Write-through photoetching machine exposure control method and device, medium and write-through photoetching machine

Abstract

The invention discloses a direct writing type photoetching machine exposure control method and device, a medium and a direct writing type photoetching machine, and the direct writing type photoetching machine exposure control method comprises the following steps: obtaining exposure data; digital micromirror control information is obtained according to the exposure data and a uniformity compensation template, and the uniformity compensation template is determined according to the influence value of the DMD digital micromirror on the photoresist thickness in the effective area of the DMD digital micromirror array and the corresponding photoresist thickness difference value; and controlling the DMD digital micromirror array according to the digital micromirror control information. According to the method disclosed by the invention, the exposure uniformity can be more finely controlled, the non-uniform glue thickness caused by factors such as equipment error and non-uniform light source is reduced, the precision of the photoetching process and the line width size consistency are improved, meanwhile, the high cost of replacing hardware and repeatedly exposing is avoided, the production efficiency and the yield are improved, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to an exposure control method for a direct-write lithography machine, an exposure control device for a direct-write lithography machine, a computer-readable storage medium, and a direct-write lithography machine. Background Art

[0002] With the continuous development of semiconductor manufacturing technology and printed circuit board technology, especially in advanced direct-write lithography machines, the critical dimensions (CD) of line width are gradually becoming more refined, and the line width uniformity (CDU) has become one of the main challenges facing the current advanced direct-write lithography machines. In the traditional lithography process, exposure uniformity directly affects the uniformity of photoresist thickness, thereby affecting the line width uniformity (CDU) of the final product. In order to meet higher precision production requirements, how to further improve exposure uniformity and solve the problem of uneven thickness has become a key issue that needs to be solved urgently.

[0003] At present, existing technologies mainly improve exposure uniformity by changing process conditions, reducing the effective width of DMD (Digital Micromirror Device), superimposing repeated exposures, replacing optical imaging systems and spatial light modulators, or performing micro-compensation. However, these methods have certain limitations. Changing process conditions will reduce the process window and affect product yield; reducing the effective width of DMD or superimposing repeated exposures will affect production capacity; replacing optical imaging systems and spatial light modulators will significantly increase hardware costs; and although the micro-compensation method can reduce local exposure unevenness, it lacks sufficient accuracy when dealing with small errors and cannot finely adjust exposure uniformity. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to propose a direct-write lithography machine exposure control method, which can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, improve the accuracy of the lithography process and the consistency of the line width, and at the same time, avoid the high cost of hardware replacement and repeated exposure, improve production efficiency and yield, and reduce production costs.

[0005] The second objective of the present invention is to provide an exposure control device for a direct-write lithography machine.

[0006] A third object of the present invention is to provide a computer-readable storage medium.

[0007] The fourth objective of the present invention is to provide a direct-write lithography machine.

[0008] In order to achieve the above-mentioned purpose, the exposure control method of a direct-write lithography machine in an embodiment of the first aspect of the present invention includes: acquiring exposure data; obtaining digital micromirror control information according to the exposure data and a uniformity compensation template, wherein the uniformity compensation template is determined based on the influence value of the DMD digital micromirror on the photoresist thickness in an effective area of ​​the DMD digital micromirror array and the corresponding photoresist thickness difference value, and the effective area includes multiple areas with different light intensities, and the influence values ​​of the areas with different light intensities on the photoresist thickness are different; controlling the DMD digital micromirror array according to the digital micromirror control information.

[0009] According to the exposure control method of the direct-write lithography machine of the embodiment of the present invention, the digital micromirror control information for adjusting the DMD digital micromirror array is obtained by acquiring exposure data and combining with a uniformity compensation template. Among them, the uniformity compensation template is determined based on the influence value of the area with different light intensity on the photoresist thickness and the difference value of the thickness in the effective area of ​​the DMD digital micromirror array. The influence value of the DMD digital micromirror on the photoresist thickness in the area with different light intensity is different. By adjusting the transmittance of the micromirror in the DMD digital micromirror array, the exposure dose can be accurately controlled, thereby realizing the fine control of the photoresist thickness. Compared with the traditional micro-compensation method, the influence value of the DMD digital micromirror on the photoresist thickness is a fixed value, which cannot meet the uniformity requirements of higher precision. The method of the present invention can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, and improve the accuracy of the photolithography process and the consistency of the line width size. In addition, by adopting the control method of the digital micromirror array, there is no need to replace the hardware equipment or perform repeated exposure, thereby avoiding the high cost of hardware upgrades and process complications, further improving production efficiency and yield rate, and reducing overall production costs.

[0010] In some embodiments, the uniformity compensation template is in W columns and D rows, and the active area of ​​the DMD digital micromirror array is in W columns and D rows, wherein 0<W≤M, 0<D≤N.

[0011] In some embodiments, the effective area of ​​the DMD digital micromirror array includes a fixed light intensity area and a gradually changing light intensity area, the gradually changing light intensity area is at least one edge area of ​​the effective area, the light intensity of the gradually changing light intensity area gradually changes from a first light intensity to a second light intensity along a target direction, the light intensity of the fixed light intensity area is the second light intensity, wherein the target direction is a direction from the outside of the DMD digital micromirror array to the inside of the DMD digital micromirror array.

[0012] In some embodiments, the light intensity gradient region is W columns and D1 rows, and the light intensity fixed region is W columns and (D-D1) rows, wherein (D / 10)≤D1≤(D / 5).

[0013] In some embodiments, the light intensity gradient region is W1 column and D row, and the light intensity fixed region is (W-W1) column and D row, wherein (W / 10)≤W1≤(W / 5).

[0014] In some embodiments, the influence value of the DMD digital micromirror on the photoresist thickness in the effective area includes a first influence value, and the first influence value is the influence value of the DMD digital micromirror on the photoresist thickness in the fixed light intensity area, and the influence values ​​of all the DMD digital micromirrors in the fixed light intensity area on the photoresist thickness are the same, and the first influence value is obtained by the following steps: obtaining a first photoresist thickness corresponding to when all DMD digital micromirrors in the effective area are in an on state; controlling any one of the DMD digital micromirrors in the fixed light intensity area to turn off, and obtaining a second photoresist thickness corresponding to when any one of the DMD digital micromirrors in the fixed light intensity area is in an off state; and determining the first influence value according to the second photoresist thickness and the first photoresist thickness.

