CN110824852A

CN110824852A - Laser system and lithographic apparatus

Info

Publication number: CN110824852A
Application number: CN201810916154.3A
Authority: CN
Inventors: 张俊霖; 易威廷; 陈政宏; 傅中其; 刘柏村; 陈立锐; 郑博中
Original assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
Current assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
Priority date: 2018-08-13
Filing date: 2018-08-13
Publication date: 2020-02-21

Abstract

A laser system includes a sub-laser device configured to emit an output laser, and a laser power amplifying device configured to amplify a power of the output laser and emit the output laser. The laser power amplifying device comprises a containing cavity, a gain medium, an incident light-transmitting element, an emergent light-transmitting element, an energy pump and a control unit, wherein the containing cavity is used for containing the gain medium, the incident light-transmitting element is arranged at the first opening, the emergent light-transmitting element is arranged at the second opening, and the energy pump is configured to provide energy to the gain medium. A first Brewster angle is formed between the incident light-transmitting element and the output laser. The present disclosure also provides a lithographic apparatus.

Description

Laser system and lithographic apparatus

Technical Field

The present disclosure relates generally to laser systems, and more particularly to laser systems for use in lithographic apparatus.

Background

Semiconductor devices have been used in a variety of electronic applications, such as personal computers, cellular phones, digital cameras, and other electronic devices. Semiconductor devices are generally manufactured by sequentially depositing materials for insulating or dielectric layers, conductive layers, and semiconductor layers onto a wafer, and patterning the various material layers using photolithographic techniques to form circuit elements and devices thereon. Many integrated circuits are typically fabricated on a single wafer, and individual dies on the wafer are singulated between the integrated circuits along a dicing line. For example, the individual dies are typically packaged separately in a multi-chip module or other type of package.

Due to the requirement of miniaturization of the size of semiconductor processes, extreme ultraviolet rays are used in a lithography apparatus as a light source in an exposure process to form a photoresist on a wafer into a pattern required for the semiconductor process.

However, while current lithographic apparatus using extreme ultraviolet light as the light source in the exposure process meet their objectives, many other requirements have not been met. Accordingly, there is a need to provide improved solutions for lithographic apparatus.

Disclosure of Invention

The present disclosure provides a laser system including a sub-laser device configured to emit an output laser having a first power, and a laser power amplifying device configured to amplify the first power of the output laser and emit the output laser having a second power. The laser power amplifying device comprises a containing cavity, a gain medium, an incident light-transmitting element, an emergent light-transmitting element, an energy pump and a control unit, wherein the containing cavity is used for containing the gain medium, the incident light-transmitting element is arranged at the first opening, the emergent light-transmitting element is arranged at the second opening, and the energy pump is configured to provide energy to the gain medium.

The output laser with the first power penetrates through the incident light-transmitting element, enters the accommodating cavity and passes through the gain medium, and the output laser with the second power in the accommodating cavity penetrates through the emergent light-transmitting element and is emitted out of the laser power amplifying device. A first Brewster angle is formed between the incident light-transmitting element and the output laser which is irradiated on the incident light-transmitting element and has the first power.

The disclosure provides a lithographic apparatus including an excitation chamber, a target emitter disposed on the excitation chamber and configured to emit a target, a sub-laser device configured to emit an output laser having a first power, and a laser power amplifying device configured to amplify the first power of the output laser and emit the output laser having a second power. The laser power amplifying device comprises an accommodating cavity, an incident light-transmitting element, an emergent light-transmitting element and an energy pump, wherein the accommodating cavity is used for accommodating a gain medium, the incident light-transmitting element is arranged on one side of the accommodating cavity, the emergent light-transmitting element is arranged on the other side of the accommodating cavity, and the energy pump is configured to provide energy to the gain medium.

The lithographic apparatus also includes a laser transmitter configured to receive the output laser emitted by the laser power amplifying device and to transmit a pulsed laser to the target. The output laser with the first power penetrates through the incident light-transmitting element, enters the accommodating cavity and passes through the gain medium, and the output laser with the second power in the accommodating cavity penetrates through the emergent light-transmitting element and is emitted out of the laser power amplifying device. A first Brewster angle is formed between the incident light-transmitting element and the output laser which is irradiated on the incident light-transmitting element and has the first power.

Drawings

FIG. 1 is a schematic view of a lithographic apparatus according to some embodiments of the present disclosure.

FIG. 2 is a flow chart of steps of a lithographic method according to some embodiments of the present disclosure.

Fig. 3 is a schematic diagram of a seed laser apparatus according to some embodiments of the present disclosure.

Fig. 4 is a schematic diagram of a laser power amplification device, according to some embodiments of the present disclosure.

Fig. 5 is a schematic diagram of a laser system according to some embodiments of the present disclosure.

FIG. 6 is a schematic view of a lithographic apparatus according to some embodiments of the disclosure.

Description of reference numerals:

lithographic apparatus 1

Light source device 10

Exposure chamber 20

Lighting device 30

Photomask assembly 40

Photomask holder 41

Optical projection device 50

Reflecting mirror 51

Wafer seat 60

Excitation chamber A10

Light ray channel A11

Target emitter A20

Target retriever A30

Ray collector A50

Through hole A51

Laser emitter A60

Laser system A70

Seed laser device A71

Resonant Cavity A711

Seed energy Pump A712

Total reflection mirror A713

Partial mirror A714

Laser power amplifiers A72, A72a, A72b, A72c

The containing cavity A721

First opening A7211

Second opening A7212

Energy Pump A722

Incident light-transmitting element A723

Outgoing light-transmitting element A724

Polarized reflective layer A725

Laser emitter A73

Laser sensors A74, A75

Laser conduction devices A76, A77

First focus C1

Second focal point C2

First direction D1

Second direction D2

Target E1

Brewster angles G1, G2

Gain medium H1

Pulsed laser L1

Output laser light L2, L21, L22 pulsed laser light L3

Return laser light L4, L41, L42

Photomask M1

Substrate M11

Pattern layer M12

Wafer W1

Photoresist layer W11

Excitation zone Z1

Concentration zone Z2

Detailed Description

The following description provides many different embodiments, or examples, for implementing different features of the disclosure. The particular examples set forth below are intended merely to illustrate the disclosure and are not intended to limit the disclosure. For example, the description of a structure having a first feature over or on a second feature may include direct contact between the first and second features, or another feature disposed between the first and second features, such that the first and second features are not in direct contact.

