Line width narrowing module and heat dissipation control system thereof

Abstract

The invention relates to the field of semiconductor lithography, and discloses a line width narrowing module and a heat dissipation control system thereof, the line width narrowing module comprises a shell, a prism, a grating and a cooling assembly are fixedly arranged in the shell, and the prism is used for performing beam expansion on an alignment molecule laser spot; the grating is used for selecting the spectrum of the alignment molecule laser and forming diffraction laser; the cooling assembly comprises a first cold plate group and a second cold plate group, the first cold plate group is fixedly attached to the prism to reduce the temperature of the prism, and the second cold plate group is fixedly attached to the grating to reduce the temperature of the grating; the first cold plate set and the second cold plate set are each provided with a cooling channel for cooling liquid to flow. The cold plate group is arranged on the surfaces of the prism and the grating, cooling liquid is input into the cooling channel of the cold plate group, heat accumulated on the prism and the grating is efficiently taken away, thermal distortion of the prism and the grating is avoided, the stability of laser wavelength is finally guaranteed, the heat dissipation efficiency is higher, and the cost is lower.

Description

Technical Field

[0001] The invention relates to the field of semiconductor lithography, and in particular to a line width narrowing module and a heat dissipation control system thereof. Background Art

[0002] Excimer laser refers to the laser emitted when the molecules formed by the mixed gas of inert gas and halogen gas excited by electron beam transition to their ground state. Since excimer laser is in the ultraviolet band, it has the characteristics of large single photon energy, large single pulse energy, high power, uniform spot, good beam quality, and single pulse coordination. It is widely used in many fields such as semiconductor lithography, panel annealing, medical treatment and scientific research. In order to realize the chip manufacturing of advanced process, the lithography machine needs to have ultra-high resolution. In this way, the excimer laser used as the light source of the lithography machine needs to have an extremely narrow spectral line width. In order to make the laser line width generated by the excimer laser meet the needs of semiconductor lithography, it is necessary to select its spectrum, that is, to narrow the line width.

[0003] In the line width narrowing module, the excimer laser will be amplified by multiple prisms and then incident on the Litterot structure grating. After passing through the Litterot structure grating, the diffracted laser of the excimer laser is reflected. Lasers of different wavelengths are reflected at different angles after diffraction. The diffracted laser that is partially reflected back into the discharge cavity oscillates in the laser cavity, so that the lasers of the same wavelength gain gain and the particle number flip efficiency of the lasers of the same wavelength is improved, thereby enhancing the power of the lasers of the same wavelength and suppressing the generation of lasers of different wavelengths.

[0004] In the prior art, due to the high energy of single photons of excimer laser, its absorption rate cannot be very low when passing through prisms and gratings. The absorption is more significant on the light-passing surface. The excimer laser will generate heat on the light-passing surface of the prism and the diffraction surface of the grating, which will cause the prism and grating to be distorted due to heat. The distortion of the prism and grating will change the diffraction angle and grating constant of the grating laser, thereby changing the wavelength of the laser returned to the discharge cavity and making it no longer stable. Summary of the invention

[0005] The technical problem to be solved by the present invention is: how to improve the heat dissipation efficiency of the line width narrowing module. In order to solve the above technical problem, the present invention provides a line width narrowing module, including a housing, wherein the housing is fixedly provided with:

[0006] A prism, wherein the prism is used to expand the excimer laser spot;

[0007] A grating, wherein the grating is used to select the spectrum of the excimer laser and form a diffracted laser;

[0008] A cooling assembly, the cooling assembly comprising a first cold plate group and a second cold plate group, the first cold plate group is fixedly attached to the prism to reduce the temperature of the prism, and the second cold plate group is fixedly attached to the grating to reduce the temperature of the grating; the first cold plate group and the second cold plate group are both provided with cooling channels for the flow of coolant.

[0009] Preferably, a plurality of mounting grooves are provided in the shell, and the mounting grooves are used to accommodate and install the prism and the grating; an opening is provided on one side of the shell, and the opening is used for the incidence and emission of the excimer laser.