[0015] In some embodiments, the influence value of the DMD digital micromirror on the photoresist thickness in the effective area also includes a second influence value, and the second influence value is the influence value of the DMD digital micromirror on the photoresist thickness in the light intensity gradient area, and the second influence value is obtained by the following steps: controlling any one of the DMD digital micromirrors in the target row or column in the light intensity gradient area to turn off, and obtaining a third photoresist thickness corresponding to any one of the DMD digital micromirrors in the target row or column when it is in the off state; determining the second influence value according to the third photoresist thickness and the first photoresist thickness.

[0016] In some embodiments, the light intensity gradient area includes multiple rows or columns, and the direct-write lithography machine exposure control method also includes: traversing each row or column of the light intensity gradient area to obtain multiple third photoresist thicknesses; determining the second impact value according to each third photoresist thickness and the first photoresist thickness.

[0017] In some embodiments, the photoresist thickness difference value is determined by the following steps: obtaining a photoresist thickness influence curve based on the first influence value and the second influence value; determining the peak and valley values ​​of the photoresist thickness influence curve, and the photoresist thickness difference value is the difference between the peak and valley values.

[0018] In some embodiments, the uniformity compensation template is formed by the following steps: when the impact value of the target DMD digital micromirror in the effective area on the photoresist thickness is greater than the photoresist thickness difference value, adjusting the switching state of the DMD digital micromirror in the light intensity gradient area, wherein the target DMD digital micromirror is any DMD digital micromirror in the effective area; or, when the impact value of the target DMD digital micromirror in the effective area on the photoresist thickness is less than or equal to the photoresist thickness difference value, adjusting the switching state of the DMD digital micromirror in the fixed light intensity area; generating the uniformity compensation template according to the adjusted state information of the DMD digital micromirrors in the fixed light intensity area and the light intensity gradient area.

[0019] In order to achieve the above-mentioned purpose, the exposure control device of a direct-write lithography machine according to the second aspect of the present invention includes: a memory, in which a uniformity compensation template is stored; and a controller, which is connected to the memory and is used to execute the exposure control method of the direct-write lithography machine described in the above embodiment.

[0020] According to the direct-write lithography machine exposure control device of the embodiment of the present invention, the controller is connected to the memory, and is used to execute the direct-write lithography machine exposure control method described in the above embodiment, and obtains the digital micromirror control information for adjusting the DMD digital micromirror array by acquiring exposure data and combining the uniformity compensation template. Among them, the uniformity compensation template is determined based on the influence value and the thickness difference value of the region with different light intensity in the effective area of ​​the DMD digital micromirror array on the photoresist glue thickness. The influence value of the DMD digital micromirror on the photoresist glue thickness in the region with different light intensity is different. By adjusting the transmittance of the micromirror in the DMD digital micromirror array, the exposure dose can be accurately controlled, thereby realizing the fine control of the photoresist thickness. Compared with the traditional micro-compensation method, the influence value of the DMD digital micromirror on the photoresist glue thickness is a fixed value, which cannot meet the uniformity requirements of higher precision. The method of the present invention can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, and improve the accuracy of the photolithography process and the consistency of the line width size. In addition, by adopting the control method of the digital micromirror array, there is no need to replace the hardware equipment or perform repeated exposure, thereby avoiding the high cost of hardware upgrades and process complications, further improving production efficiency and yield rate, and reducing overall production costs.

[0021] In order to achieve the above-mentioned purpose, a computer-readable storage medium of an embodiment of the third aspect of the present invention stores a computer program thereon, and when the computer program is executed, the exposure control method of the direct-write lithography machine described in the above embodiment is implemented.

[0022] According to the computer-readable storage medium of an embodiment of the present invention, by adopting the exposure control method of the direct-write lithography machine described in the above embodiment, the exposure uniformity can be controlled more finely, the uneven thickness of the glue caused by equipment errors, uneven light sources and other factors can be reduced, the accuracy of the lithography process and the consistency of the line width size can be improved, and at the same time, the high cost of replacing hardware and repeated exposure can be avoided, the production efficiency and yield rate can be improved, and the production cost can be reduced.

[0023] In order to achieve the above-mentioned purpose, the direct-write lithography machine of the fourth aspect of the present invention includes the exposure control device of the direct-write lithography machine described in the above embodiment; or, the direct-write lithography machine includes: a DMD digital micromirror array, an illumination system and a dimming unit, the dimming unit is located on the illumination path of the DMD digital micromirror array by the illumination system, and the dimming unit is used to adjust the light intensity projected onto the DMD digital micromirror array so that the effective area of ​​the DMD digital micromirror array is divided into a fixed light intensity area and a gradually changing light intensity area; a control system, the control system is connected to the DMD digital micromirror array and the illumination system, and the control system is used to control the DMD digital micromirror array according to the exposure control method of the direct-write lithography machine described in the above embodiment during exposure.

