CN103088374A - Ultrasound-assisted electroforming method for improving thickness uniformity of micro-electroforming coating - Google Patents

Abstract

The invention provides an ultrasound-assisted electroforming method for improving thickness uniformity of a micro-electroforming coating, belongs to the technical field of micro-manufacture, relates to micro-electroforming metal category, and in particular relates to an ultrasound-assisted electroforming method for improving thickness uniformity of a micro-electroforming coating. The method is characterized in that in an ultrasound-assisted micro-electroforming process, an electroforming tank which is provided with a cathode back panel, an anode and electroforming liquid is arranged in an ultrasound cleaning machine with a temperature control device, and ultrasound vibration is applied while electroforming is carried out. The method has the effects and benefits that the defects of poor university, low processing efficiency and the like caused by the existing method can be overcome, a uniform coating can be obtained under a condition of higher current density; the method is simple and practicable, and is good in universality; and the production efficiency and mechanical performance of the electroforming microdevice are improved and the service life of the electroforming microdevice is prolonged.

Description

A kind of ultrasonic auxiliary electrical casting method that improves the micro-electroforming cast layer thickness homogeneity

Technical field

The invention belongs to the micro-fabrication technology field, relate to little electroforming metal class, specially refer to a kind of ultrasonic auxiliary electrical casting method that improves the micro-electroforming cast layer thickness homogeneity.

Background technology

Along with the development of device microminiaturization and micro electro mechanical system (MEMS) technology, little electroforming process is applied in fields such as aerospace, precision optical machinery, biologic medical, Mould Machining, communications as a kind of important fine machining method.In the process of utilizing little electroforming process making device, the inconsistent problem of cast layer fringe region and intermediate zone thicknesses often appears, particularly work as current density greater than 1A/dm ²The time, the ununiformity of cast layer is more obvious.Mostly the existing technology of improving uniformity is from aspects such as the distribution of current density and sizes, as " Micrometer-Nanometer Processing Technology " the 5th phase 45-49 page in 2008, a kind of method of improving microstructure cast layer thickness evenness by interpole in the interpolation cathode sheets has been proposed, and the interpole live width is larger, and the cast layer thickness evenness is better.But this method need to design separately mask plate, does not have versatility, and the metal that deposits to interpole is unwanted metal, easily causes waste of material." optics and precision engineering " the 16th the 3rd phase of volume 452-458 page in 2008 has proposed a kind ofly to obtain the method for even cast layer by regulating current density, and to provide the current density parameter that obtains the excellent homogeneity cast layer be i=0.4 ~ 0.8A/dm ², but this current density value is too small for actual production, and working (machining) efficiency is low, is not suitable for quick production.

The drawbacks limit such as although existing improving one's methods improved the homogeneity of cast layer to a certain extent, and versatility is poor, electroforming efficient is low its application in practice, therefore need a kind of method of novel raising cast layer thickness evenness.

Summary of the invention

Purpose of the present invention provides a kind of ultrasonic auxiliary electrical casting method, to solve the deficiencies such as the versatility that existing method brings is poor, working (machining) efficiency is low, uses present method can be greater than 1.5 A/dm ²Current density under obtain cast layer comparatively uniformly.

Technical scheme of the present invention is a kind of ultrasonic method of assisting electroforming that applies in traditional electroforming process.Comprise making, ultrasonic auxiliary little electroforming of ni substrate pre-treatment, little electroforming glued membrane and remove the glued membrane operation.It is characterized in that in the operation of ultrasonic auxiliary little electroforming, the electrotyping bath that negative electrode backboard, anode and electroforming solution are housed is placed in supersonic cleaning machine with temperature regulating device, apply ultrasonic vibration in the time of electroforming.Its making step is as follows:

(1) ni substrate pre-treatment: at first ni substrate is ground and polishing, making its roughness Ra value is 0.03～0.04 μ m, then use successively acetone and ethanol to carry out ultrasonic cleaning each 20 minutes to ni substrate, rinse with deionized water again, the baking oven of putting into 120 ℃ after nitrogen dries up cured 120 minutes, was cooled to room temperature after taking-up;

(2) little electroforming glued membrane is made: uses desk-top sol evenning machine spin coating SU-8 photoresist material on ni substrate, regulates the sol evenning machine rotating speed obtaining certain thickness glued membrane, through standing, front baking, exposure, after dry by the fire and the operation such as development obtains required microstructure glued membrane.

