CN114488697A - Photoresist bubble elimination device and photolithography system - Google Patents

Abstract

The invention provides a photoresist bubble eliminating device and a photoetching system, wherein the device comprises a pipeline, a buffer bottle and an ultrasonic generator; the ultrasonic generator is provided with a cavity, and the cavity is provided with a liquid inlet and a liquid outlet and is used for allowing the ultrapure water to enter the cavity from the liquid inlet and to be discharged out of the cavity from the liquid outlet; the pipeline is used for conveying photoresist; the buffer bottle is arranged on the pipeline, communicated with the pipeline and used for containing the photoresist, and at least one part of the buffer bottle is positioned in the range of the cavity. Compared with the prior art, the invention has obvious effect of eliminating the tiny bubbles in the photoresist and can prevent a great amount of photoetching defects caused by the tiny bubbles in the photoresist in the gluing and developing process.

Description

Photoresist bubble elimination device and photolithography system

technical field

The invention relates to the technical field of semiconductors, in particular to a photoresist bubble elimination device and a photolithography system.

Background technique

Since the invention of semiconductors, the transformation of patterns has been achieved by photolithography. Photolithography has become the key technology for the preparation of microelectronic devices and optoelectronic devices in today's science and technology. Following Moore's Law, the size and density of semiconductor devices continue to shrink, and the current semiconductor lithography process has entered the 5nm era. The essence of lithography is pattern transfer. First, photoresist is applied to the surface of the wafer to form a photosensitive material, and the pre-designed circuit pattern of the mask is projected onto the surface of the photosensitive material by irradiating ultraviolet light through a lithography machine. The developer is developed to complete the image transfer. As the size of integrated circuits continues to shrink, the challenges of the lithography process are also increasing. If the photoresist coating is slightly biased, it will directly affect the photochemical reaction, interfere with the pattern transfer, and eventually form a large number of defects on the silicon wafer. Therefore, it is very important to ensure the high-quality supply and coating of photoresist.

The general photoresist supply process is: open the photoresist bottle provided by the supplier, insert it into the machine pipeline and install it on the machine, pressurize it with nitrogen, and pass through the filter membrane, the photoresist enters the buffer bottle of the machine Then, the photoresist is pressed into the conveying pipeline by the pressure pump, and reaches the nozzle at the end of the machine for photoresist coating. In the actual process, the photoresist is transported for a long time and pressurized with nitrogen, and it is inevitable that fine bubbles will be formed inside. The bubbles are coated on the surface of the wafer through the pipeline. The yield rate of the large area of the circle is reduced or even scrapped.

In the prior art, in order to solve the problem of air bubbles in the photoresist, various methods have been adopted, such as the following three methods:

1. First, store the photoresist in a stable storage cabinet for more than 12 hours, and try to reduce internal air bubbles by standing. This method can only reduce the large air bubbles generated during transportation, and the removal effect of micro air bubbles is not ideal.

2. After installing the machine, press the photoresist into the filter membrane by nitrogen pressure, and reduce the tiny bubbles in the photoresist through the small aperture filter membrane. Due to the large pressure difference between the inside and outside, the filter membrane efficiency is low. , only a small amount of air bubbles can be removed, but not all air bubbles can be removed. The bubbles follow the photoresist into the buffer bottle, triggering the alarm of the bubble detector in the buffer bottle at any time. When the bubble alarm is triggered, the equipment engineer needs to remove the photoresist and spray the photoresist containing air bubbles out of the pipeline. Taking the actual operation online as an example, it takes at least one hour to clear the pipeline, which not only causes a large amount of light The resin is wasted, and it affects the normal operation of the machine, resulting in a lot of machine time waste.

3. At present, some patents have disclosed technical solutions for removing photoresist bubbles, and the principle is usually reduced pressure treatment. Reducing the pressure helps to remove bubbles to a certain extent, but the efficiency is not high, and the pressure reduction is likely to cause a drop in the saturated vapor pressure of the liquid, resulting in rapid evaporation of the liquid, deterioration of the lithography material, and greater impact.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a photoresist bubble elimination device and a photolithography system, which aim to prevent a large number of photolithography defects caused by the internal fine air bubbles of the photoresist during the process of coating and developing.

Based on one aspect of the present invention, the present invention provides a photoresist bubble elimination device, comprising:

The ultrasonic generator has a cavity, and the cavity has a liquid inlet and a liquid outlet, for the ultrapure water to enter the cavity from the liquid inlet, and from the liquid outlet expelling the cavity;

A pipeline, which is used to deliver the photoresist;

a buffer bottle, which is arranged on the pipeline and communicated with the pipeline, and is used for accommodating the photoresist, and at least a part of the buffer bottle is located within the scope of the cavity.

