CN114488697A

CN114488697A - Photoresist bubble eliminating device and photoetching system

Info

Publication number: CN114488697A
Application number: CN202210158300.7A
Authority: CN
Inventors: 钱晓飞; 刘小虎; 朱祎明
Original assignee: Shanghai Huali Microelectronics Corp
Current assignee: Shanghai Huali Microelectronics Corp
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2022-05-13

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 eliminating device and photoetching system

Technical Field

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

Background

Since the invention of semiconductors, the conversion of patterns has been achieved by photolithography. The photolithography technology becomes the key technology for preparing microelectronic devices and optoelectronic devices by the current scientific technology. Following Moore's law, semiconductor devices are being scaled down and increased in density, and the current semiconductor lithography process has entered the 5nm era. The essence of the photoetching is pattern transfer, firstly, photoresist is coated on the surface of a wafer to form a photosensitive material, ultraviolet light is irradiated through a photoetching machine to project a circuit pattern designed in advance on a photomask onto the surface of the photosensitive material, and after photochemical reaction, the circuit pattern is developed by using a developing solution to complete the pattern transfer. As the size of integrated circuits is continuously reduced, the challenge of the photolithography process is increased, and if the photoresist coating has a slight deviation, the photochemical reaction is directly affected, the pattern transfer is disturbed, and finally a large number of defects are formed on the silicon wafer. Therefore, it is important to ensure high-quality supply and coating of the photoresist.

The general photoresist supply flow is: opening a photoresist bottle provided by a supplier, inserting the photoresist bottle into a machine table pipeline, installing the photoresist bottle on the machine table, pressurizing through nitrogen, enabling the photoresist to enter a buffer bottle of the machine table after passing through a filter membrane, then pressing the photoresist into a conveying pipeline through a pressure pump, and enabling the photoresist to reach a nozzle at the end of the machine table for photoresist coating. In the actual process, the photoresist is transported for a long time and pressurized by nitrogen, fine bubbles are inevitably formed in the photoresist, the bubbles are coated on the surface of the wafer through a pipeline, and defects are formed on the surface after photoetching development, so that the large-area yield of the wafer is reduced and even the wafer is scrapped.

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

1. firstly, the photoresist is stored in a stable storage cabinet for more than 12 hours, and internal bubbles are reduced as much as possible by standing, so that only large bubbles generated in the transportation process can be reduced by the method, and the removal effect of the micro bubbles is not ideal.

2. After the machine table is installed, photoresist is pressed into the filter membrane through nitrogen pressurization, micro bubbles in the photoresist are reduced through the small-aperture filter membrane, and due to the fact that the pressure difference between the inside and the outside is large and the efficiency of the filter membrane is low, only a small amount of bubbles can be removed, and all bubbles cannot be removed. Bubbles enter the buffer bottle along with the photoresist, and a bubble detector in the buffer bottle is triggered to alarm at any time. After triggering the bubble and reporting to the police, need equipment engineer to carry out the photoresist and clear away, with the photoresist blowout pipeline that contains the bubble to on-line actual operation is the example, and the work of clearing away of pipeline needs an hour at least, not only causes a large amount of photoresists extravagantly like this, influences the normal operation of board moreover, causes a large amount of machine-hour extravagantly.

3. Some patents disclose the solution of removing bubbles from the photoresist, and the principle is usually a pressure reduction process. The reduced pressure is helpful to remove bubbles to a certain extent, but the efficiency is not high, and the pressure reduction easily causes the reduction of the saturated vapor pressure of the liquid, leads to the rapid evaporation of the liquid, causes the deterioration of the photoetching material and causes greater influence.

Disclosure of Invention

The invention aims to provide a photoresist bubble eliminating device and a photoetching system, aiming at preventing a large number of photoetching defects caused by fine bubbles inside photoresist in the gluing and developing process.

According to an aspect of the present invention, there is provided a photoresist bubble removing 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.

