JPH10270342A - Device and method for manufacturing semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of reproducing treatment by quickly detecting a printing trouble which occurs during exposure by providing a means which again measures the position of a sample shot after exposure and discriminates the defectless/defective state of the exposure, based on the measured results. SOLUTION: In the figure, S1x-S4x and S1y-S4y indicate the positions of sample shot marks, respectively. In this embodiment, arrangement abnormality caused by a trouble which occurs during exposure is detected by executing a step of finding correction coordinates for alignment as they are immediately after printing. In an alignment process, such correction coordinates of a whole wafer that make the deviation between the designed positions of alignment marks for measuring positional coordinates preset on the wafer and the actual positions of the marks the minimum are found and printing of each shot is performed in accordance with the correction coordinates. Consequently, the presence/absence of the trouble can be detected during exposure from measurement results obtained after exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-and-repeat type exposure apparatus for sequentially printing a plurality of regions on a substrate on a wafer, and an exposure method using the apparatus.

[0002]

2. Description of the Related Art In the manufacture of a semiconductor chip to be subjected to overlay exposure, it is necessary to accurately align a plurality of circuit patterns and perform printing. For this reason, a plurality of alignment patterns previously provided on a wafer are required. Correction coordinates for printing are obtained from the position information of the mark for use (alignment mark), and actual printing is performed according to the correction coordinates.

Hereinafter, a conventional semiconductor exposure process will be described with reference to a flowchart of FIG. First, in step s1, a wafer is loaded and set on a wafer stage. Next, in step s2, the position is moved to the alignment mark position to be measured first, and in step s3,
Measure the position of the mark.

Next, the process proceeds to step s4, where it is determined whether or not the measurement of the designated mark has been completed. If it is determined that the measurement has not been completed, the process returns to step s2, and the process from step s2 to step s3 is performed. The process is repeated, and when it is determined that the measurement of all marks has been completed, step s5
Proceed to. In step s5, correction coordinates are calculated from the measured position information of the mark. Next, the process proceeds to step s6 to perform exposure. Then, in step s7, it is determined whether or not the exposure of all shots is completed, and the exposure of step s6 is repeated until the exposure of all shots is completed. When the exposure of all shots is completed, the process proceeds to step s8 to collect the wafer.

In step s8, after collecting the wafer,
In step s9, it is determined whether or not processing of all wafers has been completed. If it is determined that processing has not been completed, step s9 is performed.
Returning to step 1, the next wafer is loaded, the above processing is continued, and if it is determined that the processing has been completed, the operation of the apparatus is terminated.

As can be seen from this flowchart,
In the conventional semiconductor manufacturing process, printing is performed by step-and-repeat after calculating and correcting corrected coordinates for alignment. However, there is no process for confirming array coordinates after printing is completed.

[0007]

However, during printing, due to equipment or equipment trouble, the actual state of the wafer changes due to shift or rotation with respect to the correction coordinates obtained immediately before the exposure, and deviates from the correction coordinates. Sometimes.
In this case, since the pattern is not correctly superimposed, the chip becomes a defective chip and the reproducing process is performed. However, depending on the process, the defective chip may not be found until several steps later. The reproduction process has to be performed retroactively, which is inefficient. Further, there is a possibility that a large number of defective chips will be manufactured until a trouble is found.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor manufacturing apparatus and a semiconductor manufacturing method capable of solving the above problems by quickly detecting the occurrence of a trouble and performing an efficient and safe exposure process. .

[0009]

According to the present invention, there is provided an exposure apparatus for sequentially exposing a pattern on an original to a plurality of shot positions on a substrate by a step-and-repeat method. The position measurement is performed for a predetermined sample shot position among the above, the coordinates of each shot position are obtained based on the result, and the exposure is performed by sequentially positioning each shot position based on the obtained coordinates. It is characterized in that a means is provided for measuring the position of the sample shot again and judging the suitability of the exposure based on the result. Here, the position measurement is performed by detecting a mark provided at each sample shot position, and the coordinates of each shot position are obtained from the design coordinates of each shot position and the result of the position measurement.

