CN1448786A - Reticle holder and lithography exposure system that can accommodate several reticles - Google Patents

Abstract

The present invention discloses a photomask holder capable of mounting several photomasks and a lithography exposure system. A photomask holder capable of mounting several photomasks has a plurality of windows capable of mounting a plurality of photomasks to perform a lithography exposure procedure and define an exposure combination area composed of these photomasks on a wafer, wherein a fine-tuning device is provided on the side of each photomask to adjust the position and angle of the photomask when the photomask is mounted in the window so that the plurality of photomasks are completely parallel to each other. Thus, when using the lithography exposure system, the photomask holder capable of mounting several photomasks can be moved, and the photomask to be exposed can be moved under the exposure light source to perform the lithography exposure procedure and form a pattern composed of any combination of these photomasks on the surface of the wafer.

Description

Reticle holder and lithography exposure system that can accommodate several reticles

technical field

The present invention is related to a photomask holder (M) used for mounting photomasks (R) in the lithography process, in particular to a photomask holder capable of installing several photomasks (MU) at the same time, and using The photomask holder is used for a lithography exposure system for lithography exposure.

Background technique

With the continuous development of the semiconductor industry, the lithography resolution and optical control capabilities have been greatly improved, making the development and design of ultra-large integrated circuits (ULSI) continue to challenge the smaller line width. Moreover, the size of various components is also reduced to sub-micron to further increase the density of integrated circuits. However, in order to effectively increase the number of circuits on each wafer ( ) to increase the degree of circuit integration, it is often necessary to expand the size of the exposure area ( ) for the lithography process to effectively achieve the goal. For example, when a 64 Megabit DRAM memory is manufactured with a 0.35-micron line width process technology, the wafer area is about 10 mm×20 mm, and the conventional exposure area is about 22 mm×22 mm. However, when the 0.18 micron line width process technology is used to manufacture DRAM memory with 1Gigabit, the wafer area will increase to about 15 mm × 30 mm, which obviously requires a larger exposure area.

Please refer to Figure 1, which shows a step-and-repeat lithography system ( ) traditionally used for lithography procedures. Wherein, the exposure light source 12 will be incident into the projection image system (projection image system) 18 after passing through the aperture 14 and the mask 16, and then gather on the surface of the wafer 22 above the platform 20, and in the exposure area 24, define The same and reduced pattern as on the mask 16 is produced. After the first exposure is completed, the platform 20 moves along the direction of the arrow 26 to displace the wafer 22 so as to perform the second exposure process at the position adjacent to the first exposure area 24 . Then, by repeating the above steps, the desired pattern can be gradually defined on the wafer 22 . It is worth noting that since the entire exposure area 24 is irradiated in one exposure process, a larger lens needs to be installed in the projection system 18 in order to completely transmit the pattern of the mask 16 .

Please refer to Fig. 2, wherein when the exposure region 30 to be defined has an area of about 25 millimeters * 33 millimeters, the diameter of lens 35 often increases to about 44 millimeters, so that can cover whole exposure region 30 completely, in other words, in order to increase exposure The area of the area is required to meet the requirements of high-density integrated circuits. In the traditional step-and-repeat lithography system, it is often necessary to relatively increase the size of the lens to achieve the required effect. However, as the size of the lens increases, it is easy to cause the exposed image when defining the pattern, resulting in problems such as distortion, deformation, and aberration. Moreover, since the entire exposure area is irradiated in one exposure, when the wafer has a surface with very large step differences, it will also make it more difficult to adjust the depth of focus.

In order to overcome the problems of the step-and-repeat lithography system 10 , in current semiconductor manufacturing processes, a step-and-scan lithography system 40 as shown in FIG. 3 is often used to perform related lithography processes. Wherein, the exposure light source 42 will irradiate on the grating 44, and pass through the slit 46 on the grating 44, transmit the light beam of the strip-shaped block to the mask 48, and then pass through the focusing effect of the projection system 50, so as to define the corresponding The miniature pattern 52 is on the surface of the wafer 54 . Then, the photomask support 56 that is used to install the photomask 48 will move along the scanning direction of the arrow 58, and the platform 60 that is used to carry the wafer 54 will also move along the direction of the arrow 62 at the same time, and then carry out the next time The exposure program is used to gradually define the exposure area on the wafer 54 through sequential exposure operations. In other words, when using the step-scan lithography system 40 to carry out the exposure process, instead of completing the irradiation of the entire exposure area in one exposure process, the entire exposure area is divided into several strip-shaped areas, and then The linear light source scans the mask 48 sequentially to define the pattern of the entire exposure area segment by segment.

In this way, in each exposure process, the linear light source passing through the slit 46 will only irradiate a part of the strip-shaped area on the mask 48, and through the projection system 50, on the surface of the wafer 54 Define a strip-shaped partial pattern. Therefore, the lenses in the projection system 50 do not suffer from the aforementioned problems of the step-and-repeat lithography system 10 when the area of the exposure area is increased. With reference to shown in Figure 4, wherein when the area product (25 millimeters * 33 millimeters) of whole exposure area 70 is identical with the example in Figure 2, the lens 75 that uses only needs to have the diameter of about 26 millimeters, just can carry out effectively required lithography process. At this time, the exposure operation performed through the slit 46 will generate the slit exposure area 76 through the lens 75 . Then, after the relative movement of the mask 48 and the wafer 54 occurs, the exposure procedure can be performed again, and the entire exposure area 70 is defined frame by frame along the direction of the arrow 78 .