Optionally, the photoresist bubble eliminating device further comprises an exhaust buffer chamber, and the exhaust buffer chamber is connected with the buffer bottle through an electromagnetic valve; the exhaust buffer chamber may be purged with nitrogen.

Optionally, the photoresist bubble removing apparatus further comprises 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.

Optionally, the photoresist device further comprises at least one filtering component arranged on the pipeline, and the buffer bottle and the filtering component are sequentially arranged according to the 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.

Optionally, the degassing filter membrane is tubular, and a gap is formed between the degassing filter membrane and the inner wall of the pipeline to form an interlayer; 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.

Optionally, a third pressure gauge and a pressure pump are arranged on a pipe section of the pipeline far 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.

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

Optionally, at least one bubble detector is respectively arranged in the buffer bottle and on the pipeline, and is used for detecting the bubble content of the photoresist and sending an alarm signal when detecting that the bubble content of the photoresist exceeds a threshold value.

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

According to another aspect of the invention, there is also provided a lithography system comprising a photoresist bubble removal apparatus as described above.

In summary, in the photoresist bubble removing device and the photolithography system provided by the invention, the photoresist bubble removing 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. Furthermore, a stripping filter membrane can be arranged in the pipeline to discharge a small amount of bubbles possibly remained so as to further filter the bubbles in the photoresist and ensure the quality of the photoresist.

Drawings

It will be appreciated by those skilled in the art that the drawings are provided for a better understanding of the invention and do not constitute any limitation to the scope of the invention. Wherein:

FIG. 1 is a schematic view of a photoresist bubble removal apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of an ultrasonic generator according to an embodiment of the present invention;

FIG. 3 is a schematic view of a degassing filter membrane coupled to a pipeline according to an embodiment of the present invention.

In the drawings:

10-an ultrasonic generator; 100-a cavity; 101-liquid inlet; 102-a liquid outlet; 20-pipeline; 200-interlayer; 30-a buffer bottle; 40-an exhaust buffer chamber; 50-degassing filter membrane; a2-second pressure gauge; b2 — second vacuum pump; a3-third pressure gauge; 60-pressure pump; 70-a nozzle; 80-a 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 Description

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be noted that the drawings are in greatly simplified form and are not to scale, but are merely intended to facilitate and clarify the explanation of the embodiments of the present invention. Further, the structures illustrated in the drawings are often part of actual structures. In particular, the drawings may have different emphasis points and may sometimes be scaled differently.

As used in this application, the singular forms "a", "an" and "the" include plural referents, the term "or" is generally employed in a sense including "and/or," the terms "a" and "an" are generally employed in a sense including "at least one," the terms "at least two" are generally employed in a sense including "two or more," and the terms "first", "second" and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "proximal end" and "distal end" generally refer to the corresponding two parts, which include not only the end points, but also the terms "mounted", "connected" and "connected" should be understood broadly, e.g., as a fixed connection, as a detachable connection, or as an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. Furthermore, as used in the present invention, the disposition of an element with another element generally only means that there is a connection, coupling, fit or driving relationship between the two elements, and the connection, coupling, fit or driving relationship between the two elements may be direct or indirect through intermediate elements, and cannot be understood as indicating or implying any spatial positional relationship between the two elements, i.e., an element may be in any orientation inside, outside, above, below or to one side of another element, unless the content clearly indicates otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

An embodiment of the invention provides a photoresist bubble eliminating device and a photoetching system, aiming at preventing a large amount of photoetching defects caused by fine bubbles inside photoresist in the gluing and developing process.