The terms first and second, etc. in this specification are used for clarity of explanation only and do not correspond to and limit the scope of the claims. The terms first feature, second feature, and the like are not intended to be limited to the same or different features.

Spatially relative terms, such as above or below, are used herein for ease of description of one element or feature relative to another element or feature in the figures. Devices that are used or operated in different orientations than those depicted in the figures are included. The shapes, sizes, thicknesses, and angles of inclination in the drawings may not be drawn to scale or simplified for clarity of illustration, but are provided for illustration only.

FIG. 1 is a schematic view of a lithographic apparatus 1 according to some embodiments of the present disclosure. The lithographic apparatus 1 is used to perform a lithographic process on a wafer W1. The photolithography process may include a photoresist coating process, a soft bake process, an exposure process, a development process, a hard bake process, and other suitable processes.

In the present embodiment, the lithographic apparatus 1 may be an exposure apparatus for performing an exposure process on a wafer W1. The lithographic apparatus 1 may comprise a light source device 10, an exposure chamber 20, an illumination device 30, a photomask device 40, an optical projection device 50, and a wafer holder 60. The lithographic apparatus 1 may comprise all of the above-described devices, but it is not necessary to include all of them, as long as the purpose of the use of the lithographic apparatus 1 is achieved.

The lithographic apparatus 1 should not be limited to the devices described in this disclosure. The lithographic apparatus 1 may comprise other suitable devices, such as a coating device, a soft bake device, a developing device, and/or a hard bake device, etc., to enable the lithographic apparatus 1 to perform a complete lithographic process on the wafer W1.

The light source device 10 is used for generating light to the illumination device 30. The light may be extreme ultraviolet (EUV light). In the present embodiment, the wavelength range of the extreme ultraviolet light may be defined as a range between 10nm and 121 nm. In some embodiments, the wavelength of the light may be in a range from 10nm to 20 nm. Therefore, the light source device 10 can be an extreme ultraviolet light source device. However, the light source device 10 should not be limited to generating extreme ultraviolet rays. The light source apparatus 10 may be configured to emit any photon of any wavelength and intensity from excitation at target E1.

The exposure chamber 20 is disposed at one side of the light source device 10. In some embodiments, the illumination device 30, the mask device 40, the optical projection device 50, and the wafer holder 60 may be disposed in the exposure chamber 20. However, because the gas molecules absorb the extreme ultraviolet light, a vacuum may be maintained inside the exposure chamber 20 to prevent loss of the extreme ultraviolet light.

The illumination device 30 is used for guiding the light (extreme ultraviolet) provided by the light source device 10 to a photomask M1 disposed on the light source device 10. The illumination device 30 may include one or more optical elements, such as at least one lens, at least one mirror, and/or at least one refractor. The light emitted from the light source device 10 is refracted, reflected, and/or condensed by the illumination device 30 and then directed to the photomask M1 or the photomask device 40.

The mask device 40 is used to hold a mask (or reticle) M1. In some embodiments, the photomask apparatus 40 may be used to move the photomask M1 so that light emitted by the illumination device 30 is directed to different areas of the photomask M1. In some embodiments, the mask device 40 may include a mask holder 41 for holding the mask M1. The photomask holder 41 may be an electrostatic holder (e-chuck).

In some embodiments, the mask M1 may be a reflective mask M1. In one example, photomask M1 may include a substrate M11. The material of the substrate M11 may be Low Thermal Expansion Material (LTEM) or fused quartz (fused quartz). In some embodiments, the low thermal expansion material comprises doped SiO₂Of TiO 2₂Or other suitable materials having low thermal expansion properties.

In some embodiments, the photomask M1 may include a plurality of reflective layers disposed on the substrate M11 and configured to reflect light or extreme ultraviolet radiation. The multilayer complex reflective layer includes a plurality of film pairs (film pairs), such as molybdenum-silicon (Mo/Si) film pairs, wherein in each film pair, one layer of molybdenum is disposed on top of or below another layer of silicon. In some embodiments, the film pairs may Be molybdenum-beryllium (Mo/Be) film pairs, or other suitable materials that are highly reflective of ultraviolet light.

The photomask M1 may further include a pattern layer M12 disposed on the substrate M11. The patterned patterning layer M12 may be used to define an Integrated Circuit (IC). When the light (extreme ultraviolet) emitted from the illumination device 30 irradiates the patterned layer M12, a patterned light is formed.

In some embodiments, the patterned layer M12 may be an absorbent layer. The absorption layer may include TaBN (tanalum boronnide) for absorbing light or extreme ultraviolet rays. In some embodiments, photomask M1 may be an extreme ultraviolet phase shift photomask M1(EUV phase shift mask), and patterned layer M12 may be a reflective layer.

An optical projection device (POB) 50 is disposed between the photomask M1 and the wafer pedestal 60, and is used to form the pattern of the photomask M1 on the wafer W1. In some embodiments, the optical projection device 50 may include a plurality of optical elements, such as at least one lens, at least one mirror, and/or at least one refractor. The light emitted from the photomask M1 carries an image of the pattern defined on the photomask M1, and is refracted, reflected, and/or condensed by the optical projection device 50 and then directed to the wafer W1 or the wafer pedestal 60.

In the present embodiment, the optical projection apparatus 50 includes a plurality of reflectors 51 for reflecting light (or extreme ultraviolet rays). The light emitted from the photomask M1 is reflected and condensed by the optical projection device 50 and then guided to the wafer W1 or the wafer stage 60.

