TWI445064B - Super micro-atomized spray painting method - Google Patents

Description

Ultra-micro atomization spraying method

The invention relates to a processing technology of a semiconductor microstructure. Further, the invention is a chemical atomization spraying processing method capable of improving productivity.

Three-dimensional stacked package, micro-electro-mechanical system (MEMS) package, vertical integrated sensor array and desktop MOS power device flip-chip soldering technology, IC integrated packaging technology from 2D to 3D development, requires crystals with large undulations The circular surface is evenly coated with a protective isolation dielectric layer (such as photoresist, liquid photo-image solder resist, etc.). The conventional rotary coating method is suitable for uniformly coating the photoresist on a flat surface, which is difficult to meet the requirements of the three-dimensional microstructure of the wafer. , atomized spray technology came into being.

In the existing atomization spraying technology, the pre-processed wafer has two processing methods: one is to scan on a rotating wafer through a nozzle, and the atomized liquid particles are sprayed on the wafer by using a change in scanning speed and wafer rotation speed. Surface, this method is variable, difficult to control, resulting in poor surface uniformity; the other way is to use a nozzle to scan the entire wafer over the wafer, and the uniformity is more uniform. Ok, but the production yield is greatly reduced.

The main object of the present invention is to provide an ultra-micro atomized spraying method which solves the problems of poor surface uniformity and low productivity in the prior art.

The technical scheme of the present invention is as follows: an ultra-micro atomized spraying method, in which two or more nozzles are homogenously subjected to two-dimensional scanning motion along the XY axis, and the atomized chemical liquid is applied to the entire wafer, and the wafer is rotated. Spray the second time and repeat the spin spray until the target thickness is reached.

In the foregoing ultra-micro atomization spraying method, the nozzle is an ultrasonic nozzle or two fluid nozzles, and the chemical liquid is ultra-micro atomized. After atomization, the diameter of the liquid particles is 0.1-200 micrometers, and after atomization, the small particles of the liquid are pressurized gas. Under the action of accelerated spraying onto the surface of the wafer, the wafer is heated to adhere the chemical to the surface of the wafer.

In the aforementioned ultra-micro atomization spraying method, the gas pressure is controlled between 0.5 and 1.5 bar.

In the aforementioned ultra-micro atomization spraying method, the wafer is heated while being sprayed, and the heating temperature is controlled at 50-120 °C.

In the aforementioned ultra-micro atomization spraying method, the wafer is in a fixed state when being sprayed.

In the aforementioned ultra-micro atomization spraying method, the nozzle is located vertically above the wafer to be sprayed, and the distance of the nozzle from the wafer to be sprayed is in the range of 15-30 mm.

In the aforementioned ultra-micro atomization spraying method, the wafer rotation angle is an integral multiple of 30°.

In the aforementioned ultra-micro atomization spraying method, the flow rate of the liquid flowing into each nozzle is controlled at 1-8 ml/min.

In the aforementioned ultra-micro atomization spraying method, the scanning pitch of the nozzle in the Y-axis direction is controlled within a range of 4-10 mm, and the scanning speed of the nozzle in the X-axis direction is controlled at 40-180 mm/min.

In the aforementioned ultra-micro atomization spraying method, the distance between nozzles S≧R+D, R is the radius of the wafer, and D is the size of the nozzle forming a spot on the wafer.

The beneficial effects of the invention are:

1. The present invention greatly improves the yield by using two or more nozzles to work simultaneously. The single nozzle coating yields 7-8 pieces per hour, with a double nozzle yield of up to 15 sheets per hour, and the yield can be nearly doubled as the nozzle increases.

2. The nozzle of the invention can adopt two fluid nozzles, the cost is reduced, it is suitable for more chemicals, and it is not easy to block and is easy to maintain.

3. The liquid and gas of each nozzle of the invention are supplied by independent pipes without mutual interference, and the precision can be ensured.

4. When the nozzle of the invention is in operation, the wafer is heated, the liquid adhering to the wafer is quickly solidified, the liquid is prevented from flowing, the coating is covered by the sharp corners, and the thick coating is not accumulated at the groove, thereby improving the uniformity of the coating. Sex.

5. The invention can improve the yield and improve the uniformity of the coating, and can realize the homomorphic ultra-micro atomized spraying of two or more nozzles.

The invention and its various features and advantages will be more fully described by reference to the accompanying drawings.

The present invention processes microstructures (e.g., microelectronic structures) by ultra-micro atomized spray coating, which are typically etched. The coating acts as a mask to protect these structures, at least not to be greatly affected by the chemicals used in subsequent processes.

