simplify the manufacturing process, lower the cost and completely solve the shortcomings arising from the elastic joint formed by the solder ball or photoresist.
0] Illustrated below are the self-assembly processes of the micro-blade structure for the micro-fan application: [0051] Firstly, depositing a phosphosilicate glass (PSG) sacrificial layer on a silicon substrate and depositing a low stress microstructure layer on the said sacrificial layer; [00521 As shown in Figure 9, patterning and etching the Poly-Si microstructure layer to form the main body 50 and the microblades 51 of the micro-fan by virtue of a photolithography process; [0053] Coating a photosensitive polyimide thin film on the microstructure layer; 100541 Patterning and etching the polyimide thin film to form an elastic joint 52 between micro-blade 51 and main body 50 by using of photolithography process; 100551 Carrying out a wet etching process to etch the sacrificial layer beneath micro-blade layer and release the micro-blade structure 51; [00561 Lastly proceeds the reflow process of polyimide to result in the contraction of the elastic joint 52 further to rotate and lift the micro-blade 51 in completion of the self-assembly of the microstructure.
7] By means of the aforementioned polyimide-based microstructure design, the present invention at least mitigates the various shortcomings arising of the solder ball or the photoresist based microstructure. As the invention can be extensively applied to a myriad of miniaturizing industries, it can at least mitigate all the drawbacks of the prior art and satisf' the requirements of low cost, simple manufacturing process arid miniaturization.
Accordingly, the present invention is not only novel and invnetive but also has an industry utility.

Claims (13)

