TW445512B - Processing technology to define pattern by combining two coherent light beams and using interference to proceed multiple direct exposure - Google Patents

Abstract

The present invention provides a surface photoresist exposure method of special submicron grade interval to break the limitation of the current semiconductor exposure process, and which can be used in various sorts of surface acoustic wave device process. Its processing method is founded by using two light beams to be incident into the photoresist special angle to form grating. At first, two light beams directly expose the photoresist at larger angle to define a primitive shape of electrode of the surface acoustic wave device, then, form another set of gratings with larger spacing by using two light beams incident with smaller angle, and overlaps according to the design requirement. Then continue to define the shape of electrodes in the other parts following similar double light beam interference method to complete defining the shape of electrodes of surface acoustic wave, finally, the remaining exposure requirement may be compensated by focusing direct writing or microform overlapping. The present method utilizes double light beam interference to form submicron gratings to break the bottleneck of the current semiconductor processing equipment, and which can be used to update the process of surface acoustic wave device for increasing the frequency of the surface acoustic devices.

Description

44b5 t 2. V. Explanation of the invention (1) The present invention provides a special submicron "❿ ^" ^ ㈣ "surface light-resistance blasting method with a grade gap, in particular, a method that uses two coherent beams to generate interference at different angles. Stripe, to directly define the pattern of various surface acoustic wave components. According to the rapid development of Taiwan ’s semiconductor industry in recent years, the surrounding wireless communication and electronic information industry has made rapid progress, and its related products have already occupied a significant position in the global market * and In the future research and development of semiconductor components, components based on micro-optical electromechanical process technology will be expected to become the industrial star of the 21st century due to their superior performance in many aspects. The academic community has invested considerable funds and manpower for this. Surface acoustic wave elements manufactured using micro-optical electromechanical process technology (Surface

Acoustic Wave Devicec or SAW Device), because its operating frequency band is from 10MHz to 2GHz, which is suitable for the communication frequency band of mobile phones, so it has a great demand in the global communication market. Interdigital sensors (Interdigital Transducer or IDT) are the key structure for the operation of surface acoustic wave components. Its geometrical appearance is a simple, staggered comb structure. As the operating frequency band increases, the line width of its comb structure will gradually decrease. At present, the main frequency bands for global mobile phone communications are 900MHz and 8MHz. The finger sensor line widths required for both are sub-micron grade, unless the semiconducting process has a very expensive stepper exposure setup. Manufacturers, ordinary manufacturers simply cannot process surface acoustic wave components of this type of interdigital transducer structure at a reasonable cost. This is the key to the fact that such interdigital sensor components cannot be produced at a low cost.

V. Explanation of the invention (2) Therefore, the present invention is to provide a surface photoresist exposure method with a special sub-micron level gap, in particular, a process technology that uses two beams to interfere with each other to generate a grating overlap. Produced by the surface acoustic wave element of micrometer interdigital sensor line width. According to the above-mentioned object, the present invention refers to a method for manufacturing an interdigital sensor, the finger sensor structure has a substrate, and the substrate may be a piezoelectric material directly or a thin layer of piezoelectric silicon is added to the surface. The metal is plated as an electrode, and a photoresist layer is coated on the metal electrode. The manufacturing method includes the following steps: a. Two coherent beams are incident on the photoresist at a special angle to form a small interference. Stripe; adjust the moving platform, and then continue to expose the designed position according to the same method and angle on the entire surface of the substrate to define a preliminary comb-like structure pattern; b. Use two coherent beams according to the design requirements to compare A small beam angle incident photoresist defines another group of gratings with a larger distance, and makes this group of gratings overlap with the first group of gratings according to the design requirements; c. Use beam focusing to write directly or directly reduce the imaging The method 'according to design requirements' makes up for the ultimate waterfall light requirements. Regarding the technology, means and effects used in the present invention, a better example will be given in conjunction with the drawings to explain it in detail. It is believed that a deep and specific understanding can be obtained. Brief description of the circle type: The first circle shows the conventional surface acoustic wave element and the finger-shaped sensor structure;

