Illumination system, photolithography machine and illumination uniformity compensation method

Abstract

The present invention provides an illumination system, a photolithography machine, and an illumination uniformity compensation method. The illumination unit is used to provide a first illumination. The light homogenization unit is used to homogenize the first illumination and convert the first illumination into a second illumination. The compensation unit includes at least one optical plate with multiple light transmittances. The compensation unit can move in the same direction as or opposite to the light propagation direction of the second illumination. The second illumination passes through the optical plate to form a corresponding third illumination. The illumination uniformity of the third illumination is greater than the second illumination uniformity. Therefore, the present invention compensates for the light homogenization effect of the light homogenization unit by setting a compensation unit with multiple light transmittances, so that the second illumination is adjusted by the compensation unit with different light transmittances to obtain the third illumination with greater illumination uniformity and better uniformity, which is beneficial to improving the exposure effect of the photolithography machine equipment and thus improving product performance.

Description

Technical Field

[0001] The present invention relates to the field of micro-lithography technology in semiconductor manufacturing, and in particular to an illumination system, a lithography machine and an illumination uniformity compensation method. Background Art

[0002] Microlithography in semiconductor manufacturing uses an illumination system to accurately project the pattern on the mask onto a silicon wafer coated with photoresist. In the exposure process, illumination uniformity is the main factor affecting the exposure effect. However, as the use time of the lithography machine increases, the performance of its illumination system will decay, and the uniformity of illumination cannot be guaranteed. Uneven illumination will seriously affect the exposure effect and thus affect the performance and yield of semiconductor devices.

[0003] Therefore, a new lighting system and lighting uniformity compensation method are needed to ensure the uniformity of lighting, enhance the exposure effect, and improve product performance and yield. Summary of the invention

[0004] The object of the present invention is to provide an illumination system, a photolithography machine and an illumination uniformity compensation method to solve the problem of illumination non-uniformity in an exposure process.

[0005] In order to solve the above technical problems, the present invention provides a lighting system, which includes: an illumination unit, a uniform light unit and a compensation unit;

[0006] The illumination unit is used to provide a first illumination having a plurality of light propagation directions;

[0007] The light homogenization unit is used to homogenize the first light and convert the first light into a second light with a light propagation direction;

[0008] The compensation unit includes at least one optical plate with multiple light transmittances; the optical plate can move in a direction that is the same as or opposite to the propagation direction of the light of the second illumination;

[0009] The second illumination passes through the optical plate to form a corresponding third illumination; wherein the illumination uniformity of the third illumination is greater than the illumination uniformity of the second illumination.

[0010] Optionally, in the illumination system, the optical flat plate has a first surface and an opposite second surface, and light transmittances on the first surface and / or the second surface are different.

[0011] Optionally, in the lighting system, the first surface and\or the second surface have different light transmittances, and at least one anti-reflection film may be coated on the first surface and\or the second surface.

[0012] Optionally, in the lighting system, the first surface and\or the second surface have different light transmittances, a chrome layer may be plated on the first surface and\or the second surface, and the chrome layer may be formed in a dotted manner.

[0013] Optionally, in the illumination system, the illumination system further comprises a relay lens group, and the relay lens group is used to transmit the second light to the compensation unit, or transmit the third light to the substrate to be processed.

[0014] Optionally, in the illumination system, the compensation unit is movably disposed between the relay lens group and the substrate to be processed, or is movably disposed between the relay lens group and the light homogenization unit.

[0015] Optionally, in the lighting system, a moving direction of the compensation unit is the same as a propagation direction of light of the second illumination.

[0016] Optionally, in the illumination system, a distance between the compensation unit and the relay lens assembly is less than or equal to a focal length of the relay lens assembly.

[0017] Optionally, in the illumination system, the compensation unit includes one optical flat plate, or a plurality of optical flat plates arranged along a light propagation direction of the second illumination.

[0018] Optionally, in the lighting system, the illumination unit includes a light emitter and an ellipsoidal reflector; the light emitter is disposed at a focus of the ellipsoidal reflector, and the light emitter provides the first illumination, and the first illumination is converged at another focus of the ellipsoidal reflector and emitted through the action of the ellipsoidal reflector.