The die pad 60 is disposed below the photomask M1. In the present embodiment, the wafer seat 60 is disposed below the optical projection apparatus 50. The wafer holder 60 is used to hold the wafer W1. The die pad 60 may be an electrostatic chuck (e-chuck).

The wafer W1 may be made of silicon or other semiconductor material. In some embodiments, the wafer W1 may be made of a compound semiconductor (compound semiconductor) material, such as silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs), or indium phosphide (InP). In some embodiments, the wafer W1 may be made of an alloy semiconductor (alloy semiconductor), such as silicon germanium (SiGe), silicon carbide (SiGeC), gallium arsenide phosphide (GaAsP), or gallium indium phosphide (GaInP). In some embodiments, the wafer W1 may be a silicon-on-insulator (SOI) or germanium-on-silicon (GOI) substrate.

In addition, the wafer W1 may have various device elements (device elements). For example, the device elements formed on the wafer W1 may include transistors (transistors), diodes (diodes), and/or other suitable elements. A variety of different processes may be used to form the device elements described above. Such as a deposition process, an etching process, an implantation process, a photolithography process, and/or other suitable processes.

In some embodiments, the wafer W1 is coated with a photoresist layer W11 that is chemically reactive to light (or ultraviolet light). When the patterned light emitted from the optical projection apparatus 50 irradiates the photoresist layer W11, the photoresist layer W11 is patterned.

The light source device 10 may use a dual-pulse laser plasma (dual-pulse LPP) mechanism to generate plasma from the target E1 and emit extreme ultraviolet rays from the plasma. The light source device 10 may include an excitation chamber a10, a target emitter a20, a target recycler a30, a light collector a50, a laser emitter a60, and a laser system a 70.

The light source device 10 may include all of the above devices, but need not include all of the above devices as long as the purpose of using the light source device 10 is achieved. The light source apparatus 10 should not be limited to the apparatus described in the present disclosure and may include other suitable elements.

The excitation chamber a10 may be located on one side of the exposure chamber 20. The excitation chamber A10 may be connected to the exposure chamber 20 via a light channel A11. Since the gas molecules will absorb the extreme ultraviolet light, a vacuum may be maintained inside excitation chamber a10 to prevent loss of the extreme ultraviolet light.

It is noted that in some embodiments, after the excitation chamber a10 is filled with a gas such as hydrogen, the excitation chamber a10 is pumped into a vacuum state by a vacuum pump. At this point, a small amount of gas remains in the excitation chamber a 10. In some embodiments, the pressure within the excitation chamber a10 may be less than or equal to about 0.001 atmosphere.

Target emitter a20 is disposed on firing chamber a10 and is operable to generate a plurality of target E1. In the embodiment , a firing machine A20 for firing is located in a firing chamber A10. Target emitter A20 may emit target E1 in a first direction D1 toward a shock wave region Z1 in the shock wave cavity A10. Target E1 may be irradiated by pulsed laser light L1, L2 emitted by laser emitter a60 and laser emitter a73 and excited to extreme ultraviolet in excitation region Z1 within excitation chamber a 10.

Target E1 may be liquid or solid. In the present embodiment, the target E1 may be in a liquid state and may be a tin droplet (tindrop). In some embodiments, the target E1 may be a liquid material including tin, such as eutectic alloy (eutectic alloy) including tin, lithium (Li), and xenon (Xe). In some embodiments, the target E1 has a diameter in the range of about 20um to about 40 um. In this embodiment, the target E1 may be about 30um in diameter. In some embodiments, target launcher A20 may emit target E1 at a speed in a range of 50 meters to 100 meters per second. In this embodiment, target launcher A20 may emit target E1 at a rate of about 80 meters per second

Target transmitter A20 may transmit a target E1 frequency in a range between about 40kHz and 300 kHz. In other words, target transmitter A20 may transmit a target E1 in a range of approximately every 3.3 microseconds to 25 microseconds. In some embodiments, target emitter A20 emits target E1 at a frequency greater than 55kHz, 60kHz, or 70 kHz.

Target retriever a30 is disposed in excitation chamber a10 to retrieve target E1 emitted from target emitter a 20. In this embodiment, a float collector A30 is located in a swash plate chamber A10. Target retriever a30 and target emitter a20 may be on opposite sides of firing chamber a 10. In the present embodiment, excitation zone Z1 is located between target retriever a30 and target emitter a 20.

A light concentrator A50 is located within the shock wave cavity A10 for concentrating the extreme ultraviolet light in a concentration zone Z2. In some embodiments, the condensation zone Z2 is located in the illumination device 30. The beam concentrator A50 is used to reflect the EUV light and transmit the EUV light to the illuminator 30 in the exposure chamber 20 via the beam channel A11.

In this embodiment, the light collector A50 may be a truncated oval. The light collector a50 may be coated with a reflective layer of the body frame body panel to reflect extreme ultraviolet light. The light collector A50 may have a central through hole A51 for allowing the pulsed laser light L1, L3 emitted by the laser emitter A60 and the laser emitter A73 to pass through

In the present embodiment, the light collector A50 can be, for example, an elliptical lens having a first focal point C1 located in the excitation region Z1 and a second focal point C2 located in the light-collecting region Z2. When the target E1 excites euv light at the first focus C1 after being irradiated by the pulsed laser L3 emitted from the laser emitter a73, the euv light may be reflected to the second focus C2 by the light collector a 50. Since the second focal point C2 can be located in the illumination device 30 in the light converging region Z2, the euv light can be focused on the illumination device 30 by the light concentrator a50 in the present embodiment.

In some embodiments, the second focal point C2 may be located in the light channel a11, and the ultraviolet light at the second focal point C2 may be transmitted to the illumination device 30 through suitable optical elements, such as refractive mirrors or reflective mirrors.

It should be noted that the shape or structure of the light concentrator A50 is not limited as long as it can concentrate the masterultraviolet light excited by target E1 in a region. For example, the light ray collector a50 may be in an elliptical shape.

