JP2007142217A - Immersion lithography exposure apparatus and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a megasonic ultrasonic wave immersion lithography apparatus for removing air bubbles from liquid during the process period of lithography exposure by adding sound wave vibrations to immersion liquid, and to provide its method. <P>SOLUTION: An optical system 13 for projecting light onto a wafer 34 through a photomask 14 is included. An optical transmission chamber 18 is made adjacent to the optical system 13, and exposure liquid 32 is loaded. At least one megasonic ultrasonic wave plate 30 is connected in an operable state to the optical transmission chamber 18, sound waves are generated in the exposure liquid 32, and microbubbles in the exposure liquid 32 are removed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photolithography process applied to the manufacture of a semiconductor integrated circuit for forming an integrated circuit pattern on a photoresist, and more particularly, to a megalithography in which immersion liquid is subjected to sonic vibration and bubbles are removed from the liquid during the lithography exposure process. The present invention relates to a sonic ultrasonic immersion lithography apparatus and method.

  In general, various processing steps are applied when fabricating an integrated circuit on a semiconductor wafer. These steps include depositing a conductive layer on a silicon wafer substrate and having a metal interconnect pattern required by standard lithographic and photolithography techniques, eg photoresists such as titanium oxide and silicon oxide, and others Forming a photomask, and performing a dry etching process on the wafer substrate, removing the conductive layer from a region not covered by the photomask, and etching the conductive layer according to the shape of the mask pattern on the substrate; In general, the step of exposing the upper surface of the conductive interconnect layer by removing or stripping the mask layer from the substrate with reactive plasma or chlorine gas, and adding water and nitrogen gas to the wafer substrate, Cooling and drying the substrate. That.

  A common integrated circuit manufacturing technique known as dual damascene technology sequentially deposits a lower dielectric layer and an upper dielectric layer on a substrate. The lower dielectric layer is then patterned and etched to form via openings therein, and the upper dielectric layer is patterned and etched to form trench openings therein. In the etching step, the trench and via openings are etched in the corresponding dielectric layer with a patterned photoresist layer. Next, conductive copper wires are formed in the trench and via openings using electrochemical plating (ECP) technology, and horizontal and vertical integrated circuit wirings are formed on the substrate.

  The method of applying the photoresist material on the surface of the wafer or on the dielectric layer or conductive layer on the wafer is to rotate the wafer at a high speed in a stationary bowl or coater cup, A photoresist solution is dropped onto the central portion of the wafer. Excess liquid and particulate exiting the rotating wafer during the photoresist formation step are received by the coater cup. The photoresist liquid dropped on the central portion of the wafer is diffused toward the edge of the wafer by surface tension due to the rotational centrifugal force of the wafer. As a result, the photoresist liquid can be uniformly formed on the entire surface of the wafer.

  During the photolithography process of semiconductor production, light energy is applied to the photoresist material previously deposited on the wafer via a reticle or mask to define a circuit pattern, which is defined on the photoresist material. The circuit pattern defines a circuit on the wafer by subsequent processing step etching. A reticle is a transparent plate on which a circuit image in a photoresist coat layer on a wafer is patterned. Since the reticle includes only those designed with circuit pattern images of several dies, for example, four dies on the wafer, the entire surface of the wafer had to be traversed step by step. In contrast, the photomask contained circuit pattern images of all the dies on the wafer, so that the circuit pattern images of all the dies could be transferred to the wafer with only one exposure.

Automatic coater / development track system for wafer processing equipment (automated coater)
/ developer track system) performs the steps of spin coating a photoresist on the wafer and other steps of the photolithography process. The wafer processing apparatus transports wafers between photolithography operation stations such as, for example, vapor prime resist spin coat, development, baking and chilling stations. Automated wafer processing can minimize particle generation and wafer damage. Automatic wafer tracks can perform various processing operations simultaneously. There are two types of automated truck systems widely used in the semiconductor industry: Tokyo Electron Limited (TEL) trucks and Silicon Valley Group (SVG) trucks.

