JP2745413B2 - Exposure equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and more particularly, to a temperature adjustment mechanism of a wafer chuck that mounts and holds a wafer.

[Prior Art] In a semiconductor lithography process, an exposure apparatus exposes a wafer through a mask to transfer and form a pattern on the wafer. In order to form a high-precision pattern, it is necessary to keep the temperature of the wafer constant and to minimize deformation due to heat. For this reason, a cooling medium for adjusting the temperature is supplied to the wafer chuck for sucking the wafer, thereby keeping the temperature of the wafer on the wafer chuck constant. In a conventional exposure apparatus, a constant amount of medium has always flowed through a medium flow path passing through a wafer chuck.

[Problems to be Solved by the Invention] However, in the above-described conventional technology, it is necessary to always supply a constant amount of a cooling medium at a flow rate necessary for suppressing a rise in temperature due to wafer exposure. When the medium flows through the medium flow path in the wafer chuck, the wafer chuck and the surrounding wafer support vibrate with this flow. The displacement due to this vibration is between 0.0 μm and 0.
The pattern formation accuracy at the time of exposure was reduced to several μm.

On the other hand, if the cooling medium is flowed at such a flow that the vibration accompanying the flow of the cooling medium does not affect the pattern formation accuracy, the temperature rise of the wafer cannot be suppressed below the allowable temperature.

The present invention has been made in view of the above-described drawbacks of the related art, and has a wafer support unit capable of suppressing a wafer temperature rise during exposure to an allowable temperature or less without lowering pattern formation accuracy due to flow vibration. And an exposure apparatus provided with the temperature adjustment mechanism.

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, a wafer suction means for mounting and holding a wafer to be exposed through a mask, and a medium for adjusting the temperature of the wafer suction means are provided. A medium flow path for flowing, a flow rate adjusting means for adjusting a flow rate of the medium flowing through the medium flow path, and a control means for controlling the flow rate adjusting means, wherein the control means responds to exposure and non-exposure. The flow rate adjusting means is controlled such that the medium flow rate during exposure is smaller than the medium flow rate during non-exposure.

[Operation] At the time of exposure, the flow rate is set so that the vibration of the flow does not affect the pattern formation accuracy. At the time of non-exposure, a cooling medium having a flow rate sufficient to absorb the temperature rise is used.

FIG. 1 is a block diagram of an exposure apparatus according to the present invention. In the figure, 1 is a light source for performing exposure, 2 is a shutter for exposing for a desired exposure time, 3 is a mask having a pattern to be transferred, 4 is a wafer for exposing and transferring a pattern, and 5 is a wafer for suction. A wafer chuck 6 for fixing and holding, a positioning stage 6 for positioning the mask and the wafer, a flow control valve 7 for adjusting a flow rate of the temperature control medium, and a temperature control valve 8 for controlling the temperature of the wafer chuck. Flow path through which the temperature adjusting medium flows, 9
Is a temperature control pump for circulating the medium, and the medium temperature is controlled to be constant by a heat exchange means (not shown).
10 is a flow control unit for controlling the operation of the flow control valve 7, 11 is an exposure control unit for controlling the exposure procedure, 12 and 13 are outlets and inlets of the flow path in the wafer chuck for the temperature control medium, and 14 is the exposure. This is an exposure state signal line indicating whether the apparatus is in exposure or non-exposure.

The operation of the exposure apparatus having the above configuration is as follows. A cooling medium is sent from the pump 9. This medium temperature is 23 ℃ ±
It is controlled at 2/100 ° C and repeats circulation. The cooling medium is channel 8
The wafer enters the wafer chuck 5 from the inlet 13 through the through hole, absorbs the heat of the wafer chuck 5 and the wafer 4, and is discharged from the outlet 12. The discharged medium returns to the pump 9 through the flow control valve 7, where the temperature is again controlled to 23 ° C. ± 2/100 ° C., and the circulation is repeated.