[0019] Optionally, in the lighting system, the illumination unit includes a laser emitter, and the laser emitter is used to provide the first illumination.

[0020] Optionally, in the lighting system, the light homogenization unit includes at least one quartz rod; the quartz rod is arranged along the propagation direction of the light of the second illumination.

[0021] Optionally, in the lighting system, the light homogenization unit includes a first lens group and a second lens group; the first light passes through the first lens group and the second lens group in sequence to be converted into the second light; wherein the first lens group is used to converge the first light, and the second lens group is used to adjust the illumination uniformity of the first light.

[0022] Optionally, in the lighting system, the lighting system further includes a third lens group, and the third lens group is used to couple the first illumination provided by the illumination unit into the light homogenization unit.

[0023] Based on the same inventive concept, the present invention also provides a photolithography machine, comprising the above-mentioned illumination system.

[0024] Based on the same inventive concept, the present invention also provides a method for compensating for illumination uniformity, comprising:

[0025] The illumination unit provides first illumination;

[0026] The image detector acquires the light intensity distribution of the second light emitted by the light homogenization unit;

[0027] An optical plate is set according to the obtained light intensity distribution, and the second light passes through the optical plate to form a third light correspondingly;

[0028] The optical flat plate has a variety of light transmittances, so that the illumination uniformity of the third illumination is greater than the second illumination uniformity.

[0029] Optionally, in the illumination uniformity compensation method, setting the optical plate according to the acquired light intensity distribution includes: moving the optical plate in a direction that is the same as or opposite to a propagation direction of the second illumination, so that the illumination uniformity of the third illumination meets a preset requirement.

[0030] In summary, the present invention provides an illumination system, a photolithography machine, and an illumination uniformity compensation method. The illumination system comprises: an illumination unit, a light homogenization unit, and a compensation unit. The illumination unit is used to provide a first illumination with multiple light propagation directions. The light homogenization unit is used to homogenize the first illumination and convert the first illumination into a second illumination with one light propagation direction. The compensation unit comprises at least one optical plate with multiple light transmittances; wherein the compensation unit can move in the same direction or the opposite direction as the light propagation direction of the second illumination. The second illumination passes through the optical plate to form a corresponding third illumination, and the illumination uniformity of the third illumination is greater than the illumination uniformity of the second illumination. Therefore, the present invention compensates for the light homogenization effect of the light homogenization unit by setting the compensation unit with multiple light transmittances, so that the second illumination is adjusted by the compensation unit with different light transmittances to obtain the third illumination with greater illumination uniformity and better uniformity, which is conducive to improving the exposure effect of the photolithography machine equipment and thus improving product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the structure of a lighting system according to an embodiment of the present invention;

[0032] Figure 2 is a schematic structural diagram of an optical flat plate plated with a chrome layer according to an embodiment of the present invention;

[0033] Figure 3 is a partially enlarged schematic diagram of an optical flat plate plated with a chrome layer according to an embodiment of the present invention;

[0034] Figure 4 1 is a schematic diagram of the structure of an optical flat plate coated with an anti-reflection film according to an embodiment of the present invention;

[0035] Figure 5 1 is a schematic diagram of the structure of an optical flat plate coated with an anti-reflection film according to an embodiment of the present invention;

[0036] Figure 6 1 is a schematic diagram of the structure of an optical flat plate coated with an anti-reflection film according to an embodiment of the present invention;

[0037] Figure 7 is a schematic diagram of the structure of a lighting system according to an embodiment of the present invention;

[0038] Figure 8 is a schematic diagram of light intensity illumination distribution of a first light field according to an embodiment of the present invention;

[0039] Fig. 9 is a line graph of static inhomogeneity and integrated inhomogeneity versus moving distance in the first light field of an embodiment of the present invention;

[0040] Fig.10 is a line graph of integrated illumination and moving distance in the first light field of an embodiment of the present invention;

[0041] Fig.11 is a schematic diagram of light intensity illumination distribution of a second light field according to an embodiment of the present invention;

