JPS62102537A - Substrate processor - Google Patents

Abstract

PURPOSE:To reduce the size of a substrate processor by providing a hand for temporarily holding a processed substrate on a stage, supplying unprocessed substrate onto the stage by a single supplying and recovering hand, and recovering the processed substrate. CONSTITUTION:A wafer W1 is removed from a wafer carrier, and placed by a hand HA on a chuck WC. Then, an XY stage is moved, and the hand HC is rotated 180 deg. in parallel with the exposing operation of the wafer W1. Thereafter, the stage is moved to a delivering position side, and the wafer W1 is removed by the hand HC on the chuck WC on the way. Unexposed wafer W2 is brought from the hand HA onto the chuck WC, the the hand HC is simultaneously rotated 180 deg., and the exposed wafer is handed to the hand HA side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a substrate processing apparatus suitable for semiconductor manufacturing.

[Background of the Invention] A device called a stepper is known as an exposure device used in semiconductor manufacturing. This stepper moves a substrate such as a semiconductor wafer step by step under a projection lens, reduces a pattern image formed on an original plate or reticle using a projection lens, and sequentially exposes multiple locations on one wafer. It is something. Steppers are seen as the mainstream of future aligners (exposure devices) in terms of performance such as resolution and overlay accuracy.

The sizes of semiconductor wafers processed by such aligners are diversifying depending on the type of semiconductor device that is the product. That is, in devices such as MOS memories that are produced in small quantities and in large quantities, large diameter semiconductor wafers are used in order to reduce costs by increasing the number of devices acquired per wafer through batch processing. Currently, the mainstream size of semiconductor wafers in this field is φ6″ (φ150#), but in 1987, the size of semiconductor wafers increased from φ8″ to 10″ (φ200#).
#I~250#I).

On the other hand, in low-volume, high-mix production devices such as gate arrays,
The size of semiconductor wafers remains at φ3'' to φ4''. In addition, FE with GaAs substrate, which has been attracting attention recently,
Due to the difficulty of crystal technology for T and light emitting elements, the maximum diameter is φ3.
”.

Due to this current situation, there is currently a stepper that can handle semiconductor wafers with a diameter of 8" to 10", and a diameter of φ3" to φ4.
Even when used for semiconductor wafers with diameters of φ3″ to φ4
There is a strong desire to realize an exposure apparatus that has fewer disadvantages than exposure apparatuses for ``.

However, the conventional exposure equipment for φ3″ to φ4″ can be replaced with just φ8″.
~ φ3″ to φ4″ just by increasing the size to 10″
When used for commercial purposes, the following problems arise.

That is, (1) The stroke of the XY stage needs to be three to four times the wafer size, but this increase in stroke increases the size of the moving stage including this XY stage and the like.

■Therefore, it becomes difficult to guarantee the same accuracy as before the size increase. Furthermore, in order to guarantee the same accuracy, it is necessary to increase the rigidity of the guide, etc.

■As a result, the stage weight becomes even larger, ■It is necessary to strengthen the structure such as the lens holding as a countermeasure for imaging due to the stage weight and acceleration during stage movement, ■Start-up and fall speed range due to increase in moving mass Distance feed and positioning take time due to increase in positioning time due to increased vibration.

■The increased cost of the XY stage, increased size of the entire device, and increased cost of the entire device cannot be ignored.

etc.

These factors mean that the device for φ8'' to 10'', which is simply an enlarged version of the conventional device, can be used for φ3'' to φ4'' or φ5''.
For example, when used for small diameter wafers such as, the equipment is too large compared to a dedicated machine for φ3" wafers (■, ■, ■) The price is too high (■, ■) The throughput decreases (■) This results in a great disadvantage and burden to the user.

Therefore, we are currently developing compact exposure equipment that can handle diversifying wafer sizes with the same exposure equipment and that does not burden the user with the above-mentioned disadvantages even when processing small-sized wafers, and that are advantageous for large-diameter wafers. There is a need for the development of wafer handling methods.

This ``advantageous wafer handling method'' means, for example: ■ It shortens wafer exchange time and improves throughput ■ It is a chuck-hand transfer method that is advantageous for flattening wafers ■ It minimizes the wafer transport path The advantages include the ability to make the wafer more compact and the degree of freedom in the direction of the wafer placed on the XY stage; and 2) the ability to retry the wafer.

