JP2000306817A - Aligner and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent throughput of an aligner from dropping, due to the time required for exchanging original negatives at double exposure. SOLUTION: In an aligner which is provided with an original negative stage 2 which holds original negatives, a substrate stage 4 which holds a substrate, and an exposing means 5 which exposes the substrate held on the stage 4 to the patterns of the original negatives held on the stage 2 and makes double or multiple exposure by using a plurality of original negatives 1 and 1b on which different patterns are formed, the original negative stage 2 is constituted to simultaneously hold the original negatives 1a and 1b. In addition, when exposure is made by synchronously moving the stages 2 and 4 for scanning, the scanning exposure is made by respectively selecting different original plate for the forward and backward paths from the plurality of original negatives on the stage 2, while making the scanning movement forwards and backwards.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and a device manufacturing method for performing double exposure or multiple exposure on a plurality of exposure regions on a substrate in a semiconductor manufacturing process or the like. This is suitable when performing scan exposure while performing scan movement in synchronization with the substrate stage.

[0002]

2. Description of the Related Art Generally, when manufacturing a semiconductor device, L / S (line and space), isolated L (line), isolated S (space), and CH (contact hole) are used.
It is necessary to form a pattern on a silicon wafer by a combination of the above. However, when exposing the L / S, isolated L, isolated S, and CH patterns, there are optimal exposure conditions for each, and the optimal exposure conditions are different.
Conventionally, exposure conditions are determined so as to satisfy average accuracy for each shape.

However, there is a limit to improving the resolution under one exposure condition, and in order to further increase the resolution, two types of reticles having different exposure conditions are used, and the exposure is optimized for each. Depending on the conditions, a double exposure method of overprinting a high-resolution image on a predetermined region on a wafer has been considered.

FIGS. 3 and 4 show the operation of a conventional exposure apparatus when such a double exposure method is employed.
This apparatus exposes a reticle scan stage 102 holding a reticle, a wafer stage 104 holding a wafer 103, and a reticle pattern held on the reticle scan stage 102 onto a wafer 103 held on the wafer stage 104. Two reticles 10 each having a projection optical system 105 and having different patterns formed thereon.
Double exposure is performed using 1a and 101b. The exposure apparatus is a scan type exposure apparatus that performs exposure while performing synchronous scan movement between the reticle scan stage 102 and the wafer stage 104 during exposure.

When performing double exposure in this configuration,
Since only one reticle can be mounted on the reticle scan stage 102, first, as shown in FIG.
1a, and the selected reticle 101a is moved to the reticle scan stage 1 by the reticle exchange unit 107.
02 for alignment. Then, the pattern of the aligned reticle 101a is
Exposure light under the exposure conditions optimized for 1a is reduced and projected onto the wafer 103 on the wafer stage 104 via the projection optical system 105 for exposure. Reticle 10
After the exposure by the reticle 1a, the reticle 101a is temporarily replaced with the reticle exchange unit 1 as shown in FIGS.
07, the second reticle 101b on the reticle exchange unit 107 is mounted on the reticle scan stage 102. Or the first reticle 1
After returning a to the reticle stocker 108, the second reticle 1b is selected from the reticle stocker 108 and mounted on the reticle scan stage 102 by the reticle exchange unit 107 in the same manner as in the case of the first reticle. Then, the second exposure is performed by the same operation.

[0006]

However, according to this prior art, there is a drawback that the reticle exchange during the double exposure takes a long time, and the throughput of the apparatus is significantly reduced. An object of the present invention is to prevent a decrease in throughput due to a time required for exchanging an original in double exposure in an exposure apparatus and a device manufacturing method in view of the problems of the related art.

[0007]

In order to achieve this object, an exposure apparatus according to the present invention comprises: an original stage for holding an original;
A substrate stage that holds a substrate, and an exposure unit that exposes the pattern of the original held on the original stage onto the substrate held on the substrate stage, using a plurality of originals on which different patterns are formed. In an exposure apparatus for performing double exposure or multiple exposure, the original stage simultaneously holds the plurality of originals. Note that, here, the multiple exposure means an exposure that is overlapped three or more times.