[0024] According to the direct-write lithography machine of the embodiment of the present invention, by combining the DMD digital micromirror array, the lighting system, the dimming unit and the control system to work together, the uniformity of the photoresist thickness is achieved. Specifically, the dimming unit is located on the lighting path of the DMD digital micromirror array by the lighting system, and can dynamically adjust the light intensity projected onto the DMD digital micromirror array, so that the effective area of ​​the DMD digital micromirror array forms a fixed light intensity area and a gradual light intensity area. The control system dynamically adjusts the transmittance of the micromirrors in the DMD digital micromirror array by adopting the direct-write lithography machine exposure control method described in the above embodiment, and accurately controls the exposure dose in the effective area, thereby achieving fine control of the photoresist thickness. Compared with the traditional micro-compensation method, the influence value of the DMD digital micromirror on the photoresist thickness is a fixed value, which cannot meet the uniformity requirements of higher precision. The method of the present invention can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, and improve the accuracy of the photolithography process and the consistency of the line width size. In addition, by adopting the control method of the digital micromirror array, there is no need to replace the hardware equipment or perform repeated exposure, thereby avoiding the high cost of hardware upgrades and process complications, further improving production efficiency and yield rate, and reducing overall production costs.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a flow chart of an exposure control method for a direct-write lithography machine according to an embodiment of the present invention; Figure 2 is a schematic diagram of a fixed illumination intensity region and a gradually changing illumination intensity region according to an embodiment of the present invention; Figure 3 is a schematic diagram of changes in light intensity in a light intensity gradient region according to an embodiment of the present invention; Figure 4 is a block diagram of an exposure control device for a direct-write lithography machine according to an embodiment of the present invention; Figure 5 is a block diagram of a direct-write lithography machine according to an embodiment of the present invention; Figure 6 is a block diagram of a direct-write lithography machine according to yet another embodiment of the present invention.

[0027] Reference numerals: Direct writing lithography machine 100; Direct-write lithography machine exposure control device 1; DMD digital micromirror array 2; lighting system 3; dimming unit 4; control system 5; Memory 11; controller 12. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0029] Reference below Figure 1-Figure 3 The exposure control method of a direct-write lithography machine according to an embodiment of the present invention is described.

[0030] Figure 1 is a flow chart of an exposure control method for a direct-write lithography machine according to an embodiment of the present invention. Figure 1 As shown, the exposure control method of a direct-write lithography machine according to an embodiment of the present invention at least includes steps S1-S3.

[0031] S1, obtain exposure data.

[0032] In some embodiments, exposure data is the basis for exposure control of a direct-write lithography machine, and may include but is not limited to: light intensity, photoresist thickness distribution, exposure target pattern, working environment parameters (such as temperature, humidity), etc.

[0033] In some embodiments, exposure data can be collected in real time through a variety of measuring devices. For example, a light intensity detector (such as a photodiode array or a CCD / CMOS sensor) is used to detect the light intensity distribution projected onto the DMD digital micromirror array in real time to generate a light intensity distribution map. The thickness of the photoresist layer on the surface of the substrate is measured by a step meter or a white light interferometer to generate a photoresist thickness distribution curve, which provides a basis for the uniformity control of the subsequent exposure dose. The conditions in the working environment that may affect the exposure process are recorded by temperature and humidity sensors, and the exposure strategy is adjusted to reduce errors when necessary.

[0034] S2, obtaining digital micromirror control information according to the exposure data and the uniformity compensation template.

[0035] In some embodiments, the uniformity compensation template is a reference data table or function mapping for correcting the non-uniformity of the photoresist thickness during the exposure process, and is used to guide the dynamic regulation of the DMD digital micromirror. The uniformity compensation template is determined based on the influence value of the DMD digital micromirror on the photoresist thickness in the effective area of ​​the DMD digital micromirror array and the corresponding photoresist thickness difference value, and can be generated by the host computer based on the measurement data.

[0036] Among them, the influence value of the DMD digital micromirror on the photoresist thickness can refer to the contribution value of the DMD digital micromirror to the change of the photoresist thickness under specific light intensity conditions, which can be obtained through experimental measurement or simulation analysis. The effective area includes multiple areas with different light intensities. The influence values ​​of the DMD digital micromirror on the photoresist thickness in areas with different light intensities are different. This differentiated design makes it possible to generate special digital micromirror control information for the DMD digital micromirror in areas with different light intensities, thereby improving the sensitivity of exposure dose adjustment, avoiding the use of the same digital micromirror control information to cause consistent exposure dose adjustment, and thus achieving fine control of the photoresist thickness.

[0037] S3, controlling the DMD digital micromirror array according to the digital micromirror control information.

[0038] Specifically, the digital micromirror control information can be used to accurately control the switch state of each micromirror in the DMD digital micromirror array. Each micromirror switches between the "on" or "off" state according to the corresponding control information, thereby changing its transmittance. By adjusting the transmittance of the micromirror, compensation for different exposure doses can be provided within the effective area of ​​the DMD digital micromirror array, thereby accurately compensating for differences in photoresist thickness.

[0039] According to the exposure control method of the direct-write lithography machine of the embodiment of the present invention, the digital micromirror control information for adjusting the DMD digital micromirror array is obtained by acquiring exposure data and combining with a uniformity compensation template. Among them, the uniformity compensation template is determined based on the influence value of the area with different light intensity on the photoresist thickness and the difference value of the thickness in the effective area of ​​the DMD digital micromirror array. The influence value of the DMD digital micromirror on the photoresist thickness in the area with different light intensity is different. By adjusting the transmittance of the micromirror in the DMD digital micromirror array, the exposure dose can be accurately controlled, thereby realizing the fine control of the photoresist thickness. Compared with the traditional micro-compensation method, the influence value of the DMD digital micromirror on the photoresist thickness is a fixed value, which cannot meet the uniformity requirements of higher precision. The method of the present invention can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, and improve the accuracy of the photolithography process and the consistency of the line width size. In addition, by adopting the control method of the digital micromirror array, there is no need to replace the hardware equipment or perform repeated exposure, thereby avoiding the high cost of hardware upgrades and process complications, further improving production efficiency and yield rate, and reducing overall production costs.

[0040] In some embodiments, Figure 2 As shown in the figure, the uniformity compensation template is presented as a two-dimensional matrix, including W columns and D rows, where 0<W≤M, 0<D≤N. Each unit of the matrix corresponds to a data point, which is used to describe the control information of the corresponding micromirror in the DMD digital micromirror array. The effective area of ​​the DMD digital micromirror array is also presented as W columns and D rows, where 0<W≤M, 0<D≤N. And it corresponds one-to-one with the uniformity compensation template to ensure that the compensation information is completely matched with the digital micromirrors in the effective area. The definition of the effective area indicates the number and distribution of the DMD digital micromirrors involved in the photolithography operation, so that the exposure control is concentrated within the range that actually needs to be adjusted, improving the calculation efficiency and resource utilization. Through the correspondence between the uniformity compensation template and the effective area, the switching state of each digital micromirror can be accurately controlled, the light dose can be accurately adjusted, and the thickness distribution of the photoresist can be further optimized.