  A typical method for producing a circuit pattern on a wafer is to put the wafer into an automated track system and then apply the photoresist onto the wafer by spin coating. Thereafter, the photoresist is processed by soft baking. Then, after cooling, the wafer is typically placed in an exposure apparatus such as a stepper that aligns and etches the array of wafers having a die pattern on a chromium-coated quartz reticle. After proper alignment and focusing, the stepper will expose a small area of the wafer and then move to the next area until the die pattern on the reticle is exposed on the entire surface of the wafer. The steps are repeated. The photoresist is exposed to light passing through the reticle to transfer a circuit pattern image. In the photoresist portion to which this image pattern is exposed, a circuit pattern is formed by crosslinking and curing. Then, after the alignment step and the exposure process are performed, the wafer is exposed and then baked, and the photoresist pattern is developed by the development and hard baking steps.

  Subsequently, the circuit pattern defined in the photoresist by development and curing is transferred to the lower metal layer in an etching step, and the metal not covered by the cross-linked photoresist in the metal layer is etched away from above the wafer. It protects the characteristic metal under the crosslinked photoresist and is not removed by the etchant. Alternatively, the material to be etched may be a dielectric layer, and via openings and trench openings are etched into the dielectric layer to match the circuit pattern, for example, by dual damascene technology. Subsequently, the via opening and the trench opening are filled with a conductive metal such as copper to define the metal conductor. This forms a properly defined patterned microelectronic circuit on the wafer, the patterning of which is very similar to a cross-linked photoresist circuit pattern.

  Lithography applied to the semiconductor manufacturing industry is immersion lithography, and an exposure apparatus used in the immersion lithography technique includes a photomask and a plurality of lenses installed on an optical transmission chamber. Through this light transmission chamber, an exposure liquid containing water is sprayed. During this operational step, the light transmission chamber is placed above the exposure area on the wafer covered by the photoresist. When the exposure liquid is sprayed through the light transmission chamber, the light is transmitted through the photomask, the lens, and the exposure liquid in the light transmission chamber onto the photoresist in the exposure area. Therefore, the circuit pattern image in the photomask is transferred to the photoresist by the optical transmission of the exposure liquid. The exposure liquid in the light transmission chamber can increase the analysis degree of the circuit pattern image transmitted on the photoresist.

  Before the exposure liquid is sprayed by the light transmission chamber, the gas is generally removed from the liquid such as water, and most of the ultrafine bubbles are removed from the liquid. However, during the step in which the liquid was sprinkled by the light transmission chamber, some ultrafine bubbles remained in the liquid. The remaining ultrafine bubbles tend to adhere to the hydrophobic surface of the photoresist in general, so that the circuit pattern image projected on the photoresist may be distorted. Therefore, there is a demand for an apparatus and method that can substantially remove ultrafine bubbles in the exposure liquid in the immersion lithography process so that the circuit pattern image on the photoresist projected into the exposure area is not distorted. It was.

A first object of the present invention is to provide an apparatus for substantially removing ultrafine bubbles from an exposure solution before or during the immersion lithography process.
A second object of the present invention is to provide a megasonic ultrasonic exposure apparatus that substantially removes ultrafine bubbles from an exposure solution before or during the process of immersion lithography.
It is a third object of the present invention to provide a megasonic ultrasonic exposure apparatus that improves the quality of a circuit pattern image projected onto a photoresist during an immersion lithography process.
A fourth object of the present invention is to provide a megasonic ultrasonic exposure apparatus that substantially removes ultrafine bubbles from an exposure solution before or during an immersion lithography process using sound waves.
It is a fifth object of the present invention to provide a megasonic ultrasonic immersion lithography exposure method that substantially removes ultrafine bubbles from an exposure solution before or during an immersion lithography process using sound waves. is there.
A sixth object of the present invention is to provide a megasonic ultrasonic immersion lithography exposure method that substantially removes ultrafine bubbles and fine particles from the exposure lens before or during the immersion lithography process using sound waves. There is to do.

  To achieve the foregoing and other objectives, the present invention provides a megameter that substantially removes ultrafine bubbles from an exposure solution prior to, during, or both before and during immersion lithography. A sonic ultrasonic immersion lithography exposure apparatus is provided. The apparatus of the present invention includes an optical transmission chamber installed above a photoresist-coated wafer, an optical housing having a photomask and a lens installed above the optical transmission chamber, and optical transmission of immersion liquid. And an inlet conduit for spraying into the chamber. At least one megasonic ultrasound plate is operatively connected to the inlet conduit and the sound waves passing through the immersion fluid are uninterrupted when the immersion fluid is sprayed through the inlet conduit and into the light transmission chamber. Like that. Since the sound waves substantially remove the ultrafine bubbles in the exposure liquid, the exposure process can be performed by putting the liquid into a light transmission chamber in a state substantially free of bubbles. In an exposure apparatus according to another embodiment of the present invention, an optical transmission chamber is surrounded by an annular megasonic ultrasonic plate.