1. A self-assembly microstructure comprising: at least a stationary part of a microstructure layer; and at least a movable part of the microstructure layer; wherein the said stationary part and the said movable part use an integrated polyimide thin film as an elastic joint wherein after a high-temperature reflow process, a large surface tension force is generated from the said elastic joint to rotate and lift-up the said movable part of the said microstructure.
2. The self-assembly microstructure of claim I applied to self-assembly of a micro-fan.
3. The self-assembly microstructure of claim 2, wherein the said micro-fan comprises a main body and a set of micro-blades, the said elastic joint is formed between the said main body and the said micro-blades with the said polyimide thin film, and the said surface tension force is generated from the said elastic joint by means of the said reflow process to rotate and lift the said micro-blades.
4. The self-assembly microstructure of claim 1 applied to self-assembly of a scratch drive actuator.
5. The self-assembly microstructure of claim 1 applied to self-assembly of a micro-optical bench chip.
6. The self-assembly microstructure of claim 1 applied to self-assembly of a micro-optical switch.
7. The self-assembly microstructure of claim 1 applied to a micro-passive component.
8. The self-assembly microstructure of claim 7, wherein the said micro-passive device is a micro-inductor.
9. The self-assembly microstructure of claim 7, wherein the said micro-passive device is a micro-capacitor.
10. The self-assembly microstructure of claim 1, wherein the fabrication processes of the said microstructure comprises: a. depositing a sacrificial layer on a silicon substrate and depositing a low stress microstructure layer on the said sacrificial layer; b. patterning and etching a low-stress microstructure form on the said sacrificial layer; c. coating a polyimide thin film on the said microstructure layer; d. patterning and etching an elastic joint form on the said polyimide thin film; e. carrying out a wet etching process to etch and release a pre-defmed portion of the said sacrificial layer; and f. carrying out a reflow process to result in a contraction of the said elastic joint to rotate and lift a pre-defined portion of the said microstructure layer.
11. The self-assembly microstructure of claim 10, wherein the said sacrificial layer is a phosphosilicate glass (PSO).
12. The self-assembly microstructure of claim 10, wherein the said low-stress microstructure layer is a polycrystalline silicon (Poly-Si).
13. A self-assembly microstructure with photosensitive polyimide thin film substantially as described herein with reference to and as shown in any of Figures 5 to 8 of the accompanying drawings. * ** * * * * ** * * * 0* * * S * S. S. * S S *SS
13. A self-assembly microstructure substantially as described herein with reference to and as shown in any of Figures 5 to 8 of the accompanying drawings.
Amendments To The Claims have Been Filed As Follows 1. A self-assembly microstructure with photosensitive polyimide thin film comprising: at least a stationary part of a microstructure layer; and at least a movable part of the microstructure layer; wherein the said stationary part and the said movable part use an integrated polyimide thin film as an elastic joint, wherein said an elastic joint is a photosensitive polyimide thin film material, wherein after a high-temperature reflow process, a large surface tension force is generated from the said elastic joint to rotate and lift-up the said movable part of the said microstructure.
2. The self-assembly microstructure with photosensitive polyimide thin film of claim 1 applied to self-assembly of a micro-fan.
3. The self-assembly microstructure with photosensitive polyimide thin film of claim 2, wherein the said micro-fan comprising: a. depositing a sacrificial layer on a silicon substrate and depositing a low stress microstructure layer on the said sacrificial layer; b. patterning and etching the Poly-Si microstructure layer to form the main body and the set of micro-blades of the micro-fan by virtue of a photolithography process; c. Coating a photosensitive polyimide thin film on the said of main body and the said of micro-blades; d. Patterning and etching the polyimide thin film to form an elastic joint between micro-blade and main body by using of photolithography process; e. Carrying out a wet etching process to etch the sacrificial layer beneath micro-blade layer and release the micro-blade structure; f. proceeding the reflow process of polyimide to result in the contraction of the elastic joint further to rotate and lift the micro-blade.
4. The self-assembly microstructure with photosensitive polyimide thin film of claim I applied to self-assembly of a scratch drive actuator.
5. The self-assembly microstructure with photosensitive polyimide thin film of claim 1 applied to self-assembly of a micro- optical bench chip.
6. The self-assembly microstructure with photosensitive polyimide thin film of claim 1 applied to self-assembly of a micro- optical switch.
7. The self-assembly microstructure with photosensitive polyimide thin film of claim 1 applied to a micro-passive component.
8. The self-assembly microstructure with photosensitive polyimide thin film of claim 7, wherein the said micro-passive device is a micro-inductor.
9. The self-assembly microstructure with photosensitive polyimide thin film of claim 7, wherein the said micro-passive device is a micro-capacitor.
10. The self-assembly microstructure with photosensitive polyimide thin film of claim 1, wherein the fabrication processes of the said microstructure comprises: a. depositing a sacrificial layer on a silicon substrate by means of the Plasma Enhanced Chemical Vapor Deposition (PECVD) system and ** depositing a low stress microstructure layer on the said sacrificial layer by means of the Low Pressure Chemical Vapor Deposition (LPCVD) system; b. carrying out a first photolithography process and etching the microstructure layer 30 to define the entire contour by using an Inductively Coupled Plasma (ICP) etching system; : c. using a spin coater to deposit a photosensitive polyimide thin film on the said microstructure layer; d. carrying out a photolithography process to define a shape of the polyimide elastic joint; e. immersing the wafer in BOE to carry out wet etching of the pre-defined portion of the sacrificial layer then releasing the microstructure layer; and f. carrying out a reflow process of the elastic joint by using high temperature oven under a high temperature of 380 C-405 C t o result in a molten state, within said the elastic joint generating a contracted deformation to rotate and lift a pre-defined portion of the said microstructure layer.
11. The self-assembly microstructure with photosensitive polyimide thin film of claim 10, wherein the said sacrificial layer is a phosphosilicate glass (PSG).
12. The self-assembly microstructure with photosensitive polyimide thin film of claim 10, wherein the said low-stress microstructure layer is a polycrystalline silicon (Poly-S i).
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070039919A1 (en) * 2005-08-17 2007-02-22 Sunonwealth Electric Machine Industry Co., Ltd. Polymide thin film self-assembly process
US20070040229A1 (en) * 2005-08-17 2007-02-22 Sunonwealth Electric Machine Industry Co., Ltd. Self-assembly microstructure with polymide thin-film elastic joint

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070039919A1 (en) * 2005-08-17 2007-02-22 Sunonwealth Electric Machine Industry Co., Ltd. Polymide thin film self-assembly process
US20070040229A1 (en) * 2005-08-17 2007-02-22 Sunonwealth Electric Machine Industry Co., Ltd. Self-assembly microstructure with polymide thin-film elastic joint

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