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

FIG. 1 is a schematic diagram of a photoresist bubble removal apparatus according to an embodiment of the invention. As shown in fig. 1, the photoresist bubble removing apparatus includes an ultrasonic generator 10, a pipe 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, and referring to fig. 2, the ultrasonic generator 10 has a chamber 100, and the chamber 100 has a liquid inlet 101 and a liquid outlet 102, for allowing the ultrapure water to enter the chamber 100 from the liquid inlet 101 and to exit the chamber 100 from the liquid outlet 102. Line 20 is used to deliver photoresist. A buffer bottle 30 disposed on the pipe 20 and communicating with the pipe 20, for containing the photoresist, wherein at least a portion of the buffer bottle 30 is located within the chamber 100 and can be immersed in ultrapure water. Further, at least one bubble detector 80 is respectively disposed in the buffer bottle 30 and on the pipeline 20, and is configured to detect the bubble content of the photoresist, and send an alarm signal when detecting that the bubble content of the photoresist exceeds a threshold value. For example, three bubble detectors 80 are arranged in the vertical direction in the buffer bottle 30, and two bubble detectors 80 can be arranged on the pipeline 20. The alarm signal may be, for example, an audio signal, which prompts the operator whether the bubble content is above the standard.

Specifically, one end of the pipeline 20 is connected to a photoresist bottle 90 provided by a supplier, the other end of the pipeline 20 is connected to the nozzle 70, the buffer bottle 30 is disposed on the pipeline 20, and the buffer bottle 30 is located in the cavity 100 of the ultrasonic generator. The accessible lets in nitrogen gas to photoresist bottle 90 to in nitrogen gas pressurization's mode with photoresist pressing pipeline 20, thereby in getting into buffer bottle 30, eliminate the bubble in the photoresist in buffer bottle 30 through the cooperation of ultrasonic wave generating device and ultrapure water, after the bubble detecting device in buffer bottle 30 no longer sends alarm signal, continue to impress the photoresist in pipeline 20, after the bubble detecting device that sets up in pipeline 20 also no longer sends alarm signal, spout the photoresist through the nozzle 70 that pipeline 20 set up afterwards and carry out the photoresist coating.

It can be understood that the ultrasonic generator 10 can emit ultrasonic waves, which refers to sound waves with a frequency higher than 20000Hz, and the ultrasonic waves have good directivity, strong reflection capability, and fast propagation in liquid (in this embodiment, ultrapure water is introduced into the chamber 100), and can obtain high concentrated energy. When the ultrasonic waves are transmitted in the liquid, alternate pressure is generated, and the ultrasonic waves extrude medium molecules in a positive pressure phase to increase the density of the medium; and in the negative pressure phase, the medium molecules are loosened, and the density of the medium is reduced. When a large enough sound wave amplitude acts on the medium, the average distance between medium molecules is changed, the medium molecules are broken, namely, micro-bubbles are formed, and when the tension continues to exist, the micro-bubbles expand and grow and have violent collision. The gas component in the solution diffuses through the gas-liquid interface with the cavitation bubbles, and when the gas component reaches a certain size, the cavitation bubbles collapse and escape on the surface of the solution, so that ultrasonic degassing is formed. Compared with the prior art, the method has the advantages that the effect of eliminating fine bubbles in the photoresist is remarkable, and the defect of mass photoetching caused by the fine bubbles in the photoresist in the gluing and developing process can be prevented. On one hand, the ultrapure water can provide a sound wave propagation medium for the ultrasonic generator 10, on the other hand, the ultrapure water sequentially passes through the cavity 100 from the liquid inlet 101 and the liquid outlet, so that the ultrapure water is in a flowing state, the temperature rise of the buffer bottle 30 caused by the temperature rise of the ultrapure water after the ultrasonic works for a long time is avoided, the photoresist performance is finally influenced, and the flowing ultrapure water can enable the buffer bottle 30 to be kept in the temperature range of the photoetching machine. Preferably, the liquid inlet 101 is near the bottom of the chamber 100, and the liquid outlet is near the top of the chamber 100, so that ultrapure water enters from the lower part of the chamber 100 and is discharged from the upper part of the chamber 100. In one embodiment, the ultrapure water is kept at a constant temperature of 22 ℃ and the flow rate is 10-50 ml/min.

