CN1258199C - Deep etching plane magnet coil and making method - Google Patents

Abstract

The invention relates to a method for manufacturing planar electromagnetic coils used in micro-motors, micro-electromagnetic sensors and actuators. Use photolithography to define the coil pattern on the surface of the Si sheet, and then use Si deep etching to etch the coil groove and the coil lead through hole on the surface of the Si sheet according to the defined coil pattern, and electroform the metal in the coil groove to obtain the metal structure , The surface roughness etched on the inner surface of the coil slot embeds the coil in the coil slot. The coil includes: a base (1), a coil slot (2), a coil lead through hole (3), an insulating layer (4), a seed layer (5), a metal wire (6), and a lead metal layer (7). Etching deep grooves in the shape of coils on the surface of the Si sheet, the coils are embedded in the deep grooves, and are not easy to fall off from the grooves, which solves the problem of weak adhesion between the coils and the substrate. Solve the problem of bonding photoresist and substrate and difficult problem of removing negative glue. The thin film photolithography process requires a large tolerance, is easy to implement and repeat, and is conducive to improving the yield.

Description

Deep etched planar electromagnetic coil and manufacturing method

Technical field: The present invention belongs to the technical field of micro-electro-mechanical systems, and relates to a method for manufacturing planar electromagnetic coils used in micro-motors, micro-electromagnetic sensors, and actuators.

Background technology: Planar electromagnetic coils are important components of various micro-motors, micro-electromagnetic sensors, and actuators in MEMS. In the past, most of the manufacturing processes of planar electromagnetic coils used LIGA and UV-LIGA processes. The LIGA process required the use of synchrotron radiation light sources and X-ray masks. For LIGA technology, the photoresist used is SU-8 negative resist or other positive thick resist. Since the surface of the Si or SiO ₂ substrate is very smooth, the contact area between the coil and the substrate is very small, so the coil made by the above method has the problem of poor adhesion to the substrate, and the coil is easily detached from the substrate under the action of electromagnetic force. The surface falls off, affecting its service life. After electroforming, there is also the problem that the photoresist is difficult to remove. In particular, when the above-mentioned method is used to manufacture a double-plane electromagnetic coil, the process is difficult, the repeatability is very poor, and the yield is very low.

Contents of the invention: In order to solve the problems of poor adhesion between the coil and the substrate in the background technology, difficulty in removing the glue after electroforming, difficult process, poor repeatability and low yield, the present invention proposes a method that can be used to make planar electromagnetic coils New process method.

The present invention proposes to firstly define a coil pattern on the surface of the Si sheet by using ordinary photolithography technology, and then use the Si deep etching technology to etch the coil pattern on the surface of the Si sheet to obtain the coil groove and the coil groove for inlaying the coil metal wire. Coil lead through holes, metal electroforming in the coil slot to obtain the metal structure of the coil, using the surface roughness produced during the etching process on the inner surface of the coil slot, the coil is firmly embedded in the coil slot.

The planar electromagnetic coil structure of the present invention includes: a base 1, a coil slot 2, a coil lead through hole 3, an insulating layer 4, a seed layer 5, a metal wire 6, and a lead metal layer 7, and the surface of the base 1 is etched with a coil slot 2 and a coil Lead through hole 3, the through hole prepared on the body of the base 1 is the coil lead through hole 3; an insulating layer 4 is grown on the outer surface of the base 1, the coil slot 2 and the coil lead through hole 3; The bottom of the coil slot 2 has a seed layer 5 and a metal wire 6; there are a seed layer 5 and a lead metal layer 7 on the side wall of the coil lead through hole 3 with an insulating layer 4, and the metal wires 6 are more equidistant on the same plane. The secondary coil is wound and embedded in the coil slot 2, and the two ends of the metal wire 6 are respectively prepared with coil lead through holes 3.

When the planar electromagnetic coil manufactured by the present invention is in operation, the power supply can be connected to the coil lead holes at both ends of the metal wire. When a current passes through the metal wire, an electromagnetic field will be generated in a direction perpendicular to the plane where the coil is located.