  The present invention provides a method for substantially removing ultrafine bubbles from an exposure solution. This exposure liquid is applied during an immersion lithography process to transfer a circuit pattern image from a photomask or reticle onto a photoresist-coated wafer. This method includes passing sound waves through the exposure liquid before, during, or before and during the process of spraying the exposure liquid into the light transmission chamber by the immersion lithography exposure apparatus. Yes. This sound wave substantially removes the ultrafine bubbles from the exposure liquid, removes the ultrafine bubbles from the surface of the photoresist, the ultrafine bubbles adhere to the photoresist on the wafer surface, and the apparatus The distortion of the circuit pattern image transferred onto the photoresist through the film is prevented.

  The present invention provides a method of substantially removing ultrafine bubbles and fine particles from an exposure lens. The exposure lens is applied during an immersion lithography process to transfer a circuit pattern image from a photomask or reticle onto a photoresist-coated wafer. This method includes passing sound waves through the exposure liquid before, during, or before and during the process of spraying the exposure liquid into the light transmission chamber by the immersion lithography exposure apparatus. Yes. The method further includes exchanging the exposure solution before the exposure process, during the process period, or both before and during the process period. The sound wave substantially removes the ultrafine bubbles and fine particles from the lens surface and prevents the ultrafine bubbles and fine particles from adhering to the exposed lens surface. It is possible to prevent the circuit pattern image to be transferred from being distorted.

  As can be seen from the above, the megasonic ultrasonic immersion lithography apparatus and method of the present invention can apply ultrasonic vibration to the immersion liquid to remove bubbles in the liquid during the lithography exposure process.

  The present embodiment provides a new megasonic ultrasonic immersion lithography exposure apparatus that substantially removes ultrafine bubbles from an exposure solution before, during, or both before and during immersion lithography. To do. The apparatus of this embodiment includes an optical housing in which a photomask and a lens are installed. An optical transmission chamber is installed below the lens of the optical housing. Then, the inlet conduit and the optical housing are connected to spread the immersion liquid into the light transmission chamber. At least one megasonic ultrasound plate is operatively connected with the inlet conduit so that the sound waves passing through the immersion fluid are not interrupted when the immersion fluid is sprayed through the inlet conduit into the light transmission chamber. To. In another embodiment, an annular megasonic ultrasound plate surrounds the light transmission chamber.

  When the apparatus of this embodiment is activated, the light transmission chamber is installed above the exposure area on the wafer coated with photoresist. The sound waves generated by the one or more megasonic ultrasonic plates remove the ultrafine bubbles in the exposure liquid and make the liquid entering the light transmission chamber substantially free of bubbles. During the exposure process, light is transmitted through the photomask and lens of the optical housing, through the exposure liquid in the light transmission chamber, and onto the photoresist covering the wafer. Since the exposure liquid has no bubbles, a circuit pattern image without distortion is transferred onto the photoresist to substantially obtain a high degree of analysis.

  The present embodiment provides a method for substantially removing ultrafine bubbles in an exposure liquid, and this exposure liquid is applied to an exposure process of an immersion lithography process, from a photomask or a reticle to a photoresist-coated wafer. The circuit pattern image is transferred to the exposure area. In the method of the first embodiment, sound waves are transmitted through the exposure liquid, and ultrafine bubbles are removed from the liquid before the exposure process. The method according to the second embodiment transmits sound waves through the exposure liquid both before and during the exposure process. The third embodiment of the present invention intermittently transmits sound waves through the exposure liquid during the exposure process. The megasonic ultrasonic power provided to the exposure liquid from one or more megasonic ultrasonic plates is preferably about 10 to 1000 kHz.