Page 5 4 45 51 2 V. Description of the invention (3) The second diagram is a schematic diagram of the exposure of the two coherent light beams of the present invention to the surface of the photoresist layer at a large angle; the third circle shows the first of the present invention. Generates two coherent beams incident on the surface of the photoresist layer for exposure at a small angle. The fourth ® (a) shows the present invention—using the amplitude mask to modify the outer shape of the incident coherent beam to define the outer shape of the grating. (B) Shown is a schematic circle of the present invention using a phase mask to modify the outer shape of the incident coherent beam to define the outer shape of the grating or to modify the phase distribution of the wavefront phase of the finally required coherent beam; Shown here is a schematic diagram of the process of a defined partial comb electrode of the present invention; (b) Shown is a schematic circle of a process of a defined partial comb electrode of the present invention; (c) Shown is a focused direct writing or direct miniature imaging of the present invention Obtain the schematic circle of the linear external electrode; The sixth circle shows the schematic diagram of the linear external electrode of the preferred embodiment of the present invention; The seventh ® (a) is not a definition of a part of the invention of the arc-shaped comb electrode; The present invention shows a half an eight w ^ »comb electrodes arc portion defined process ® FIG.; (C) a focusing system of the present invention or a direct write imaging d45512 FIG miniature

Obtain a schematic diagram of an arc-shaped external electrode. Figure 8 shows a surface acoustic wave of the present invention.

(Fine) The surface acoustic wave element with function correction is shown in the V reference number: π refers to the comb electrode of the sensor structure 12 and refers to the external electrode of the sensor 21 reflection sharp 22 focusing through sharp 23 two of the larger angle Coherent beam 24 Photoresist layer 2 5 Substrate and metal electrode 26 Displacement platform 2 * 7 Two coherent beams with smaller included angles 32 Directly push the photoresist layer with larger coherent beams with larger included angle Exposure Station 33 The pattern obtained by directly exposing the photoresist layer with two coherent beams at a small included angle 34 Focusing and writing in one beam completes the comb-shaped electrode pattern 35 Line-shaped external electrodes 36 Arc-shaped external electrodes 41 Amplitude-type light Leather 42 Phase First Single 51 Incident Beam

V. Description of the invention (5) 61. Focusing miniature exposure pattern using a beam of light. 62 Focusing miniature exposure pattern using a phase mask. First, please refer to the second circle and the third figure. Optical-mechanical architecture diagram, as shown in the circle, an exposure method shown in this embodiment is a type of direct exposure with two coherent beam interferences. The exposure amount is changed to control the comb according to the design requirements of the interdigital sensor element. Pattern of the electrode. The fourth figure (a), (b) is a photolithography process of a preferred embodiment of the present invention, and the fourth figure (a) is the present invention uses an amplitude mask to modify the shape of the incident beam or the shape of the focal point to change Phosphorescent pattern of external electrodes. The fourth (b) is the use of a phase mask in the present invention to modify the light wavefront of the incident light east to change the explosion aperture of the external electrode or directly modify the light wavefronts of two coherent beams to obtain the required light wave. Front phase distribution. The fifth circle (a), (b), and (c) are the lithography process of another preferred embodiment of the present invention. The fifth circle (a) is the light-mechanical architecture of the second circle of the present invention, which makes the two channels harmonize. The light beam 23 'interfered at a larger angle and entered the photoresist layer 24 to produce an exposure' By adjusting the moving platform 26, exposure was successively performed according to design requirements to obtain the first group of exposure circles 32; then, as shown in the fifth circle (b) According to the design requirements of the present invention, the two coherent light beams 23 interfere with each other at a small included angle and expose the photoresist layer 24. By adjusting the moving platform 26, the exposure is successively performed according to the design requirements to obtain a second group of exposure patterns 3 3 ; Finally, use a beam to focus on direct writing or direct miniature to directly expose to obtain a third group of exposure patterns 34. The sixth figure is a finger-type sensor structure.