[0041] In some embodiments, the active area of ​​the DMD digital micromirror array includes a light intensity gradient area ( Figure 2 Area1) and the area with fixed light intensity ( Figure 2 The illumination intensity gradient area is at least one edge area of ​​the effective area, for example, Figure 2 As shown in (a)-(f) in the figure, the illumination intensity gradient area can be the upper edge area, lower edge area, left edge area or right edge area of ​​the effective area, or can be located in the upper edge, lower edge or left and right edge areas at the same time.

[0042] In some embodiments, the illumination intensity of the illumination intensity gradient region gradually changes from the first illumination intensity to the second illumination intensity along the target direction, wherein the target direction is the direction from the outside of the DMD digital micromirror array to the inside of the DMD digital micromirror array. Specifically, by adding an aperture element, the imaging beam width or the imaging range size can be adjusted so that the illumination intensity of area Area1 gradually increases from weak to strong, thereby forming an illumination intensity gradient region.

[0043] Among them, the aperture element is an optical device used to adjust the width of the light beam or the imaging range, thereby affecting the light intensity distribution in the imaging area. The aperture changes the light intensity distribution through the optical system by blocking part of the light beam. For example, in some areas, the gradual increase in occlusion will cause the light intensity to gradually decrease, while in other areas, the gradual decrease in occlusion will cause the light intensity to gradually increase. The aperture element is directly located in the illumination path of the optical system and is responsible for adjusting the shape, width and intensity of the light beam entering the DMD digital micromirror. The aperture itself does not have a reflective function. It changes the light intensity irradiated to the surface of the DMD digital micromirror by controlling the distribution of the incident light beam, thereby forming a gradient area of ​​light intensity.

[0044] In some embodiments, Figure 3 As shown, the light intensity can be set according to an exponential growth trend. For example, the light intensity can be set according to 1, 2, 4, 8, 16, ..., As the light intensity gradually increases, the light intensity in the gradual light intensity change area can eventually converge with the light intensity in the fixed light intensity area, thus achieving a smooth transition. Among them, the fine adjustment of the exposure dose can achieve , lines is the effective number of rows or columns of the DMD digital micromirror.

[0045] In some embodiments, the illumination intensity of the fixed illumination intensity area is the second illumination intensity, that is, in this area, the illumination intensity does not change and remains consistent. This area may be located in the middle part of the effective area.

[0046] In some embodiments, if the illumination intensity gradient region is the upper edge region or the lower edge region of the effective region, the illumination intensity gradient region is W columns and D1 rows, and the illumination intensity fixed region is W columns and (D-D1) rows, where (D / 10)≤D1≤(D / 5). The purpose of this restriction is to ensure that the size of the illumination intensity gradient region is moderate, neither too small, resulting in an inconspicuous change in illumination intensity, nor too large, resulting in the illumination intensity gradient region affecting too much illumination intensity distribution, thereby affecting exposure uniformity and accuracy.

[0047] In some embodiments, if the illumination intensity gradient region is the left edge region or the right edge region of the effective region, the illumination intensity gradient region is W1 column and D row, and the illumination intensity fixed region is (W-W1) column and D row, where (W / 10)≤W1≤(W / 5). Similarly, by limiting the size of W1, the size of the illumination intensity gradient region and the illumination intensity fixed region can be balanced to avoid the negative impact caused by too small or too large illumination intensity gradient region, thereby ensuring the quality and stability of the exposure process.

[0048] In some embodiments, the influence value of the DMD digital micromirror on the photoresist thickness in the effective area includes a first influence value, the first influence value is the influence value of the DMD digital micromirror on the photoresist thickness in the fixed light intensity area, and the influence values ​​of all DMD digital micromirrors on the photoresist thickness in the fixed light intensity area are the same.

[0049] Specifically, the DMD digital micromirror array controls the reflection direction of light through the switching state of the micromirror, thereby controlling the light intensity irradiated to the surface of the photoresist. In a direct-write lithography machine, when the DMD digital micromirror is in the on state, it reflects light to the photoresist, producing an exposure effect; when the micromirror is off, it does not reflect light, thereby reducing or completely eliminating the light. The change in photoresist thickness is mainly caused by the intensity of light. During the exposure process, the stronger the light intensity, the greater the change in the thickness of the photoresist. Therefore, the switching state of the DMD digital micromirror directly affects the light intensity, thereby affecting the change in the thickness of the photoresist. In the area of ​​fixed light intensity, all DMD digital micromirrors have the same impact on the thickness of the photoresist, which means that in this area, no matter which DMD micromirror is in the on or off state (on or off), its impact on the thickness of the photoresist is the same, and will not change due to the position of the micromirror or other factors. In other words, each micromirror has the same effect on the exposure amount (i.e., light intensity) of the photoresist and the resulting change in the thickness of the photoresist.

[0050] In some embodiments, the first impact value is obtained by the following steps: obtaining a first photoresist thickness corresponding to when all DMD digital micromirrors in the effective area are in an on state, controlling any DMD digital micromirrors in the fixed light intensity area to turn off, obtaining a second photoresist thickness corresponding to when any DMD digital micromirrors in the fixed light intensity area are in an off state, and determining the first impact value based on the second photoresist thickness and the first photoresist thickness.

[0051] Specifically, when all DMD digital micromirrors in the effective area are in an open state, the corresponding photoresist thickness detected is a first photoresist thickness. In this state, all DMD digital micromirrors reflect light beams, resulting in maximum illumination intensity. In this way, the photoresist thickness under maximum exposure can be determined.