In other words, by using the step-and-scan lithography system 40 to define the pattern of the entire exposure area in a segmented manner, it is indeed possible to solve the limitation of the expansion of the exposure area of the conventional step-and-repeat lithography system 10 . However, it should be specially noted that the current typical photomask is often designed to be 6 inches (about 152 mm) square. Therefore, although the step-scan lithography system can meet the requirement of increasing the area of the exposure area, the size of the exposure area is still limited due to the limitation of the size of the mask.

In particular, in the current semiconductor manufacturing process, if you want to change the design of the photomask specification, you may have to completely replace all the equipment and structures for photomask production. In addition to increasing the consumption of funds, it may also make the entire process more complicated. . Wherein, in order to increase the area of the exposure area, a mask with a larger size is manufactured, which not only tends to generate more defects, but also has a relatively non-uniform absolute dimension (CD). Moreover, since a larger size photomask will accommodate more patterns, the possible position errors (larger placement errors) between these patterns may also cause the low yield rate of the exposed patterns.

Moreover, whether it is the aforementioned step-and-repeat lithography system or the step-and-scan lithography system, the exposure operation is performed on a single mask, which greatly increases the time of the entire lithography process. For example, when multiple exposures are required, the first mask will be installed on the mask holder first, and then the exposure procedure will be performed after the positioning is completed. Then, after the first photomask exposure operation is completed, the first photomask is removed, and the second photomask is installed at the same time, and repeated exposure is performed on the same position of the wafer.

But in this way, unnecessary time will be consumed when replacing the previously used photomask, or the positioning procedure after the photomask is installed, and the output of the overall production capacity will be reduced. In addition, in addition to the need to replace the photomask in the above-mentioned repeated exposure process, when the pattern on the entire wafer is composed of several photomasks, the photomask needs to be replaced continuously to perform the required lithography procedures. Therefore, how to reduce the time spent on changing the mask so as to increase the wafer productivity of the entire lithography process has become an extremely important issue at present.

Contents of the invention

The main purpose of the present invention is to provide a photomask support that can install several photomasks, and a plurality of photomasks can be installed on it at the same time, and several photomasks can be installed by moving it under the exposure light source The mask holder and the wafer position are moved at the same time, so that different mask patterns can be defined on the surface of the crystal map in the same lithography exposure process.

Another object of the present invention is to provide a lithography exposure system including a mask holder capable of mounting several masks, so as to define the pattern of the mask on the wafer.

The invention provides a photomask holder capable of installing several photomasks, and has a plurality of windows on it, which can be used to install a plurality of photomasks for lithography exposure procedure. On the side of each photomask, there is a fine-tuning device, which can adjust the position and angle of the photomask when the photomask is installed in the window, so that the plurality of photomasks are completely parallel to each other. In this way, when using the lithography exposure system, the mask holder that can accommodate several masks can be moved, and the mask to be exposed is moved to the bottom of the exposure light source to perform the lithography exposure process, while on the surface of the wafer , forming a pattern composed of any combination of these masks.

In a preferred embodiment, the exposure light source of the lithography exposure system can be used to create the parallel beam required for the lithography process, and the exposure beam can be irradiated on the mask holder that can accommodate several masks . In addition, the photomask holder capable of installing several photomasks can move in the plane, so that different photomasks pass directly under the exposure light source successively, so as to define the patterns of these photomasks on the crystal surface in sequence. In order to precisely adjust the position and moving distance of the photomask holder which can accommodate several photomasks, a laser interferometer can be used for measurement. In this way, the exposure beam that penetrates the mask holder that can accommodate several masks will project the lithographic exposure beam on the surface of the wafer after passing through the lower lens group, and define corresponding picture of. At the same time, by controlling the platform used to carry the wafer, it can be moved corresponding to the position of the photomask holder that can accommodate several photomasks, so that the patterns of a plurality of different photomasks can be sequentially defined on the photomask corresponding position on the wafer.

The present invention also provides a lithography exposure system, which can define the pattern of the mask on the wafer. The lithography exposure system at least includes: The photomask bracket of a block photomask has a plurality of windows for installing a plurality of photomasks, wherein there is a fine-tuning device on the side of the photomask, which can be adjusted when the photomask is installed in the window The position and angle of the photomask, so that the plurality of photomasks are completely parallel to each other, and the photomask holder can move in the plane, so that different photomasks pass directly under the exposure light source one by one to define in sequence The pattern of the photomask is on the surface of the wafer; the laser interferometer is used to measure the position and moving distance of the photomask holder that can install several photomasks, so that the operator can precisely control the number of photomasks that can be installed. The movement of the mask holder of a mask; the projection system is located under the mask holder that can accommodate several masks, and is used to transmit and reduce the exposure beam passing through the mask, and project the reduced exposure beam On the surface of the wafer, a corresponding pattern is defined; and the platform, used to carry the wafer, can move corresponding to the position of the photomask holder that can install several photomasks, so that the plurality of photomasks The pattern of the photomask is exposed to the corresponding position on the wafer by lithography.