Laser emitter A60 is positioned alongside excitation chamber A10. In this embodiment, the pre-laser-Rich radiator A60 can be located in the Rich chamber A10. Laser emitter A60 may be used to generate a pulsed laser light L1. In one embodiment, pulsed laser L1 may be a pre-pulse laser (pre-pulse laser) E1 at charges in region Z1. The pulse laser light L1 passes through the light condenser a50 via the through hole a51 and is irradiated to the excitation region Z1.

In the present embodiment, the laser emitter a60 emits pulsed laser light L1 along a second direction D2. The second direction D2 may be perpendicular to the first direction D1. In some embodiments, laser emitter A60 may emit pulsed laser light L1 at the same frequency that target emitter A20 emits target E1.

In some embodiments, the power of the pulsed laser L1 is in a range of about 1kW to about 5 kW. In the present embodiment, the power of the pulsed laser L1 may be about 2 kW.

In some embodiments, laser emitter A60 may be a carbon dioxide (CO)₂) A laser emitter. In another embodiment of the present invention, the substrate is,laser emitter A60 may be a neodymium-doped yttrium aluminum garnet (Nd: YAG) laser emitter.

The laser system a70 is used to supply output laser L2 to the laser emitter a 73. In some embodiments, laser system a70 may supply laser light to laser emitter a 60. In some embodiments, the laser of laser emitter a60 may be provided via other suitable laser systems a 70.

Laser system a70 may include a seed laser device a71, a plurality of laser power amplification devices a72, and a laser emitter a 73. The seed laser device a71 is used to emit an output laser L2 to the laser power amplifying device a 72. In some embodiments, the output laser L2 emitted by the seed laser device a71 may have a power ranging from about 5W to about 15W. In the present embodiment, the power of the output laser L2 emitted by the seed laser device a71 may be about 10W.

Each laser power amplifying device a72 is configured to amplify the power of the output laser L2 and emit the output laser L2 with amplified power to the laser emitter a 73. For example, the power of the laser generated by the seed laser device a71 is 10W. After passing through the plurality of laser power amplifiers a72, the power of the laser was in the range of about 18kW to 40 kW. In some embodiments, the power of the laser is about 30 kW.

Each laser power amplifying device a72 is used to amplify the power of the output laser light L2 by a factor in the range of about 1.2 times to 300 times. For the sake of clarity, in the present embodiment, the laser system a70 includes three laser power amplifying devices a72 (e.g., a72a to a72 c). However, the number of the laser power amplifying devices a72 should not be limited. The number of laser power amplifiers a72 may range from about one to ten. In some embodiments, laser system a70 includes one or two laser power amplifiers a 72. In some embodiments, the laser system a70 includes four or more laser power amplifiers a 72.

In some embodiments, the seed laser device a71 is configured to emit an output laser L2 having a first power. The laser power amplifying device a72a amplifies the first power of the output laser light L2 and emits the output laser light L2 having a second power. The laser power amplifying device a72b amplifies the second power of the output laser light L2 and emits the output laser light L2 having the third power. The laser power amplifying device a72c amplifies the third power of the output laser light L2 and emits the output laser light L2 having the fourth power. In this embodiment, the first power is greater than the second power, the second power is greater than the third power, and the third power is greater than the fourth power.

For example, the laser power amplifier a72a may be a pre-laser power amplifier. The output laser beam L2 of the seed laser apparatus a71 is irradiated to the laser power amplifier apparatus a72 a. The laser power amplifier a72a is configured to amplify the power of the output laser beam L2 and emit the amplified output laser beam L2 to the laser power amplifier a72 b.

In some embodiments, the laser power amplifying device a72a is configured to amplify the power of the output laser L2 by a factor in a range of about 30 times to about 300 times. For example, the laser power amplifying device a72a amplifies the power of the output laser light L2 by 100 times. The laser power amplifier a72a amplifies an output laser beam L2 with a power of 10W to 1000W.

The laser power amplifier a72b is configured to amplify the power of the output laser beam L2 and emit the amplified output laser beam L2 to the laser power amplifier a72 c. The laser power amplifier a72c is configured to amplify the power of the output laser L2 and emit the amplified output laser L2 to the laser emitter a 73.

In some embodiments, the laser power amplifier a72b and the laser power amplifier a72c may each amplify the power of the output laser light L2 by a factor in a range of about 1.2 to 30. In some embodiments, the output laser L2 of 1000W of power provided by the laser power amplifying device a72a can be amplified to 30kW by more laser power amplifying devices a72b, a72 c.

The laser emitter a73 is used for receiving the output laser L2 emitted from the laser power amplifier a72 and emitting a pulse laser L3. Laser emitter A73 is positioned alongside excitation chamber A10. In this embodiment, the main laser Rich emitter A70 may be located within the Rich cavity A10. Laser emitter A73 may be used to generate a pulsed laser light L3. In some embodiments, pulsed laser L3 may be a main-pulse laser (main-pulse laser) E1 at charges in region Z1. The pulse laser light L3 passes through the light condenser a50 via the through hole a51 and is irradiated to the excitation region Z1.

As shown in FIG. 1 , a pulse pendulum laser L1 can be used to change the E1 of the supplied window, i.e., . After axially irradiating E1 in the excitation region Z1, the axially fluidized stone laser L1 can apply E1 to the axially fluidized stone paint, so that E1 of droplets of the clothes is formed into a mist-like shape, E1. The cutter E1 for mist cutter in the zone Z1 irradiated by a diesel ridge laser L2, the cutter E1 for cutter can excite the diesel ridge laser L2 is changed to the computer , which causes the cutter E to generate ultraviolet.

As shown in fig. 1, after the pulsed laser L3 is irradiated to target E1 in the excitation region Z1, the target E1 reflects part of the pulsed laser L3 to form a return beam L4. The return beam L4 may be irradiated to the seed energy pump a712 via a laser emitter a73, a laser power amplifier a72c, a laser power amplifier a72b, and a laser power amplifier a72a in sequence. In some embodiments, the laser emitter a73 may emit pulsed laser light L3 in the second direction D2. In other words, the pulsed laser light L3 may be parallel to the pulsed laser light L1.