[0010] Preferably, the first cold plate group includes a first cold plate and a second cold plate that are arranged opposite to each other, the first cold plate and the second cold plate are parallel to the optical path of the excimer laser, and are respectively attached and fixed to the upper surface and the lower surface of the prism.

[0011] Preferably, the second cold plate group comprises a third cold plate and a fourth cold plate which are arranged opposite to each other, the third cold plate and the fourth cold plate are parallel to the optical path of the excimer laser, and are respectively attached and fixed to the upper surface and the lower surface of the grating.

[0012] Preferably, the first cold plate, the second cold plate, the third cold plate and the fourth cold plate are provided with a first cooling channel, the first cooling channel is a U-shaped structure, and the first cooling channel includes a first water inlet and a first water outlet protruding from the first cold plate, the second cold plate, the third cold plate and the fourth cold plate.

[0013] Preferably, the shell is provided with mounting through holes corresponding to the first water inlet and the first water outlet.

[0014] Preferably, the first cold plate, the second cold plate, the third cold plate and the fourth cold plate are all provided with a second cooling channel and a third cooling channel, and the second cooling channel and the third cooling channel respectively include a second water inlet and a second water outlet and a third water inlet and a third water outlet protruding from the first cold plate or the second cold plate or the third cold plate or the fourth cold plate.

[0015] Preferably, the second cooling channel and the third cooling channel are arranged vertically and parallel to the excimer laser optical path.

[0016] Preferably, the second cooling channel and the third cooling channel both have a wavy structure, and the structures of the second cooling channel and the third cooling channel are symmetrical to each other; the second water inlet and the third water inlet are arranged opposite to each other on the same side, and the second water outlet and the third water outlet are arranged opposite to each other on the same side.

[0017] The present invention also provides a line width narrowing module heat dissipation control system, comprising a line width narrowing module, a lens, a sensor, a controller and a regulating valve;

[0018] The lens is arranged at one side of the opening of the line width narrowing module, and the lens is used to partially reflect the diffracted laser emitted from the line width narrowing module;

[0019] The sensor is used to receive the diffracted laser reflected by the lens and collect beam quality information of the diffracted laser;

[0020] The controller is electrically connected to the sensor and acquires the beam quality information output by the sensor;

[0021] The regulating valve is connected to the controller and the cooling channel in the line width narrowing module respectively. The regulating valve is used to receive a control signal output by the controller and adjust the flow rate of the coolant in the cooling channel according to the control signal.

[0022] Compared with the prior art, the line width narrowing module provided in the embodiment of the present invention has the following beneficial effects:

[0023] In the present invention, a cold plate group is arranged on the surface of the prism and the grating, and then a coolant is continuously input into the cooling channel in the cold plate group, so that the accumulated heat generated on the prism and the grating can be efficiently taken away, and the prism and the grating are prevented from being distorted by heat, and finally the stability of the laser wavelength returned to the discharge cavity is guaranteed. Compared with the heat dissipation by inert gas, the heat dissipation efficiency is higher, the cost is lower, and no eddy current is generated to cause the jitter of the laser output wavelength and line width, so that the use of the entire excimer laser is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of the present invention;

[0025] Figure 2 is a top view of the cooling channel of the present invention;

[0026] Figure 3 is a cross-sectional view of a cooling channel of the present invention;

[0027] Figure 4 is a heat dissipation control system of the present invention;

[0028] Figure 5 This is a reference diagram of the principle of the excimer laser of the present invention.

[0029] In the figure: 1, housing; 11, mounting groove; 12, opening; 13, mounting through hole;

[0030] 2. Prism; 3. Grating; 4. Excimer laser;

[0031] 5. Cooling assembly; 51. First cold plate group; 511. First cold plate; 512. Second cold plate; 52. Second cold plate group; 521. Third cold plate; 522. Fourth cold plate;

[0032] 6. First cooling channel; 61. First water inlet; 62. First water outlet; 7. Second cooling channel; 71. Second water inlet; 72. Second water outlet; 8. Third cooling channel; 81. Third water inlet; 82. Third water outlet;

[0033] 100. Heat dissipation control system; 101. Lens; 102. Sensor; 103. Controller; 104. Adjusting valve. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0035] like Figures 1 to 3 as well as Figure 5 As shown, a preferred embodiment of the present invention provides a line width narrowing module, which includes a housing 1 in which:

[0036] Prism 2, prism 2 is used to expand the beam of excimer laser 4;

[0037] Grating 3, grating 3 is used to select the spectrum of excimer laser 4 and form diffracted laser;

[0038] The cooling assembly 5 includes a first cold plate group 51 and a second cold plate group 52. The first cold plate group 51 is fixed to the prism 2 to reduce the temperature of the prism 2, and the second cold plate group 52 is fixed to the grating 3 to reduce the temperature of the grating 3. The first cold plate group 51 and the second cold plate group 52 are both provided with cooling channels for the flow of coolant.

[0039] Specifically, in the prior art, the line width narrowing module generally adopts gas heat dissipation, for example, inert gas nitrogen is filled into the line width narrowing module, and the grating 3 and the prism 2 are immersed in the inert gas. In addition to removing the residual air in the line width narrowing module, the light-transmitting surface of the grating 3 of the line width narrowing module can also be blown by the inert gas, which has a certain heat dissipation effect. However, the airflow of this blowing is very small, and generally only the light-transmitting surface of the grating 3 is blown. If the grating 3 and the prism 2 are blown at the same time, it is easy to generate vortex between the airflows, and the increase of the airflow blowing to the grating 3 or the prism 2 is also very large. It is easy to produce vortex, and large vortex can easily cause distortion of the laser wavefront, thereby causing jitter of the laser output wavelength and line width. The vortex is also not conducive to the deposition of particulate matter in the line width narrowing module. After being carried by the gas vortex, the particles are more likely to come into contact with the light-transmitting surfaces of the grating 3 and the prism 2. When irradiated by the laser, it is more likely to cause thermal damage to the grating 3 and the prism 2. The thermal conductivity effect of the gas is generally low. When the gas flow rate is also limited to a lower range, its heat dissipation efficiency is further reduced, and the heat dissipation effect is very unsatisfactory. Therefore, the heat dissipation of the line width narrowing module has always been a problem in conventional technical solutions.

[0040] In the present embodiment, a first cold plate group 51 and a second cold plate group 52 are respectively provided for the prism 2 and the grating 3. The two cold plate groups are respectively attached and fixed on the surface of the prism 2. Cooling channels are also provided in the two cold plate groups. When the coolant in the cooling channel flows continuously, the coolant can take away the heat on the prism 2 and the grating 3 through the cold plate group to avoid heat accumulation. The heat dissipation efficiency of the coolant is higher than that of the inert gas, and the heat dissipation efficiency can be further improved by increasing the flow rate of the coolant. The air flow disturbance is not generated in the cavity of the online wide-narrowing module, and the heat dissipation efficiency is more stable. In addition, the attachment of the cold plate group to the prism 2 or the grating 3 can also increase the contact area and further improve the heat dissipation efficiency. It should be understood that the cold plate group is attached to the top surface, bottom surface or side surface of the prism 2 or the grating 3 except the light-transmitting surface.

[0041] On the basis of the above embodiment, a plurality of mounting grooves 11 are provided in the housing 1 for accommodating and mounting the prism 2 and the grating 3 ; an opening 12 is provided on one side of the housing 1 for the incidence and emission of the excimer laser 4 .

[0042] Specifically, in the actual technical solution, the prism 2 in the housing 1 is installed in the installation groove 11 near the side of the opening 12. A plurality of prisms 2 can be provided, and a plurality of corresponding installation grooves 11 can also be provided. The excimer laser 4 generated by the excimer laser 4 is incident on the inside of the housing 1 through the opening 12, and then refracted by the prism 2 and incident on the grating 3 at the blazing angle of the grating 3. After the excimer laser 4 passes through the grating 3, the diffracted laser is reflected, and the diffracted laser returns through the prism 2, then exits through the opening 12 and finally returns to the discharge cavity of the excimer laser 4. According to the different laser wavelengths required, the installation positions of the prism 2 and the grating 3 can be adjusted, and the positions of the corresponding installation grooves 11 are adjusted according to actual needs, wherein the shape of the installation groove 11 needs to match the shape of the prism 2 or the grating 3 to ensure the stability of the positions of the prism 2 and the grating 3.