The use of the photomask holder and lithography exposure system which can accommodate several photomasks of the present invention has quite a lot of advantages. First of all, since the mask holder capable of installing several masks can simultaneously install several masks, after the initial fine-tuning is completed, all the masks can be arranged completely parallel and fixed. In this way, in the subsequent scanning exposure process, no matter what the pattern required on the surface of the crystal map is, the required scanning can be performed through the corresponding photomask on the photomask holder that can accommodate several photomasks Exposure procedures without the need to spend a lot of time changing the mask or positioning. Moreover, with the help of the positioning mirror on the mask holder that can accommodate several masks, the laser interferometer can accurately measure the moving distance and position of the mask holder that can install several masks, so that it can be According to the pattern requirements on the wafer, the corresponding mask is moved to perform the scanning exposure operation. In this way, the wafer production capacity in the lithography process can be greatly increased.

In contrast, when traditionally using a single mask for scanning exposure procedures, the mask holder is often removed and the next mask is replaced after the scanning exposure of the entire batch of wafers is completed, and then the wafers in the batch are re-installed. The first wafer is fixed on the platform by chucking, and the pattern definition of this mask is performed. Obviously, using this method to define the pattern on the wafer, every time the mask is replaced, the wafer needs to be re-adsorbed and positioned, and the accumulated errors during the process will often reduce the efficiency of the overall lithography process. yield. But when utilizing the photomask support that can install several photomasks of the present invention, owing to can follow the demand of pattern, carry out required lithographic exposure procedure to wafer surface at any time, therefore can be in whole wafer After the surface pattern is defined, the next wafer is replaced. In this way, the entire wafer only needs to be sucked and positioned once from the beginning to the end, and the error that may occur in this part can be minimized.

In addition, as mentioned above, since the position of the mask in the window can be moved, the width W of the window interval can be further reduced when manufacturing a mask holder capable of mounting several masks. In this way, the exposure area on the wafer can be expanded to achieve the purpose of fully utilizing the surface space of the wafer. Alternatively, by adjusting the moving speed of the wafer when the strip light source scans across the window interval, the interval in the exposure area can be greatly reduced, and even the exposure areas defined by different masks can be aligned on the wafer. directly connected together.

Description of drawings

1 is a cross-sectional view of the structure of a lithography exposure system, showing the situation of step-and-repeat lithography exposure using a single mask holder according to the conventional technology;

Fig. 2 is a top view of the projection lens, showing the proportional relationship between the exposure area and the projection lens when the step-and-repeat lithography exposure system is applied;

3 is a cross-sectional view of the structure of the lithography exposure system, showing the situation of step-scan lithography exposure using a single mask holder according to the conventional technology;

Fig. 4 is a top view of the projection lens, showing the proportional relationship between the exposure area and the projection lens when the step-scan lithography exposure system is applied;

5 is a top view of a photomask holder capable of accommodating several photomasks, showing a photomask holder capable of accommodating a plurality of photomasks according to the present invention;

6 is a structural cross-sectional view of a lithography exposure system, showing the situation of step-scan lithography exposure using a mask holder capable of accommodating several masks according to the technology of the present invention;

7 is a top view of a photomask holder capable of mounting several photomasks, showing the situation of using a laser interferometer to measure the position and moving distance of the photomask holder capable of mounting several photomasks;

FIG. 8 is a top view of a wafer, showing the use of a photomask holder capable of holding several photomasks to define an exposure bonding area composed of several photomask patterns on the crystal surface in the same scanning exposure process;

FIG. 9 is a top view of a wafer, showing the use of a photomask holder capable of mounting several photomasks to define an exposure bonding area composed of several photomask patterns on the wafer surface;

FIG. 10 is a top view of the mask, showing the area relationship between the scanning area and a single mask;

Fig. 11 is a top view of the double mask holder, showing the situation of installing the mask on the double mask holder;

FIG. 12 is a top view of the triple mask holder, showing the arrangement of the mask when installed on the triple mask holder;

Figure 13 is a top view of a wafer, showing that a mask is used to cover part of the mask pattern when a mask holder that can hold several masks is used for the scanning exposure process, and in the same exposure area, defined by several photomasks The relevant conditions of the exposure bonding area composed of the mask pattern;

FIG. 14 is a top view of a wafer, showing that when a scanning exposure process is performed using a mask holder capable of holding several masks, a double exposure process is performed on the same exposure area on the wafer surface.

Detailed ways

The invention provides a photomask holder capable of installing several photomasks. The photomask holder which can install several photomasks has a plurality of windows, and a plurality of photomasks can be installed on it at the same time to carry out the lithography exposure process, and define the pattern formed by these photomasks on the wafer. Exposure pattern. There is a fine-adjustment device on the side of each photomask, which can adjust the position and angle of the photomask when the photomask is installed in the window, so that the plurality of photomasks are completely parallel to each other. In addition, positioning mirrors are installed on the corners of the mask holder where several masks can be installed, so that the laser interferometer can be used to control the photomasks where several masks can be installed. The position and movement distance of the cover bracket. In this way, when using the lithography exposure system, the photomask to be exposed can be moved to the bottom of the exposure light source by moving the photomask holder which can hold several photomasks, and the photolithography exposure process is carried out on the surface of the wafer. , forming a pattern composed of these reticles. A detailed description of the present invention is as follows.