[0010] In general, the suitability of the exposure is determined by comparing the position measurement results before and after the exposure and determining whether or not the difference is within a predetermined allowable range. At this time, the exposure processing may be stopped, or a message to the effect that the determination has been made may be output, the determined substrate may be collected, and the exposure processing may be continued for the next substrate. Further, the device manufacturing method of the present invention is a method of manufacturing a device by sequentially exposing a pattern on an original plate to a plurality of shot positions on a substrate by a step-and-repeat method, wherein a predetermined sample of the shot positions is sampled. An exposure apparatus having the features described above, in which a position is measured for a shot position, coordinates of each shot position are obtained based on the result, and exposure is performed by sequentially positioning each shot position based on the obtained coordinates. Is used.

According to the present invention having the above configuration, it is possible to confirm immediately after exposure that correct exposure has been performed, in accordance with the correction coordinates obtained immediately before exposure, and to quickly detect the occurrence of a trouble. can do.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

[0013]

Embodiment 1 FIG. 1 shows an example of the arrangement of sample shots for measuring the arrangement of shots immediately after exposure according to this embodiment. In FIG. 1, S1x to S4x and S1y are shown.
S4y indicate the mark positions of the sample shots. Note that the sample shots in FIG. 1 are the same as those for calculating the correction coordinates for alignment.

In this embodiment, attention is paid particularly to the overlaying process of the semiconductor pattern printing process, and the processing for obtaining the correction coordinates for the overlay is carried out immediately after the completion of the printing, so that the alignment due to the trouble during exposure can be achieved. This is to detect an abnormality. In the alignment process, the entire wafer is corrected so that these deviations are minimized based on the deviation between a preset design position of the alignment mark for position coordinate measurement on the wafer and the actual mark position. The coordinates are obtained, and each shot is printed according to the corrected coordinates. Therefore, if the same mark is measured after exposure as long as the corrected state does not change due to a device or facility trouble during exposure, the deviation amount should be very small. As described above, it is possible to detect the presence or absence of a trouble during the exposure based on the measurement result after the exposure.

Hereinafter, the semiconductor exposure process according to this embodiment will be described with reference to the flowchart of FIG. First, in step s1, a wafer is loaded and set on a wafer stage. Next, in step s2, the position is moved to the alignment mark position s1 × shown in FIG. 1, and in step s3, the position of the mark is measured. Next, the process proceeds to step s4, where it is determined whether or not the measurement of the designated mark has been completed. If it is determined that the measurement has not been completed, the process returns to step s2, and the process proceeds from step s2 to step s2.
The process up to 3 is repeated, and when it is determined that the measurement of all the marks has been completed, the process proceeds to step s5. In step s5, correction coordinates are calculated from the measured position information of the mark. Next, in step s6, it is determined whether or not the wafer on which the mark measurement has been completed is already exposed. If the wafer has been exposed, the process proceeds to step s12. If not, the process proceeds to step s7 to perform exposure.

Next, in step s8, it is determined whether or not the exposure of all shots has been completed. If not, the process returns to step s7 and repeats the exposure of step s7 until the exposure of all shots is completed. When the exposure for all shots is completed, the process proceeds to step s9. Steps
In step 9, it is determined whether or not to confirm the array coordinates after exposure according to the present invention. If so, the process returns to step s2, and the position of the alignment mark is measured again. Proceeding to step s10, the wafer is collected.

When the process returns to step s2 to confirm the array coordinates after exposure, it is determined in step s6 that the wafer has already been exposed, so the process proceeds to step s12. In step s12, the correction amount based on the array coordinates obtained from the position information measured after the exposure is compared with the correction amount based on the array coordinates obtained from the position information measured before the exposure, and the result is set in advance. If it is within the tolerance, it is determined that there is no abnormality in the exposure, and step s10
Then, the wafer is collected. On the other hand, if the comparison result of the correction amounts exceeds the tolerance, it is determined that there is an abnormality, and the process proceeds to step s13 to interrupt the processing. When the sequence is interrupted, the process waits for an instruction to collect a wafer by the operator.