The positive effect of the present invention: In order to solve the problems in the background technology that the coil is not firmly adhered to the substrate, it is difficult to remove the glue after electroforming, the process is difficult, the repeatability is poor and the yield is low, the present invention proposes:

(1) Use the deep etching technology of Si to etch deep grooves on the surface of the Si sheet according to the shape of the coil, which solves the problem of weak adhesion between the coil and the substrate, and utilizes the surface roughness generated during the etching process on the inner surface of the deep groove The degree is that when the coil, that is, the metal wire, is formed by electroforming in the deep groove, it can be firmly embedded and adhered in the deep groove, and it is not easy to fall off from the groove.

(2) The production process adopts ordinary ultraviolet lithography technology and Si deep etching technology. The photoresist adopts positive thin film, and does not need PMMA, SU-8 negative film and positive film film used in LIGA and UV-LIGA technology. Therefore, the problem of bonding between the photoresist and the substrate and difficult removal of the negative resist can be solved.

(3) The common thin-resist lithography process is adopted, and the process conditions require a large tolerance, which is easy to implement and repeat, and is conducive to improving the yield rate. Therefore, it overcomes the difficulties of LIGA and UV-LIGA technology, which are difficult to process, poor repeatability, and low yield rate. question.

Description of drawings:

Fig. 1 is the three-dimensional schematic diagram of structure of the present invention

Fig. 2 is the schematic cross-sectional view of the deep etched structure of the substrate of the present invention,

Fig. 3 is a schematic cross-sectional view of the structure of the present invention

Fig. 4 is a specific process diagram of the double planar coil of the present invention.

Fig. 5 is a specific process diagram of the single planar coil of the present invention.

Detailed ways:

Embodiment 1: The double-plane electromagnetic coil includes two parts on the substrate 1, the A surface and the B surface, and the A surface and the B surface of the substrate 1 are composed of a coil groove 2, a coil lead through hole 3, an insulating layer 4, a seed layer 5, The metal wire 6 and the lead metal layer 7 are composed. First use ordinary ultraviolet lithography technology to define the coils on the A surface and the B surface of the substrate 1 respectively. The graphics can be selected as rectangles, triangles, circles or polygons; use Si deep etching technology to etch the coils on the A surface and the B surface respectively. Groove 2 and coil lead wire through hole 3; Thermal oxidation is carried out on the substrate 1 after deep etching, and an insulating layer 4 is thermally oxidized and grown on the outer surface of the substrate 1, the inner surface of the coil groove 2 and the coil lead wire hole 3; The metal seed layer 5 is deposited in the thermally oxidized coil groove 2 and the coil lead through hole 3; the substrate 1 is electroformed on both sides by micro-electroforming technology, and finally the metal wire 6 and the lead metal layer 7 constituting the coil are obtained. Utilizing the surface roughness produced during the etching process on the inner surface of the coil slot 2 and the coil lead through hole 3 , the coil metal wire can be firmly embedded and adhered in the coil slot 2 and the coil lead through hole 3 .

Structural material selection:

The substrate 1 is made of high-resistance Si single crystal material, the insulating layer 4 is made of SiO ₂ material formed by thermal oxidation, the seed layer 5 is made of metal copper, and the metal wire 6 and the lead metal layer 7 are made of metal copper.

Specific process:

The technological process of the double-plane electromagnetic coil proposed by the present invention is shown in FIG. 4 .

(1) On both sides of the A surface and the B surface of the substrate 1, respectively photoetch the planar coil and the coil lead hole pattern; use Si deep etching technology to etch the coil slot 2 and the coil lead through hole 3, wherein the coil slot 2 The depth is 20 μm to 60 μm, and the coil lead through hole 3 is a through hole, as shown in (a) in Figure 4;

(2) thermally oxidizing the above-etched base 1 structure to form an insulating layer 4 on its surface to obtain the structure shown in (b) in FIG. 4 ;

(3) Sputtering and depositing the seed layer 5 in the coil groove 2 and the coil lead through hole 3 where the insulating layer 4 has been formed, to obtain a structure as shown in (c) in FIG. 4 ;

(4) The metal wire 6 and the lead metal layer 7 are electroformed in the coil slot 2 and the coil lead through hole 3 sputtered with the seed layer 5 to obtain the structure shown in (d) of FIG. 4 .