Please refer to FIG. 5 , which shows a multiple-reticle holder 100 provided by the present invention and capable of accommodating several reticles. The photomask holder 100, which can accommodate several photomasks, has a plurality of windows for installing photomasks to be exposed. Taking the mask holder 100 as an example, since it has six windows, six masks (mask 1 to mask 6 ) can be installed at the same time. And, for each photomask, there is a corresponding fine-tuning device (manipulator) 102 on its side, after the photomask is installed on the photomask holder 100 that can install several pieces of photomasks, adjust the position of the photomask. Fine-tune the position. Generally speaking, after the photomask is mounted to the corresponding window, the fine-tuning device 102 can be controlled to make the photomask on the plane of the photomask holder 100 on which several photomasks can be mounted, along the x-axis or y-axis. Axis movement, or a slight rotation along the θ angle, to adjust to an appropriate position or angle. That is, by controlling the trimming device 102, the mask in the window can be adjusted to a proper position. In this way, by manipulating the fine-tuning device 102 of the masks 1 to 6, all the masks can be arranged in a completely parallel manner.

It should be particularly noted that although for each mask, it has a degree of freedom to move along the x-axis, y-axis, or θ angle. However, in practical applications, the above three degrees of freedom may not necessarily need to be adjusted for each mask. Take the mask holder that can hold two masks as an example, one of the masks only needs to be moved and adjusted along the θ angle, and the other mask can be fine-tuned in three degrees of freedom at the same time, so that the two masks achieve full parallelism.

In addition, for each mask, the number and position of the trimming devices 102 installed on the side are not the same. Taking the photomask 6 in FIG. 5 as an example, since it is arranged on the edge of the whole group of photomasks (1 to 6), the trimming device 102 can be installed on its three sides 104 . Generally speaking, it is only necessary to select any side 104 to install the microsilk device 102, so that the photomask 6 can be fine-tuned in three degrees of freedom. Of course, under the requirements of the manufacturing process or other considerations, the fine-tuning device 102 may also be installed on two sides or three sides of the photomask 6 at the same time. As for the photomask 5 located in the middle of the entire group of photomasks (1 to 6), since its two sides along the y-axis direction are respectively adjacent to the photomask 4 and the photomask 6, it is not suitable for use. To install the fine-tuning device. Therefore, the trimming device 102 can only be installed on the upper and lower sides 106 of the photomask 5 along the scanning direction (X-axis).

In this way, when the six masks (1 to 6) are installed on the mask holder 100 which can hold several masks, the step-scan lithography system can be used to perform the exposure process. Please refer to FIG. 6 , where the exposure light source 142 forms a strip-shaped light source after passing through the slit 146 on the grating 144 , and irradiates on the mask holder 100 that can hold several masks. After the strip-shaped light source scans part of the mask 1 , part of the pattern illuminated by the light can be transmitted to the corresponding exposure area 152 on the wafer 154 through the projection system 150 . Then, same as above, the mask holder 100 that can accommodate several masks will move a distance along the scanning direction of the X axis after each exposure process, and the wafer 154 carried by the platform 160 will also move It will move a distance in the corresponding direction for the next exposure procedure. In this way, all the patterns of the mask 1 can be transferred to the surface of the wafer 154 in a scanning manner one by one.

After the pattern of the photomask 1 has been completely scanned and its pattern has been defined on the surface of the wafer 154, the photomask support 100 that can accommodate several photomasks can continue to move along the direction of the X axis, and then the photomask 2 Carry out scanning exposure procedure. Or when there are other needs or considerations in the whole lithography process, the mask holder 1000 that can hold several masks can be controlled to move along the X-axis and the Y-axis, so as to move the next part of the exposure process A photomask is moved under the slit 146 . For example, after scanning the pattern of reticle 1, if the reticle 6 is to be scanned next, the reticle holder 100, which can accommodate several reticles, will move along the x-axis and y-axis, so that the reticle 6 is located directly below the slit 146 for scanning exposure procedures. Among them, in order to accurately control the moving distance and position when moving the photomask holder 100 that can accommodate several photomasks, the relevant distance can be measured and adjusted by using a laser interferometer. The position of the photomask holder 100 where several photomasks can be installed.

Referring to FIG. 7 , the light beam emitted by the laser 110 will generate transmitted light and reflected light respectively after passing through the lens 112 . Wherein, after the transmitted light is irradiated to the reference mirror 114 , it will be reflected so that the light beam returns to the lens 112 and gathers on the sensor 116 . At the same time, the reflected light generated by the lens 112 will irradiate the positioning mirror 118 on the corner of the multiple mask holder 100 to generate reflection, and the reflected light beam will also gather on the sensor 116 after passing through the lens 112 . In this way, by analyzing the waveform difference of the two reflected light beams from the reference mirror 114 and the positioning mirror 118 , the moving distance of the mask holder 100 which can hold several masks along the x-axis or y-axis can be determined.