  The exposure liquid used in the megasonic ultrasonic immersion lithography method of this embodiment may be of any kind. The exposure liquid of this embodiment contains ammonium, hydrogen peroxide, and water whose concentration is usually a volume ratio between about 1: 1: 10 and 1: 1: 1000. In other embodiments, the exposure liquid includes ammonium and water with concentrations typically ranging from about 1:10 to 1: 1000 in volume ratio. In another embodiment, the exposure liquid is deionized water. In another embodiment, the exposure liquid is ozone water (Ozonated Water), and the ozone concentration is generally between about 1-1000 ppm. The exposure liquid contains a nonionic surfactant, an anionic surfactant or a cationic surfactant having a concentration of usually between about 1 and 1000 ppm.

  As shown in FIG. 1, reference numeral 10 denotes a megasonic ultrasonic immersion lithography exposure apparatus (hereinafter simply referred to as “exposure apparatus”) of the present embodiment. The exposure apparatus 10 includes a wafer stage 28 for placing a wafer 34 having a photoresist layer (not shown) deposited thereon. The optical housing 12 includes an optical system 13 that includes a laser 15 and a nearest objective lens 16 located above the wafer stage 28. The photomask or reticle 14 is operably fitted in the optical housing 12 installed above the objective lens 16. The photomask or reticle 14 is formed with a circuit pattern (not shown) on the photoresist layer that is transferred onto the wafer 34 during the lithography process. This lithography process will be described below. The light transmission chamber 18 is installed on the wafer stage 28 under the nearest objective lens 16. During the lithography process, the laser beam 15a passes through a photomask or reticle 14 to generate a circuit pattern image 15b, which is transmitted to the nearest objective lens 16 and light transmission chamber 18 and projected onto the wafer 34, respectively. Is done.

  The inlet liquid storage tank 20 is provided with a tank for the exposure liquid 32, and the inlet conduit 22 extends from the inlet liquid storage tank 20. A drainage conduit 22 a extends from the inlet conduit 22 and is connected to the optical transmission chamber 18. An outlet liquid storage tank 26 is provided in connection with the light transmission chamber 18 through a collection conduit 24a and an outlet conduit 24, respectively. According to this embodiment, a megasonic ultrasound plate 30 is installed on the inlet conduit 22 and, as will be appreciated by those skilled in the art, when the exposure liquid 32 passes through the inlet conduit 22, there is a mega A sound wave (not shown) is generated by the sonic ultrasonic plate 30.

  The operation of the exposure apparatus 10 will be described in more detail below. The exposure liquid 32 is provided from the inlet liquid storage tank 20 and enters the light transmission chamber 18 through the inlet conduit 22 and the drainage conduit 22a, respectively. The megasonic ultrasonic plate 30 generates sound waves (not shown) in the exposure liquid 32 to remove all or most of the ultrafine bubbles in the exposure liquid 32. The laser beam 15a emitted from the optical housing 12 generates a circuit pattern image 15b, and these circuit pattern images 15b pass through the objective lens 16 and the exposure liquid 32 installed in the light transmission chamber 18 respectively, and pass through the wafer. 34 is projected onto the coated photoresist. The exposure liquid 32 is discharged from the light transmission chamber 18 and is put into the outlet liquid storage tank 26 through the collecting conduit 24a and the outlet conduit 24, respectively.

  Subsequently, as shown in FIGS. 3A to 3C and FIG. 1, the exposure apparatus 10 operates by selecting one of the three types described below. In step 1 of the flowchart shown in FIG. 3A, the light transmission chamber 18 is first installed above the exposure area on the wafer 34. Subsequently, after the megasonic ultrasonic plate 30 is turned on (step 2), the exposure liquid 32 is sprayed from the inlet liquid storage tank 20 to the optical transmission chamber 18 through the inlet conduit 22 (step 3). Then, when the exposure liquid 32 passes through the inlet conduit 22, the megasonic ultrasonic plate 30 generates sound waves in the exposure liquid 32. Then, the ultrafine bubbles in the exposure liquid 32 are removed by sound waves, and the ultrafine bubbles are eliminated at the entrance where the exposure liquid 32 enters the optical transmission chamber 18. In addition, since the sound wave is transmitted from the drainage conduit 22a to the light transmission chamber 18, ultrafine bubbles on the photoresist surface are also removed.

  As shown in Step 4, before the circuit pattern image is exposed on the exposure area on the wafer 34, the megasonic ultrasonic plate 30 is turned off. The above-described circuit pattern image is transmitted through the exposure liquid 32 (step 5), and the exposure liquid 32 is not deformed by the influence of the ultrafine bubbles and is highly deformed on the surface of the photoresist on the wafer 34. Transcript. After performing the exposure process 5, the optical transmission chamber 18 is moved to the next exposure area on the wafer 34, and Steps 1 to 5 are repeated in Step 6.