After collecting the wafers in step s10, it is determined in step s11 whether or not the processing of all the wafers has been completed. If it is determined that the processing has not been completed, the flow returns to step s1 to carry in the next wafer. The above processing is continued, and if it is determined that the processing has been completed, the operation of the apparatus is terminated. In the present embodiment, utilizing the existing alignment correction processing (steps s2 to s5),
Although the arrangement coordinates have been checked, completely different arrangement coordinate measurement processing may be added.

[0019]

Second Embodiment In the first embodiment, when the array coordinates after exposure exceed the tolerance, the operation of the apparatus is interrupted and the operator waits for assistance. However, in recent years, online automatic operation has been performed in semiconductor manufacturing lines. The present embodiment corresponds to such automatic driving.

FIG. 3 is a flowchart showing a semiconductor exposure process according to this embodiment. In FIG. 3, the operations from step s1 to step s12 are the same as those from step s1 to step s12 in FIG. In FIG. 3, when it is determined in step s12 that the array coordinates after exposure are abnormal, an abnormality occurrence report is made to the host computer in step s13. Next, step s14
Then, it is determined whether or not the abnormal wafer is to be automatically collected. If the abnormal wafer is to be automatically collected, the process proceeds to step s15, where exposure information such as a lot number, a wafer number, an exposure amount, and an alignment offset in which the abnormality has occurred is stored. To the host computer, and proceeds to step s16, where abnormal wafers are collected in another wafer carrier for reproduction processing. Thereafter, the process proceeds to step s11, where the exposure process is continuously performed.

If it is determined in step s14 that automatic collection is not to be performed, the flow advances to step s17 to interrupt the operation of the apparatus and wait for an assist by the operator. Whether or not to automatically collect abnormal wafers can be selected in advance at the start of the exposure processing. In addition, the host computer can manage the history of the occurrence of abnormalities by recording the date and time of the occurrence together with the abnormality occurrence report.

[0022]

Embodiment 3 Next, a method for producing a device using the above-described exposure apparatus will be described. FIG. 4 shows a small device (I
1 shows a flow of manufacturing semiconductor chips such as C and LSI, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, and the like. In step S21 (circuit design), the circuit of the semiconductor device is designed. In step S22 (mask production), a mask on which the designed pattern is formed is produced. On the other hand, in step S23 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass. Step S24 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step S25 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step S24, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step S26 (inspection), inspections such as an operation check test and a durability test of the semiconductor device manufactured in step S25 are performed. Through these steps, a semiconductor device is completed and shipped (step S27).

FIG. 5 shows a detailed flow of the wafer process. In step S31 (oxidation), the surface of the wafer is oxidized. In step S32 (CVD), an insulating film is formed on the wafer surface. In step S33 (electrode formation), electrodes are formed on the wafer by vapor deposition. Step S34
In (ion implantation), ions are implanted into the wafer. In step S35 (resist processing), a photosensitive agent is applied to the wafer. In step S36 (exposure), the circuit pattern of the mask is printed onto the wafer by exposure using an exposure apparatus having means for confirming the suitability of the above-described exposure. Step S37
In (development), the exposed wafer is developed. Step S3
In step 8 (etching), portions other than the developed resist image are removed. In step S39 (resist removal), unnecessary resist after etching is removed. By repeating these steps S, multiple circuit patterns are formed on the wafer.

In the present embodiment, in each of the repetitive processes, as described above, after the exposure (step S36), it is determined whether or not exposure has been performed at an accurate position, so that a defective wafer can be prevented from flowing to a subsequent process. , Enabling efficient device manufacturing. By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device, which was conventionally difficult to manufacture, at low cost.