Optionally, the photoresist bubble elimination device further includes an exhaust buffer chamber, the exhaust buffer chamber is connected to the buffer bottle through a solenoid valve; the exhaust buffer chamber can be supplied with nitrogen gas.

Optionally, the photoresist bubble elimination device further includes a first pressure gauge and a first vacuum pump; the first pressure gauge is used to detect the pressure value in the exhaust buffer chamber; when the first pressure gauge detects When the pressure value of is outside the first preset range, the first vacuum pump evacuates the exhaust buffer chamber.

Optionally, the photoresist device further includes at least one filtering component disposed on the pipeline, the buffer bottle and the filtering component are arranged in sequence according to the conveying direction of the photoresist; the filtering The assembly includes a degassing filter membrane arranged in the pipeline, the degassing filter membrane has a plurality of filter holes, and the filter holes are used for filtering the air bubbles of the photoresist.

Optionally, the degassing filter membrane is tubular, and there is a gap between the degassing filter membrane and the inner wall of the pipeline to form an interlayer; the filtering assembly further includes a second pressure gauge and a second vacuum pump; The second pressure gauge is used to detect the pressure value in the interlayer; when the pressure value detected by the second pressure gauge is outside the second preset range, the second vacuum pump evacuates the interlayer.

Optionally, a third pressure gauge and a pressure pump are provided on the pipe section of the pipeline away from the buffer bottle; the first pressure gauge is used to detect the pressure value in the pipeline; the pressure pump is used for The photoresist is driven along the conduit.

Optionally, a nozzle is provided at one end of the pipeline away from the buffer bottle.

Optionally, at least one air bubble detector is respectively provided in the buffer bottle and on the pipeline for detecting the air bubble content of the photoresist, and when it is detected that the air bubble content of the photoresist exceeds a threshold value. Send an alarm signal.

Optionally, the liquid inlet is close to the bottom of the cavity, and the liquid discharge port is close to the top of the cavity.

Based on another aspect of the present invention, the present invention also provides a photolithography system, which includes the photoresist bubble elimination device as described above.

To sum up, in the photoresist bubble elimination device and lithography system provided by the present invention, the photoresist bubble elimination device includes a pipeline, a buffer bottle and an ultrasonic generator; the ultrasonic generator has a cavity, and the cavity It has a liquid inlet and a liquid outlet for the ultrapure water to enter the cavity from the liquid inlet and discharge the cavity from the liquid outlet; the pipeline is used to transport the photoresist ; A buffer bottle is arranged on the pipeline and communicated with the pipeline, and is used for accommodating the photoresist, and at least a part of the buffer bottle is located within the range of the cavity. With the above configuration, the air bubbles in the photoresist in the buffer bottle can be degassed by ultrasonic waves through the cooperation of the ultrasonic generator and the ultrapure water. Compared with the prior art, the present invention has the effect of eliminating the fine air bubbles in the photoresist. Significantly, it can prevent the photoresist from causing a large number of photolithography defects due to internal fine air bubbles during the process of coating and developing. Further, a lift-off filter membrane can also be arranged in the pipeline to discharge a small amount of air bubbles that may remain, so as to further filter out air bubbles in the photoresist and ensure the quality of the photoresist.

Description of drawings

It should be understood by those of ordinary skill in the art that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention. in:

1 is a schematic diagram of a photoresist bubble elimination device according to an embodiment of the present invention;

2 is a schematic diagram of an ultrasonic generator according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the fitting of a pipeline and a degassing filter membrane according to an embodiment of the present invention.

In the attached picture:

10-ultrasonic generator; 100-cavity; 101-liquid inlet; 102-liquid outlet; 20-pipeline; 200-interlayer; 30-buffer bottle; 40-exhaust buffer chamber; 50-degas filter membrane ; A2-second pressure gauge; B2-second vacuum pump; A3-third pressure gauge; 60-pressure pump; 70-nozzle; 80-bubble detector; 90-photoresist bottle; A1-first pressure gauge; A2-second pressure gauge; A3-third pressure gauge; A3-third pressure gauge; B1-first vacuum pump; B2-second vacuum pump.

Detailed ways

In order to make the objects, advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, each drawing needs to show different emphases, and sometimes different scales are used.