[0042] Fig.12 is a line graph of static inhomogeneity and integrated inhomogeneity versus moving distance in the second light field of an embodiment of the present invention;

[0043] Fig.13 is a line graph of integrated illumination and moving distance in the second light field of an embodiment of the present invention;

[0044] Fig.14 is a schematic diagram of light intensity illumination distribution of a third light field according to an embodiment of the present invention;

[0045] Fig.15 is a line graph of static inhomogeneity and integrated inhomogeneity versus moving distance in the third light field of an embodiment of the present invention;

[0046] Fig.16 is a line graph of integrated illumination and moving distance in the third light field of an embodiment of the present invention;

[0047] Fig.17 is a schematic diagram of light intensity illumination distribution of a fourth light field according to an embodiment of the present invention;

[0048] Fig.18 is a line graph of static inhomogeneity and integrated inhomogeneity versus moving distance in a fourth light field according to an embodiment of the present invention;

[0049] Fig.19 is a line graph of integrated illumination and moving distance in the fourth light field of an embodiment of the present invention;

[0050] Wherein, the accompanying drawings are described as follows:

[0051] 100-illumination unit; 101-ellipsoidal reflector; 102-illuminator;

[0052] 200-light homogenization unit; 300-compensation unit; first surface-300a; second surface-300b;

[0053] 400-coupling lens group; 500-relay lens group; 600-collimating lens group; M-substrate to be processed; A-first light field; B-second light field; D-third light field; E-fourth light field. DETAILED DESCRIPTION

[0054] The following is a further detailed description of an illumination system, a photolithography machine, and an illumination uniformity compensation method proposed in the present invention in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the accompanying drawings is often a part of the actual structure. In particular, the emphasis that each drawing needs to show is different, and sometimes different proportions are used.

[0055] To solve the above technical problems, this embodiment provides a lighting system, such as Figure 1 As shown, it includes: an illumination unit 100, a light homogenization unit 200 and a compensation unit 300. The illumination unit 100 is used for first illumination with multiple light propagation directions. The light homogenization unit 200 is used to homogenize the first illumination and convert the first illumination into a second illumination with one light propagation direction. The compensation unit 300 includes at least one optical plate with multiple light transmittances. The optical plate can move in the same direction as or in the opposite direction to the light propagation direction of the second illumination. The second illumination passes through the optical plate to form a corresponding third illumination. The illumination uniformity of the third illumination is greater than the illumination uniformity of the second illumination.

[0056] In this example, the compensation unit 300 is added to compensate for the uneven illumination of the second illumination. Figure 2-6 , the compensation unit 300 may include at least one optical flat plate. The optical flat plates are arranged along the light propagation direction of the second illumination. Each of the optical flat plates has a first surface 300a and an opposite second surface 300b. In order to achieve different transmittances, at least one anti-reflection film may be plated on the first surface 300a and / or the second surface 300b of the optical flat plate, and each region of the same anti-reflection film has the same light transmittance, and different types of anti-reflection films have different light transmittances. That is, the same anti-reflection film may be plated in different regions of the first surface 300a and the second surface 300b to achieve different light transmittances in each region on the optical flat plate. Alternatively, different types of anti-reflection films may be plated in different regions of the first surface 300a and the second surface 300b, and different light transmittances in each region on the optical flat plate may also be achieved.

[0057] In addition, this embodiment also provides an optical flat plate, see Figure 2-3 , a chrome layer is plated on the first surface 300a and / or the second surface 300b of the optical flat plate, and the chrome layer is formed in a dotted manner. The chrome layer has a certain light-reflecting effect. When the concentration of metal chromium is higher, the light reflectivity of the chrome layer is higher, and the corresponding light transmittance is lower. Therefore, the chrome layer of the same concentration or the chrome layer of different concentrations can be plated on different areas of the first surface 300a and / or the second surface 300b, respectively, to achieve different light transmittances in different areas on the optical flat plate.

[0058] If the required light transmittance distribution is more complex, multiple optical plates can be provided, and the light transmittance of each region of each optical plate can be different, and the optical plates can be arranged parallel to each other. Of course, when coating the anti-reflection film or chromium layer, it can be selected to be coated on a single surface or on both surfaces.