[0043] Based on the above embodiment, the first cold plate group 51 includes a first cold plate 511 and a second cold plate 512 which are arranged opposite to each other. The first cold plate 511 and the second cold plate 512 are parallel to the optical path of the excimer laser 4 and are respectively fixed to the upper surface and the lower surface of the prism 2 .

[0044] Furthermore, the second cold plate group 52 includes a third cold plate 521 and a fourth cold plate 522 which are arranged opposite to each other. The third cold plate 521 and the fourth cold plate 522 are parallel to the optical path of the excimer laser 4 and are respectively attached and fixed to the upper surface and the lower surface of the grating 3 .

[0045] Specifically, in this embodiment, the two cold plate groups each include two cold plates. The two cold plates in the first cold plate group 51 are respectively attached to the upper surface and the lower surface of the prism 2, and the two cold plates in the second cold plate 512 are respectively attached to the upper surface and the lower surface of the grating 3. Compared with attaching to the side wall of the prism 2 or the grating 3, the design and installation structure is simpler and more reliable, and the contact area is larger, and the heat dissipation efficiency is also better. In addition, the two cold plates in the same cold plate group are arranged relative to each other from top to bottom, and the laser generates heat in the middle of the light-transmitting surface of the prism 2 or the light-transmitting surface of the grating 3 and transfers it to the surroundings. The cold plates arranged on the upper surface and the lower surface can make the heat in the prism 2 or the grating 3 transfer more and more evenly to the upper and lower surfaces, the heat transfer is more even, the heat transfer distance is also closer, and the temperature gradient of the prism 2 and the grating 3 is smaller. In this way, the heat transfer efficiency is not only higher and more even, but also makes the temperature distribution of the prism 2 and the grating 3 more symmetrical and even, and the thermal deformation of the prism 2 and the grating 3 is also symmetrical on the upper and lower sides, and the deformation is smaller.

[0046] In embodiment 2, the first cold plate 511, the second cold plate 512, the third cold plate 521 and the fourth cold plate 522 are provided with a first cooling channel 6, the first cooling channel 6 is a U-shaped structure, and the first cooling channel 6 includes a first water inlet 61 and a first water outlet 62 protruding from the first cold plate 511, the second cold plate 512, the third cold plate 521 and the fourth cold plate 522.

[0047] Furthermore, the housing 1 is provided with mounting through holes 13 corresponding to the first water inlet 61 and the first water outlet 62 .

[0048] Specifically, in one embodiment, a single first cooling channel 6 is provided in each cold plate, and the coolant enters the first cooling channel 6 from the first water inlet 61 and then flows out from the first water outlet 62, wherein the first water inlet 61 and the first water outlet 62 both pass through the mounting through hole 13 to the outside of the shell 1, and multiple first water inlets 61 can be converged into a liquid delivery pipeline through pipes and valves, and connected to the regulating valve 104, and the first water outlet 62 can also be converged into a liquid discharge pipeline, and finally discharged into the storage cavity or storage box of the coolant. The first cooling channel 6 is a U-shaped structure, which enables the first water inlet 61 and the first water outlet 62 to be arranged on the same side of the cold plate, which is convenient for processing the shell 1 and the mounting through hole 13 thereon, as well as the arrangement of the equipment.

[0049] In embodiment three, the first cold plate 511, the second cold plate 512, the third cold plate 521 and the fourth cold plate 522 are all provided with a second cooling channel 7 and a third cooling channel 8, and the second cooling channel 7 and the third cooling channel 8 respectively include a second water inlet 71 and a second water outlet 72 protruding from the first cold plate 511 or the second cold plate 512 or the third cold plate 521 or the fourth cold plate 522, and a third water inlet 81 and a third water outlet 82.

[0050] Furthermore, the second cooling channel 7 and the third cooling channel 8 are arranged vertically and parallel to the optical path of the excimer laser 4 .

[0051] Furthermore, the second cooling channel 7 and the third cooling channel 8 both have a wavy structure, and the structures of the second cooling channel 7 and the third cooling channel 8 are symmetrical to each other; the second water inlet 71 and the third water inlet 81 are arranged on the same side opposite to each other, and the second water outlet 72 and the third water outlet 82 are arranged on the same side opposite to each other.

[0052] Specifically, in this embodiment, a second cooling channel 7 and a third cooling channel 8 are respectively provided in a single cold plate, and the second cold plate 512 channel and the third cooling channel 8 are arranged in parallel up and down, and the second cooling channel 7 is closer to the prism 2 or the grating 3. In the actual heat dissipation process, after the coolant in the second cooling channel 7 absorbs the heat from the prism 2 or the grating 3, the coolant in the third cooling channel 8 can continue to absorb and take away the heat of the coolant in the second cooling channel 7, and the world's step-by-step heat dissipation has a higher heat dissipation efficiency. In the actual operation process, the coolant in the second cooling channel 7 and the third cooling channel 8 can also be made of different materials or flow rates, thereby further improving the overall heat dissipation efficiency of the line width narrowing module.

[0053] Among them, the third cooling channel 8 and the second cooling channel 7 are arranged in parallel and are both parallel to the optical path of the excimer laser 4, which can increase the contact area between the third cooling channel 8 and the second cooling channel 7 and the prism 2 or the grating 3, thereby improving the heat dissipation efficiency.

[0054] In addition, the second cooling channel 7 and the third cooling channel 8 are both arranged in a wavy shape. On the one hand, the contact time and contact area between the coolant in the cooling channel and the prism 2 or the grating 3 are increased, which can take away more heat and have a higher heat dissipation efficiency. On the other hand, the second cooling channel 7 and the third cooling channel 8 are arranged in parallel upward, but the second water inlet 71 and the third water inlet 81 are arranged relative to each other, and the second water outlet 72 and the third water outlet 82 are also arranged relative to each other. When the coolant is introduced into the second cooling channel 7 and the third cooling channel 8, the two coolants will exert two relative impact forces on the cold plate. When the pressures of the two coolants are the same, the two impact forces are also the same and will offset each other, so that the cold plate can better resist the impact of the coolant, the position of the cold plate is more stable, and it is not easy to loosen, so it can better fit the prism 2 or the grating 3, and the heat dissipation effect is more stable.

[0055] like Figure 4 As shown, the present invention also provides a heat dissipation control system 100 for an excimer laser line width narrowing module, comprising a line width narrowing module, a lens 101, a sensor 102, a controller 103 and a regulating valve 104;

[0056] The lens 101 is disposed on one side of the line width narrowing module opening 12, and the lens 101 is used to partially reflect the diffracted laser emitted from the line width narrowing module;

[0057] The sensor 102 is used to receive the diffracted laser reflected by the lens 101 and collect the beam quality information of the diffracted laser;

[0058] The controller 103 is electrically connected to the sensor 102 and acquires the beam quality information output by the sensor 102;

[0059] The regulating valve 104 is connected to the controller 103 and the cooling channel in the line width narrowing module respectively. The regulating valve 104 is used to receive the control signal output by the controller 103 and adjust the flow rate of the coolant in the cooling channel according to the control signal.

[0060] Specifically, the diffracted laser reflected by the grating 3 passes through the prism 2 and then exits into the discharge cavity of the excimer laser 4 through the opening 12 of the housing 1. In this process, the laser passes through the lens 101, which can reflect part of the laser to the sensor 102. After receiving the reflected laser, the sensor 102 can obtain the beam quality information of the reflected laser, and then obtain the beam quality of the diffracted laser reflected by the grating 3. After the sensor 102 obtains the beam quality information, it transmits the beam quality information to the controller 103, which determines the thermal distortion of the prism 2 and the grating 3 in the current line width narrowing module according to the beam quality information, and sends a control signal to the regulating valve 104 to control the opening of the regulating valve 104, thereby adjusting the flow rate of the coolant, and finally adjusting the heat dissipation efficiency of the line width narrowing module, and accurately controlling the temperature in the line width narrowing module.

[0061] In summary, the embodiment of the present invention provides a line width narrowing module for an excimer laser 4, which can be respectively attached to the upper and lower surfaces of the prism 2 and the grating 3 through multiple cold plates, thereby improving the heat dissipation efficiency and uniformity of the prism 2 and the grating 3, avoiding the problem of excessive temperature in a local area of ​​the prism 2 or the grating 3, uneven temperature distribution, and thermal distortion, so that the heat dissipation efficiency of the entire line width narrowing module is higher and the use control is more stable. The provision of the second cooling channel 7 and the third cooling channel 8 makes the position of the cold plate more stable and less prone to loosening, and its heat dissipation effect is naturally more stable. The internal pipeline of the cold plate is designed as two independent and structurally symmetrical loops, which effectively resist water flow impact and reduce the impact of water flow impact on the stability of the optical path.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A line width narrowing module, characterized in that: It comprises a housing, in which: A prism, wherein the prism is used to expand the excimer laser spot; A grating, wherein the grating is used to select the spectrum of the excimer laser and form a diffracted laser; A cooling assembly, the cooling assembly comprising a first cold plate group and a second cold plate group, the first cold plate group is fixedly attached to the prism to reduce the temperature of the prism, and the second cold plate group is fixedly attached to the grating to reduce the temperature of the grating; the first cold plate group and the second cold plate group are both provided with cooling channels for the flow of coolant.

2. The line width narrowing module according to claim 1, characterized in that: A plurality of mounting grooves are arranged in the shell, and the mounting grooves are used to accommodate and install the prism and the grating; an opening is arranged on one side of the shell, and the opening is used for the incidence and emission of the excimer laser.

3. The line width narrowing module according to claim 1, characterized in that: The first cold plate group includes a first cold plate and a second cold plate which are arranged opposite to each other. The first cold plate and the second cold plate are parallel to the optical path of the excimer laser and are respectively attached and fixed to the upper surface and the lower surface of the prism.

4. The line width narrowing module according to claim 3, characterized in that: The second cold plate group includes a third cold plate and a fourth cold plate which are arranged opposite to each other. The third cold plate and the fourth cold plate are parallel to the optical path of the excimer laser and are respectively attached and fixed to the upper surface and the lower surface of the grating.

5. The line width narrowing module according to claim 4, characterized in that: The first cold plate, the second cold plate, the third cold plate and the fourth cold plate are provided with a first cooling channel, the first cooling channel is a U-shaped structure, and the first cooling channel includes a first water inlet and a first water outlet protruding from the first cold plate, the second cold plate, the third cold plate and the fourth cold plate.

6. The line width narrowing module according to claim 5, characterized in that: The shell is provided with mounting through holes corresponding to the first water inlet and the first water outlet.

7. The line width narrowing module according to claim 4, characterized in that: The first cold plate, the second cold plate, the third cold plate and the fourth cold plate are all provided with a second cooling channel and a third cooling channel, and the second cooling channel and the third cooling channel respectively include a second water inlet and a second water outlet and a third water inlet and a third water outlet protruding from the first cold plate or the second cold plate or the third cold plate or the fourth cold plate.

8. The line width narrowing module according to claim 7, characterized in that: The second cooling channel and the third cooling channel are arranged vertically and parallelly, and are parallel to the excimer laser optical path.

9. The line width narrowing module according to claim 7, characterized in that: The second cooling channel and the third cooling channel both have a wavy structure, and the structures of the second cooling channel and the third cooling channel are symmetrical to each other; the second water inlet and the third water inlet are arranged opposite to each other on the same side, and the second water outlet and the third water outlet are arranged opposite to each other on the same side.

10. A heat dissipation control system for a line width narrowing module, characterized in that: A line width narrowing module comprising any one of claims 1 to 9, further comprising a lens, a sensor, a controller and a regulating valve; The lens is arranged at one side of the opening of the line width narrowing module, and the lens is used to partially reflect the diffracted laser emitted from the line width narrowing module; The sensor is used to receive the diffracted laser reflected by the lens and collect beam quality information of the diffracted laser; The controller is electrically connected to the sensor and acquires the beam quality information output by the sensor; The regulating valve is connected to the controller and the cooling channel in the line width narrowing module respectively. The regulating valve is used to receive a control signal output by the controller and adjust the flow rate of the coolant in the cooling channel according to the control signal.

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