JPS6134937A - Semiconductor printing device - Google Patents

Abstract

PURPOSE:To prevent dispersion of a reticle pattern, which is printed on wafers, from generating by a method wherein the amount of light of the lamp is detected in every the prescribed period, such as in every wafer, and the exposing time is changed. CONSTITUTION:A wafer 2 is made to shift by a shifting stage 3, a shutter 8 is opened, the output signal of a photo detector 12 is read in through the A/D converter of a control circuit 11 and the value of the amount of light, which is proportioned to the amount of light at that time, is obtained. The measured value of the amount of light, the reference amount of light in hitherto and the reference exposing time in hitherto are respectively set at A, B and (t), and the exposing time T=(B/A)t for the subsequent printing is calculated. Then, the stage 3 is made to shift to the prescribed printing position, and after that, when a printing of the reticle pattern is performed on the surface of the wafer 2, the exposing time is controlled according to the calculated correction time. By this way, the reticle pattern can be printed correcting a secular change of light of a lamp 7, a change of the aging transmittivities of lenses 9 and 10 and a reticle 1. As a result, dispersion of the lineal width and the resolution, which occur along with a change of the amount of light, can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a semiconductor printing apparatus, and in particular, to the aging of an ultra-high pressure mercury lamp as a light source! 8 [Pattern printing with respect to degree changes sometimes relates to a semiconductor printing apparatus in which the shutter opening time is controlled.

[Background of the Invention J] FIG. 1 shows an example of a conventional semiconductor printing apparatus, in which 1 is a reticle, 2 is a wafer, 3 is a moving stage, and 4 is a reduction projection lens.

In the apparatus shown in the figure, for example, first, the motor 5 moves the movable stage 3 to the M1 shot position. Next, by opening the shutter 8 for a certain period of time, the light from the light source 7 passes through the lenses 9 and 1o, the pattern on the reticle 1 is reduced by the projection lens 4, and one shot is printed onto the wafer 2.

Next, the moving stage is moved to the next shot position with the shutter closed.

By repeating this operation, a pattern as shown by 13 is printed onto the wafer 2.

By the way, in this case, the power supply voltage of the lamp 7 changes over time or the lamp 7 deteriorates, which causes the brightness of the lamp 7 to change, but in conventional devices, the shutter was always open for a certain period of time for exposure. ,
There is a drawback that variations can be seen in the line width or resolution of the printed patterns.

[Object of the Invention] In view of the above-mentioned problems with the conventional type, the present invention provides a method for semiconductor printing in which the light intensity of the light source is adjusted to 72 as appropriate, and the exposure time is corrected based on this monitored light intensity. Based on the concept, the purpose is to eliminate uneven exposure between shots or between wafers and to eliminate variations in line width or resolution of patterns printed on wafers.

[Explanation of Examples] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 shows a schematic configuration of an embodiment of the present invention. In the figure, 1 is a reticle, 2 is a wafer, 3 is a moving stage,
4 is a reduction projection lens, 5 is a motor for moving the moving stage, 6 is a mirror, 7 is a lamp, 8 is a shutter, 9 and 10 are lenses, 11 is a control device, 12 is a photodetector that detects light intensity, and 13 is a printing device. is a pattern.

FIG. 3 is a diagram showing various operating states of the apparatus shown in FIG. 2, and is a schematic cross-sectional view showing a part of the H position perspective view of FIG. 2. The numbers added to FIG. 3 correspond to the same numbers in FIG.

FIG. 4 presents a schematic flowchart for explaining the operation of the embodiment. Next, while referring to Figures 3 and 4, the second
The operation of the device shown in the figure will be explained.

First, in step 10 of FIG. 4, the wafer 2 is placed on the moving stage (XY stage) 3, and in step 20, the wafer 2 is placed on the
to the observation position [position shown in Figure 3 (1)].