Further, the photoresist bubble removing apparatus further comprises a gas exhaust buffer chamber 40, wherein the gas exhaust buffer chamber 40 is connected with the buffer bottle 30 through a solenoid valve (not shown); the exhaust buffer chamber 40 may be purged with nitrogen. When the solenoid valve is opened, nitrogen gas is introduced into the buffer bottle 30 from the buffer chamber, and the photoresist that has been ultrasonically degassed is pressed into the pipe 20 for delivery. The photoresist bubble eliminating device also comprises a first pressure gauge A1 and a first vacuum pump B1; the first pressure gauge A1 is used for detecting the pressure value in the exhaust buffer chamber 40; when the pressure value detected by the first pressure gauge A1 is out of a first preset range, the first vacuum pump B1 vacuumizes the exhaust buffer chamber 40. And (3) closing the electromagnetic valve, and when the first pressure gauge A1 detects that the pressure exceeds a first preset range (generally, the air pressure rises), operating the first vacuum pump B1, and supplementing the air pressure drop by introducing nitrogen to ensure that the air pressure in the buffer bottle 30 is stabilized to the normal pressure.

Preferably, the photoresist device further comprises at least one filtering component (preferably at least two) arranged on the pipeline 20, and the buffer bottle 30 and the filtering component are sequentially arranged according to the conveying direction of the photoresist; the filtering component includes a degassing filter membrane 50 disposed in the pipeline 20, and the degassing filter membrane 50 has a plurality of filter holes for filtering bubbles of the photoresist. The aperture of the filter pores on the degassing filter membrane 50 is small, the requirement that only gas is allowed to permeate but liquid cannot permeate is met, and a small amount of fine bubbles possibly remaining can be discharged by arranging the degassing filter membrane 50 so as to further filter bubbles in the photoresist and ensure the quality of the photoresist. It should be noted that the material of the line 20 and the degassing filter membrane 50 may be the same, for example, both are thin films.

FIG. 3 is a schematic view of a degassing filter membrane coupled to a pipeline according to an embodiment of the present invention. Further, the degassing filter membrane 50 is tubular, and referring to fig. 3, the degassing filter membrane 50 has a gap with the inner wall of the pipeline 20 to form an interlayer 200; the filtering component also comprises a second pressure gauge A2 and a second vacuum pump B2; the second pressure gauge A2 is used for detecting the pressure value in the interlayer 200; when the pressure value detected by the second pressure gauge a2 is out of a second preset range, the second vacuum pump B2 vacuumizes the interlayer 200. After the degassing filter membrane 50 filters the 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 the 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 the photoresist is processed by the ultrasonic generator 10 and the degassing filter membrane 50, and the bubble detector 80 in the pipeline 20 does not send out an alarm signal, and the photoresist can be pressed to the nozzle 70 by the pressure pump 60 for gluing. The first pressure gauge A1 is used for detecting the pressure value in the pipeline 20 and ensuring that the pressure value in the pipeline 20 is within a set range, so that the conveying speed of the photoresist is ensured to be within a preset speed range, the photoresist is prevented from being conveyed too fast or too slow, the photoresist is ensured to be stably sprayed out by the nozzle 70, and uniform gluing is ensured.

Based on the photoresist bubble removal device, the embodiment further provides a lithography system comprising the photoresist bubble removal device. Further, the lithography system comprises a machine table and the photoresist bubble eliminating device, and the photoresist bubble eliminating device is arranged in the machine table.

The invention can eliminate bubbles in the photoresist only by replacing part of parts in the machine under the condition of not interfering the main body of the machine, has simple device and small operation risk, does not need to transform the machine, and can be popularized in a large scale. The inventor finds that by using the photoetching system comprising the photoresist bubble eliminating device, the loss of the photoresist can be reduced by 1-3 ten thousand dollars per month, the operation time of machine loss is reduced by 20-40 hours, and the defect rate of wafers caused by bubbles is greatly reduced.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art according to the above disclosure are within the scope of the present invention.

Claims

1. A photoresist bubble removal apparatus, comprising:

a pipe for transferring the photoresist;

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.