(3) ultrasonic auxiliary little electroforming: will be fixed in the ni substrate of SU-8 glue microstructure on the negative electrode backboard, again with the negative electrode backboard, anode and electroforming solution are put into electrotyping bath, at last electrotyping bath is placed in the supersonic cleaning machine with temperature regulating device, the frequency of supersonic cleaning machine is 40kHz, regulating bath temperature is 50 ℃, and ultrasonic power is 250W, and current density is 1.5A/dm ², apply ultrasonic vibration in the time of electroforming, obtain the nickel cast layer after electroforming;

(4) remove glued membrane: the ni substrate after electroforming is immersed SU-8 glue is housed removes photoresist in the beaker of liquid, soak in the water-bath environment of 85 ℃, until SU-8 glue all removes, take out ni substrate with microstructure with deionized water rinsing after, then dry up with nitrogen.

Effect of the present invention and benefit are: solved the deficiencies such as the versatility that existing method brings is poor, working (machining) efficiency is low, can obtain more uniform cast layer under higher current density condition, and simple, versatility is good, has improved mechanical property and the work-ing life of production efficiency and electroforming micro element.

Description of drawings

Fig. 1 is the exposure process schematic diagram.

Fig. 2 is the developing procedure schematic diagram.

Fig. 3 is the electroforming process schematic diagram.

Fig. 4 is the operation schematic diagram that removes photoresist.

In Fig. 1 ~ Fig. 4: 1 ni substrate, 2 SU-8 photoresist materials, 3 mask plates, 12 nickel cast layers, UV represents UV-light.

Fig. 5 is the ultrasonic mode schematic diagram that applies.

In Fig. 5: 4 negative electrode backboards, 5 anodes, 6 electroforming solution, 7 electrotyping baths, 8 supersonic cleaning machines, 9 water, 10 ultrasonic transducers, 11 electrocasting machine power supplys.

Fig. 6 is snakelike cast layer mask plate schematic diagram.

Embodiment

Be described in detail the concrete embodiment of the present invention below in conjunction with technical scheme and accompanying drawing.

For example: the snakelike cast layer of electroforming one on ni substrate 1, cast layer live width are 200 μ m, long 20mm, and adjacent line-to-line is apart from being 200 μ m, mask plate is as shown in Figure 6.Ni substrate 1 is of a size of 63 * 63 * 5mm, and concrete steps are as follows:

(1) ni substrate pre-treatment: ni substrate 1 is ground and polishing, making its roughness Ra value is 0.03～0.04 μ m, then use successively acetone and ethanol to carry out ultrasonic cleaning each 20 minutes to ni substrate 1, with drying up with nitrogen again after deionized water rinsing, the baking oven of putting into 120 ℃ dried by the fire 120 minutes, was cooled to room temperature after taking-up;

(2) whirl coating and front baking: utilize desk-top photoresist spinner spin coating SU-8 photoresist material on ni substrate 1, setting the photoresist spinner rotating speed is 800r/min, time is 18s, can obtain the glue-line that thickness is 60 μ m, then the horizontal positioned substrate makes it from smooth 30min, then the ni substrate that will scribble the SU-8 photoresist material is positioned in electric drying oven with forced convection, regulates dry the temperature inside the box to 65 ℃ baking 40 minutes, again temperature is increased to 85 ℃ and continues baking 40 minutes, be cooled to room temperature after taking-up;

(3) exposure and rear baking: the ni substrate that scribbles SU-8 glue after utilizing ultraviolet exposure machine to front baking carries out contact exposure, and exposure dose is 400mJ/cm ², the time is 5 minutes, sees accompanying drawing 1.Then after the ni substrate after exposing is positioned on the hot plate of 85 ℃, baking was cooled to room temperature after 90 seconds;