[0059] Among them, Figure 4 As shown, a first anti-reflection film is coated on a part of the first surface 300a to form two regions with different light transmittances. The light transmittance of the region coated with the first anti-reflection film is C1, and the light transmittance of the region not coated with the first anti-reflection film is C2. Figure 5 As shown, a second anti-reflection film is coated on a part of the second surface 300b, and two regions with different light transmittances are formed. The light transmittance of the region coated with the second anti-reflection film is C3, and the light transmittance of the region not coated with the second anti-reflection film is C2. Since the light transmittance of each region on the optical flat plate is equal to the product of the light transmittance of the corresponding region of the first surface 300a and the light transmittance of the corresponding region of the second surface 300b. Therefore, Figure 6As shown, the optical flat plate can form three different light transmittances, namely: C1*C3, C2*C2 and C2*C3. Similarly, an optical flat plate with different light transmittances in different areas can be obtained through combined design. Among them, the setting of the light transmittance of each area on each optical flat plate is determined according to the non-uniformity of the second light. For example, if the second light is projected on the central area of ​​the optical flat plate with stronger light and the edge area with weaker light, the light transmittance of the edge area can be increased according to the setting requirements, and the light transmittance of the central area can be reduced.

[0060] Please continue reading Figure 1 , the illumination unit 100 includes an ellipsoidal reflector 101 and a light emitter 102. The light emitter 102 is arranged at a focus of the ellipsoidal reflector 101, and the light emitter 102 provides illumination in different illumination directions, and the illumination is converged at another focus of the ellipsoidal reflector 101 by the action of the ellipsoidal reflector 101 and then irradiated as the first light. Preferably, the light emitter 102 includes but is not limited to a mercury lamp. Through the convergence function of the ellipsoidal reflector 101, light with different illumination angles can be transmitted to the light homogenizing unit 200. Preferably, the light homogenizing unit 200 includes at least one quartz rod. Optionally, it is one or more quartz rods. The quartz rods are arranged along the light propagation direction of the second illumination. When there are multiple quartz rods, each quartz rod can be stacked along the light propagation direction of the second illumination. The first illumination can achieve a preliminary adjustment of the illumination uniformity of the first illumination through the quartz rod to form the second illumination with the same illumination direction.

[0061] In addition, the illumination system further includes a third lens group and a relay lens group 500. The third lens group is a coupling lens group 400 in this example. After the coupling action of the coupling lens group 400, the first illumination is propagated to the light homogenizing unit 200 along the same direction. The compensation unit 300 is movably disposed between the relay lens group 500 and the substrate M to be processed, or movably disposed between the relay lens group 500 and the light homogenizing unit 300. When the compensation unit 300 is movably disposed between the relay lens group 500 and the substrate M to be processed, the relay lens group 500 can transmit the second illumination to the compensation unit 300. The compensation unit 300 is movably disposed between the relay lens group 500 and the light homogenizing unit 300, and the relay lens group 500 can transmit the third illumination to the substrate M to be processed. The moving direction of the compensation unit 300 is the same as the light propagation direction of the second illumination. Furthermore, different moving distances of the compensation unit 300 will produce different light homogenization effects. To obtain a better light homogenization effect, the distance between the compensation unit 300 and the relay lens assembly 500 is less than or equal to the focal length of the relay lens assembly 500 .

[0062] In addition to the above combination, the lighting system can also be in another combination to achieve the same uniform light effect. Figure 7 As shown, the illumination unit 100 includes a laser emitter, and the laser emitter is used to provide the first illumination. The third lens group between the illumination unit 100 and the light homogenizing unit 200 is replaced by a collimating lens group 600 from the coupling lens group 400. The collimating lens group 600 includes a beam expander and a diffractive optical element, which are used to adjust the illumination direction of the first illumination so that the first illumination can be transmitted to the light homogenizing unit 200. The diffractive optical element can diffract the first illumination through the beam expander to form a certain angle distribution and then project it to the light homogenizing unit 200.