Generally speaking, when the beam generated by the laser 110, as shown in the figure, is irradiated to the positioning mirror 118 on the side of the X-axis of the mask holder 100, which can accommodate several masks, it can be used to measure The distance that the mask holder 100 that can hold several masks moves along the y-axis. Similarly, with the erection of another lens group (not shown in the figure), another sensor can be detected by the other side of the mask holder 100 (along the y-axis direction) on which several masks can be installed. ) reflected light beams generated by the positioning mirror 120. In this way, the moving distance of the mask holder 100 which can hold several masks along the X-axis can be measured. For the mask holder 100 that can accommodate several masks, the operator can effectively and accurately grasp the movement along the X-axis or the Y-axis. Therefore, during the relevant lithography process, the mask to be subjected to the exposure process can be moved to the lower part of the slit 146 by controlling the movement of the mask holder 100 which can hold several masks.

It should be pointed out that when the photomask is installed on the photomask holder 100 which can hold several photomasks, the fine adjustment device 102 is used to make each photomask align with each other and maintain a parallel relationship. Therefore, in the actual exposure process, when the first mask exposure scanning has been completed, and then the second mask is to be exposed and scanned, it is not necessary to align the first mask. Actions. In other words, when the photomask is installed on the photomask holder 100 which can hold several photomasks, since each photomask is completely aligned with each other and appears completely parallel, as long as the scanning exposure of the first photomask is performed, , the alignment action is performed for the first mask, which can be regarded as the completion of the pre-alignment of each mask at the same time. Therefore, it is only necessary to move the photomask holder 100 which can hold several photomasks by means of the laser interferometer, so that the next photomask to be exposed is moved directly below the slit 146, and the exposure scanning process can be directly carried out. , without the need to perform alignment actions for this mask.

In this way, in the present invention, the time it takes to replace a photomask to be scanned and exposed is actually only to move the photomask holder 100 that can accommodate several photomasks, so that the next photomask is positioned at the strip-shaped light source. The time spent below is just that. In contrast, the traditional step-and-scan exposure procedure requires removing the entire mask holder, then taking out the exposed mask, installing the next mask to be scanned, and moving the mask holder into the , and perform the positioning procedure again, and complete the preparation before the scanning exposure. Obviously, the time of the entire lithography process will be greatly lengthened, and the output of the overall production capacity will be reduced. Moreover, for each photomask to be scanned and exposed, because a positioning action needs to be performed again, it is easy to cause additional alignment errors, thereby reducing the yield of the overall lithography process.

Generally speaking, when using the photomask holder 100 of the present invention that can accommodate several photomasks to perform scanning exposure, several adjacent photomasks can be scanned in sequence along the scanning direction (X axis), and in A larger exposed composite field is created on wafer 154 . Alternatively, a corresponding exposure area is formed on the wafer 154 by performing scanning exposure on a single mask. Please refer to FIG. 8 , in which when using a mask holder 100 that can hold several masks for exposure, the scanning exposure can be performed sequentially along the scanning direction for mask 1, mask 2, and mask 3. . Since the exposure sequence of these masks is just in line with the moving direction of the mask holder 100 that can accommodate several masks, it is switched without additional movement of the mask holder 100 that can accommodate several masks. After the scanning exposure of the mask 1 is completed, the scanning exposure of the mask 2 can be performed. Similarly, after the scanning exposure of the mask 2 is completed, the scanning exposure of the mask 3 is performed along the way. In this way, the exposure bonding area including the patterns of the mask 1 , the mask 2 and the mask 3 can be directly defined on the wafer 154 .

Therefore, as shown in FIG. 8, by sequentially scanning masks 1, 2, and 3, in the same scanning exposure process, along the surface of the wafer 154, the areas including mask 1 can be defined sequentially. , The exposed combined area of the pattern of the photomask 2 and the photomask 3 . Wherein, the arrows crossing the exposure areas 1, 2, and 3 indicate that these three areas are defined in the same step-scan exposure procedure. Generally speaking, the scanning exposure combined with the masks 1 to 3 is not limited to start from the first column or the first row on the wafer 154, but can start from any position on the wafer 154 as the process requires. conduct. In this figure, it is shown that the exposure bonding regions are defined successively from the outermost side of the wafer 154 toward the right. As for the part areas of the second to seventh columns and the seventh to eighth rows on the wafer 154, since the exposure area combining three photomasks cannot be accommodated, it is only for the photomasks 1 and 2. Scanning the exposure program to generate a combination of exposures including areas 1,2.

Please refer to FIG. 9 , which shows the scan pattern generated by combining the six masks and the related step-scan pattern as required by the process. Among them, according to the exposure bonding area defined on the wafer 154, it can be divided into the step-scan exposure process combined with the mask 1, 2, 3, and the step-scan exposure process combined with the mask 4, 5. There is a scanning exposure process, and there is also a step-and-scan exposure process using the mask 6 alone. Moreover, as mentioned above, since the scanning exposure process combining several masks is performed by using the mask holder 100 which can accommodate several masks, it has the ability to quickly switch the mask for scanning exposure. Therefore, even if the above-mentioned three different exposure regions are distributed very irregularly, after using the mask holder 100 of the present invention, which can accommodate several masks, it is still possible to quickly place a mask at the corresponding position on the wafer 154. , defining the desired pattern.

Generally speaking, when using a step-scan lithography system to scan and expose a mask, if the distance scanned by the strip light source through the slit is 9 inches, and the long strip light source (slot) of the slit has With a length of 6 inches, the entire scan field will have an area of 9 inches by 6 inches. If the above-mentioned scanning area is performed using a single mask, the mask is often made larger than the scanned area. Please refer to FIG. 10 , wherein if the actual scanning area 200 is 9 inches x 5 inches, the manufactured photomask 202 needs to be larger than the actual scanning area 200, so that when the photomask 202 is installed on the photomask holder, Provides a bounding area that borders the bracket. Therefore, the area of the entire photomask 202 is about (9-a) inches×(6-a) inches, and the part of the width a is used as a border area. When the photomask 202 is installed on the photomask holder in a uniform and symmetrical manner, as shown in the figure, each side of the photomask 202 has a border portion of about 1/2a bordering on the photomask holder . In other words, the parameter a here represents the total width of the boundary area on the mask. In general, the boundary area (1/2a) of each side of the photomask 202 in the figure is about 5 millimeters, so considering that the total boundary area of the whole photomask 202 on the x-axis or y-axis is about 10 mm. mm (width a).

Please refer to FIG. 11 , which shows the scope of the scan field of a mask holder that can hold two masks and can hold several masks when performing a step-and-scan exposure process. As mentioned above, on the double-reticle holder 210, two windows are formed for carrying and installing the reticle 1 and 2 to be scanned and exposed. Wherein, since the reticle 1 and the reticle 2 respectively have a border with a width of about a, so as to border on the reticle holder 210 . Therefore, for the mask 1 and 2, the actual size will be the same as the dotted square in the figure. When the photomask 1 and the photomask 2 are installed symmetrically with respect to the window, for each photomask, the border portion of each side thereof has a width of approximately 1/2a. In other words, the width W of the spacer between the two windows is approximately equal to a, so as to provide enough space for the border between the masks 1 and 2 . In this way, when the size of each mask is about 6 inches x 6 inches, when the step-scan lithography system is used for scanning exposure, the actual scanning area includes two windows and the window interval, It is about (6-a) inches x (12-a) inches.

Of course, in order to reduce the distance W between the windows, we can try to shift the two masks to the left and right sides. For example, photomask 1 can move toward the left position, while photomask 2 can move toward the right position, so that the two photomasks will occupy less space in the boundary area of the central part of the support, and the distance between them can be reduced. W can effectively shrink. In a preferred embodiment, the spacing distance W can be controlled between 0.1 mm and 5 mm. However, it should be pointed out that, when designing the window spacing of a mask holder that can hold several masks, it is necessary to consider the possible rotation space when the mask is fine-tuned in the window.

Please refer to FIG. 12 again, which shows the range of the actual scanning area when a triple-reticle holder 220 is used to perform a step-and-scan exposure process. As mentioned above, the mask 1 can be moved to the right as much as possible, and the mask 3 can be moved to the left as much as possible. In this way, for the mask 1, the boundary area on the left side is about a, while the boundary area on the right side is close to 0. Similarly, for mask 3, the boundary area on the right side is about a, while the boundary area on the left side is close to 0. In other words, for the photomask 2 located in the center, the window spacing on the left and right sides of the photomask 2 can be used by the border area of the photomask 2 . Therefore, at this time, the distance W between the windows is about 1/2a, and three photomasks (1 to 3) can be installed on the support at the same time. In this case, when the size of each photomask is 6 inches x 6 inches, its actual scanning area includes the mask area exposed by the three windows and the window spacing between the three windows, which is approximately It is about (6-a) inches x (18-2a) inches.

Because the photomask support provided by the present invention can be equipped with several photomasks has the ability of rapid positioning, even if the number of photomasks that need to be exposed is very large, and the pattern arrangement on the surface of the wafer is very complicated, However, it is still possible to quickly complete the required lithography exposure process by using a mask holder that can hold several masks. Please refer to FIG. 13, where when the process needs to define the patterns of six different reticles in an extremely irregular manner on the surface of the wafer 154, since the reticle holder that can accommodate several reticles can place six reticles at the same time. There is a photomask on it, so compared with the traditional exposure process of a single photomask, the device and method of the present invention do not need to remove the photomask holder to replace another photomask after scanning and exposing one photomask. The reticle to be scanned. In other words, even when the entire batch of wafers has different pattern distributions, the pattern requirements of each wafer can be adjusted according to the pattern requirements of each wafer by virtue of the rapid positioning capability of the mask holder that can accommodate several masks. Related scan exposure actions.

In addition, when the manufacturing process requires, partial patterns of several different photomasks can be defined in the same exposure area on the wafer 154 by using a mask to block part of the photomask, and These partial patterns are used to form the entire pattern in the exposed area. As shown in the exposure area of the third row and the second column, by using the mask to cover (masked off) part of the mask, the part of mask 1, mask 2, and mask 4 can be defined one by one. Part of the pattern, and combined into the required exposure pattern in the same exposure area, where the upper left corner of this exposure area defines a part of the pattern of the mask 4, and the upper right part of the area defines the mask 2, the area in the lower left corner defines a part of the pattern of mask 1, and the area in the lower right corner does not define any pattern in the scanning operation.