  In step 1a of the flowchart shown in FIG. 3B, the light transmission chamber 18 is first installed above the exposure area on the wafer. Subsequently, after the megasonic ultrasonic plate 30 is turned on (step 2a), the exposure liquid 32 is provided from the inlet liquid storage tank 20 to the optical transmission chamber 18 through the inlet conduit 22 (step 3a). The sound waves generated by the megasonic ultrasonic plate 30 remove the ultrafine bubbles in the exposure liquid 32 passing through the inlet conduit 22, and substantially eliminate the ultrafine bubbles at the entrance where the exposure liquid 32 enters the optical transmission chamber 18. The ultrafine bubbles adhering to the wafer 34 can be removed.

  In step 4a, the photoresist on the wafer 34 is exposed while the megasonic ultrasonic plate 30 is continuously turned on. During the exposure process (step 4a), the ultrasonic bubbles in the exposure liquid 32 and on the photoresist surface on the wafer 34 are continuously removed by the megasonic ultrasonic plate 30. Therefore, the circuit pattern image 15b transmitted from the optical housing 12 and passing through the light transmission chamber 18 is projected with high resolution onto the photoresist surface on the wafer 34 without being distorted due to the influence of ultrafine bubbles. Then, after the exposure process 4a is completed, the megasonic ultrasonic plate 30 is turned off (step 5a). Subsequently, the optical transmission chamber 18 is moved to the next exposure region on the wafer 34, and Steps 1a to 5a are repeated in Step 6a.

  In step 1b of the flowchart shown in FIG. 3C, the light transmission chamber 18 is first installed above the exposure area on the wafer. Subsequently, after the megasonic ultrasonic plate 30 is turned on (step 2b), the exposure liquid 32 is provided from the inlet liquid storage tank 20 to the optical transmission chamber 18 by the inlet conduit 22 (step 3b). The sound wave generated by the megasonic ultrasonic plate 30 can remove ultrafine bubbles in the exposure liquid 32 and on the photoresist surface on the wafer 34, so that the exposure liquid 32 enters the optical transmission chamber 18. It is possible to prevent ultrafine bubbles from being generated and attached to the portions and the surface of the photoresist of the wafer 34.

  In step 4b, the megasonic ultrasonic plate 30 is intermittently turned on and off to perform the exposure process. Thereby, during the exposure period of the wafer, the ultrafine bubbles in the exposure liquid 32 are continuously removed by the megasonic ultrasonic plate 30. And after performing the exposure process 4b, the optical transmission chamber 18 is moved to the next exposure area | region on the wafer 34, and step 1b-5b is repeated in step 5b.

  In step 1c of the flowchart shown in FIG. 3D, the light transmission chamber 18 is first installed above the exposure area on the wafer. Subsequently, after the megasonic ultrasonic plate 30 is turned on (step 2c), the exposure liquid 32 is provided from the inlet liquid storage tank 20 to the optical transmission chamber 18 by the inlet conduit 22 (step 3c). The sound wave generated by the megasonic ultrasonic plate 30 can remove the ultrafine bubbles in the exposure liquid 32 that passes through the inlet conduit 22, so that the exposure liquid 32 enters the optical transmission chamber 18 and the wafer 34. It is possible to substantially prevent ultrafine bubbles from adhering to the surface.

  In step 4c, when the megasonic ultrasonic plate 30 is continuously turned on, the photoresist on the wafer 34 is exposed. Therefore, during the exposure process (step 4c), the megasonic ultrasonic plate 30 continuously removes ultrafine bubbles in the exposure liquid 32 and on the photoresist surface on the wafer. Therefore, the circuit pattern image transmitted from the optical housing 12 and passing through the light transmission chamber 18 is projected with high resolution onto the photoresist surface on the wafer 34 without being distorted by the influence of the ultrafine bubbles. When the exposure step 4c is completed, the megasonic ultrasonic plate 30 can be maintained in the on state. Subsequently, the optical transmission chamber 18 is moved to the next exposure region on the wafer 34 (step 5c), and the photoresist on the wafer 34 is exposed by the optical transmission chamber 18 (step 6c). In step 7c, Repeat steps 5c-6c.