Embodiment 2: The single-plane electromagnetic coil is included in the A surface part of the substrate 1, and the A surface of the substrate 1 is composed of a coil slot 2, a coil lead through hole 3, an insulating layer 4, a seed layer 5, a metal wire 6 and a lead metal layer 7 . First, ordinary ultraviolet lithography technology is used to define the pattern of the coil on the A surface of the substrate 1. The pattern of the coil can be selected as a rectangle, a triangle, a circle or a polygon; the Si deep etching technology is used to etch the coil slot 2 and the A surface. Coil lead through hole 3; thermal oxidation is performed on the substrate 1 after deep etching, and an insulating layer 4 is thermally oxidized on the outer surface of the substrate 1, the inner surface of the coil slot 2 and the coil lead hole 3; after thermal oxidation by sputtering The metal seed layer 5 is deposited in the coil groove 2 and the coil lead through hole 3; the substrate 1 is electroformed on one side by micro-electroforming technology, and finally the metal wire 6 and the lead metal layer 7 constituting the coil are obtained. Utilizing the surface roughness produced during the etching process on the inner surface of the coil slot 2 and the coil lead through hole 3 , the coil metal wire can be firmly embedded and adhered in the coil slot 2 and the coil lead through hole 3 .

Structural material selection:

The structural material of embodiment 2 is the same as that of embodiment.

Specific process:

The technological process that the present invention proposes is as shown in Figure 5.

(1) On the surface A of the substrate 1, the planar coil and the coil lead hole pattern are photoetched; the coil slot 2 and the coil lead through hole 3 are etched out using Si deep etching technology, wherein the depth of the coil slot 2 is 20 μm to 60 μm, The coil lead through hole 3 is a through hole, as shown in (a) in Figure 5;

(2) thermally oxidizing the above-etched base 1 structure to form an insulating layer 4 on its surface to obtain the structure shown in (b) in FIG. 5 ;

(3) Sputtering and depositing the seed layer 5 in the coil groove 2 and the coil lead through hole 3 where the insulating layer 4 has been formed, to obtain the structure shown in (c) in FIG. 5 ;

(4) The metal wire 6 and the lead metal layer 7 are electroformed in the coil groove 2 sputtered with the seed layer 5 and the coil lead through hole 3 to obtain the structure shown in (d) of FIG. 5 .

Claims (2)

1, loses the manufacture method of plane solenoid deeply, it is characterized in that: utilize the normal optical lithography to define coil pattern on Si sheet surface, utilize the Si deep etching technology again, by the coil pattern that has defined, obtain being used for the coil groove and the coil lead through hole of damascene wiring plain conductor in Si sheet surface etch, carry out metal plating in the online ring recess, obtain the metal structure of coil, the surface roughness of utilizing coil groove inner surface to be produced in etching process is embedded in coil in the coil groove securely.

2, lose the plane solenoid deeply, comprise: substrate (1), coil lead through hole (3), insulating barrier (4), Seed Layer (5), lead-in wire metal level (7), it is characterized in that also comprising: coil groove (2), metal wire (6), wired ring recess of substrate (1) surface etch (2) and coil lead through hole (3) have insulating barrier (4) in the growth of the outer surface of substrate (1), coil groove (2) and coil lead through hole (3); In the bottom of the coil groove (2) that has insulating barrier (4) Seed Layer (5) and metal wire (6) are arranged; At the sidewall of the coil lead through hole (3) that has insulating barrier (4) Seed Layer (5) and lead-in wire metal level (7) are arranged, metal wire (6) at grade equidistantly repeatedly coiling and being embedded in the coil groove (2) constitute.

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