[0052] Further, any DMD digital micromirror in the fixed illumination intensity region is controlled to be turned off. This means that a certain micromirror in the fixed illumination intensity region no longer reflects the light beam, thereby reducing the illumination intensity in the region. After turning off the micromirror, the thickness of the photoresist at this time is recorded, which is the second photoresist thickness. Since the light beam reflection of one digital micromirror is reduced, the second photoresist thickness will be slightly smaller than the first photoresist thickness.

[0053] Furthermore, by comparing the difference between the first photoresist thickness and the second photoresist thickness, the influence value of any DMD digital micromirror on the photoresist thickness in the fixed illumination intensity region, ie, the first influence value, can be determined.

[0054] In some embodiments, the influence value of the DMD digital micromirror on the photoresist thickness in the effective area also includes a second influence value, and the second influence value is the influence value of the DMD digital micromirror on the photoresist thickness in the light intensity gradient area. Specifically, in the light intensity gradient area, since the light intensity is not constantly distributed in the gradient area, the influence of the DMD digital micromirror on the photoresist thickness will vary depending on the light intensity at its location.

[0055] Among them, the influence value of the DMD digital micromirrors in each row or column in the illumination intensity gradient region on the thickness of the photoresist is the same, which depends on whether the illumination intensity gradient region is located in the upper and lower edge regions or the left and right edge regions of the effective area. If the illumination intensity gradient region is located in the upper and lower edge regions of the effective area, the illumination intensity of each row in the illumination intensity gradient region is the same. However, the influence values ​​of the DMD digital micromirrors in different rows on the thickness of the photoresist are different, because the illumination intensity of different rows presents a distribution trend from weak to strong or from strong to weak. Similarly, if the illumination intensity gradient region is located in the left and right edge regions of the effective area, the illumination intensity of each column in the illumination intensity gradient region is the same. The influence values ​​of the DMD digital micromirrors in different columns on the thickness of the photoresist are different, because the illumination intensity of different columns presents a distribution trend from weak to strong or from strong to weak.

[0056] Therefore, compared with the first impact value which is a fixed value, the second impact value reflects the dynamic impact of photoresist thickness caused by changes in light intensity. The second impact value is actually a value that changes with position and light intensity distribution, rather than a constant impact value.

[0057] In some embodiments, the second impact value is obtained by the following steps: controlling any one DMD digital micromirror of the target row or column in the light intensity gradient region to be turned off, obtaining a third photoresist thickness corresponding to any one DMD digital micromirror of the target row or column being in the turned-off state, and determining the second impact value according to the third photoresist thickness and the first photoresist thickness.

[0058] Among them, the target row or column can be any row or any column in the light intensity gradient area. By obtaining the influence value of any DMD digital micromirror in the target row or column on the photoresist thickness, the influence values ​​of all DMD digital micromirrors in the row or column on the photoresist thickness can be obtained, that is, the second influence value.

[0059] In some embodiments, the illumination intensity gradient region includes multiple rows or columns, and the direct-write lithography machine exposure control method further includes: traversing each row or column of the illumination intensity gradient region to obtain multiple third photoresist thicknesses, and determining a second impact value according to each third photoresist thickness and the first photoresist thickness. Due to the differences in illumination intensity distribution, the multiple second impact values ​​are different, and these values ​​provide data support for subsequent photoresist thickness compensation or optimization strategies.

[0060] In some embodiments, the photoresist thickness difference value is determined by the following steps: a photoresist thickness influence curve is obtained according to a first influence value and a second influence value, and the photoresist thickness influence curve reflects the change in photoresist thickness at different positions. By determining the peak and valley values ​​of the photoresist thickness influence curve, the photoresist thickness difference value is the difference between the peak and valley values, reflecting the fluctuation range of the photoresist thickness affected by exposure control. Among them, the peak value is the position where the photoresist is the thickest in the photoresist thickness influence curve, corresponding to the maximum value of the photoresist thickness. The valley value is the position where the photoresist is the thinnest in the photoresist thickness influence curve, corresponding to the minimum value of the photoresist thickness. The difference between the peak and valley values ​​represents the fluctuation amplitude of the photoresist thickness.

[0061] In some embodiments, the photoresist thickness difference value can directly reflect the uniformity of the photoresist thickness affected by exposure control. Specifically, the larger the photoresist thickness difference value, the more serious the non-uniformity of the photoresist thickness distribution; conversely, the smaller the photoresist thickness difference value, the more uniform the photoresist thickness distribution.

[0062] In some embodiments, the uniformity compensation template is formed by the following steps: when the impact value of the target DMD digital micromirror in the effective area on the photoresist thickness is greater than the photoresist thickness difference value, the switching state of the DMD digital micromirror in the light intensity gradient area is adjusted, wherein the target DMD digital micromirror is any DMD digital micromirror in the effective area.

[0063] Specifically, when the impact value of the target DMD digital micromirror on the photoresist thickness in the effective area is greater than the photoresist thickness difference value, it means that the photoresist thickness difference value is small, that is, the difference between the peak and valley values ​​of the photoresist thickness impact curve is small, and the overall thickness distribution is relatively uniform, with only a small difference. In this case, more detailed photoresist thickness compensation is required. Because the impact value of the DMD digital micromirror on the photoresist thickness in the light intensity gradient area is small, and the micromirror impact value in this area has a wide range of variation, the exposure dose can be more finely controlled by adjusting the switching state of the DMD digital micromirror in the light intensity gradient area, thereby achieving accurate adjustment of the photoresist thickness.

[0064] For example, if the difference in photoresist thickness is 5 nanometers, the influence value of the DMD digital micromirror on the photoresist thickness in the area of ​​gradual illumination intensity (the second influence value) is 6 nanometers to 10 nanometers, and the influence value of the DMD digital micromirror on the photoresist thickness in the area of ​​fixed illumination intensity (the first influence value) is 10 nanometers. In this case, although both the first influence value and the second influence value are greater than the difference in photoresist thickness, if the first influence value of 10 nanometers is used for adjustment, due to its greater influence, it may lead to over-compensation, thereby generating unnecessary exposure dose adjustments. Therefore, using the second influence value to adjust the thickness of the photoresist can achieve fine-grained control of the photoresist thickness.