[0025]

According to the present invention, the coordinate measurement of the wafer after exposure is performed by utilizing the existing alignment processing, so that the system does not need to be largely changed.
It can be easily introduced. Further, according to the present invention, it is possible to quickly detect a printing trouble during exposure, to improve the efficiency of the reproducing process, and to prevent the production of a large number of defective chips. In addition, as a response to online automation, by automatically collecting abnormal wafers and reporting wafer exposure information when an abnormality occurs to the host computer, it becomes possible to record exposure information for each wafer when an abnormality occurs. A quicker reproduction process becomes possible without going through.

[Brief description of the drawings]

FIG. 1 is a layout diagram of sample shots used in the present invention.

FIG. 2 is a flowchart illustrating a semiconductor exposure process according to the first embodiment.

FIG. 3 is a flowchart illustrating a semiconductor exposure process according to a second embodiment.

FIG. 4 is a view showing a flow of manufacturing a micro device according to a third embodiment.

FIG. 5 is a diagram showing a detailed flow of the wafer process of FIG. 4;

FIG. 6 is a flowchart showing a conventional semiconductor exposure process.

[Explanation of symbols]

S1x, S1y, S2x, S2y, S3x, S3y, S
4x, S4y: alignment mark position.

Claims (10)

[Claims] An exposure apparatus for sequentially exposing a pattern on an original to a plurality of shot positions on a substrate by a step-and-repeat method, wherein position measurement is performed on a predetermined sample shot position among the shot positions,
Based on the result, the coordinates of each shot position are obtained, and based on the obtained coordinates, the position is sequentially determined with respect to each shot position and exposure is performed. After the exposure, the position of the sample shot is measured again. An exposure apparatus comprising: means for determining whether or not exposure is appropriate based on the condition. 2. The position measurement is performed by detecting a mark provided at each sample shot position.
2. The exposure apparatus according to claim 1, wherein the coordinates of each shot position are obtained from design coordinates of each shot position and a result of the position measurement. 3. The method according to claim 1, wherein the determination of the suitability of the exposure is performed by comparing the position measurement results before and after the exposure and determining whether the difference is within a predetermined allowable range. Or the exposure apparatus according to 2. 4. The exposure apparatus according to claim 1, wherein, as a result of the determination of the suitability of the exposure, when the determination is negative, the exposure processing is stopped. 5. As a result of the determination of the suitability of the exposure, when it is determined that the exposure is not appropriate, the fact is outputted, the substrate determined as such is collected, and the exposure processing for the next substrate is continued. 4. The exposure apparatus according to claim 1, wherein: 6. A method of manufacturing a device by sequentially exposing a pattern on an original to a plurality of shot positions on a substrate by a step-and-repeat method, wherein a position of a predetermined sample shot position among the shot positions is determined. Measurement is performed, the coordinates of each shot position are obtained based on the result, and the position is sequentially determined with respect to each shot position based on the obtained coordinates to perform the exposure. After the exposure, the position measurement is performed again on the sample shot. A device manufacturing method comprising the steps of: determining whether or not exposure is appropriate based on the result. 7. The position measurement is performed by detecting a mark provided at each sample shot position.
7. The device manufacturing method according to claim 6, wherein the coordinates of each shot position are obtained from design coordinates of each shot position and a result of the position measurement. 8. The method according to claim 6, wherein the determination of the suitability of the exposure is performed by comparing the position measurement results before and after the exposure and determining whether the difference is within a predetermined allowable range. Or the device manufacturing method according to 7. 9. The device manufacturing method according to claim 6, wherein the exposure process is stopped when it is determined that the exposure is appropriate or not. 10. As a result of determining whether or not the exposure is appropriate,
9. The device manufacturing method according to claim 6, wherein when the determination is negative, the fact is output, the determined substrate is collected, and the exposure processing is continued for the next substrate.