  In step 1d of the flowchart shown in FIG. 3E, the light transmission chamber 18 is first installed above the exposure area on the wafer. Subsequently, after the megasonic ultrasonic plate 30 is turned on (step 2d), the exposure liquid 32 is provided from the inlet liquid storage tank 20 to the optical transmission chamber 18 by the inlet conduit 22 (step 3d). The sound wave generated by the megasonic ultrasonic plate 30 can remove the ultrafine bubbles in the exposure liquid 32 that passes through the inlet conduit 22. Therefore, by removing the fine particles adhering to the lower surface of the nearest objective lens 16, the superfine bubbles are substantially removed from the entrance where the exposure liquid 32 enters the optical transmission chamber 18, and the bottom of the nearest objective lens 16 is removed. The fine particles attached on the surface are removed.

  As shown in step 4d, when the megasonic ultrasound plate 30 is continuously turned on, the inlet conduit 22 provides the second liquid to the light transmission chamber 18 from the inlet liquid storage tank 20 instead of the first liquid. (Step 4d), the photoresist on the wafer 34 is exposed. Therefore, the megasonic ultrasonic plate 30 is not turned on during the exposure process (step 6d) (step 5d). Thus, the circuit pattern image 15b transmitted from the optical housing 12 and passing through the light transmission chamber 18 is projected on the photoresist surface on the wafer 34 with high resolution without being distorted due to the influence of fine particles. After performing the exposure step 6d, the optical transmission chamber 18 is moved to the next exposure region on the wafer 34, and steps 6d to 7d are repeated in step 6d.

  In step 1e of the flowchart shown in FIG. 3F, first, the light transmission chamber 18 is installed above the exposure area on the wafer. Subsequently, after the megasonic ultrasonic plate 30 is turned on (step 2e), the exposure liquid 32 is provided from the inlet liquid storage tank 20 to the optical transmission chamber 18 through the inlet conduit 22 (step 3e). Since the sound wave generated by the megasonic ultrasonic plate 30 can remove the ultrafine bubbles in the exposure liquid 32 passing through the inlet conduit 22, the fine particles adhering to the lower surface of the nearest objective lens 16 are removed. By doing so, it is possible to substantially prevent fine particles from adhering to the lower surface of the nearest objective lens 16 due to the generation of ultrafine bubbles at the entrance where the exposure liquid 32 enters the light transmission chamber 18.

  In Step 4e, when the megasonic ultrasonic plate 30 is continuously turned on, the second liquid is provided from the inlet liquid storage tank 20 to the optical transmission chamber 18 by the inlet conduit 22 instead of the first liquid (Step 4e). Then, the photoresist on the wafer 34 is exposed. Therefore, during the exposure process (step 5e), the megasonic ultrasonic plate 30 is still continuously turned on (step 2e). As a result, the circuit pattern image 15b transmitted from the optical housing 12 and passing through the light transmission chamber 18 is projected with high resolution onto the photoresist surface on the wafer 34 without being distorted by the influence of the fine particles. After performing the exposure process 5e, the optical transmission chamber 18 is moved to the next exposure area on the wafer 34, and Steps 5e to 6e are repeated in Step 5e.

  Subsequently, as shown in FIG. 2, an exposure apparatus according to another alternative embodiment is denoted by reference numeral 10a. An annular megasonic ultrasonic plate 30 a surrounds the light transmission chamber 18. And the exposure apparatus 10a is operated like the flowchart shown to FIG. 3A. After the exposure liquid 32 is sprayed on the optical transmission chamber 18, the annular megasonic ultrasonic plate 30a is turned on and turned off before the exposure process is performed. As shown in the flowchart of FIG. 3B, the annular megasonic ultrasonic plate 30a is maintained in the ON state during the process period in which the exposure liquid 32 is sprayed to the optical transmission chamber 18 and the entire exposure process period. In the flowchart shown in 3C, the annular megasonic ultrasonic plate 30a is intermittently turned on in the exposure process. For this reason, ultrafine bubbles are generated in the exposure liquid 32 installed in the light transmission chamber 18 in any state, and the circuit pattern image 15b on the wafer 34 is distorted during the exposure process. There is no.