Further, the device manufacturing method of the present invention provides a method of manufacturing a device by exposing a pattern of an original held on an original stage onto a substrate held on a substrate stage. In the device manufacturing method of performing double exposure or multiple exposure using one original, when performing the double exposure or multiple exposure, the plurality of originals are simultaneously held on the original stage, and selectively used. It is characterized by the following.

In this configuration, when performing double exposure or multiple exposure, a plurality of originals simultaneously held on the original stage are selected and used. Therefore, it is necessary to carry out the originals on the original stage and replace them. There is no. Therefore, conventionally, in the case of double exposure, after exposing each exposure area with the first original, the first original is carried out from the original stage and replaced with the second original. Compared to having to perform two-layer exposure with two shots, such as performing the second exposure over the region,
According to the present invention, exposure of two layers is continuously performed at each shot position as one shot without exchanging the reticle, so that the throughput is improved. Here, the layer simply means the overlap of each exposure in double exposure or multiple exposure.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the present invention, the exposure is a scan type exposure performed while performing a scan movement in synchronization with an original stage and a substrate stage. By changing the scan timing in each of the forward path and the return path from among the plurality of originals on the stage, different ones are selected and used for scan exposure. At this time, the operation start position, acceleration or moving speed of the scan movement of the original stage is changed for each original on the original stage. The original stage holds a plurality of originals arranged side by side in the scanning movement direction. The exposing means changes the exposing condition corresponding to each of the plurality of originals. Further, when a plurality of originals are supplied onto the original stage, the originals are transported by using a transport unit that simultaneously holds and transports the originals.

[0011]

1 and 2 are views showing the operation when double exposure is performed in an exposure apparatus according to one embodiment of the present invention. In the figure, reference numerals 1a and 1b denote reticles each having a pattern of a different layer used under different exposure conditions optimized so as to improve the resolution. Reference numeral 2 denotes that both the reticles 1a and 1b can be simultaneously mounted. A reticle scan stage capable of aligning each reticle at a reticle setting position; 3 a wafer of a silicon substrate on which patterns of reticle 1a and reticle 1b are reduced and exposed; 4 a wafer 3 mounted thereon; And a wafer stage 5 for positioning an exposure area on the wafer 3, and the exposure light 6 transmitted through the reticle 1a or 1b is applied to the wafer 3 by a factor of 1/4 to 1/5. 8 is a projection optical system composed of a reduction projection lens for reducing projection at a magnification of Reticle stocker where Le is accommodated, 7 reticle 1a from the reticle stocker 8, 1b
A reticle exchange unit that selects and takes out another reticle, mounts it on the reticle scan stage 2, aligns it, and collects it from the reticle scan stage 2 to the reticle stocker 8.

In this configuration, when two types of reticles 1a and 1b are mounted on the reticle scan stage 2 for exposure, first, as shown in FIG. 1A, the reticle exchange unit 7 causes the reticle stocker 8 to move from the reticle stocker 8. 1a and 1b are selected and taken out, and the reticle 1a is aligned and mounted on the reticle scan stage 2 as shown in FIG.
As shown in (c), the alignment and mounting of the reticle 1b on the reticle scan stage 2 are performed in the scanning direction with respect to the reticle 1a.

Next, an exposure operation is performed. That is, FIG.
As shown in FIG. 1A, the reticle 1a is irradiated with exposure light under optimized exposure conditions while the reticle 1a is scanned and moved by the reticle scan stage 2, and at the same time, the wafer mounted on the wafer stage 4 is moved. 3
Is moved in synchronization with the scanning movement of the reticle 1a, so that the pattern formed on the reticle 1a is reduced and projected on the wafer 3 by the projection optical system 5.

After the completion of the exposure using the reticle 1a, the reticle 1a is further continuously provided as shown in FIG.
Scan movement of the reticle 1b in the direction opposite to the case of the exposure by the reticle 1b, and in synchronization with this, the wafer 3 is also scanned and moved in the reverse direction. , Reticle 1a
As in the case of (1), projection exposure is performed on the reticle 1b under the optimized exposure conditions.