Next, in step 30, the shutter 8 is opened, and in step 40, the output signal of the photodetector 12 is sent to the control circuit 11.
When read through an A/D converter (not shown), a value proportional to the amount of light at that time can be obtained. At this time, the light from the illumination device (lamp) 7 is irradiated onto the photodetector 12 via the reticle 1 and the reduction projection lens 4, but this light irradiates the range shown by a in FIG.
It doesn't hit the wafer.

In step 50, the light amount measured in step 40 is A, the reference light amount up to now is B, and the reference exposure time up to now is t, and the exposure time for subsequent printing is T'=
Calculate (B/A)t. This allows the subsequent exposure time to be corrected.

Next, in step 30, close the shutter that was opened,
After moving the stage 3 to a predetermined baking position in step 60, for example, the position shown in FIG. 3(2), step 70
In step 50, the reticle pattern is printed onto the wafer surface, and at this time the exposure time (opening time of shutter 8) is controlled according to the correction time calculated in step 50.

Next, in step 80 it is determined whether or not the exposure of the final shot has been completed, and if it is not the final shot, the stage 3 is moved to the next shot position in step 90, and in step 70
The operations from 1 to 3 are repeated until the exposure of the final shot is completed.

When it is determined in step 80 that the exposure of the final shot has been completed, wafer 2 is ejected in step 100, and in step 110 it is determined whether or not the baking of all wafers has been completed, and there are still wafers to be baked. If there is,
Returning to step 10, the next wafer is placed on the stage 3, and the operations after step 10J''l are repeated until all wafers are baked.

By performing printing in this manner, it is possible to correct changes in light intensity of the lamp 7 over time, changes in transmittance of lenses, reticles, etc. It is possible to suppress variations in the

[Modified Example of Embodiment] In the above embodiment, the light amount is measured for each wafer, but if you want to increase the throughput, taking into consideration variations in throughput and printing, you may want to measure the amount of light once every few wafers.
The check interval may be changed depending on whether throughput or printing variation is more important and the fluctuation factors of the lamp 7, such as once every few shots if you want to minimize the variation in pattern printing (if you want to minimize the variation in pattern printing) . Furthermore, in the above embodiment, the xY stage 3 is moved to a specific light intensity observation position when observing the light intensity, but for example, the wafer receiving position (step 10 in FIG. 4) and the wafer ejection position (step 10 in FIG. 4) 100)
If the photodetector 12 is placed on the xY stage so that the amount of light can be observed at the same time when wafers are being received and transferred, the present invention can be carried out without interfering with throughput.

[Effects of the Invention] As explained above, the present invention solves the phenomenon that the line width or resolution of a printing pattern varies due to changes in the light intensity of a lamp, for example, by detecting the light intensity for each wafer and adjusting the exposure time based on the detected light intensity. By changing the value, the printing has the effect of eliminating variations in the pattern.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional semiconductor printing apparatus, FIG. 2 is a schematic diagram of a semiconductor printing apparatus according to an embodiment of the present invention, and FIG. 3 is a schematic side view of the apparatus shown in FIG. 2 in various operating states. , FIG. 4 is a schematic flowchart for explaining the operation of the embodiment. DESCRIPTION OF SYMBOLS 1... Reticle, 2... Wafer, 3... Moving stage, 4... Reduction projection lens, 5... Motor, 6...
...Mirror, 7...Light level lamp, 8...Shutter,
9, 10... Lens, 11... Control device, 12...
・Photodetector, 13...Printing is a pattern.

Claims (1)

[Claims] In a semiconductor printing apparatus that exposes and transfers a pattern image formed on a reticle to a wafer placed on a moving stage via a projection optical system, a light intensity detector is provided on the moving stage, and a light intensity detector is provided on the moving stage to expose the wafer. First, move the stage so that the intensity detector is under the projection optical system, then open the shutter to detect the light intensity, and control the subsequent exposure time of the wafer based on the light intensity at this time. A semiconductor printing device characterized by: