CN102011125B - Metal wet etching device and process for preparing MEMS structure - Google Patents

Abstract

The invention discloses a metal film wet etching device and process for preparing an MEMS structure on a silicon chip with a large size. The process mainly comprises the following steps of: placing the patterned silicon chip on a clamp with a special design; during the corrosion process, immerging the silicon chip in etching liquid, and enabling the clamp to slowly and evenly rotate under the driving of a motor; slightly stirring the etching liquid by adopting high-purity nitrogen, and observing and monitoring the change on the surface of the silicon chip until completely removing the related film layers needing to be removed. By adopting the device and the process, the etched patterns with little etching and excellent evenness can be obtained on the silicon chip in the large size.

Description

A kind of metal Wet-method etching device and etching technics that is used for the preparation of MEMS structure

Technical field

The present invention relates to metal wet etching technique field, be specifically related to a kind of metal Wet-method etching device and etching technics of the MEMS of being used for structure preparation.

Background technology

Along with science and technology development; Electromechanical devices miniaturized day by day, integrated and intelligent; And microelectromechanical-systems (Micro electromechanical system, MEMS) manufacturing technology realizes being applied to real intelligent with the microminiaturized most important means of electromechanical devices of different field just.Because MEMS makes the based semiconductor process manufacturing technology, therefore also help the reduction of manufacturing cost simultaneously.

As everyone knows, etching is the essential step operation in the semiconductor technology, its objective is and remove the thin film layer of not sheltered by resist (like photoresist material), thereby obtain on the film with resist film on the technology of identical figure.Etching can be divided into two kinds of wet method and dry etchings again.Wherein the characteristics of wet etching isotropic etching make the crossing of thin film layer that is difficult to avoid resist is sheltered carve (Over Etch).And this even less than 1 μ m cross to carve for the semiconductor fabrication that develops into the ULSI stage all be unacceptable; Because it causes the waste of valuable silicon area, therefore the semiconductor maker adopts dry etching (Dry Etch) technology with anisotropic character now.But for integrated level lower the MEMS device, the totally unnecessary requirement of the utilization ratio of chip area is so harsh.With respect to dry etching, the low cost of wet-etching technology and high etching selection ratio still have very big magnetism still more.In addition, a lot of materials of using in the MEMS technology, particularly metallic substance (like NiCr, Au, Cu etc.) with semiconductor technology and incompatible, also untappedly go out perhaps can't adopt dry etch process.And this is not a problem for wet-etching technology, sells because early have on the market to various metallic substance and business-like etching agent.

But as stated; In the wet-etching technology crossing of mask below rete carved; Particularly uneven cross to carve still proposed very big challenge for its widespread use in MEMS technology in the sheet, and this challenge is for large-diameter silicon wafer-like 150mm (or 6 inches) silicon chip-seem more severe.Though a lot of patent and documents about wet-etching technology have been arranged, have not seen homogeneity and the report of crossing the amount at quarter so far as yet for the etching result.The present invention is directed to this, and a kind of Wet-method etching device and technology of novelty is provided.

Summary of the invention

Problem to be solved by this invention is: metal Wet-method etching device and etching technics that how a kind of MEMS of being used for structure preparation is provided; This device and technology have overcome existing defective in the prior art, are particularly suitable for for reaching the microstructure preparation that homogeneity, repeatability are had relatively high expectations between sheet in live width and the sheet.

Technical problem proposed by the invention is to solve like this: the metal Wet-method etching device that a kind of MEMS of being used for structure preparation is provided; It is characterized in that; The motor that is arranged on the bracing or strutting arrangement 120 connects motor speed controller and small-sized DC variable-speed motor 20; Said small-sized DC variable-speed motor 20 is through union lever 30 suspension silicon chip anchor clamps 40; The corresponding below of said silicon chip anchor clamps 40 is provided with the corrosive fluid container 50 that supports through container support frame 130, and the bottom of said corrosive fluid container 50 is provided with equally distributed inlet mouth, and high pure nitrogen feeds from this inlet mouth; The air pressure of control high pure nitrogen realizes being contained in the mild agitation of the etching agent in the corrosive fluid container 50; The lower end of said silicon chip anchor clamps 40 is placed with metallic diaphragm silicon chip 80 to be etched, and said small-sized DC variable-speed motor 20 drives silicon chip anchor clamps 30 and at the uniform velocity slowly rotates under the transmission of motor speed controller 10, makes the metallic diaphragm silicon chip to be etched 80 that immerses etching liquid accomplish etching.

According to the metal Wet-method etching device that is used for the preparation of MEMS structure provided by the present invention, it is characterized in that said high pure nitrogen is stored in the high pure nitrogen bottle, feed in the corrosion container 50 through the gas pipeline 110 that is connected with inlet mouth.

According to the metal Wet-method etching device that is used for the preparation of MEMS structure provided by the present invention, it is characterized in that said union lever 30 comprises straight bar part 31, spring 32, bearing 33 and crotch 34.