(4) develop: the ni substrate after exposing is immersed in the SU-8 glue developing solution, does not all dissolve until be subject to the colloid of UV-irradiation, rinses well with deionized water after ni substrate is taken out, and sees accompanying drawing 2;

(5) little electroforming: will be fixed in the ni substrate of SU-8 glue microstructure on negative electrode backboard 4, with negative electrode backboard 4, anode 5 and electroforming solution 6 are put into electrotyping bath 7, again electrotyping bath 7 is placed in the supersonic cleaning machine 8 with temperature regulating device, the frequency of supersonic cleaning machine is 40kHz, it is 50 ℃ that bath temperature is set, and ultrasonic power is 250W, and it is 1.5A/dm that adjusting electrocasting machine power supply 11 arranges current density ², apply ultrasonic vibration in the time of electroforming, obtain nickel cast layer 12, see accompanying drawing 3 and accompanying drawing 5.The formula of electroforming solution is nickel sulfamic acid: 365 ~ 375g/L, nickelous chloride: 6 ~ 10g/L, boric acid: 55 ~ 60g/L, electroforming solution pH value: 3.8 ~ 4.1;

(6) remove glued membrane: the micro-mould after electroforming is immersed SU-8 glue is housed removes photoresist in the beaker of liquid, soak, until in cast layer, SU-8 glue is all removed, obtain microstructure with deionized water rinsing, see accompanying drawing 4 in the water-bath environment of 85 ℃.

That adopts that the present invention proposes applies the method that electroforming assist in ultrasonic vibration in the electroforming process, can under higher current density, still can obtain comparatively uniform cast layer.At current density 1.5A/dm ², ultrasonic power 250W, temperature 50 C condition under electroforming, apply ultrasonic resulting cast layer contrast and do not apply ultrasonic resulting cast layer, thickness evenness improves 22%.

Claims (1)

1. ultrasonic auxiliary electrical casting method that improves the micro-electroforming cast layer thickness homogeneity, comprise making, ultrasonic auxiliary little electroforming of ni substrate pre-treatment, little electroforming glued membrane and remove the glued membrane operation, it is characterized in that in the operation of ultrasonic auxiliary little electroforming, the electrotyping bath that negative electrode backboard, anode and electroforming solution are housed is placed in supersonic cleaning machine with temperature regulating device, apply ultrasonic vibration in the time of electroforming, its making step is as follows:

(1) ni substrate pre-treatment: at first ni substrate is ground and polishing, making its roughness Ra value is 0.03～0.04 μ m, then use successively acetone and ethanol to carry out ultrasonic cleaning each 20 minutes to ni substrate, rinse with deionized water again, the baking oven of putting into 120 ℃ after nitrogen dries up cured 120 minutes, was cooled to room temperature after taking-up;

(2) little electroforming glued membrane is made: uses desk-top sol evenning machine spin coating SU-8 photoresist material on ni substrate, regulates the sol evenning machine rotating speed obtaining certain thickness glued membrane, through standing, front baking, exposure, after dry by the fire and the operation such as development obtains required microstructure glued membrane;

(3) ultrasonic auxiliary little electroforming: will be fixed in the ni substrate of SU-8 glue microstructure on the negative electrode backboard, again with the negative electrode backboard, anode and electroforming solution are put into electrotyping bath, at last electrotyping bath is placed in the supersonic cleaning machine with temperature regulating device, the frequency of supersonic cleaning machine is 40kHz, regulating bath temperature is 50 ℃, and ultrasonic power is 250W, and current density is 1.5A/dm ², apply ultrasonic vibration in the time of electroforming, obtain the nickel cast layer after electroforming;

(4) remove glued membrane: the ni substrate after electroforming is immersed SU-8 glue is housed removes photoresist in the beaker of liquid, soak in the water-bath environment of 85 ℃, until SU-8 glue all removes, take out ni substrate with microstructure with deionized water rinsing after, then dry up with nitrogen.

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