[0065] Alternatively, when the impact value of the target DMD digital micromirror in the effective area on the photoresist thickness is less than or equal to the photoresist thickness difference value, the switching state of the DMD digital micromirror in the fixed light intensity area is adjusted.

[0066] Specifically, when the impact value of the target DMD digital micromirror in the effective area on the photoresist thickness is less than or equal to the photoresist thickness difference value, it means that the photoresist thickness difference value is large, that is, the difference between the peak and valley values ​​of the photoresist thickness impact curve is large, and the uniformity of the photoresist thickness is poor. In this case, the thickness compensation of the photoresist needs to be adjusted to a large extent. Since the illumination intensity in the area with fixed illumination intensity is greater than the illumination intensity in the area with gradually changing illumination intensity, the impact value of the DMD micromirror in the area with fixed illumination intensity (the first impact value) is greater than the micromirror impact value in the area with gradually changing illumination intensity (the second impact value). In this case, using the first impact value for adjustment can quickly and effectively change the exposure dose, thereby achieving a large compensation for the photoresist thickness and improving the uniformity of the photoresist thickness.

[0067] For example, if the difference in photoresist thickness is 15 nanometers, the influence of the DMD digital micromirror on the photoresist thickness in the area of ​​gradual illumination intensity (the second influence value) is 5 nanometers to 10 nanometers, and the influence of the DMD digital micromirror on the photoresist thickness in the area of ​​fixed illumination intensity (the first influence value) is 10 nanometers. In this case, using the second influence value for adjustment will cause the compensation process to be too slow, and it will not be possible to quickly compensate for the difference in photoresist thickness. On the contrary, using the first influence value (10 nanometers) for compensation can more efficiently adjust the exposure dose, thereby quickly adjusting the photoresist thickness and achieving a better compensation effect.

[0068] In some embodiments, a uniformity compensation template is generated based on the state information of the DMD digital micromirrors in the adjusted fixed illumination intensity area and the gradient illumination intensity area. The template describes the precise switch control of the DMD digital micromirrors in different areas, which is used to compensate for the difference in photoresist thickness during the exposure process, thereby achieving uniform distribution of photoresist thickness.

[0069] Reference below Figure 4 An exposure control device for a direct-write lithography machine according to an embodiment of the present invention is described.

[0070] Figure 4 is a block diagram of an exposure control device for a direct-write lithography machine according to an embodiment of the present invention. Figure 4 As shown, the exposure control device 1 of a direct-write lithography machine includes: a memory 11 and a controller 12 .

[0071] In some embodiments, a uniformity compensation template is stored in the memory 12. The uniformity compensation template can be generated by a host computer, and its value range is [0, 1], where 0 indicates that the DMD digital micromirror is off, and 1 indicates that the DMD digital micromirror is on. Therefore, the data in the uniformity compensation template records the switch state of the DMD digital micromirror in different areas (such as the area with gradual illumination intensity change and the area with fixed illumination intensity). These state information is based on preset compensation rules, and the exposure dose is precisely adjusted to ensure the uniform distribution of the photoresist thickness, thereby optimizing the exposure process.

[0072] In some embodiments, the uniformity compensation template in the memory 12 can be dynamically updated according to different photoresist materials, photolithography process conditions or photoresist thickness differences to better adapt to changes in actual exposure, thereby improving the stability and accuracy of the exposure process.

[0073] In some embodiments, the memory 12 may adopt the memory structure of FPGA, or use other types of solid-state storage devices, such as flash memory, RAM or other types of non-volatile memory. These storage media provide efficient storage and reading speed, ensuring the flexibility and response speed of the exposure control system in real-time operation.

[0074] In some embodiments, the controller 12 is connected to the memory 11, and is used to execute the exposure control method of the direct-write lithography machine described in the above embodiment, read the uniformity compensation template in the memory 11, and select the correct compensation strategy. For example, when the difference in photoresist thickness is small, the controller 12 can select a fine compensation strategy, that is, adjust the micromirror switch state in the area of ​​gradual illumination intensity; and when the difference in photoresist thickness is large, the controller 12 can select a faster compensation strategy, that is, adjust the micromirror switch state in the area of ​​fixed illumination intensity. The decision of this process is executed by the controller 12 to ensure the accuracy and efficiency of exposure dose adjustment.

[0075] In some embodiments, the controller 12 may be a Field-Programmable Gate Array (FPGA). FPGA is a highly flexible hardware platform with parallel processing capabilities that can execute complex control algorithms and is particularly suitable for executing tasks that require parallel computing and rapid response. In this case, the FPGA may contain a dedicated logic circuit to perform specific exposure control tasks.

[0076] In addition, the controller 12 can also be other types of processors, such as a microcontroller (MCU, Microcontroller Unit), a digital signal processor (DSP, Digital Signal Processor), a central processing unit (CPU, Central Processing Unit), an application-specific integrated circuit (ASIC, Application-Specific Integrated Circuit), or an embedded processor (such as ARM architecture), and the specific choice depends on the design requirements and implementation methods.

[0077] According to the direct-write lithography machine exposure control device 1 of the embodiment of the present invention, the controller 12 is connected to the memory 11, and is used to execute the direct-write lithography machine exposure control method described in the above embodiment, and obtains the digital micromirror control information for adjusting the DMD digital micromirror array by acquiring exposure data and combining the uniformity compensation template. Wherein, the uniformity compensation template is determined based on the influence value and the thickness difference value of the region with different light intensity in the effective area of ​​the DMD digital micromirror array on the photoresist glue thickness. The influence value of the DMD digital micromirror on the photoresist glue thickness in the region with different light intensity is different. By adjusting the transmittance of the micromirror in the DMD digital micromirror array, the exposure dose can be accurately controlled, thereby realizing the fine control of the photoresist thickness. Compared with the traditional micro-compensation method, the influence value of the DMD digital micromirror on the photoresist glue thickness is a fixed value, which cannot meet the uniformity requirements of higher precision. The method of the present invention can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, and improve the accuracy of the photolithography process and the consistency of the line width size. In addition, by adopting the control method of the digital micromirror array, there is no need to replace the hardware equipment or perform repeated exposure, thereby avoiding the high cost of hardware upgrades and process complications, further improving production efficiency and yield rate, and reducing overall production costs.

[0078] The embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the exposure control method of the direct-write lithography machine described in the above embodiment is implemented. The specific implementation process of the exposure control method of the direct-write lithography machine can refer to the description of the above embodiment.

[0079] In some embodiments, the computer-readable storage medium may be a storage device that can store data and maintain data integrity after power failure. This may include flash memory, EPROM (programmable read-only memory), EEPROM (erasable programmable read-only memory), etc. The storage medium stores a computer program, and when the computer program is executed, the exposure control method of the direct-write lithography machine described in the above embodiment is implemented.

[0080] According to the computer-readable storage medium of an embodiment of the present invention, by adopting the exposure control method of the direct-write lithography machine described in the above embodiment, the exposure uniformity can be controlled more finely, the uneven thickness of the glue caused by equipment errors, uneven light sources and other factors can be reduced, the accuracy of the lithography process and the consistency of the line width size can be improved, and at the same time, the high cost of replacing hardware and repeated exposure can be avoided, the production efficiency and yield rate can be improved, and the production cost can be reduced.

[0081] Reference below Figure 5-Figure 6 A direct-write lithography machine according to an embodiment of the present invention is described.

[0082] Figure 5is a block diagram of a direct-write lithography machine according to an embodiment of the present invention, such as Figure 5 As shown, the direct-write lithography machine 100 includes the direct-write lithography machine exposure control device 1 described in the above embodiment. The controller 12 in the direct-write lithography machine exposure control device 1 is connected to the memory 11, and is used to execute the direct-write lithography machine exposure control method described in the above embodiment, read the uniformity compensation template in the memory 11, and select the correct compensation strategy. For example, in the case where the difference in photoresist thickness is small, the controller 12 can select a fine compensation strategy, that is, adjust the micromirror switch state in the area of ​​gradual light intensity change; and in the case where the difference in photoresist thickness is large, the controller 12 can select a faster compensation strategy, that is, adjust the micromirror switch state in the area of ​​fixed light intensity, thereby meeting the uniformity compensation requirements of the photoresist thickness, reducing the uneven thickness of the photoresist caused by factors such as equipment errors and uneven light sources, and improving the accuracy of the photolithography process and the consistency of the line width size.

[0083] Figure 6 is a block diagram of a direct-write lithography machine according to another embodiment of the present invention, such as Figure 6 As shown, the direct-write lithography machine 100 includes: a DMD digital micromirror array 2, an illumination system 3 and a dimming unit 4.

[0084] In some embodiments, the DMD digital micromirror array 2 can be a light source modulator used in a direct-write lithography machine 100. Each micromirror in the DMD digital micromirror array 2 can independently control the switch state, and use the reflection effect to project the light beam to the exposure surface or deviate from the exposure surface. The core function of the DMD digital micromirror array 2 is to accurately adjust the direction of the reflected light beam according to the received digital signal, thereby controlling the light intensity distribution of the exposure area.

[0085] In some embodiments, the illumination system 3 is responsible for providing a light source and irradiating light onto the DMD digital micromirror array 2. During the photolithography process, the illumination system 3 is responsible for providing a uniform light source and adjusting the intensity and distribution of the light according to requirements.

[0086] In some embodiments, the dimming unit 4 can be an aperture element, which is located on the illumination path of the illumination system 3 to the DMD digital micromirror array 2. The dimming unit 4 is used to adjust the light intensity projected onto the DMD digital micromirror array 2 so that the effective area of ​​the DMD digital micromirror array 2 is divided into a fixed light intensity area and a gradually changing light intensity area.

[0087] In some embodiments, the control system 5 is connected to the DMD digital micromirror array 2 and the lighting system 3. The control system 5 is used to control the DMD digital micromirror array 2 according to the exposure control method of the direct-write lithography machine described in the above embodiment during exposure, and accurately control the switch state of each DMD digital micromirror according to the uniformity compensation template stored in the memory 11. Specifically, during the exposure process, when the thickness difference of the photoresist is small, the control system 5 can select a fine compensation strategy, that is, only adjust the switch state of the micromirror in the area where the light intensity gradually changes, so as to avoid overexposure. In the case where the thickness difference of the photoresist is large, the control system 5 can adopt a faster compensation strategy, that is, adjust the switch state of the micromirror in the area where the light intensity is fixed, so as to compensate for the uneven exposure more quickly and directly.

[0088] According to the direct-write lithography machine 100 of the embodiment of the present invention, by combining the DMD digital micromirror array 2, the lighting system 3, the dimming unit 4 and the control system 5 to work together, the fine control of the uniformity of the photoresist thickness is achieved. Specifically, the dimming unit 4 is located on the lighting path of the DMD digital micromirror array 2 of the lighting system 3, and can dynamically adjust the light intensity projected to the DMD digital micromirror array 2, so that the effective area of ​​the DMD digital micromirror array 2 forms a fixed light intensity area and a gradual light intensity area. The control system 5 dynamically adjusts the light transmittance of the micromirrors in the DMD digital micromirror array 2 by adopting the direct-write lithography machine exposure control method described in the above embodiment, and accurately controls the exposure dose in the effective area, thereby achieving fine control of the photoresist thickness. Compared with the traditional micro-compensation method, the influence value of the DMD digital micromirror on the photoresist thickness is a fixed value, which cannot meet the uniformity requirements of higher precision. The method of the present invention can more finely control the exposure uniformity, reduce the uneven thickness of the glue caused by factors such as equipment errors and uneven light sources, and improve the accuracy of the photolithography process and the consistency of the line width size. In addition, by adopting the control method of the digital micromirror array, there is no need to replace the hardware equipment or perform repeated exposure, thereby avoiding the high cost of hardware upgrades and process complications, further improving production efficiency and yield rate, and reducing overall production costs.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0090] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A direct-write lithography machine exposure control method, characterized in that: include: Get exposure data; Obtaining digital micromirror control information according to the exposure data and a uniformity compensation template, wherein the uniformity compensation template is determined according to an influence value of a DMD digital micromirror on a photoresist thickness in an effective area of ​​a DMD digital micromirror array and a corresponding photoresist thickness difference value, wherein the effective area includes a plurality of areas with different light intensities, and the areas with different light intensities have different influence values ​​on the photoresist thickness; The DMD digital micromirror array is controlled according to the digital micromirror control information.

