JPH0219956Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a contact type semiconductor exposure apparatus.

BACKGROUND ART As is well known, the exposure process in the manufacturing process of semiconductor devices is performed by either the so-called contact method or the projection method, and one example of a semiconductor exposure apparatus used in the contact method is is as shown in FIG.

This semiconductor exposure apparatus 1 includes a light source 6, a lens 7,
It has an opening 4a in the center, and is equipped with a holder 4 on which a mask 5 is placed so as to cover the opening 4a, and a stage 3 on which a wafer 2 is placed.The stage 3 rises inside the opening 4a of the holder 4. Alternatively, it is lowered to bring the upper surface of the wafer 2 and the lower surface of the mask 5 into close contact. In addition, the lower part of the stage 3 and the opening 4a
A flexible diaphragm 8 is provided between the diaphragm 8 and the vicinity of the lower edge to form a sealed space, and the space is evacuated via a degassing passage 4b formed on the side surface of the opening 4a. It is designed to further promote close contact between the wafer and the mask.

By the way, exposure of a mask pattern onto a wafer is normally repeated multiple times using different masks, and if the relative positional relationship between the wafer and each mask differs even slightly for each exposure, it may be critical to the product. This leads to the occurrence of defects. Therefore, before exposure, the wafer 2 and the mask 5 must be relatively moved so that the relative positions between the wafer 2 and the mask 5 are in a predetermined relationship (hereinafter referred to as "alignment"). .) is being carried out. Normally, this alignment is performed by moving the stage 3 on which the wafer 2 is placed, and for this purpose, the stage 3 is movable in four axial directions by a pulse motor or the like.

For this alignment, two patterns 11 as shown in FIG. 4a are formed at predetermined positions on each mask 5 during mask pattern formation, and two patterns 11 as shown in FIG. 4b are formed at predetermined positions on the wafer 2. Two patterns 12 as shown are printed in the previous step.
Further, the distance between each two patterns is kept extremely precisely and constant. An enlarged view of an example of these patterns 11 and 12 is shown in FIG.
Shown in b. The pattern 11 consists of two sets of parallel lines 11
The wire 11b and the wire 11c are in contact at one end, forming a chevron. Pattern 12 is line 1
2a and a line 12b, one end of which touches to form a chevron. still,
In FIG. 4, only the patterns 11 and 12 are exaggerated and shown in a large size, but in reality, the height of the chevron of pattern 11 is about 130 μm, and the height of pattern 1 is approximately 130 μm.
The height of the chevron 2 is about 435 μm.

When the wafer 2 and the mask 5 on which such a pattern is formed are placed on the above-mentioned exposure apparatus 1, if both the patterns 11 and 12 are as shown in FIG. 7a, the wafer 2 and the mask 5 are However, normally the two patterns are shifted as shown in Figure 8a, for example.
Alignment between wafer 2 and mask 5 must be performed. This alignment is performed by moving the stage 3 laterally and placing the alignment detection device 20 above the opening 4a.

An example of a conventional alignment detection device is shown by the reference numeral 20 in the left half of FIG. 3, and since it is a well-known device, a detailed explanation thereof will be omitted and only the explanation of the reference numerals will be given below. 21 is a laser such as He-Ne, 22 is a polygon mirror, 23 is an f-theta lens, 24 is a half mirror, 25 is a field lens, 26 is a roof prism, 27 is a mirror, 28 is an erector, 29 is an observation system, and 30 is a Right photodetector, 31 is a condenser lens, 32 is a stopper, 33 is a relay lens, 34 is a right objective lens,
35 is a lamp, 36 is a left objective lens, and 37 is a left photodetector.

By scanning both the patterns 11 and 12 of the mask 5 and the wafer 2 on the exposure device 1 with a laser beam in the direction of the arrow shown in FIG. The photodetectors 30 and 37 obtain pulse signals as shown in FIG. 8b. By processing these pulse signals, the relative positional relationship between the wafer 2 and the mask 5 can be determined, so the stage 4 is moved and alignment is automatically performed. Finally, when the pulse signal shown in FIG. 7b is obtained and the two are in a predetermined relative positional relationship and automatic alignment is completed, the alignment detection device 20 is moved to the right and the light source 6 and lens 7 are moved back to their original positions. After returning to the position, exposure is performed.