[Object of the Invention] An object of the present invention is to further downsize a substrate processing apparatus.

[Summary and Effects of the Invention] In order to achieve the above object, the present invention provides a hand that temporarily holds the processed substrate on the stage when exchanging the substrate on the stage, and a single supply/recovery hand that holds the processed substrate on the stage. To easily supply a substrate onto a stage and recover a processed substrate held by a temporary holding hand.

By supplying and collecting the substrates with a single hand in this manner, the conventionally separate collecting hand is no longer required, and the apparatus can be made compact.

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

FIG. 1 shows a schematic configuration of a wafer stage and its vicinity at a wafer transfer position of a semiconductor exposure apparatus (stepper) according to an embodiment of the present invention. Although the reticle stage, projection lens, TTL alignment optical system, etc. of the apparatus shown in the figure are not particularly shown, it is assumed that these are constructed in the same manner as a conventional stepper for, for example, φ3'' wafers.

In the same figure, WD is a base, and on this base WD, Y
A wafer stage is mounted, which includes a stage WY that is movable in the direction WY, a stage WX that is movable in the X direction, and a stage θZ that is movable in the θ rotation and the Z direction (up and down). Stage WY and stage WX constitute an XY stage. Further, structures such as the projection lens described above are also mounted or fixed on the base WD.

MX and MY are optical software for laser length measurement using a laser interferometer, HA is a hand for supplying and collecting wafers, and HB
is a hand for collecting small diameter wafers, HC is a hand for transferring wafers, Wl and W2 are wafers, and WC is a wafer chuck. The wafer chuck WC has a hand relief part L so that the hand HB can enter the back side of the wafer when the hand HB directly collects the wafer from the chuck WC.
L.

LR is provided on the left and right. In addition, the hand HC has a finger portion FG1 for picking up the wafer from the chuck WC.
It consists of an arm AM and the like for raising, lowering and rotating the finger portion FG. The center of rotation of arm AM is eccentric to the wafer W1 to be picked up.

FIG. 2 is a top view and an AA sectional view of the wafer chuck WC. This chuck WC has a large number of linear suction grooves G on its upper surface, and these suction grooves are divided into groups as appropriate, and nipples DI, D2, and D are arranged in each group.
3, a separate system of vacuum is supplied. These groups depend on the size of the wafer loaded on this chuck WC, and even when the wafer is transferred on the chuck WC, all suction grooves of the group connected to either nipple D1 or D3 and nipple D2 are selected. The setting is such that all suction grooves in the connected groups are always covered by the wafer. Note that the pattern composed of suction grooves can be arbitrarily determined depending on the size of the wafer loaded on the chuck wC and the state when transferred, as long as the wafer is always held well and flattened. can.

Further, although this chuck WC supports the wafer in a line, it may also have a so-called bottle chuck configuration in which the wafer is supported at a point, or a large number of suction holes are provided instead of suction grooves to support the wafer in a plane. You can do it like this.

FIG. 3 is an explanatory diagram showing each operation stage of the apparatus of FIG. 1. In the figure, RT is a reticle and PO is a projection lens.

Next, the operation of the exposure equipment according to the above configuration will be explained. Here, as shown in Figure 4, the XY stage is possible! [I.J.
Territory 1ii! TE is 200 shoes x 230m, which is equivalent to a ridge dedicated to φ3" wafers (Y stage WY movable distance 230M,
Movable distance of X stage WX 200m>, projection lens PO
The case where the effective screen of the projection lens PO is φ20aw and as many actual device patterns of 5s+X16m as possible are formed on the φ10'' wafer will be explained.The effective screen of the projection lens PO is φ20aw.
Since it is 20 m+, two real element patterns are formed on the reticle RT, and two real element patterns (10 MAX 16 m+) are printed in one exposure to improve the throughput. Further, with the conventional exposure method, it is impossible to print an actual element pattern on the entire surface of the wafer W1, no matter how it is mounted on the XY stage. Therefore, as shown in FIG. 4, the exposure surface of the wafer is divided into two regions each included in the movable region of the XY stage, and after exposing one region, the position of the wafer with respect to the XY stage is transferred. to expose the other area. As is clear from Figure 4, the maximum diameter of the wafer that can be processed when the wafer is divided into two areas for exposure is the diagonal stroke of the rectangular movable area of the XY stage, and the It is determined by the size of the area TE to be exposed.