2. The exposure control method of a direct-write lithography machine according to claim 1, characterized in that: The uniformity compensation template is arranged in W columns and D rows, and the effective area of ​​the DMD digital micromirror array is arranged in W columns and D rows, wherein 0<W≤M, 0<D≤N.

3. The exposure control method of a direct-write lithography machine according to claim 2, characterized in that: The effective area of ​​the DMD digital micromirror array includes a fixed illumination intensity area and a gradually changing illumination intensity area, wherein the gradually changing illumination intensity area is at least one edge area of ​​the effective area, and the illumination intensity of the gradually changing illumination intensity area gradually changes from a first illumination intensity to a second illumination intensity along a target direction, and the illumination intensity of the fixed illumination intensity area is the second illumination intensity, wherein the target direction is a direction from the outside of the DMD digital micromirror array to the inside of the DMD digital micromirror array.

4. The exposure control method of a direct-write lithography machine according to claim 3, characterized in that: The illumination intensity gradient region is W columns and D1 rows, and the illumination intensity fixed region is W columns and (D-D1) rows, wherein (D / 10)≤D1≤(D / 5).

5. The exposure control method of a direct writing lithography machine according to claim 3, characterized in that: The illumination intensity gradient region is W1 column and D row, and the illumination intensity fixed region is (W-W1) column and D row, wherein (W / 10)≤W1≤(W / 5).

6. The exposure control method of a direct-write lithography machine according to any one of claims 3 to 5, characterized in that: The influence value of the DMD digital micromirror on the photoresist thickness in the effective area includes a first influence value, the first influence value is the influence value of the DMD digital micromirror on the photoresist thickness in the fixed light intensity area, the influence values ​​of all the DMD digital micromirrors on the photoresist thickness in the fixed light intensity area are the same, and the first influence value is obtained by the following steps: Obtaining a first photoresist thickness corresponding to when all DMD digital micromirrors in the effective area are in an on state; Controlling any one DMD digital micromirror in the fixed illumination intensity region to turn off, and obtaining a second photoresist thickness corresponding to when any one DMD digital micromirror in the fixed illumination intensity region is in a turned-off state; The first influence value is determined according to the second photoresist thickness and the first photoresist thickness.

7. The exposure control method of a direct writing lithography machine according to claim 6, characterized in that: The influence value of the DMD digital micromirror on the photoresist thickness in the effective area also includes a second influence value, and the second influence value is the influence value of the DMD digital micromirror on the photoresist thickness in the light intensity gradient area, and the second influence value is obtained by the following steps: Controlling any one DMD digital micromirror of a target row or column in the light intensity gradient region to turn off, and obtaining a third photoresist thickness corresponding to when any one DMD digital micromirror of the target row or column is in a turned-off state; The second influence value is determined according to the third photoresist thickness and the first photoresist thickness.

8. The exposure control method of a direct writing lithography machine according to claim 7, characterized in that: The illumination intensity gradient region includes multiple rows or multiple columns, and the direct-write lithography machine exposure control method further includes: Traversing each row or each column of the light intensity gradient region to obtain a plurality of third photoresist thicknesses; The second influence value is determined according to each of the third photoresist thicknesses and the first photoresist thickness.

9. The exposure control method of a direct-write lithography machine according to claim 7 or 8, characterized in that: The photoresist thickness difference value is determined by the following steps: Obtaining a photoresist thickness influence curve according to the first influence value and the second influence value; The peak value and the valley value of the photoresist thickness influence curve are determined, and the photoresist thickness difference value is the difference between the peak value and the valley value.

10. The exposure control method of a direct writing lithography machine according to claim 1, characterized in that: The uniformity compensation template is formed by the following steps: When the influence value of the target DMD digital micromirror in the effective area on the photoresist thickness is greater than the photoresist thickness difference value, adjusting the switching state of the DMD digital micromirror in the light intensity gradient area, wherein the target DMD digital micromirror is any DMD digital micromirror in the effective area; Alternatively, when the influence value of the target DMD digital micromirror in the effective area on the photoresist thickness is less than or equal to the photoresist thickness difference value, adjusting the switching state of the DMD digital micromirror in the fixed illumination intensity area; The uniformity compensation template is generated according to the adjusted state information of the DMD digital micromirrors in the fixed illumination intensity area and the gradually changing illumination intensity area.

11. An exposure control device for a direct-write lithography machine, characterized in that: include: A memory, wherein a uniformity compensation template is stored in the memory; A controller, wherein the controller is connected to the memory and is used to execute the exposure control method of the direct-write lithography machine according to any one of claims 1 to 10.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the exposure control method of the direct-write lithography machine described in any one of claims 1 to 10 is implemented.

13. A direct writing lithography machine, characterized in that: The direct-write lithography machine comprises the direct-write lithography machine exposure control device according to claim 11; Alternatively, the direct-write lithography machine comprises: A DMD digital micromirror array, an illumination system and a dimming unit, wherein the dimming unit is located on an illumination path of the illumination system to the DMD digital micromirror array, and the dimming unit is used to adjust the illumination intensity projected onto the DMD digital micromirror array, so that an effective area of ​​the DMD digital micromirror array is divided into an area with fixed illumination intensity and an area with gradually changing illumination intensity; A control system, wherein the control system is connected to the DMD digital micromirror array and the illumination system, and the control system is used to control the DMD digital micromirror array during exposure according to the direct-write lithography machine exposure control method according to any one of claims 1 to 10.

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