Article 8 I-445512 V. Description of the invention (6) External electrode 35 'If the beam is focused and written directly, the mobile platform 26 must be moved in a single f direction. If it is directly reduced, the platform is only exposed to another You only need to move when you have completed a complete set of samples. You can complete the exposure circle samples that define the line type and the finger sensor electrode contacts. The seventh circle (a), (b), and ((;)) The external electrode 3 6 'adjust the moving platform 26 for bi-axial movement'. If the direct miniature method is adopted, the situation is the same as that in the sixth figure, and the moving platform needs to be adjusted only when another set of complete circles are exposed. In addition, it is worth mentioning that in the process of forming the grating by successive exposures, because the overall exposure of the field sample periphery is generally in the millimeter (mm) level, the diffraction efficiency of light waves is not yet clear, so the shape of the incident beam periphery can be modified. To define the outer shape of each group of gratings: This technique can be used to complete the direct beam writing or direct microcosm of the previous beam focusing. method In addition to directly defining the outer shape of the incident light with an amplitude mask, phase light leather can also be used to achieve the same purpose. In addition, 'phase masks can also be used to modify the phase distribution inside the beam' One beam is formed by phase-type light leather trimming, and the interference is performed in the manner of the predetermined angle described above. Then, exposure circles of external electrodes with different pitches can be defined. As shown in the eighth solid, it is a kind of process provided by the present invention. Schematic diagram of a surface acoustic wave element modified by a surface acoustic wave signal with a chirp function. 'The distance between the comb electrodes is not completely equal. To achieve this effect by interference, it is necessary to use the phase mask described above. It is necessary to carry out the correction of light wavefront to achieve such circular patterns with different grating pitches.

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Claims (1)

> -445 5 1 'ά VI. Scope of patent application A method for directly exposing a photoresist by interfering at least two times with two coherent beams at different angles. The manufacturing method includes a substrate placed on a moving platform. The surface of the material is plated with metal electrodes to make various surface acoustic wave elements with interdigital sensor structures. The manufacturing method of the present invention includes the following steps: a. Interfering exposure by using at least two coherent beams, incident on the photoresist layer at the same time to cause interference, and exposing the exposed photoresist layer, according to the design of various finger-type sensor structures , Control the exposure of the coherent beam and the angle between the two incident beams, and adjust the position of the mobile platform according to the design, to define the pattern of the comb electrode of the interdigital sensor structure; b_ at least once again use the two coherent beams, According to the design of each finger sensor structure, 'control the exposure of the coherent beam, adjust the angle between the two coherent beams to form an interference pattern', and adjust the position of the mobile platform according to the design of the finger sensor structure, to define the interdigital type The pattern of the comb electrode contact part in the sensor structure to define the connection between the comb electrode and the external electrode; c_ Use at least one beam to complement the method, and adjust the mobile platform according to the finger-type sensor structure design to make up for the remaining exposure The amount and position of light to form a complete external electrode 'to fully define the circle of the entire interdigital sensor structure D. Use etching technology to etch away the photoresist layer and other non-electrode metal coatings> 2. According to the method described in the first paragraph of the patent application, where the photoresist is a negative photoresist . Page 11 445512 3. According to the method described in item 1 of the scope of patent application ', wherein the moving platform for moving the exposure position is a uniaxial one. 4. According to the method described in item 1 of the scope of patent application, the moving platform for moving the exposure position is a biaxial β. 5. According to the method described in item 1 of the scope of patent application, one of the beams is used to supplement the The method can be focused on those who focus on the laser. 6. According to the method described in item 1 of the scope of the patent application, one of the methods used to fill the beam can be a direct imager. 7. According to the method described in the first paragraph of the patent application park, the angle between the two coherent beams used for exposure is variable. 8. The method according to item 1 of the scope of patent application, wherein the size and peripheral shape of the two coherent beams used for exposure are variable. 9. The method according to item 5 of the scope of patent application, wherein the shape of the light spot and the wavefront of the photoresist can be controlled by a phase mask. 10. The method according to item 5 of the patent application park, wherein the shape of the light spot of the photoresist can be controlled by an amplitude beam. 11. According to the method described in item 4 of the scope of patent application, wherein the loop pattern of the external electrode contacts of the interdigital sensor structure is a linear type. 12. The method according to item 4 of the scope of patent application, wherein the pattern of the external electrode contacts of the interdigital sensor structure is a curve. 13. According to the method described in item 1 of the scope of the patent application, wherein the substrate with the interdigital sensor structure is an electric material. 14. According to the method described in the first aspect of the patent application, wherein the substrate with the interdigital sensor structure is a thin wafer with a thin layer of electrical calendar.