As used herein, the singular forms "a," "an," and "the" include plural referents, the term "or" is generally employed in its sense including "and/or", and the term "a number" It is usually used in the sense including "at least one", the term "at least two" is usually used in the sense including "two or more", in addition, the terms "first", "the second" "Second" and "Third" are for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", "third" may expressly or implicitly include one or at least two of those features, "one end" and "the other end" and "proximal end" and "Distal" usually refers to two corresponding parts, which not only include end points, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection, or It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication between the two elements or the interaction relationship between the two elements. In addition, as used in the present invention, the arrangement of one element on another element generally only means that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the relationship between the two elements may be direct or indirect through intermediate elements connection, coupling, cooperation or transmission, and should not be construed as indicating or implying the spatial positional relationship between two elements, that is, one element can be in any position inside, outside, above, below or on one side of the other element, unless the content Also clearly stated. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

An embodiment of the present invention provides a photoresist bubble elimination device and a photolithography system, which are intended to prevent a large number of photolithography defects caused by fine air bubbles in the photoresist during the process of coating and developing.

The photoresist bubble removing device and the photolithography system of this embodiment will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a photoresist bubble removing apparatus according to an embodiment of the present invention. As shown in FIG. 1 , the photoresist bubble elimination device includes an ultrasonic generator 10 , a pipeline 20 and a buffer bottle 30 . FIG. 2 is a schematic diagram of an ultrasonic generator 10 according to an embodiment of the present invention. Referring to FIG. 2, the ultrasonic generator 10 has a cavity 100, and the cavity 100 has a liquid inlet 101 and a liquid outlet 102 for supplying The ultrapure water enters the cavity 100 from the liquid inlet 101 and is discharged from the cavity 100 from the liquid outlet 102 . Line 20 is used to deliver photoresist. a buffer bottle 30, which is arranged on the pipeline 20 and communicated with the pipeline 20, and is used for accommodating the photoresist, at least a part of the buffer bottle 30 is located within the range of the cavity 100, And can be immersed in ultrapure water. Further, at least one bubble detector 80 is respectively provided in the buffer bottle 30 and on the pipeline 20 for detecting the bubble content of the photoresist, and when the bubble content of the photoresist is detected An alarm signal is issued when the threshold is exceeded. For example, three bubble detectors 80 are arranged in sequence along the vertical direction of the buffer bottle 30 , and two bubble detectors 80 may be arranged on the pipeline 20 . The alarm signal can be, for example, a sound signal to prompt the operator whether the air bubble content exceeds the standard.

Specifically, one end of the pipeline 20 is connected to the photoresist bottle 90 provided by the supplier, and the other end of the pipeline 20 is connected to the nozzle 70. The pipeline 20 is provided on the buffer bottle 30, and the buffer bottle 30 is located in the cavity of the ultrasonic generating device within 100. By introducing nitrogen into the photoresist bottle 90, the photoresist can be pressed into the pipeline 20 by means of nitrogen pressure, so as to enter the buffer bottle 30, and the buffer bottle can be removed by the cooperation of the ultrasonic generating device and the ultrapure water. The bubbles in the photoresist in 30 are eliminated. When the bubble detection device in the buffer bottle 30 no longer sends out an alarm signal, the photoresist is continued to be pressed into the pipeline 20. After the alarm signal is issued again, the photoresist is then sprayed out through the nozzle 70 provided in the pipeline 20 to perform photoresist coating.

Understandably, the ultrasonic generator 10 can emit ultrasonic waves, and ultrasonic waves refer to sound waves with a frequency higher than 20,000 Hz. Ultrapure water is passed through), and a higher concentrated energy can be obtained. When the ultrasonic wave propagates in the liquid, alternating pressures will be generated. In the positive pressure phase, the ultrasonic wave squeezes the medium molecules to increase the density of the medium; in the negative pressure phase, the medium molecules are loosened and the medium density is reduced. When a sufficiently large acoustic wave amplitude acts on the medium, the average distance between the medium molecules changes, and the medium breaks apart, that is, microbubbles are formed. When the tension continues, these microbubbles will expand and grow and collide violently. The gas components in the solution will diffuse with these cavitation bubbles through the gas-liquid interface. After reaching a certain size, the cavitation bubbles collapse and escape on the surface of the solution, which forms the effect of ultrasonic degassing. Compared with the prior art, the present invention has a remarkable effect of eliminating fine air bubbles in the photoresist, and can prevent a large number of photolithography defects caused by the fine air bubbles in the photoresist during the process of coating and developing. On the one hand, the ultrapure water can provide a sound wave propagation medium for the ultrasonic generator 10; After working for a long time, the temperature of the buffer bottle 30 rises due to the rise of the temperature of the ultrapure water, which ultimately affects the performance of the photoresist. The flowing ultrapure water can keep the buffer bottle 30 within the temperature range of the lithography machine. Preferably, the liquid inlet 101 is close to the bottom of the cavity 100 , and the liquid discharge port is close to the top of the cavity 100 , so that ultrapure water enters from below the cavity 100 and is discharged from above the cavity 100 . In one embodiment, the ultrapure water is kept at a constant temperature of 22°C, and the flow rate is 10-50ml/min.