  In the present invention, preferred embodiments have been disclosed as described above. However, these embodiments are not intended to limit the present invention, and any person who is familiar with the technology can use various embodiments within the scope and spirit of the present invention. Changes and modifications can be made. Therefore, the scope of protection of the present invention is based on the contents specified in the claims.

1 is a schematic diagram showing a configuration of a megasonic ultrasonic immersion lithography exposure apparatus according to a first embodiment of the present invention. 1 is a schematic diagram showing a configuration of a megasonic ultrasonic immersion lithography exposure apparatus according to a first embodiment of the present invention. It is a flowchart which shows the manufacturing step by 1st Embodiment of this invention. It is a flowchart which shows the manufacturing step by 2nd Embodiment of this invention. It is a flowchart which shows the manufacturing step by 3rd Embodiment of this invention. It is a flowchart which shows the manufacturing step by 4th Embodiment of this invention. It is a flowchart which shows the manufacturing step by 5th Embodiment of this invention. It is a flowchart which shows the manufacturing step by 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a Exposure apparatus 12 Optical housing 13 Optical system 14 Photomask 15 Laser 15a Laser beam 15b Circuit pattern image 16 Objective lens 18 Optical transmission chamber 20 Inlet liquid storage tank 22 Inlet conduit 22a Drain conduit 24 Outlet conduit 24a Collection conduit 26 Outlet Liquid storage tank 28 Wafer table 30, 30a Megasonic ultrasonic plate 32 Exposure liquid 34 Wafer

Claims (15)

An optical transmission chamber for loading the exposure liquid;
An ultrasonic plate that is operatively connected to the light transmission chamber and transmits a plurality of sound waves through the exposure liquid;
An immersion type lithography exposure apparatus comprising: an optical system that introduces light from a light source into the exposure liquid adjacent to the light transmission chamber.   The immersion lithography exposure apparatus according to claim 1, further comprising an inlet conduit connected to the light transmission chamber, for spraying the exposure liquid into the light transmission chamber, and supporting the ultrasonic plate.   The immersion lithography exposure apparatus according to claim 2, further comprising an outlet conduit connected to the optical transmission chamber in which the exposure liquid is sprayed. The optical system comprises:
The immersion lithography exposure apparatus according to claim 3, further comprising a laser that emits a laser beam that passes through a photomask and a lens and transmits a circuit pattern image from the photomask through the exposure liquid onto the wafer. . The ultrasonic plate is
The immersion lithography exposure apparatus according to claim 1, further comprising at least one annular megasonic ultrasonic plate surrounding the light transmission chamber. Preparing a photomask having a circuit pattern;
A step of preparing an exposure solution;
Transmitting a plurality of sound waves to the exposure liquid;
Passing a beam through the photomask and the exposure liquid, respectively, onto a photoresist-coated wafer and exposing the wafer;
A lithography exposure method comprising: Transmitting the sound wave with the exposure liquid,
7. The lithography exposure method according to claim 6, further comprising the step of transmitting the sound wave through the exposure liquid before or during a process of exposing the photoresist-coated wafer.   The lithography exposure method according to claim 6, wherein the exposure liquid contains a mixture of ammonium, hydrogen peroxide, and water.   The lithography exposure method according to claim 6, wherein the exposure liquid contains deionized water or ozone water.   The lithography exposure method according to claim 6, further comprising providing a surfactant in the exposure liquid. Transmitting the sound wave with the exposure liquid,
The lithographic exposure method according to claim 6, further comprising a step of transmitting the sound wave by the exposure liquid with a megasonic ultrasonic power of 10 to 1000 kHz. Megasonic ultrasonic immersion lithographic exposure comprising an optical system, a light transmission chamber between the closest objective lens of the optical system and a photoresist-coated wafer, and a megasonic ultrasonic plate connected to the light transmission chamber Preparing the device;
Preparing a photomask having a circuit pattern;
Providing a first liquid in the light transmission chamber;
Transmitting a plurality of sound waves passing through the first liquid;
Providing a second liquid in the light transmission chamber;
Transmitting the laser beam through the optical system and the second liquid onto the wafer, respectively, and exposing the wafer.   The immersion lithography exposure method according to claim 12, wherein the first liquid contains a mixture of ammonium, hydrogen peroxide, and water.   The immersion lithography exposure method according to claim 12, wherein the first liquid includes deionized water or ozone water.   The immersion lithography method according to claim 12, wherein the second liquid includes deionized water or a surfactant.

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