When the reticle RT and the like are set and a command is given to start exposure, this exposure apparatus starts the following divided exposure operation under the control of a CPU (not shown).

That is, first, with the chuck WC tilted so that the major axis direction coincides with the direction of the diagonal line a-a of the movable area in FIG. Place it (Figure 3a). The positional relationship of the wafer W1 with respect to the chuck WC at this time is shown in FIG. 2 by a two-dot chain line. If the hand HC holds the wafer W2, the hand HA receives and carries out the wafer (FIG. 3b).

Next, the XY stage is moved, and the first shot S11 of the first area of the wafer W1 is sent under the projection lens PO for exposure (Fig. 3b).Hereafter, while moving the XY stage, the first shot S11 of the first area of the wafer W1 is exposed. . . . All the shots in the first area on the right side of the dividing line DL in FIG. 4 are exposed in a step-and-repeat manner. In parallel with this exposure operation, the hand HC is rotated 180 degrees to the state shown in FIG. 3C.

1st f! When the exposure of the four areas is completed, the XY stage is moved to the transfer position side (rightward in the drawing), and on the way, the wafer W1 on the chuck Wc is picked up by the hand HC (FIG. 3C). Then, when the XY stage reaches the transfer position (Fig. 3 d), the hand HC is lowered to transfer the wafer W1.
is again placed on the chuck Wc, and the chuck WC side is positioned below the second region of the wafer W1 (FIG. 3e). In this state, the XY stage is moved in the same manner as above, and the first shot S21 of the second area of the wafer W1 is sent under the projection lens PO for exposure (FIG. 3f), hereinafter S22 and S23.
,... and so on, the second line on the left side of the dividing line OL in Fig. 4.
Expose all shots of the area in a step-and-repeat manner. In parallel with these exposure operations, a new unexposed wafer w2 is supplied to the hand HA (FIG. 3f).

When the exposure of the entire surface of the wafer is completed in this way, the XY stage is moved to the transfer position, where the exposed wafer W1 on the chuck Wc is picked up by the hand HC (
Figure 3g). Then, the unexposed wafer W is transferred from the hand HA.
2 is brought onto the chuck Wc (Fig. 3h), and at the same time, the hand HC is rotated 180 degrees to return to the state of Fig. 3(a), where the unexposed wafer is shown as wl and the exposed wafer is shown as W2. .

In this way, when the wafer is carried out from the chuck wC by the hand HA, the hand HC first picks up the exposed wafer from the chuck WC, and then moves the wafer 18o.

Since the chuck wc rotates to hold out the exposure flow wafer to the hand HA side, the chuck wc does not need a notch for letting the hand HA escape, and can support the wafer over a wider range, that is, more stably. Further, since a hand for collecting wafers (particularly a hand for large-diameter wafers) is not required, it is useful for downsizing the apparatus.

In this apparatus, wafers that are large enough to fit into the chuck WC, that is, the diameter is less than the minor axis of the chuck WC, for example, φ5'', are collected directly from the XY stage by the hand HB. This eliminates the hassle of replacing or setting the hand HC when processing small-diameter wafers, and provides the same ease of use as a machine dedicated to small-diameter wafers.

In this apparatus, wafers are transferred during exposure of one wafer, which causes a time loss.・However, between a 10 inch full stroke XY stage and an 8 inch full stroke XY stage, the step time for the same distance is longer for the 10'' device due to the mass etc. as mentioned above.For example, the step time per 10 IIW If it is 0.4 seconds for an 8" device, it will be 0.5 seconds for a 10" device.

Therefore, in the case of a φ10'' wafer shown in Fig. 4, the number of shots is 250, so the step time per wafer is 8.
It takes 100 seconds for a 10'' device and 125 seconds for a 10'' device. In other words, in an 8" device, even if a 10 second reloading time is allowed, the processing time per wafer is still 15 seconds shorter than in a 10" device.

[Modified example] In the above-mentioned embodiment, the chuck WC is tilted at an angle of about 45 degrees to the Y axis and the Y axis, more precisely, parallel to the diagonal line a to a of the movable area of the XY stage. However, when the dividing line OL can be set parallel to the X or Y axis, that is, when processing a wafer of φ230rIn or less in the above description, it is not necessarily necessary to tilt the dividing line OL.

Furthermore, in the above, the chuck WC is tilted with respect to the Y-axis and the Y-axis, but the chuck WC is set so that its major axis is parallel or perpendicular to the Y-axis, and the chip arrangement on the wafer is tilted. (See Figure 4C). In this case, the main step feeding of the wafer can be done by driving the X stage and Y stage simultaneously, so the combined speed of the X stage and Y stage is faster than when the conventional X stage is used alone. This increases speed and helps improve throughput. In other words, if the speed ratio of the X stage and Y stage is 4:3, the above chip arrangement is θ relative to the Y axis.
= jan-1 (3/4) When tilted, the speed is 5, which is the fastest.

Furthermore, in the above description, when transferring a wafer during exposure, the wafer is simply raised and lowered, and the wafer is shifted by the amount of movement ω of the XY stage during this raising and lowering. A mechanism for moving the image plane in a direction parallel to the image plane of the projection lens PO without a rotational component may be provided above the XY stage, and the above-mentioned transfer may be performed by this mechanism.

Furthermore, when collecting the wafer with the hand HB mentioned above, if the hand HC picks up the wafer from the XY stage, then rotates this hand HC by 90'' and transfers it to the hand HB, the hand relief part LR of the chuck WC, LL becomes unnecessary, and the wafer can be supported over a wider range, that is, more stably.

[Other Examples] In the above-mentioned embodiments, only the wafer is loaded/unloaded (carried in, unloaded, and transferred) to/from the XY stage while the chuck WC is placed on the XY stage. It is also possible to attach and detach the XY stage together with the chuck. In this case, two of the same shape
If you prepare two chucks and use them in the wafer transport system when one is on the XY stage, there is no problem in exchanging unexposed wafers and exposed wafers using the supply/recovery hand HA. It can be implemented.

FIG. 5 shows a case where the wafer W and the wafer chuck WC are attached to and removed from the XY stage while being integrated (carrying (exchange) → first area exposure → transfer → second area exposure → unloading (exchange)). It is an operation explanatory diagram.

This operation is performed in the same manner as when only the wafer is loaded and unloaded in FIG. 3, except that the wafer W and chuck WC are always integrated.

The advantages of handling the wafer W and chuck WC in this way are that the possibility of wafer damage is reduced compared to when handling the wafer alone, and the chuck W
If the external dimensions of C are made constant, there is no need to replace or reset the mechanical parts such as hand HC and hand H in FIG. 9, which will be described later, in accordance with the wafer dimensions.

FIG. 6 shows an example of a chuck used for this integration attachment/detachment. In the figure, the chuck WC is configured in the shape of a disk whose diameter is slightly larger than the diameter of the wafer W. N.R.
, NL are notches for separating the wafer from the chuck WC and transferring it when loading and unloading the wafer to and from a wafer carrier (not shown). In addition, this chuck WC has a portion PR that protrudes in the diametrical direction so as not to be covered by the wafer.
.

PL is provided, and alignment marks AR and Am are provided on the protrusions PR and PL, respectively. With these marks AR, AL and alignment marks on the wafer,
If the relative positional relationship between the wafer and the chip is measured in advance in the transport system, etc., when the wafer is placed on the XY stage, by referring to the marks AR and AL, the wafer can be aligned faster and more efficiently. Helps you do it with precision. Also,
Alignment mark AR on the chuck prior to integration transfer of the wafer and chuck during exposure.

The positional relationship between AL and the equipment side or reticle side reference mark (not shown) and the XY stage is read and this value is memorized, and after the transfer, the positional relationship between the marks AR, AL and the equipment side or the reticle side reference mark (not shown) and the XY stage is stored again. After reading the positional relationship between the This will also help improve throughput if you expose more than

FIG. 7 shows another embodiment of the integrated removable type. In the same figure, HA is a wafer chuck WC replacement hand, H
C is a hand for lifting and lowering the chuck WC. The operation is exactly the same as shown in FIG. Note that the hand HA realizes wafer and chuck exchange with respect to the stage WXY by holding the wafer chuck WC on its side and rotating it around the axis AS.

In the transport system, the unexposed wafer WO is transferred to the supply carrier SC.
The wafer is taken out from the wafer chuck WCO, pre-aligned at an alignment position (not shown), and placed on the waiting wafer chuck WCO. Further, the exposed wafer received from the hand I-IA is transported together with the chuck to a predetermined position, and then separated from the chuck and stored in the collection carrier Re.

FIG. 8 shows a hand HC suitable for the above-mentioned integrated attachment and detachment.

It schematically shows the structure of chuck WC and stage WS. Hold wafer W and chuck WC in hand 1
-When handing over to 1c, rubber pads P of hand HC
1 covers the hole H1 on the surface of the chuck WC, and vacuum is supplied through the tube T1. Then, the pipe U1,
Packing P1, pipe line U2 and suction hole H2 are depressurized,
The chuck WC is sucked to the hand HC by the gasket P1 while holding the wafer W in the suction hole H2. Note that in this case, the suction of the wafer W by the chuck WC is sufficient as long as the wafer W and the chuck WC are not broken into one piece, so the suction holes H2 are provided in decimal numbers at the periphery of the wafer W. It is.

On the other hand, when transferring the wafer W and chuck WC to the stage WS, vacuum is supplied through the tube T2 with the opening of the rubber gasket P2 of the stage WS covering the hole H3 on the back surface of the chuck WC. Then, tube T
2 to suction hole H4 via packing P2 and pipe U3.
is depressurized, and the chuck WC is sucked onto the stage WS by the gasket P2 while holding the wafer W in the suction hole H4.

Note that in this case, it is preferable that the wafer W be adsorbed by the chuck WC to the extent that the wafer W is flattened.
The suction holes H4 are provided over the entire back surface of the wafer W.

The chuck WC may be further provided with another vacuum suction system, such as one for a hand HA having an opening on the side, as required.

[Brief explanation of drawings]

FIG. 1 is a schematic view of the main parts of a semiconductor exposure apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged top view and an A-Alli side view of the wafer chuck in FIG. 1, and FIG. FIG. 4 is an explanatory diagram of the operation of the apparatus shown in FIG. 1, FIG. 4 is a chip layout diagram of a wafer exposed by the apparatus shown in FIG. 6 is a perspective view of a wafer chuck used in the apparatus of FIG. 5; FIG. 7 is a schematic top view of a semiconductor exposure apparatus according to still another embodiment of the present invention; FIG. 6 is a perspective view of a wafer chuck used in the apparatus of FIG. , FIG. 8 is a structural explanatory diagram of a wafer chuck, a transfer hand, and an XY stage suitable for use in the apparatus of FIG. 5 or 7. RT doubleticle, PO: projection lens, WY: Y-direction movement stage, WX: X-direction movement stage, θZ: θZ stage, WXY: XY stage, HA: wafer supply/retrieval hand, HB: small diameter wafer retrieval hand, HC new wafer transfer hand, AM near-tW, Wl
, W2: wafer, DL bisecting line, 811, 812.
..., S21.822. ... Nijiyotsuto, WC:
Wafer chuck, AR, AL: alignment mark, G: suction groove, 01, D2, D3: nipple.

Claims (1)

[Claims] 1. A substrate transport means, a substrate stage, a first hand that picks up a processed substrate from the substrate stage, and places an unprocessed substrate received from the substrate transport means on the substrate stage. A substrate processing apparatus comprising: a second hand for receiving a processed substrate from the first hand and delivering the processed substrate to a substrate transport means. 2. The substrate according to claim 1, wherein the substrate is held eccentrically with respect to the rotation axis of the first hand and the center of the substrate and rotated to change the position of the substrate to facilitate handing over to the second hand. Substrate processing equipment. 3. The substrate processing apparatus according to claim 2, wherein the first hand is rotated to change the direction of the substrate and place the substrate on the substrate stage. 4. A patent claim that has a third hand for recovering the substrate in a direction different from the substrate movement direction of the second hand, and that the first hand is eccentrically rotated to deliver the processed substrate to the third hand. 2. The substrate processing apparatus according to item 2. 5. Scope of Claims: Large-diameter substrates are fed and collected by the second hand, small-sized substrates are fed by the second hand, and collected by the first and third hands. The substrate processing apparatus according to item 4. 6. The substrate processing apparatus according to any one of claims 1 to 5, which is a step-and-repeat type exposure apparatus.