In some embodiments, the power of the pulsed laser L3 is in a range of about 18kW to about 40 kW. In the present embodiment, the power of the pulsed laser L3 may be about 30 kW. The power of the pulsed laser light L3 was higher than the power of the pulsed laser light L1. In some embodiments, the power of the pulsed laser L3 is greater than 8 times to 30 times the power of the pulsed laser L1. The power of the pulsed laser light L3 may be equal to or substantially equal to the power of the output laser light L2 output by the laser power amplifier a72 c.

In some embodiments, laser emitter a73 may emit pulsed laser light L3 at the same frequency that target emitter a20 emits target E1. In some embodiments, laser emitter a73 may be a carbon dioxide laser emitter.

The power of the pulsed laser L1 and the pulsed laser L3 may be designed according to the throughput of the wafer W1. For example, 125 wafers W1 are produced per hour, the pulsed laser L1 may have a power of 2kW, and the pulsed laser L3 may have a power of about 30 kW. In some embodiments, the sum of the power of the pulsed laser L1 and the pulsed laser L3 is higher than 20kW, for example, 32 kW. It should be understood, however, that there are many variations and modifications of the embodiments of the present disclosure, which should not be taken to be limiting.

FIG. 2 is a flow chart of steps of a lithographic method according to some embodiments of the present disclosure. It is understood that in the steps of the methods of the following embodiments, additional steps may be added before, after, and between the steps, and some of the steps may be replaced, deleted, or moved.

In step S101, a photomask M1 is mounted on the photomask holder 41. In some embodiments, photomask M1 may be used to perform an euv lithography exposure process. Photomask M1 may include integrated circuit patterns to be formed on wafer W1. In step S103, a wafer W1 is disposed on a wafer pedestal 60. The wafer W1 may be coated with a photoresist layer W11.

In step S105, target emitter A20 emits a target E1 every time an interval elapses, and target E1 reaches excitation region Z1.

In step S107, after the target emitter a20 emits the target E1, the laser emitter a60 emits a pulse laser L1 to the excitation region Z1 every lapse of the above-described interval time, and irradiates a target E1. Target E1 may form atomized target E1 via pulsed laser L1.

In step S109, after the laser emitter a60 emits the pulsed laser L1, the laser emitter a73 emits a pulsed laser L3 to the excitation region Z1 every time the interval P1 elapses, and irradiates a target E1. Target E1 can form a plasma via pulsed laser L3 and emit ultraviolet light.

In step S111, the extreme ultraviolet light is sequentially guided to the photomask M1 by the light collector A50 and the illumination device 30, and a patterned light is formed. The patterned light is sequentially irradiated to a plurality of regions of the photoresist of a wafer W1, thereby completing an exposure process of a photolithography process.

Fig. 3 is a schematic diagram of a seed laser apparatus a71 according to some embodiments of the present disclosure. The seed laser device A71 is used to generate an output laser L2. The seed laser device a71 includes a resonant cavity a711, a seed energy pump a712, a total reflection mirror a713, and a partial reflection mirror a 714.

The resonant cavity A711 may be a strip structure. In some embodiments, the resonant cavity A711 can be made of glass and can be transparent. In other words, the resonant cavity A711 can be a transparent glass tube. Resonant cavity A711 may be filled with a gain medium H1.

The gain medium H1 in resonant cavity a711 can be either a solid or a gas. In some embodiments, the gain medium H1 may be a diode. In one embodiment, the gain medium H1 may be, but is not limited to, neodymium-doped yttrium aluminum garnet, carbon dioxide, or carbon monoxide. In the present embodiment, the gain medium H1 may be carbon dioxide.

The seed energy pumps A712 are disposed on opposite sides of the resonant cavity A711. The seed energy pump a712 is used to provide energy to the gain medium H1, and to excite the gain medium H1 to emit the output laser L2. In some embodiments, the seed energy pump A712 can be a light source or a set of electrodes. In this embodiment, the seed energy pump A712 may be a set of electrodes for emitting Radio frequency (Radio frequency) energy toward the gain medium H1.

The holophote A713 is disposed at one end of the resonant cavity A711. Partial mirror A714 is disposed at the other end of resonant cavity A711. The total reflection mirror a713 may be a focusing mirror for forming a beam of the output laser light L2 emitted from the gain medium H1.

Partial mirror a714 may be a partially reflective flat mirror. The partial mirror a714 is used to reflect part of the output laser light L2 to the total reflection mirror a713, and allow part of the output laser light L2 to pass through. In some embodiments, the partial mirror a714 is configured to reflect the output laser light L2 illuminating between about 90% and 99.99% of the range of the partial mirror to the total mirror a713, and allow the output laser light L2 between about 1% and 30% to pass through.

When the output laser light L2 emitted from the partial gain medium H1 is irradiated to the total reflection mirror a713, the total reflection mirror a713 reflects the output laser light L2 to the partial reflection mirror a 713. After that, the partial mirror a713 reflects part of the output laser light L2 to the total reflection mirror a 713. Therefore, most of the output laser light L2 can oscillate between the total reflection mirror a713 and the partial reflection mirror a714 and increase the power of the output laser light L2.

Fig. 4 is a schematic diagram of a laser power amplification device a72, according to some embodiments of the present disclosure.

Fig. 5 is a schematic diagram of a laser system a70 according to some embodiments of the present disclosure. The laser power amplifying device a72 includes a housing cavity a721, an energy pump a722, an incident light transmitting element a723, and an exit light transmitting element a 724. The accommodating cavity a721 may be a strip structure. In some embodiments, the accommodating chamber a721 may be made of glass material and may be transparent. In other words, the accommodating chamber a721 can be a transparent glass tube.

The receiving cavity a721 may be filled with a gain medium H2. The gain medium H2 in the accommodation cavity a721 may be the same as the gain medium H1 in the resonance cavity a 711. In some embodiments, the gain medium H2 in the receiving cavity a721 may be different from the gain medium H1 in the resonant cavity a 711. In addition, the receiving chamber a721 may have a first opening a7211 and a second opening a7212 opposite to the first opening a 7211.