[0063] Wherein, the light homogenizing unit 200 may include a first lens group and a second lens group. The first illumination passes through the first lens group and the second lens group in sequence to be converted into the second illumination. Wherein, the first lens group is used to converge the first illumination, and the second lens group is used to adjust the illumination uniformity of the first illumination. Specifically, the first lens group is a converging lens group, and the second lens group is a microlens array. The first illumination is converted into a second illumination that irradiates in parallel along the same direction by passing through the converging lens group and the microlens array respectively. The converging lens group may be a Fourier lens group. The combined effect of the converging lens group and the microlens array is the same as that of the quartz rod. Similarly, the compensation unit 300 is movably arranged between the light homogenizing unit 200 and the relay unit 500 or movably arranged between the relay lens group 500 and the substrate M to be processed.

[0064] Furthermore, the centers of the components in the illumination unit 100 , the light homogenization unit 200 , the compensation unit 300 , the coupling lens group 400 , the relay lens group 500 , and the collimating lens group 600 are all on the same optical axis.

[0065] Based on the same inventive concept, the present invention also provides a photolithography machine, comprising the above-mentioned illumination system.

[0066] Based on the same inventive concept, this embodiment further provides a method for compensating for illumination uniformity, including:

[0067] Step 1: The illumination unit 100 provides a first illumination.

[0068] The first light passes through the third lens group and the light homogenization unit 200 in sequence.

[0069] Step 2: The image detector obtains the light intensity distribution of the second light emitted by the light homogenization unit.

[0070] The image detector detects the uniformity of the illumination of the light field formed by the second illumination to determine the area of ​​the entire light field that needs light compensation and the compensated illumination, and then prepares the optical flat plate. Specifically, one or more required optical flat plates are obtained by combining different antireflection films or chrome layers.

[0071] Step three: setting the optical plate according to the acquired light intensity distribution, and the second light passes through the optical plate to form a corresponding third light.

[0072] Optionally, one or more optical plates are disposed between the light homogenizing unit 200 and the relay lens group 500, or between the relay lens group 500 and the substrate to be processed M. The optical plate is moved in the same direction as or opposite to the propagation direction of the second light, so that the illumination uniformity of the third light reaches a preset requirement. The illumination uniformity of the third light after compensation is greater than the second illumination uniformity.

[0073] Furthermore, the compensation standard for illumination uniformity includes two quantitative values, one is static non-uniformity H1 defined from a two-dimensional perspective, and the other is integral non-uniformity H2 defined from a one-dimensional perspective.

[0074] The static inhomogeneity H1 calculation formula is as follows:

[0075]

[0076] Among them, the I max is the maximum light intensity in the light field, I min is the minimum light intensity in the light field.

[0077] The integral inhomogeneity H2 calculation formula is as follows:

[0078]

[0079] The light field can be divided into a first direction and a second direction, and the first direction and the second direction are perpendicular to each other. Take multiple detection points in the first direction (X-axis direction), and integrate all the light intensity values ​​of each detection point along the second direction (Y-axis direction) to obtain the light intensity value of each detection point in the first direction (X-axis direction). max is the maximum value of the illumination intensity at each detection point in the first direction (X-axis direction) of the light field, I′ min It is the minimum value of the light intensity at each detection point in the first direction (X-axis direction) in the light field.

[0080] The relationship between the displacement of the optical plate and the static inhomogeneity H1 and the integrated inhomogeneity H2 is described in detail below. Figure 8-10 , Figure 8 8 is a schematic diagram of the light intensity distribution in the first light field A. As shown in FIG8 , the light intensity at the position close to the center of the first light field A is lower than the light intensity at the periphery of the first light field A. The light transmittance at the center is lower than the light transmittance at the periphery. And the light transmittance gradually increases in the direction radiating from the center of the first light field A to the periphery. Fig. 9As shown, the static inhomogeneity H1 of the first light field A is close to 5.00%, and the integral inhomogeneity H2 is close to 1.20%. When the displacement of the optical plate along the optical axis gradually increases, the corresponding static inhomogeneity H1 gradually decreases, while the integral inhomogeneity H2 remains the same without any change. Fig.10 Regardless of the displacement of the optical plate along the optical axis being 0 mm, 10 mm, 20 mm, 30 mm, 40 mm or 50 mm, the integrated illumination of the entire first light field A does not change (the curves formed by the integrated illumination values ​​corresponding to different displacements in the figure overlap because the integrated illumination values ​​do not change), and the corresponding integrated non-uniformity H2 will not change either.