A kind of etching technics that utilizes the metal wet method device of the above-mentioned MEMS of being used for structure preparation is characterized in that, may further comprise the steps:

Metallic diaphragm silicon chip 80 levels to be etched that 1. will be coated with graphical photoresist material are perhaps near being placed horizontally on the silicon chip anchor clamps 40 and regulating silicon chip to the appropriate location;

The air pressure regulator 100 of 2. reconciling high pure nitrogen bottle 90 bottle mouth positions makes high pure nitrogen get into etching liquid container 50, and the air pressure size is as the criterion with the soft stirring that realizes etching liquid;

3. regulating motor speed controller 10 at the uniform velocity slowly rotates silicon chip anchor clamps 40;

4. carry out etching below steadily metallic diaphragm silicon chip 80 to be etched being immersed in the liquid level of etching liquid of corrosive fluid container fully through union lever 30; After etching is accomplished; Steadily and promptly silicon chip anchor clamps 40 are taken off and are immersed in the deionized water of next door cleaning sink from union lever 30, carry out spray Cleaning for High Capacity simultaneously;

5. regulate motor speed controller and stop the motor rotation;

6. close variable valve 100;

7. the monitoring resistance of the metal film layer that silicon chip do not cover by photoresist material that is etched, the surface condition of examining under a microscope silicon chip 80 then check whether have residually, have residually if measure resistance or surface, and repeating step is 2.～6. thorough until etching;

8. remove photoresist technology to remove photoresist material after drying up the silicon chip that is etched with high pure nitrogen;

9. with standard cleaning technology cleaning silicon chip and oven dry, note and in microscope, observe metal film layer figure live width, quarter width and the keeping records excessively that obtains.

Beneficial effect of the present invention: adopt above Wet-method etching device and technology to obtain to carve less, and the etching figure that has good uniformity has realized that the metal NiCr etching is crossed quarter≤0.5 μ m, heterogeneity≤5% in the 150mm silicon chip.

Description of drawings

Fig. 1 is an apparatus structure synoptic diagram of the present invention;

Fig. 2 is the structural representation of metallic diaphragm silicon chip to be etched among Fig. 1;

Fig. 3 is the structural representation of union lever among Fig. 1.

10, motor speed controller, 20, the small-sized DC variable-speed motor, 30, union lever, 40, the silicon chip anchor clamps, 50, the corrosive fluid container, 60, gondola water faucet, 70, etching fluid; 80, metallic diaphragm silicon chip to be etched; 90, high pure nitrogen bottle, 100, air pressure regulator, 110, gas pipeline, 120, bracing or strutting arrangement, 130, the container support frame, 31, straight bar part, 32, spring, 33, bearing, 34, crotch, 81, straight bar part, 82, metal film layer, 83, photoresist material.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described:

As shown in Figure 2, metallic diaphragm silicon chip 80 to be etched comprises silicon chip 81, metal film layer 82 and patterned photoresist material 83.As shown in Figure 1, the metallic diaphragm silicon chip 80 to be etched that is coated with graphical photoresist material is positioned on the silicon chip anchor clamps 40 (as shown in Figure 3) of particular design near level attitude.The silicon chip anchor clamps 40 general polytetrafluoroethylmaterial materials that adopt.Silicon chip anchor clamps 40 link to each other with small-sized DC variable-speed motor 20 through union lever 30.The etching agent splendid attire in particular design and not with the corrosive fluid container 50 (generally adopting polytetrafluoroethylmaterial material) of etching agent reaction in; Equally distributed inlet mouth feeds high pure nitrogen from corrosive fluid container 50 bottoms; Control air pressure is realized the mild agitation of etching agent; Direct-current machine drives at the uniform velocity slowly rotation of silicon chip anchor clamps 40, when silicon chip anchor clamps 40 carry silicon chip from directly over vertical immerse etching agent and silicon chip to be immersed in etching agent fully after the timing of beginning etching.The variation of silicon chip surface observation in etching process, the resistance change of monitoring metallic diaphragm simultaneously is to obtain etch rate.Through the etching of several pieces experiment slices, can obtain satisfied etching result at last.Experimental result shows that this technology of employing can obtain good reproducibility, crosses and carves≤0.5 μ m, the graphic structure of heterogeneity≤5%.

Mf can be Ni, Cr, NiCr, Au, Ag, Cu, Ti, Al, W, Mo, any metallic material film of using in the MEMS technologies such as Pt;

Concrete technological process is following:

1. utilize standard photolithography process on the silicon substrate that deposits metal film layer, to form pattern to be etched as shown in Figure 2 (wherein 81-silicon substrate, 82-metal film layer, 83-mask).

2. silicon chip 80 levels of pattern will be formed or, silicon chip can be regulated to correct position through the bayonet socket on the anchor clamps near being placed horizontally on the silicon chip anchor clamps 40.

3. the air pressure regulator 100 of regulating high pure nitrogen bottle 90 bottle mouth positions makes high pure nitrogen get into etching liquid container 50, and the air pressure size is as the criterion with the soft stirring that realizes etching liquid 70.

4. regulating motor speed controller 10 at the uniform velocity slowly rotates silicon chip.