Energy pumps A722 are disposed on opposite sides of resonant cavity A711. The energy pump a722 is used to provide energy to the gain medium H2, and the gain medium H2 is excited to emit the output laser L2, thereby increasing the power of the output laser L2. In some embodiments, the energy pump A722 can be a light source or a set of electrodes. In this embodiment, the energy pump A722 may be a set of electrodes configured to emit RF energy toward the gain medium H2.

The incident light-transmitting element a723 is disposed in the first opening a 7211. The material of the incident light-transmitting element a723 may be a light-transmitting material with a high refractive index, such as diamond. The exit light-transmitting element a724 is disposed in the second opening a 7212. In other words, the incident light transmissive element a723 and the emergent light transmissive element a724 are respectively located on two opposite sides of the accommodating cavity a 721. The material of the emitting light-transmitting element a724 may be a light-transmitting material with a high refractive index, such as diamond.

In some embodiments, the first opening a7211 and the second opening a7212 may be located on the same side of the receiving cavity a721, or on two adjacent sides. The laser power amplifying device a72 may include a refractive element and/or a reflective element (not shown) disposed in the accommodating cavity a721 for guiding the output laser light L2 passing through the incident light transmissive element a723 to the emergent light transmissive element a 724.

The incident light transmissive element a723 and the exit light transmissive element a724 may be flat plate structures. The output laser light L2 is irradiated on the main surfaces of the incident light-transmitting element a723 and the exit light-transmitting element a 724. The incident light transmissive element a723 and the emergent light transmissive element a724 may be circular or polygonal, but not limited thereto.

In the present embodiment, the output laser L2 emitted by the seed laser device a71 or another laser power amplifying device (e.g., a72a) passes through the incident light-transmitting element a723, enters the accommodating cavity a721 of the laser power amplifying device (e.g., a72b), and passes through the gain medium H2. After the output laser light L2 passes through the gain medium H2, the power of the output laser light L2 is increased. In addition, the output laser light L2 in the accommodating cavity a721 passes through the exit light-transmitting element a724 and is emitted to another laser power amplifying device (e.g., a72 c).

In the present embodiment, a Brewster angle G1 is formed between the incident light-transmitting device a723 and the output laser L2 (or the traveling direction of the output laser L2) irradiated on the incident light-transmitting device a 723. A brewster angle G2 is formed between the light-transmitting exit element a724 and the output laser L2 (or the traveling direction of the output laser L2) irradiated on the light-transmitting exit element a 724.

The Brewster angle G1 may be defined as arctan (n2/n 1). Where n1 may be the refractive index of air and n2 may be the refractive index of incident light transmissive element a 723. The Brewster angle G2 may be defined as arctan (n4/n 3). Where n3 may be the refractive index of the gain medium H2, and n4 may be the refractive index of the exit light-transmitting element a 724.

In the present embodiment, the material of the incident light transmissive element a723 is the same as that of the emergent light transmissive element a 724. Brewster's angle G1 is substantially equal to Brewster's angle G2. In some embodiments, the material of the incident light transmissive element a723 is different from the material of the exit light transmissive element a 724. Brewster's angle G1 is not equal to Brewster's angle G2.

In some embodiments, when the incident light transmissive element a723 is made of diamond or has a refractive index in a range from about 1 to about 4, the brewster angle G1 is in a range from about 45 degrees to about 76 degrees. For example, when the incident light transmissive element a723 is made of diamond and has a refractive index of 2.4176, the brewster angle G1 is 67.5 degrees.

In some embodiments, when the exit light-transmitting element a724 is made of diamond or has a refractive index in a range from about 1 to about 4, the brewster angle G2 is in a range from about 45 degrees to about 76 degrees. For example, when the material of the exit light-transmitting element a724 is diamond and the refractive index is 2.4176, the brewster angle G2 is 67.5 degrees.

Since the incident light transmitting element a723 and the output laser light L2 have a brewster angle G1 therebetween, and the output laser light L2 is polarized light, most of the output laser light L2 can directly penetrate through the incident light transmitting element a723, and only a small portion of the output laser light L2 is reflected by the incident light transmitting element a723 due to a light leakage phenomenon, so as to form the output laser light L21.

In some embodiments, more than 98% of the output laser light L2 penetrates through the incident light-transmitting element a723, and less than 2% of the output laser light L2 is reflected by the incident light-transmitting element a 723. In some embodiments, more than 99% of the output laser light L2 penetrates through the incident light-transmitting element a723, and less than 1% of the output laser light L2 is reflected by the incident light-transmitting element a 723.

Similarly, since the brewster angle G2 is between the outgoing transparent device a724 and the output laser L2, and the output laser L2 is polarized light, most of the output laser L2 can directly penetrate through the outgoing transparent device a724 to be emitted, and only a small portion of the output laser L2 is reflected by the outgoing transparent device a724 due to light leakage, and forms an output laser L22.

In some embodiments, more than 98% of the output laser light L2 penetrates through the exit light-transmitting element a724, and less than 2% of the output laser light L2 is reflected by the exit light-transmitting element a 724. In some embodiments, more than 99% of the output laser light L2 penetrates through the exit light-transmitting element a724, and less than 1% of the output laser light L2 is reflected by the exit light-transmitting element a 724.

Therefore, by the brewster angle G1 between the incident transparent element a723 and the output laser L2 and/or the brewster angle G2 between the exit transparent element a724 and the output laser L2 irradiated on the exit transparent element a724 of the present disclosure, reflection of the output laser L2 between the incident transparent element a723 and the exit transparent element a724 can be greatly reduced, and further parasitic phenomena and parasitic lasers of the lasers can be greatly reduced, so that yield of the wafer W1 can be increased and damage of the seed laser device a71 can be prevented.

In the present embodiment, the laser system a70 further includes a plurality of laser sensors a74 and a plurality of laser sensors a 75. Each laser sensor A74 is used to detect the part of the output laser L21 reflected by the incident light-transmitting device A723. Each laser sensor A75 is used to detect the part of the output laser L22 reflected by the outgoing transparent component A724.