The double exposure is sequentially performed for each shot position on the wafer 3 to perform the exposure processing for one wafer 3. Meanwhile, the reticles 1a and 1b are alternately selected and used.

According to the present embodiment, the reciprocal scanning movement of the reticle scan stage 2 uses two different types of reticles 1a and 1b, and the same shot on the wafer 3 is obtained under different exposure conditions optimized for each. Printing of a pattern image with high image quality, that is, double exposure, can be performed without lowering the throughput. Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented. For example, in the above description, an example in which double exposure is performed has been described. Instead, three reticles are used, and a continuous reciprocating scanning operation is performed.
It is also possible to perform triple exposure.

<Embodiment of Device Manufacturing Method> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 5 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin film magnetic heads, micro machines, etc.). In step 1 (circuit design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass.
Step 4 (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 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing, bonding),
It includes steps such as a packaging step (chip encapsulation). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 6 shows the wafer process (step 4).
The detailed flow of is shown. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), a resist is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus or exposure method to align and print the circuit pattern of the mask on a plurality of shot areas of the wafer.
Step 17 (development) develops the exposed wafer.
In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps,
Multiple circuit patterns are formed on the wafer. By using the production method of this embodiment, it is possible to produce a large-sized device, which was conventionally difficult to produce, at low cost.

[0019]

As described above, according to the present invention, when performing double exposure or multiple exposure with a plurality of originals, there is no need to exchange the original with the original stage between double or multiple exposures. It can be. Therefore, the throughput of the exposure apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an operation when performing double exposure in an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a continuation of the operation in FIG. 1;

FIG. 3 is a diagram showing an operation when a double exposure method is performed in a conventional exposure apparatus.

FIG. 4 is a diagram illustrating a continuation of the operation in FIG. 3;

FIG. 5 is a flowchart showing a device manufacturing method that can use the exposure apparatus of the present invention.

FIG. 6 is a detailed flowchart of a wafer process in FIG. 5;

[Explanation of symbols]

1a, 1b, 101a, 101b: reticle, 2,10
2: reticle scan stage, 3,103: wafer,
4, 104: wafer stage, 5, 105: projection optical system, 6, 106: exposure light, 7, 107: reticle exchange unit, 8, 108: reticle stocker.

Claims (8)

[Claims] An original stage for holding an original, a substrate stage for holding a substrate, and exposure means for exposing a pattern of the original held on the original stage onto the substrate held on the substrate stage. An exposure apparatus for performing double exposure or multiple exposure using a plurality of originals on which different patterns are formed, wherein the original stage simultaneously holds the plurality of originals. 2. A scanning type exposure apparatus which performs exposure while performing a scan movement in synchronization with the original stage and a substrate stage, wherein a plurality of originals on the original stage are reciprocated while performing the scan movement in a reciprocating manner. 2. The exposure apparatus according to claim 1, wherein a scan exposure is performed by selecting and using different ones for each of the forward path and the return path. 3. The exposure apparatus according to claim 2, wherein an operation start position, an acceleration, or a moving speed of the scan movement of the original stage is changed for each original on the original stage. 4. The exposure apparatus according to claim 2, wherein the original stage holds the plurality of originals arranged side by side in the scanning movement direction. 5. The exposure apparatus according to claim 1, wherein the exposure unit changes exposure conditions in correspondence with each of the plurality of originals. 6. The exposure apparatus according to claim 1, further comprising a transporting unit that simultaneously holds the plurality of originals and transports the originals onto the original stage. 7. When a device is manufactured by exposing a pattern of an original held on an original stage onto a substrate held on a substrate stage, a plurality of originals on which different patterns are formed are duplicated. In the device manufacturing method for performing exposure or multiple exposure, when performing the double exposure or multiple exposure, the plurality of originals are simultaneously held on the original stage, and selectively used. . 8. The double exposure or the multiple exposure is performed by scan exposure in which exposure is performed while performing synchronous scan movement of the original stage and the substrate stage.
At the time of the double exposure or the multiple exposure, while performing the scan movement in a reciprocating manner, a scan exposure is performed using a plurality of originals on the original stage that are different from each other in each forward path and return path. Claim 7
3. The device manufacturing method according to claim 1.