Problems that the invention aims to solve By the way, since the wafer 2 undergoes various treatments such as diffusion in the pre-process, the wafer 2 may undergo deformations such as expansion, contraction, and warping. be. Therefore, the positions of the two patterns 12 formed on the wafer 2 may also shift. For example, in FIG. 5, the wafer 2 expands in the direction of the arrow, and the pattern 12 on the right, which should originally be at the position indicated by the dotted line, moves to the position indicated by the solid line, and the distance between the two patterns 12 becomes large. This shows the case where the

Even in such a case, if the degree of deformation is small, the degree of deviation between both patterns 11 and 12 is also small, so automatic alignment using a laser beam as described above is possible, but if the degree of deformation is If the distance between the patterns 12 and 12 exceeds a certain limit, the deviation between the patterns 11 and 12 becomes too large, and automatic alignment as described above becomes impossible. In such a case, the conventional method is to switch to manual operation and move the stage 3 up and down to adjust the distance between the lower surface of the mask 5 and the upper surface of the wafer 2 (the "print gap").
That's what it means. ) was being adjusted.

By manually adjusting the print gap, the mask 5 is slightly bent, and when viewed from the wafer 2, the two patterns 1 formed on the mask 5 are
The distance between 1 will change. Therefore, the relative positional relationship between the patterns 11 and 12 changes, and they overlap each other as shown in FIG. 8a. In this state, the automatic alignment described above can be performed.

In this way, in conventional contact-type semiconductor exposure equipment, if the wafer is deformed, alignment cannot be performed automatically, and the print gap must be adjusted manually to achieve automatic alignment. However, since the positional relationship of the patterns was adjusted to the point where it was possible to do so, there were problems in that the exposure process took a lot of time and required manual labor.

The present invention was devised to solve these problems of conventional semiconductor exposure equipment, and its purpose is to eliminate print gaps even if the wafer is deformed in the previous process. It is an object of the present invention to provide a semiconductor device that can be automatically adjusted, so that alignment work can be completely unmanned, and the exposure process can be shortened.

Means for Solving the Problems In order to achieve the above object, the semiconductor exposure apparatus of the present invention is a contact type semiconductor exposure apparatus, and includes means for storing predetermined relative positions of a plurality of patterns formed on a wafer; means for detecting the relative positions of the plurality of formed patterns; means for calculating the difference between the detected relative position and a stored predetermined relative position; and determining whether the calculated difference is within a predetermined tolerance range. means for calculating a necessary print gap based on the difference if the difference is outside a predetermined tolerance; means for adjusting the print gap based on the calculated print gap; In some cases, or after the print gap has been adjusted by the adjustment means, the apparatus is characterized by comprising means for aligning the mask and the wafer.

FIG. 1 is a block diagram schematically showing the configuration of the present invention. In the figure, 51 is a means for storing a predetermined relative position of a plurality of patterns formed on a wafer, 52 is a means for detecting a relative position of a plurality of patterns formed on a wafer, and 53 is a means for storing a predetermined relative position of a plurality of patterns formed on a wafer. means for calculating the difference from the stored predetermined relative position; 54 means for determining whether the calculated difference is within a predetermined tolerance; 55 means for calculating the necessary print gap based on the difference; 56 57 is a means for adjusting the print gap based on the calculated print gap, and 57 is a means for aligning the mask and the wafer.

Further, FIG. 2 shows a flowchart of the present invention.