In one embodiment, each of the laser sensors a74 and a75 is configured to detect the intensity of the output laser beams L21 and L22, and to obtain the intensity of the output laser beams L2. For example, the intensity of the output laser light L2 may be N times the intensity of the output laser light L21 or the output laser light L22. The above N may range from 100 to 1000.

In one embodiment, multiple input energies may be taken from the detection result of each laser sensor A74. A controller (not shown) obtains an output power from the detection result of the laser sensor a 75. Therefore, by detecting the input energy and the output energy in real time, it can be detected whether each of the laser power amplifiers a72(a72a, a72b, a72c) is operating normally in real time, thereby improving the throughput of the lithographic apparatus 1.

In addition, the controller can obtain parameters such as gain Energy (Energy gain) and light extraction efficiency (extracted efficiency) of each laser power amplifier a72 by measuring the input Energy and the output Energy of each laser power amplifier a72 in real time, so as to detect and evaluate the operation condition of each laser power amplifier a72(a72a, a72b, a72c) in real time. Therefore, when the output power of one of the laser power amplifiers a72 is different from the predetermined output power, the output power of the energy pump a722 of the laser power amplifier a72 can be adjusted in real time, thereby increasing the yield of the wafer W1.

In the present embodiment, each laser power amplifying device a72 may further include a polarization reflective layer a725 coated on the inner surface of the incident light transmissive element a723 and a polarization reflective layer a725 coated on the outer surface of the exit light transmissive element a 724. Polarized reflective layer a725 may allow output laser light L2 to pass through and may reflect return beam L4.

In the present embodiment, the output laser L2 may have a first polarization. The return light beam L4 reflected by the target has a second polarized wave. The first polarized wave is perpendicular to the second polarized wave. In some embodiments, the first polarized wave may be a vertical wave and the second polarized wave may be a horizontal wave. In some embodiments, the first polarized wave may be a horizontal wave and the second polarized wave may be a vertical wave.

Each of the polarized reflective layers a725 disposed on the outer side surface of the outgoing light transmissive element a724 reflects most of the returned light beam L4. Therefore, each of the polarized reflective layers a725 disposed on the outer surface of the exit light-transmitting element a724 can be used to reduce the return light beam L4 entering the laser power amplifier.

However, due to the light leakage phenomenon of the polarized reflective layer a725, a small portion of the return light beam L4 may penetrate through the polarized reflective layer a725 and exit the light transmissive element a 724. For example, the polarization reflection layer a725 reflects more than 98% of the return light beam L4 to form a return light beam L41, and allows less than 2% of the return light beam L4 to pass through the exit light-transmitting element a724 to enter the laser power amplification device a 72. In some embodiments, the polarization reflective layer a725 reflects more than 99% of the return light beam L4 to form the return light beam L41, and allows less than 1% of the return light beam L4 to pass through the exit light-transmitting element a724 into the laser power amplifying device a 72.

Each of the polarized reflective layers a725 disposed on the inner side surface of the incident light transmissive element a723 reflects most of the returned light beam L4. Therefore, each of the polarization reflection layers a725 disposed on the inner side surface of the incident light transmission element a723 can be used to reduce the return light beam L4 emitted from the laser power amplifier.

Similarly, a small portion of the return light beam L4 may penetrate through the polarized reflection layer a725 and the incident light transmission element a723 due to the light leakage phenomenon of the polarized reflection layer a 725. For example, the polarization reflective layer a725 reflects more than 98% of the return light beam L4 to form the return light beam L42, and allows less than 2% of the return light beam L4 to pass through the incident light transmissive element a723 to exit the laser power amplifier. In some embodiments, the polarization reflective layer a725 reflects more than 99% of the return light beam L4 to form the return light beam L42, and allows less than 1% of the return light beam L4 to pass through the incident light transmissive element a723 to exit the laser power amplifier.

After the pulsed laser light L1 is irradiated to the target E1, the target E1 reflects part of the pulsed laser light L1 to form a return beam L4. When the return light beam L4 passes through the laser power amplifying device a72, the power of the return light beam L4 is also amplified. If the return beam L4 fails to attenuate before entering the laser power amplifier a72, the over-powered return beam L4 may damage the seed laser a 71. Therefore, by disposing the polarization reflection layer a725 on each of the outgoing transparent element a724 and the incoming transparent element a723, the power of the return beam L4 passing through each of the laser power amplifiers a72 can be greatly reduced, thereby protecting the seed laser device a 71.

In the present embodiment, the laser system a70 may further include a plurality of laser guiding devices a76 and a plurality of laser guiding devices a 77. Each laser conducting device a76 is used to attenuate the energy of the return beam L41. In some embodiments, each laser guiding device A76 is used to recover the energy of the return beam L41. In some embodiments, each laser guiding device a76 can be used to detect the intensity of the return beam L41, thereby detecting the operation of the laser system a70 in real time.

Each laser conducting device a77 is used to attenuate the energy of the return beam L42. In some embodiments, each laser guiding device A77 is used to recover the energy of the return beam L42. In some embodiments, each laser guiding device a77 can be used to detect the intensity of the return beam L42, thereby detecting the operation of the laser system a70 in real time.

FIG. 6 is a schematic view of a lithographic apparatus according to some embodiments of the disclosure. In fig. 6, only one laser power amplifier a72 is provided. The seed laser device a71 emits output laser light L2 to the laser power amplifying device a 72. The laser power amplifying device a72 is configured to amplify the power of the output laser light L2 emitted by the seed laser device a71, and to emit the power-amplified output laser light L2 to the laser emitter a 73. The detailed structure and operation of the laser power amplifying device a72 are as described above, and will not be described in detail herein.