Further, the photoresist bubble elimination device further includes an exhaust buffer chamber 40, and the exhaust buffer chamber 40 is connected to the buffer bottle 30 through a solenoid valve (not shown); the exhaust buffer chamber 40 can be was purged with nitrogen. When the solenoid valve is opened, nitrogen gas enters the buffer bottle 30 from the buffer chamber, and the photoresist that has been degassed by ultrasonic wave is pressed into the pipeline 20 for transportation. The photoresist bubble elimination device also includes a first pressure gauge A1 and a first vacuum pump B1; the first pressure gauge A1 is used to detect the pressure value in the exhaust buffer chamber 40; when the first pressure gauge When the pressure value detected by A1 is outside the first preset range, the first vacuum pump B1 evacuates the exhaust buffer chamber 40 . Close the solenoid valve, when the first pressure gauge A1 detects that the pressure exceeds the first preset range (usually the pressure rises), the first vacuum pump B1 works, and the pressure drop will be supplemented by introducing nitrogen to ensure that the buffer bottle 30 is filled with nitrogen. The air pressure is stable to normal pressure.

Preferably, the photoresist device further includes at least one filtering component (preferably at least two) disposed on the pipeline 20, the buffer bottle 30 and the filtering component are arranged according to the photoresist The conveying directions are arranged in sequence; the filtering component includes a degassing filter membrane 50 arranged in the pipeline 20, the degassing filter membrane 50 has a plurality of filter holes, and the filter holes are used to filter the light Photoresist bubbles. The pore size of the filter holes on the degassing filter membrane 50 is small, which satisfies that only gas is allowed to pass through, but liquid is not permeable. By setting the degassing filter membrane 50, a small amount of fine air bubbles that may remain can be discharged to further filter out the lithography. The bubbles in the glue ensure the quality of the photoresist. It should be noted that the materials of the pipeline 20 and the degassing filter membrane 50 may be the same, for example, they are both made of thin film.

FIG. 3 is a schematic diagram of the fitting of a pipeline and a degassing filter membrane according to an embodiment of the present invention. Further, the degassing filter membrane 50 is tubular, referring to FIG. 3 , there is a gap between the degassing filter membrane 50 and the inner wall of the pipeline 20 to form the interlayer 200 ; the filtering assembly further includes a second pressure gauge A2 and the second vacuum pump B2; the second pressure gauge A2 is used to detect the pressure value in the interlayer 200; when the pressure value detected by the second pressure gauge A2 is outside the second preset range, the The second vacuum pump B2 evacuates the interlayer 200 . After the degassing membrane 50 filters the air bubbles, the air pressure in the interlayer 200 rises, the second pressure gauge A2 detects that the pressure value exceeds the second preset range, and the second vacuum pump B2 vacuumizes the interlayer 200 to reduce pressure.

Further, a third pressure gauge A3 and a pressure pump 60 are provided on the pipe section of the pipeline 20 away from the buffer bottle 30 . The pressure pump 60 is used to drive the photoresist to move along the pipeline 20, and is processed by the ultrasonic generator 10 and the degassing filter membrane 50, and the bubble detector 80 in the pipeline 20 does not issue an alarm signal, The photoresist can be pressed into the nozzle 70 by the pressure pump 60 to carry out the gluing work. The first pressure gauge A1 is used to detect the pressure value in the pipeline 20 to ensure that the pressure value in the pipeline 20 is within the set range, thereby ensuring that the delivery rate of the photoresist is within the predetermined rate range, avoiding If the photoresist is transported too fast or too slow, it is ensured that the nozzle 70 sprays the photoresist smoothly to ensure uniform coating.

Based on the above photoresist bubble elimination device, the present embodiment further provides a photolithography system, which includes the above photoresist bubble elimination device. Further, the lithography system includes a machine and the photoresist bubble elimination device as described above, and the photoresist bubble elimination device is arranged in the machine.