In addition, when different photomasks are combined to perform the step-scan process, the exposure combination areas in the fourth column and the third to fifth rows in the figure can be generated. The block exposure combination area is composed of partial scanning areas of masks 1 to 3 and partial scanning areas of masks 4 to 6 . Among them, two scanning exposure procedures can be used to define the exposure joint area in the figure or, the first scanning exposure procedure scans the reticle 1, 2 and 3 in sequence, and in the case of masking, the The upper half of the entire exposed bonding area forms a pattern composed of partial masks 1 , 2 and 3 . Then, carry out the scanning exposure process for the second time, to scan the masks 4, 5 and 6 successively, and in the case of using a mask for shielding, a part of the mask 4 is formed in the lower half of the exposure combination area. , The pattern formed by 5 and 6.

Please refer to FIG. 14 , which shows the situation of double exposure using a mask holder that can hold several masks. Among them, the masks 1 and 2, the masks 3 and 4, and the masks 5 and 6 are respectively combined to perform a double scanning exposure operation. Taking the double exposure combining mask 1 and 2 as an example, the mask 1 can be scanned first to define the pattern of the mask 1 in the selected exposure area, and then the mask holder can be equipped with several masks quickly The positioning function scans the mask 2 to perform the second scanning exposure in the same exposure area. Similarly, by using this method, the double exposure areas of the masks 3 and 4 and the double exposure areas combined with the masks 5 and 6 can be defined on the wafer 154 one by one. Of course, when required by the manufacturing process, three different masks can be used to perform a triple exposure process for the same exposure area on the wafer 154 . Or use more different masks to perform multiple exposures in the same exposure area.

In addition, it should be particularly noted that, as described above, since the part of the window interval (width about W) of the mask holder that can accommodate several masks is not transparent, so referring to FIG. 6, scanning exposure In the procedure, the portion of the bracket window spacer 101 will generate an unexposed spacer area on the wafer. As shown in FIG. 8 , although the masks 1 to 3 are in the same scanning exposure process, the patterns of the three masks are defined one by one in the corresponding exposure areas on the wafer 154 . However, in this exposed area, the spaced area caused by the bracket window spacing can still be seen.

To further reduce the width of the gap area on the wafer 154 or completely eliminate it, the moving speed of the wafer 154 can be reduced or even stopped before the step-and-scan system scans the mask 1 . After the step-and-scan system finishes scanning the frame window interval between the mask 1 and the mask 2, the wafer 154 is restored to the original moving speed. At this time, the pattern of the mask 2 can be scanned, and the space between the exposure area 1 and the exposure area 2 on the wafer 154 can be greatly reduced in width, and even the exposure area 1 can be directly connected to the exposure area 2 .

Although the present invention has been described above with a preferred example, it is not intended to limit the spirit and entity of the present invention, and is only limited to this example. For example, although the relevant operation of the step-scan lithography system is used in the present invention, the design and related manufacturing process of a photomask holder capable of accommodating several photomasks is described. However, those skilled in this field can easily understand that the application of the mask holder capable of mounting several masks can also be extended to related operations of the step-and-repeat lithography system. Wherein, since the step-and-repeat lithography exposure is one exposure, the pattern of the entire mask is defined in the exposure area on the wafer surface. Therefore, when applying the photomask holder capable of installing several photomasks of the present invention, it is also possible to control the installation of several photomasks by the positioning function of the laser interferometer after the exposure of the first photomask is completed. The movement of the mask holder makes the next mask to be exposed move to directly below the exposure light source. Then, the lithography exposure procedure can be performed on the second photomask. At the same time, by controlling the movement of the platform, the relative displacement of the wafer can be generated. In this way, the pattern of the second mask can be defined in the corresponding area on the wafer as required. Apparently, the above conveniences and advantages can also be achieved when a mask holder capable of holding several masks is used in a step-and-repeat lithography exposure system. Therefore, modifications made without departing from the spirit and scope of the present invention shall be included in the scope of claims of the present application.

Claims (18)

1, a kind of light shield support of installing the several piece light shield, have a plurality of windows, in order to install a plurality of light shields, so that carry out little shadow exposure program, can on wafer, define, wherein on the side of each this light shield, have micromatic setting by the exposing patterns that this a plurality of light shield made up, can be when this light shield of installing be in this window, adjust the position and the angle of this light shield, and make these a plurality of light shields parallel completely to each other.

2, the light shield support of installing the several piece light shield as claimed in claim 1, it is characterized in that: above-mentioned light shield support, can be applicable to stepping-scanning microlithography system, and in same scan exposure program once, scan a plurality of these light shields in regular turn, and define the exposure calmodulin binding domain CaM of forming by this a plurality of this mask pattern at this crystal column surface.

3, the light shield support of installing the several piece light shield as claimed in claim 1, it is characterized in that: above-mentioned light shield support can move on the plane at this a plurality of light shields place, and make this different light shields below by exposure light source one by one, and with the design transfer of this light shield to this crystal column surface.

4, the light shield support of installing the several piece light shield as claimed in claim 3, it is characterized in that: on the corner of above-mentioned light shield support, have at least one positioning mirror, can reflect the thunder laser beam of laser interferometer, and measure distance and the position that this multiple mask moves accurately.