In summary, a brewster angle is formed between the incident light-transmitting element and the output laser and/or a brewster angle is formed between the emergent light-transmitting element and the output laser of the laser power amplifying device according to the embodiment of the disclosure. Therefore, the probability of the resonance of the output laser in the accommodating cavity and the parasitic phenomenon can be reduced, and the laser system can be protected and the yield of the wafer can be increased.

In some embodiments, a second brewster angle is formed between the light-transmitting exit element and the output laser irradiated on the light-transmitting exit element and having the second power.

In some embodiments, the incident light-transmitting element and the emergent light-transmitting element are made of the same material, and the incident light-transmitting element and the emergent light-transmitting element are located on two opposite sides of the accommodating cavity.

In some embodiments, the laser system further includes a laser transmitter configured to receive the output laser emitted by the laser power amplifying device and having the second power and to emit a pulsed laser.

In some embodiments, the laser power amplifying device further includes a polarization reflective layer coated on the exit light transmissive element, wherein the output laser with the second power includes a first polarized wave, and wherein the polarization reflective layer allows the output laser including the first polarized wave to pass therethrough and reflects a return laser having a second polarized wave, wherein the first polarized wave is perpendicular to the second polarized wave.

In some embodiments, the laser system further includes a laser sensor configured to detect a portion of the output laser light having a first power reflected by the incident light-transmissive element or a portion of the output laser light having a second power reflected by the exit light-transmissive element.

The lithographic apparatus further includes a laser transmitter disposed on the excitation chamber and configured to receive the output laser emitted by the laser power amplifying device and to transmit a pulsed laser to the target. The output laser with the first power penetrates through the incident light-transmitting element, enters the accommodating cavity and passes through the gain medium, and the output laser with the second power in the accommodating cavity penetrates through the emergent light-transmitting element and is emitted out of the laser power amplifying device. A first Brewster angle is formed between the incident light-transmitting element and the output laser which is irradiated on the incident light-transmitting element and has the first power.

In some embodiments, the laser power amplifying device further includes a polarization reflective layer coated on the emission transparent element, and after the pulsed laser irradiates the target, the target reflects part of the pulsed laser to form a return laser to the polarization reflective layer, wherein the output laser having the second power includes a first polarized wave, the return laser has a second polarized wave perpendicular to the first polarized wave, and the polarization reflective layer allows the output laser including the first polarized wave to pass through and reflects the return laser having the second polarized wave.

In some embodiments, the laser sensor is configured to detect the portion of the output laser beam with the first power reflected by the incident light-transmitting element or the portion of the output laser beam with the second power reflected by the emergent light-transmitting element.

The above-disclosed features may be combined, modified, replaced, or transposed with respect to one or more disclosed embodiments in any suitable manner, and are not limited to a particular embodiment.

While the present disclosure has been described with reference to various embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure. Therefore, the above embodiments are not intended to limit the scope of the present disclosure, which is defined by the appended claims.

Claims

1. A laser system, comprising:

a sub-laser device configured to emit an output laser having a first power; and

a laser power amplifying device configured to amplify the first power of the output laser and emit the output laser with a second power, wherein the laser power amplifying device comprises:

the accommodating cavity is used for accommodating a gain medium and comprises a first opening and a second opening;

an incident light transmission element arranged in the first opening;

an emergent light-transmitting element arranged at the second opening; and

an energy pump configured to provide energy to the gain medium,

wherein the output laser with the first power passes through the incident light-transmitting element, enters the accommodating cavity and passes through the gain medium, and the output laser with the second power in the accommodating cavity passes through the emergent light-transmitting element and is emitted out of the laser power amplifying device,

the incident light transmission element and the output laser which is irradiated on the incident light transmission element and has the first power have a first Brewster angle therebetween.

2. The laser system of claim 1, wherein the exit transparent element has a second brewster angle with the output laser irradiated thereon and having the second power.

3. The laser system of claim 2, wherein the incident transparent element and the emergent transparent element are made of the same material, and the incident transparent element and the emergent transparent element are disposed on opposite sides of the accommodating cavity.

4. The laser system of claim 1, further comprising a laser transmitter configured to receive the output laser emitted by the laser power amplifying device and having the second power and to emit a pulsed laser.

5. The laser system of claim 1 in which the laser power amplifying device further comprises a polarized reflective layer applied to the exit optically transparent member, the output laser light having the second power comprising a first polarized wave, wherein the polarized reflective layer allows the output laser light comprising the first polarized wave to pass through and reflects a return laser light having a second polarized wave, wherein the first polarized wave is perpendicular to the second polarized wave.

6. The laser system of claim 1, further comprising a laser sensor configured to detect a portion of the output laser light having the first power reflected by the incident transparent component or a portion of the output laser light having the second power reflected by the exit transparent component.

7. A lithographic apparatus, comprising:

an excitation chamber;

a target emitter disposed on the excitation chamber and configured to emit a target;

a sub-laser device configured to emit an output laser having a first power;

a containing cavity for containing a gain medium;

an incident light transmission element arranged at one side of the accommodating cavity;

an emergent light-transmitting element arranged at the other side of the accommodating cavity; and

an energy pump configured to provide energy to the gain medium, an

A laser transmitter configured to receive the output laser emitted from the laser power amplifying device and transmit a pulse laser to the target;

8. The apparatus of claim 7, wherein the exit optically transmissive element has a second brewster angle with the output laser light impinging on the exit optically transmissive element and having the second power.

9. The apparatus of claim 7, wherein the laser power amplifying device further comprises a polarization reflecting layer applied to the exit transparent member, the polarization reflecting layer reflecting a portion of the pulsed laser light from the target to form a return laser light to the polarization reflecting layer after the pulsed laser light is irradiated to the target, wherein the output laser light having the second power comprises a first polarized wave, the return laser light has a second polarized wave perpendicular to the first polarized wave, and the polarization reflecting layer allows the output laser light comprising the first polarized wave to pass therethrough and reflects the return laser light having the second polarized wave.

10. The apparatus of claim 7, further comprising a laser sensor configured to detect the portion of the output laser light having the first power reflected by the entrance transparent element or the portion of the output laser light having the second power reflected by the exit transparent element.