Figure 1 is a top plan view of a wafer to be painted in the preferred embodiment. Figure 2 is a cross-sectional view of the wafer A-A hatching shown in Figure 1, the surface of the wafer being rugged.

Two or more nozzles are homomorphically scanned along the XY axis for two-dimensional scanning, applying the atomized chemical solution to the entire wafer, rotating the wafer, performing the second spraying, and then repeating the rotating coating until the target thickness is reached. Forming a protective isolation dielectric layer.

As shown in FIG. 3, the X-axis 301 is fixed, the Y-axis 302 can be translated on the X-axis 301 and the speed is adjustable; two identical nozzles: the movement of the first nozzle 303 and the second nozzle 304 fixed to the Y-axis 302 At block 309, the distance S between the two nozzles is indicated at 305. The first nozzle 303 and the second nozzle 304 perform a synchronous scanning motion over the wafer 306 along the trajectory 307, and the scanning pitch P in the Y-axis direction is indicated by 308. The first nozzle 303 and the second nozzle 304 are simultaneously in the same state, and the last scanning track of the second nozzle 304 and the first scanning track of the first nozzle 303 are engaged to complete the spraying once. According to the three-dimensional structure of the wafer, the wafer is rotated at a certain angle for a second scan until the target thickness is reached.

In the present invention, the homomorphism means that the process parameters of all the nozzles are the same, including: the flow rate of the chemical entering the nozzle, the gas pressure entering the nozzle, the ultrasonic energy control of the nozzle, the height of the nozzle from the wafer, and the nozzle in the X direction. Speed, scanning pitch of the nozzle in the Y-axis direction.

In the present invention, the number of nozzles depends on the size or the number or distribution of the wafer to be sprayed. The nozzle is an ultrasonic nozzle or two fluid nozzles, and the chemical liquid is ultra-micro atomized. The diameter of the liquid particles after atomization is in the range of 0.1-200 micrometers. Inside (20 micrometers in this embodiment), after atomization, small particles of liquid are accelerated to the surface of the wafer under the action of pressurized gas, and the wafer is heated to cause the chemical to quickly adhere to the surface of the wafer.

In the present invention, the nozzle is located vertically above the wafer to be sprayed, and the vertical distance from the plane of the wafer to be sprayed is in the range of 15-30 mm (22 mm in this embodiment) with an error in the range of 1 mm.

In the present invention, the angle of rotation of the wafer may be an integral multiple of 30° (60° in this embodiment), depending on the three-dimensional structure of the wafer.

In the present invention, the flow rate of the liquid flowing into each nozzle is controlled at 1-8 ml/min (3 ml/min in the present embodiment), and the error is controlled in the range of 0.5 ml/min; the inner diameter of the nozzle is in the range of 0.1 to 1 mm ( This embodiment is 0.5 mm).

In the present invention, the scanning pitch P in the Y-axis direction is controlled in the range of 4 - 10 mm (6 mm in this embodiment), depending on the size D of the nozzle forming the diameter of the spot on the wafer. The diameter of the spot circle D refers to the diameter of the nearly circular pattern formed by spraying the chemical liquid on the wafer after the nozzle is immobilized by the nozzle.

In the present invention, the distance between the nozzles is S ≧ R + D. R is the radius of the wafer. In this embodiment, the radius of the wafer is R=100 mm; D is the diameter of the spot circle. In this embodiment, the diameter D of the spot ring is in the range of 3-30 mm.

In the present invention, the scanning speed of the nozzle along the X-axis is controlled at 40-180 mm/min (100 mm/min in the present embodiment).

The nozzle of the invention has two lines of gas and liquid, and the liquid is atomized into tiny liquid particles through the nozzle, and is accelerated to the wafer under the action of the pressurized gas entering the nozzle to cover the sharp corners and the grooves of the wafer.

As shown in FIG. 4, the liquid supply line includes a chemical tank 401, a precise flow control pump 402, and a third nozzle 403. The chemical tank 401 sequentially connects the precise flow control pump 402 and the third nozzle 403 through the pipeline, respectively. In operation, the two precise flow control pumps 402 are provided with the same flow rate, the same opening and closing, ensuring that the liquids flowing into the two third nozzles 403 are in the same state.

As shown in FIG. 5, the gas supply line is provided with a pressure regulating valve 501, a digital display pressure gauge 502, a fourth nozzle 503, and a switch 504. The gas tanks are sequentially connected to the pressure regulating valve 501, the switch 504, and the fourth nozzle through pipelines. 503, the pressure regulating valve 501 is connected with a digital pressure gauge 502. The pressure regulating valve 501 is used to adjust the gas pressure, the pressure gauge 502 immediately monitors the pressure entering the fourth nozzle 503, the pressure regulating valve 501 is adjusted to make the two pressure gauges 502 the same value, and the switch 504 is used to control the supply and stop of the gas.