Under the condition of not disturbing the main body of the machine, the invention can realize the elimination of bubbles in the photoresist only by replacing some parts in the machine. The inventor found through practice that the use of the photolithography system including the photoresist bubble elimination device can reduce the loss of photoresist by 10,000 to 30,000 US dollars per month, reduce the operating time of machine loss by 20 to 40 hours, and greatly reduce the loss of photoresist by 20 to 40 hours. Reduced wafer defect rate due to air bubbles.

To sum up, in the photoresist bubble elimination device and lithography system provided by the present invention, the photoresist bubble elimination device includes a pipeline, a buffer bottle and an ultrasonic generator; the ultrasonic generator has a cavity, and the cavity It has a liquid inlet and a liquid outlet for the ultrapure water to enter the cavity from the liquid inlet and discharge the cavity from the liquid outlet; the pipeline is used to transport the photoresist ; A buffer bottle is arranged on the pipeline and communicated with the pipeline, and is used for accommodating the photoresist, and at least a part of the buffer bottle is located within the range of the cavity. With the above configuration, the air bubbles in the photoresist in the buffer bottle can be degassed by ultrasonic waves through the cooperation of the ultrasonic generator and the ultrapure water. Compared with the prior art, the present invention has the effect of eliminating the fine air bubbles in the photoresist. Significantly, it can prevent the photoresist from causing a large number of photolithography defects due to internal fine air bubbles during the process of coating and developing. Further, a lift-off filter membrane can also be arranged in the pipeline to discharge a small amount of air bubbles that may remain, so as to further filter out air bubbles in the photoresist and ensure the quality of the photoresist.

The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention. Any changes and modifications made by those of ordinary skill in the field of the present invention according to the above disclosure all belong to the protection scope of the technical solutions of the present invention.

Claims (10)

1. A photoresist bubble removal apparatus, comprising:

the ultrasonic generator is provided with a cavity, and the cavity is provided with a liquid inlet and a liquid outlet and is used for allowing the ultrapure water to enter the cavity from the liquid inlet and to be discharged out of the cavity from the liquid outlet;

a pipe for transferring the photoresist;

the buffer bottle is arranged on the pipeline, communicated with the pipeline and used for containing the photoresist, and at least one part of the buffer bottle is positioned in the range of the cavity.

2. The photoresist bubble elimination device according to claim 1, further comprising an exhaust buffer chamber, wherein the exhaust buffer chamber is connected with the buffer bottle through a solenoid valve; the exhaust buffer chamber may be purged with nitrogen.

3. The photoresist bubble removal apparatus of claim 2, further comprising a first pressure gauge and a first vacuum pump; the first pressure gauge is used for detecting the pressure value in the exhaust buffer chamber; and when the pressure value detected by the first pressure gauge is out of a first preset range, the first vacuum pump vacuumizes the exhaust buffer chamber.

4. The apparatus according to claim 1, further comprising at least one filtering component disposed on the pipeline, wherein the buffer bottle and the filtering component are sequentially arranged in a conveying direction of the photoresist; the filtering component comprises a degassing filter membrane arranged in the pipeline, the degassing filter membrane is provided with a plurality of filter holes, and the filter holes are used for filtering bubbles of the photoresist.

5. The apparatus of claim 4, wherein the degassing filter membrane is tubular and has a gap with an inner wall of the pipe to form a sandwich; the filtering component also comprises a second pressure gauge and a second vacuum pump; the second pressure gauge is used for detecting the pressure value in the interlayer; and when the pressure value detected by the second pressure gauge is out of a second preset range, the second vacuum pump vacuumizes the interlayer.

6. The photoresist bubble eliminating device according to claim 1, wherein a third pressure gauge and a pressure pump are arranged on a pipe section of the pipeline away from the buffer bottle; the first pressure gauge is used for detecting the pressure value in the pipeline; the pressure pump is used for driving the photoresist to move along the pipeline.

7. The apparatus according to claim 1, wherein a nozzle is disposed at an end of the pipe away from the buffer bottle.

8. The apparatus according to claim 1, wherein at least one bubble detector is disposed in the buffer bottle and on the pipeline, respectively, for detecting the bubble content of the photoresist and sending an alarm signal when the bubble content of the photoresist exceeds a threshold value.

9. The apparatus according to claim 1, wherein the liquid inlet is near the bottom of the chamber and the liquid outlet is near the top of the chamber.

10. A lithography system comprising a photoresist bubble removal apparatus according to any one of claims 1 to 9.

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