[0081] See also Figure 11-13 , Fig.11 10 is a schematic diagram of the light intensity distribution in the second light field B. As shown in FIG10 , the light intensity at the position close to the center of the second light field B is higher than the light intensity at the periphery of the second light field B. The light transmittance at the center is higher than the light transmittance at the periphery. And the light transmittance gradually decreases in the direction radiating from the center of the second light field B to the periphery. Fig.12 As shown, the static inhomogeneity H1 in the second light field B is close to 5.00%, and the integral inhomogeneity H2 is close to 1.20%. When the displacement of the optical plate along the optical axis gradually increases, the corresponding static inhomogeneity H1 gradually decreases, while the integral inhomogeneity H2 remains the same without any change. Fig.13 Regardless of the displacement of the optical plate along the optical axis being 0 mm, 10 mm, 20 mm, 30 mm, 40 mm or 50 mm, the integrated illumination of the entire second light field B does not change (the curves formed by the integrated illumination values ​​corresponding to different displacements in the figure overlap because the integrated illumination values ​​do not change), and the corresponding integrated non-uniformity H2 will not change either.

[0082] Therefore, it can be seen from the above that when the central light transmittance of the light field is gradually greater or less than the light transmittance of the area along the center to the surrounding direction, the static inhomogeneity H1 will change with the change of the distance the optical plate moves along the optical axis, but has no direct effect on the integrated inhomogeneity H2.

[0083] See also Figure 14-16 , Fig.14 14 is a schematic diagram of the light intensity distribution in the third light field D. As shown in FIG14, the light intensity at each position with the same X-axis coordinate but different Y-axis coordinate in the third light field D is the same. However, in the X-axis direction, starting from the X-axis coordinate corresponding to the center point of the third light field D, the light intensity corresponding to the positive and negative directions of the X-axis gradually decreases. Fig.15As shown, the static inhomogeneity H1 of the third light field D is close to 2.50%, and the integral inhomogeneity H2 is close to 1.80%. When the displacement of the optical plate along the optical axis gradually increases, the corresponding static inhomogeneity H1 gradually decreases, and the integral inhomogeneity H2 also gradually decreases. Fig.16 When the displacement of the optical plate along the optical axis is 0 mm, 10 mm, 20 mm, 30 mm, 40 mm and 50 mm, the integrated illumination near the middle part of the third light field D gradually increases, and the corresponding integrated non-uniformity H2 decreases accordingly.

[0084] See also Figure 17-19 , Fig.17 17 is a schematic diagram of the light intensity distribution in the fourth light field E. As shown in FIG17 , the light intensity at each position with the same X-axis coordinate but different Y-axis coordinate in the fourth light field E is the same. However, in the X-axis direction, starting from the X-axis coordinate corresponding to the center point of the fourth light field E, the light intensity corresponding to the positive and negative directions of the X-axis gradually increases. Fig.18 As shown, the static inhomogeneity H1 of the fourth light field E is close to 2.50%, and the integral inhomogeneity H2 is close to 1.80%. When the displacement of the optical plate along the optical axis gradually increases, the corresponding static inhomogeneity H1 gradually decreases, and the integral inhomogeneity H2 also gradually decreases. Fig.19 When the displacement of the optical plate along the optical axis is 0 mm, 10 mm, 20 mm, 30 mm, 40 mm and 50 mm, the integrated illumination near the surroundings in the fourth light field E gradually increases, and the corresponding integrated non-uniformity H2 decreases accordingly.

[0085] Therefore, in the case of the light intensity distribution of the third light field D and the fourth light field E, both the static non-uniformity H1 and the integrated non-uniformity H2 can change as the distance that the optical plate moves along the optical axis changes.