In the present invention, a pressurized gas acts on the atomized liquid particles to accelerate the spraying of the particles onto the surface of the wafer to be coated, and the gas pressure is controlled between 0.5 and 2.5 bar (1.6 bar in this embodiment).

When the nozzle of the invention is in operation, the wafer is heated when being sprayed, effectively preventing the flow of small liquid particles, accelerating the evaporation of moisture, and allowing the chemical to quickly adhere to the surface of the wafer, and the heating temperature is controlled at 50-120 ° C (this The example is 80 ° C), depending on the spray chemicals.

When the nozzle of the present invention is in operation, the wafer is in a fixed state when being sprayed, and the wafer is prevented from drifting under the influence of the pressurized gas, and the fixing manner depends on the structure of the coated wafer.

The results show that the present invention uses two or more nozzles to work simultaneously, greatly increasing productivity. The coating uniformity is optimized by adjusting parameters such as liquid flow rate, gas pressure, and scanning speed.

These and other features and advantages of the present invention will become more <RTIgt; It should be understood that the foregoing description of the preferred embodiments of the invention However, these are exemplary and not limiting. Many variations and modifications may be made without departing from the spirit of the invention, and the invention includes all such variations and modifications.

301. . . X axis

302. . . Y axis

303. . . First nozzle

304. . . Second nozzle

305. . . Distance between nozzles S

306. . . Wafer

307. . . Trajectory

308. . . Scanning pitch P in the Y-axis direction

309. . . Moving block

401. . . Chemical tank

402. . . Flow control pump

403. . . Third nozzle

501. . . Pressure regulating valve

502. . . Pressure gauge

503. . . Fourth nozzle

504. . . switch

1 is a top plan view of a wafer to be painted according to an embodiment of the present invention;

Figure 2 is a schematic cross-sectional view of the wafer A-A hatching shown in Figure 1;

Figure 3 is a schematic diagram of scanning of an embodiment of the present invention;

Figure 4 is a diagram of a liquid supply line of one embodiment of the present invention;

Figure 5 is a diagram of a gas supply line of one embodiment of the present invention.

301. . . X axis

302. . . Y axis

303. . . First nozzle

304. . . Second nozzle

305. . . Distance between nozzles S

306. . . Wafer

307. . . Trajectory

308. . . Scanning pitch P in the Y-axis direction

309. . . Moving block

Claims (9)

An ultra-micro atomized spraying method characterized in that two or more nozzles are homomorphic to perform two-dimensional scanning motion along the XY axis, and the atomized chemical liquid is applied to the entire wafer, and the wafer is rotated for the second The second spraying, and then the repeated spraying, until the target thickness is reached, the nozzle is an ultrasonic nozzle or two fluid nozzles, the chemical liquid is ultra-micro atomized, and the diameter of the liquid particles after atomization is 0.1-200 micrometers, and the liquid small particles after atomization Accelerated spraying onto the surface of the wafer under the action of pressurized gas, the wafer is heated, allowing chemicals to adhere to the surface of the wafer. The ultrafine atomization spraying method according to claim 1, wherein the gas pressure is controlled between 0.5 and 1.5 bar. The ultrafine atomization spraying method according to claim 1, wherein the wafer is heated while being sprayed, and the heating temperature is controlled at 50 to 120 °C. The ultrafine atomization spraying method according to claim 1, wherein the wafer is in a fixed state when being sprayed. The ultra-micro atomizing spraying method according to claim 1, wherein the nozzle is located vertically above the wafer to be sprayed, and the distance of the nozzle from the wafer to be sprayed is in the range of 15-30 mm. The ultrafine atomization spraying method according to claim 1, wherein the wafer rotation angle is an integral multiple of 30°. The ultra-micro atomized spraying method according to claim 1, wherein In the middle, the flow rate of the liquid flowing into each nozzle is controlled at 1-8 ml/min. The ultra-micro atomizing spraying method according to claim 1, wherein the scanning pitch of the nozzle in the Y-axis direction is controlled within a range of 4-10 mm, and the scanning speed of the nozzle along the X-axis direction is controlled at 40-180 mm/min. . The ultrafine atomization spraying method according to claim 1, wherein the distance between the nozzles is S≧R+D, R is the radius of the wafer, and D is the size of the nozzle forming a spot on the wafer.