5. the formation of union lever 30 is as shown in Figure 3, comprises the 31-straight bar part, and 32-makes spring by oneself, 33-bearing, 34-band hook part straight-bar.The silicon chip anchor clamps break away from the liquid level of etching liquid 70 when wherein making spring 32 by oneself and can guarantee that it is lax fully, and when clamp and silicon chip tensioned, can make silicon chip be immersed in the etching liquid 70 fully and anchor clamps are not touched container so that anchor clamps can rotate freely.

6. the bearing 33 of hand-held union lever 30 makes anchor clamps carry the liquid level that silicon chip just breaks away from etching liquid 70.

7. the bearing 33 of hand-held union lever 30 steadily with in complete submergence of silicon chip and the etching liquid 70 time timing begin.Behind the appropriate time (according to before experimental result resultant), steadily and promptly anchor clamps are carried silicon chip and take off and be immersed in the deionized water of next door cleaning sink from the hook 34 of union lever 30, carry out spray Cleaning for High Capacity simultaneously.

8. regulate motor speed controller and stop the motor rotation.

9. close variable valve 100.

10. the resistance of the metal film layer that is not covered by photoresist material on the monitoring wafer 80 is examined under a microscope the surface condition of silicon chip 80 then and is checked whether residual (or pollution) is arranged.Have residually if measure resistance or observe the surface, repeating step 2～10 is thorough until etching.

11. dry up the silicon chip technology of removing photoresist after 80s to remove the photoresist material 83 on the metal level 82 with high pure nitrogen.

12. with standard cleaning technology cleaning silicon chip and oven dry, microscopically is noted important indicator and keeping records such as metal layer image live width, mistake width at quarter and etching homogeneity.

So far technology finishes.

Said etching liquid be directed against more than the commercial etching liquid or the autogamy etching liquid of arbitrary metallic film material.

Claims (4)

1. one kind is used for the metal Wet-method etching device that the MEMS structure prepares; It is characterized in that; The motor that is arranged on the bracing or strutting arrangement (120) connects motor speed controller and small-sized DC variable-speed motor (20); Said small-sized DC variable-speed motor (20) is through union lever (30) suspension silicon chip anchor clamps; The corresponding below of said silicon chip anchor clamps (40) is provided with the corrosive fluid container (50) that supports through container support frame (130), and the bottom of said corrosive fluid container (50) is provided with equally distributed inlet mouth, and high pure nitrogen feeds from this inlet mouth; The air pressure of control high pure nitrogen realizes being contained in the mild agitation of the etching agent in the corrosive fluid container (50); The lower end of said silicon chip anchor clamps (40) is placed with metallic diaphragm silicon chip to be etched (80), and said small-sized DC variable-speed motor (20) drives silicon chip anchor clamps (40) and at the uniform velocity slowly rotates under the transmission of motor speed controller (10), makes the metallic diaphragm silicon chip to be etched (80) that immerses etching liquid accomplish etching.

2. the metal Wet-method etching device that is used for the preparation of MEMS structure according to claim 1 is characterized in that said high pure nitrogen is stored in the high pure nitrogen bottle, feeds in the corrosive fluid container (50) through the gas pipeline (110) that is connected with inlet mouth.

3. the metal Wet-method etching device that is used for the preparation of MEMS structure according to claim 1 is characterized in that said union lever (30) comprises straight bar part (31), spring (32), bearing (33) and crotch (34).

4. an etching technics that utilizes the metal wet method device of the described MEMS of the being used for structure preparation of claim 1 is characterized in that, may further comprise the steps:

The metallic diaphragm silicon chip to be etched (80) that 1. will be coated with graphical photoresist material is placed horizontally at silicon chip anchor clamps (40) and goes up and regulate silicon chip to the appropriate location;

The air pressure regulator (100) of 2. reconciling high pure nitrogen bottle (90) bottle mouth position makes high pure nitrogen get into corrosive fluid container (50), and the air pressure size is as the criterion with the soft stirring that realizes etching liquid;

3. regulating motor speed controller (10) at the uniform velocity slowly rotates silicon chip anchor clamps (40);

4. carry out etching below steadily metallic diaphragm silicon chip to be etched (80) being immersed in the liquid level of etching liquid of corrosive fluid container fully through union lever (30); Behind the certain hour; Steadily and promptly silicon chip anchor clamps (40) are taken off and are immersed in the deionized water of next door cleaning sink from union lever (30), carry out spray Cleaning for High Capacity simultaneously;

5. regulate motor speed controller and stop the motor rotation;

6. close air pressure regulator (100);

7. the monitoring resistance of the metal film layer that silicon chip do not cover by photoresist material that is etched, the surface condition of examining under a microscope silicon chip (80) then check whether have residually, have residually if measure resistance or surface, and repeating step is 2.～6. thorough until etching;

8. remove photoresist technology to remove photoresist material after drying up the silicon chip that is etched with high pure nitrogen;

9. with standard cleaning technology cleaning silicon chip and oven dry, microscopically is noted metal film layer figure live width, quarter width and etching homogeneity and keeping records excessively.

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