Embodiment FIG. 3 is a diagram illustrating the configuration of a main part of an embodiment of the present invention. The parts of the semiconductor exposure apparatus of this embodiment other than those shown in FIG. 3 are substantially the same as those of the semiconductor exposure apparatus 1 described above, and illustration and description thereof will be omitted. In this embodiment, the above-described alignment detection means 20 is used as means 51 for detecting the relative positions of a plurality of patterns formed on a wafer, and the alignment detection means 20 is used as a means 51 for detecting the relative positions of a plurality of patterns formed on a wafer.
12, both pulse signal trains generated in the left and right photodetectors 30, 37 are sent to the CPU 42 via the interface 41 of the microcomputer 40.
The CPU 42 determines the relative positional relationship between the two patterns 12, 12 on the wafer 2 based on both pulse signal trains. In the memory 43 of the computer 40,
A predetermined relative positional relationship between the two patterns 12, 12 on the wafer 2 is stored in advance, and the CPU 42
Then, this stored predetermined positional relationship is compared with the input positional relationship, and the difference therebetween is calculated.

If this difference is within the specified range,
The CPU 42 calculates the amount of movement of the stage 3 necessary for alignment based on the input pulse signal data, and the data is sent to the stage control device 45 via the interface 44. Based on the data, the stage control device 45 moves the stage 3 by operating the X-axis control motor Mx, the Y-axis control motor My, the Z-axis control motor Mz, and the θ-axis control motor Mθ. Make adjustments. If perfect alignment cannot be obtained by one-time alignment, the movement of the stage 3 is repeated several times to achieve perfect alignment.

If the difference is outside the predetermined range, the print gap is adjusted, the mask 5 is bent, and the relative positional relationship between the two patterns 11 and 12 is changed, so that both patterns 11 and 12 are formed as shown in FIG. 8a. This is done so that the patterns overlap. For this reason, the CPU 42
Based on the relationship between the amount of deflection of the mask 5, the print gap, and the height of the stage 3 that has been input in advance, and the difference, calculate the amount of movement in the height direction of the stage 3 to obtain the print gap necessary for the difference. and sends the data to the stage control device 45. The control device 45 controls the Z-axis control motor Mz based on the data, adjusts the height of the stage 3, and adjusts the print gap. Once the required print gap adjustment is completed, both patterns 11 and 12 will overlap, so the same process as described above is performed when the difference is within a predetermined range.

Effects of the Invention As explained above, the semiconductor exposure apparatus of the present invention can automatically adjust the print gap even if the pattern position differs from the predetermined one due to deformation of the wafer or the like. As a result, the exposure process time can be shortened, and in addition, there is no need to have a worker on hand to adjust the print gap, which is useful for cleaning the semiconductor manufacturing environment.

[Brief explanation of the drawing]

Figure 1 is a block diagram explaining the configuration of the present invention.
FIG. 2 is a flowchart for explaining the operation of the exposure apparatus of the present invention, FIG. 3 is an explanatory diagram of main parts of an embodiment of the present invention, FIG. 4a is a plan view of a mask, and FIG. 4b is a wafer FIG. 5 is a plan view of the deformed wafer, FIGS. 6 a and b are enlarged views of the mask and wafer patterns, FIGS. 7 and 8 are illustrations of pattern alignment, and FIG. 9 1 is an explanatory diagram of an example of a conventional semiconductor exposure apparatus. 2... Wafer, 3... Stage, 5... Mask, 11, 12... Pattern, 20... Alignment detection device.

Claims (1)

[Claims for Utility Model Registration] In a contact type semiconductor exposure apparatus, means for storing predetermined relative positions of a plurality of patterns formed on a wafer, means for detecting relative positions of a plurality of patterns formed on a wafer, detection. means for calculating the difference between the calculated relative position and the stored predetermined relative position; means for determining whether the calculated difference is within a predetermined tolerance; if the difference is outside the predetermined tolerance; means for calculating a necessary print gap based on the difference; means for adjusting the print gap based on the calculated print gap; and if the difference is within a predetermined tolerance, or the print gap is adjusted by the adjusting means; A semiconductor exposure apparatus characterized by comprising means for later aligning a mask and a wafer.