[0086] To sum up, this embodiment compensates for the uniform light effect of the uniform light unit 200 by setting the compensation unit 300 with a variety of light transmittances, so that the second illumination is adjusted by the compensation unit 300 with different light transmittances to obtain the third illumination with greater illumination uniformity and better uniformity, which is beneficial to improving the exposure effect of the lithography equipment and further improving product performance.

[0087] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A lighting system, characterized in that: The lighting system comprises: an illumination unit, a light homogenization unit and a compensation unit; The illumination unit is used to provide a first illumination having a plurality of light propagation directions; The light homogenization unit is used to homogenize the first light and convert the first light into a second light with a light propagation direction; The compensation unit includes at least one optical plate with multiple light transmittances; the optical plate can move in a direction that is the same as or opposite to the propagation direction of the light of the second illumination; The second illumination passes through the optical plate to form a corresponding third illumination; wherein the illumination uniformity of the third illumination is greater than the illumination uniformity of the second illumination.

2. The lighting system according to claim 1, characterized in that The optical plate has a first surface and an opposite second surface, and the first surface and / or the second surface have different light transmittances.

3. The lighting system according to claim 2, characterized in that The first surface and\or the second surface have different light transmittances, and at least one antireflection film is coated on the first surface and\or the second surface.

4. The lighting system according to claim 2, characterized in that The first surface and / or the second surface have different light transmittances, a chrome layer is plated on the first surface and / or the second surface, and the chrome layer is formed in a dotted manner.

5. The lighting system according to claim 1, characterized in that The illumination system further comprises a relay lens group, and the relay lens group is used to transmit the second light to the compensation unit, or transmit the third light to the substrate to be processed.

6. The lighting system according to claim 5, characterized in that The compensation unit is movably disposed between the relay lens group and the substrate to be processed, or is movably disposed between the relay lens group and the light homogenization unit.

7. The lighting system according to claim 6, characterized in that The distance between the compensation unit and the relay lens assembly is less than or equal to the focal length of the relay lens assembly.

8. The lighting system according to claim 1, characterized in that The compensation unit includes one optical plate, or a plurality of optical plates arranged along a light propagation direction of the second illumination.

9. The lighting system according to claim 1, characterized in that The illumination unit includes a light emitter and an ellipsoidal reflector; the light emitter is disposed at a focus of the ellipsoidal reflector, and the light emitter provides the first illumination, and the first illumination is converged at another focus of the ellipsoidal reflector by the action of the ellipsoidal reflector and emitted.

10. The lighting system according to claim 1, characterized in that The illumination unit comprises a laser emitter, and the laser emitter is used to provide the first illumination.

11. The lighting system according to claim 1, characterized in that The light homogenization unit includes at least one quartz rod; the quartz rod is arranged along the propagation direction of the light of the second illumination.

12. The lighting system according to claim 1, characterized in that The light homogenization unit includes a first lens group and a second lens group; the first light passes through the first lens group and the second lens group in sequence to be converted into the second light; wherein the first lens group is used to converge the first light, and the second lens group is used to adjust the illumination uniformity of the first light.

13. The lighting system according to claim 1, characterized in that The lighting system further includes a third lens group, and the third lens group is used to couple the first illumination provided by the illumination unit into the light homogenization unit.

14. A photolithography machine, characterized in that: The lithography machine comprises an illumination system as described in any one of claims 1-13.

15. A method for compensating illumination uniformity, characterized in that: Using the lighting system as described in any one of claims 1 to 13, the lighting uniformity compensation method comprises: The illumination unit provides first illumination; The image detector acquires the light intensity distribution of the second light emitted by the light homogenization unit; An optical plate is set according to the obtained light intensity distribution, and the second light passes through the optical plate to form a third light correspondingly; The optical plate has a variety of light transmittances, so that the illumination uniformity of the third illumination is greater than the illumination uniformity of the second illumination.

16. The illumination uniformity compensation method according to claim 15, characterized in that: Setting the optical plate according to the acquired light intensity distribution includes: moving the optical plate in a direction that is the same as or opposite to a propagation direction of the second light, so that the illumination uniformity of the third light meets a preset requirement.

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