5, the light shield support of installing the several piece light shield as claimed in claim 4, it is characterized in that: above-mentioned light shield support is on left and right two corners of the side of X-axis, can install first positioning mirror respectively, so that this light shield support is along the y axle when mobile, the laser interferometer can be by the folded light beam of this first positioning mirror, and measures the displacement and the position of this multiple mask.

6, the light shield support of installing the several piece light shield as claimed in claim 5, it is characterized in that: at above-mentioned light shield support along the side of y axle on upper and lower two corners, can install second positioning mirror respectively, so that this light shield support is when X-axis moves, the laser interferometer can be by the folded light beam of this second positioning mirror, and measures the displacement and the position of this multiple mask.

7, the light shield support of installing the several piece light shield as claimed in claim 3, it is characterized in that: above-mentioned light shield support can move along the direction of scanning of stepping-scanning microlithography system, and make this different light shields one by one pass through this exposure light source below, so that, define this different mask pattern in regular turn on this crystal column surface with in stepping-scanning sequence once.

8, the light shield support of installing the several piece light shield as claimed in claim 1, it is characterized in that: above-mentioned micromatic setting can be used to control this light shield that is installed in this light shield support window that can install the several piece light shield, this light shield is moved along the X-axis or the y axle on plane, place, or rotate with the θ angle.

9, the light shield support of installing the several piece light shield as claimed in claim 1 is characterized in that: above-mentioned light shield support can be spaced from each other with about 0.1 to 5mm the window interval of width along between this window of X-direction arrangement.

10, a kind of little shadow exposure system can define the pattern of light shield on wafer, this little shadow exposure system comprises at least:

Exposure light source can produce and carry out the required parallel beam of little shadow program;

Can install the light shield support of several piece light shield, have a plurality of windows, in order to install a plurality of light shields, wherein on the side of this light shield, have micromatic setting, can when this light shield of installing is in this window, adjust the position and the angle of this light shield, and make these a plurality of light shields parallel completely to each other, and this light shield support can move in the plane, place, and makes this different light shields one by one by under this exposure light source, with the pattern that defines this light shield in regular turn on this crystal column surface;

The laser interferometer is in order to measure position and the displacement that this can install the light shield support of several piece light shield, so that the operator can accurately control moving of this light shield support that can install the several piece light shield;

Optical projection system is positioned at this light shield support that can install several piece light shield below, and in order to transmitting and to dwindle exposing light beam through this light shield, and the exposing light beam after will dwindling is projeced on this crystal column surface, and defines corresponding pattern; And

Platform, in order to carrying this wafer, can corresponding to this can install the several piece light shield the light shield support the position and move so that make the pattern of these a plurality of light shields, little shadow is exposed to position corresponding on this wafer.

11, little shadow exposure system as claimed in claim 10, it is characterized in that: above-mentioned little shadow exposure system is stepping-scanning microlithography system, when this light shield of desiring to carry out little shadow exposure, when being positioned under this exposure light source, by the strip light source that this exposure light source produced, mode that can fractional scanning, scanned whole this light shield one by one, and, be defined in this crystal column surface with the pattern of this light shield.

12, little shadow exposure system as claimed in claim 11, it is characterized in that: but nationality mobile this and can be installed the light shield support of several piece light shield, and in regular turn this different light shields is carried out stepping-scanning, and in same scan exposure program once, definition has comprised that the exposure calmodulin binding domain CaM of a plurality of these mask pattern is in this crystal column surface.

13, little shadow exposure system as claimed in claim 12, it is characterized in that: can be successively to several this light shields, carry out stepping-scanning sequence first time, and on this crystalline substance figure surface the definition comprise these several mask pattern first the exposure calmodulin binding domain CaM, then move this again and can install the light shield support of several piece light shield, so that, carry out stepping-scanning sequence second time, so that on this crystal column surface, define the second exposure calmodulin binding domain CaM that comprises these several mask pattern to other several these light shields.

14, little shadow exposure system as claimed in claim 10, it is characterized in that: above-mentioned little shadow exposure system is stepping-heavily a cover microlithography system, when this light shield of desiring to carry out little shadow exposure, when being positioned under this exposure light source, by light source that this exposure light source produces, the pattern of this light shield can be defined in this crystal column surface.

15, little shadow exposure system as claimed in claim 14, it is characterized in that: after this light shield is finished exposure program, this the light shield support that can install the several piece light shield can move so that this light shield that the next one will be exposed, move to this exposure light source under.

16, little shadow exposure system as claimed in claim 10, it is characterized in that: on the corner of the above-mentioned light shield support of installing the several piece light shield, has at least one positioning mirror, can reflect the thunder laser beam of laser interferometer, and nationality an inductor and detects by this positioning mirror beam reflected, the distance and the position of moving with this multiple mask of accurate measurement.

17, little shadow exposure system as claimed in claim 10, it is characterized in that: above-mentioned micromatic setting can be used to control this light shield that is installed in this light shield support window that can install the several piece light shield, this light shield is moved along the X-axis or the y axle on plane, place, or rotate with the θ angle.

18, little shadow exposure system as claimed in claim 10 is characterized in that: above-mentioned little shadow exposure system more comprises a shade, can cover partly this light shield, and define required part pattern on this crystal column surface when light shield be carried out little shadow exposure program.

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