The exposure control unit 11 sends an exposure state signal indicating whether or not the apparatus is performing exposure to the flow rate control unit 10 via a signal line 14. Flow control section
Reference numeral 10 controls the flow control valve 7 to operate in two stages (flow rate A and flow rate B) depending on whether or not exposure is being performed. That is, during exposure, the flow rate A is within an allowable range so that the vibration applied to the wafer chuck 5 does not affect the pattern formation accuracy. It is assumed that the flow rate B is sufficient (flow rate A <flow rate B) so that the rise does not exceed the allowable temperature range. The exposure controller 11 further controls the light source 1, controls the opening and closing of the shutter 2, and controls the movement of the positioning stage 6 according to a predetermined sequence program.

FIG. 2 shows a flowchart of the exposure sequence of the exposure apparatus. When the exposure sequence control is started, first, the wafer 4 previously mounted and sucked on the wafer chuck 5 is sucked.
In order to transfer the pattern of the mask 3 to the first exposure position, the exposure control section 11 drives and controls the alignment stage 6 to align the first exposure position of the wafer 4 with the mask 3 (step a). . Next, the opening of the flow control valve 7 is set by the flow control unit 10 so as to obtain the flow rate A (step b). Next, the shutter 2 is opened for a predetermined time to perform exposure at the first exposure position (step c). After a lapse of a predetermined time, the shutter 2 is closed to end the exposure at the first exposure position (step d). Next, the opening of the flow control valve 7 is set by the flow control unit 10 so that the flow control valve 7 has the flow rate B (step e). Subsequently, the exposure sequence control of the second exposure position is started by aligning with the second exposure position (step f).
Thereafter, steps b, c, d, and e are repeated in the same manner, and the third
Sequence control is similarly performed after the exposure position.

FIG. 3 is a time chart showing the temperature, flow rate, exposure state, and vibration amount of the exposure apparatus on the same time axis. During exposure, the flow rate is reduced (flow rate A), the vibration is reduced (vibration amount X), and high-precision patterning is enabled.
At the time of non-exposure, the flow rate is increased (flow rate B) to lower the temperature. At this time, the vibration increases with an increase in the flow rate (vibration amount Y), but does not affect the patterning accuracy since the exposure is not performed.

FIG. 4 shows the configuration of another embodiment of the present invention. In this embodiment, a temperature sensor 15 for detecting the temperature of the wafer chuck 5 is provided, and a signal line 16 for inputting the detected temperature to the flow controller 10 is provided. The flow control unit 10 sets the flow control valve 7 in multiple stages according to the temperature of the wafer chuck 5 to control the flow during non-exposure. Thereby, more accurate temperature control can be efficiently achieved.
Other configurations, operations and effects are the same as those of the above-described embodiment.

[Effects of the Invention] As described above, in the present invention, since the flow rate control means for the temperature adjusting medium flowing in the wafer chuck is provided, the medium flow rate can be controlled according to the exposure state, Without lowering the throughput of the process, the wafer temperature is kept at a predetermined allowable temperature or lower, and a decrease in pattern accuracy due to the vibration of the flow of the medium is prevented, thereby enabling high-precision patterning.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an exposure apparatus according to the present invention, FIG. 2 is a flowchart showing an exposure sequence of the embodiment of FIG. 1, FIG. 3 is a time chart of the embodiment of FIG. The figure is a block diagram of another embodiment of the present invention. 1 ... light source, 2 ... shutter, 3 ... mask, 4 ...
Wafer, 5 ... Wafer chuck, 6 ... Positioning stage, 7 ... Flow control valve, 8 ... Flow path, 9 ...
Pump, 10 ... Flow control unit, 11 ... Exposure control unit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Uda, Inventor 3- 30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Isamu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Shunichi Uzawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-63-73519 (JP, A) JP-A-64-23530 (JP) JP-A-1-205419 (JP, A) JP-A-63-38319 (JP, U) JP-A-1-140818 (JP, U)

Claims (3)

(57) [Claims] 1. A wafer suction means for mounting and holding a wafer to be exposed via a mask, a medium flow path for flowing a medium for adjusting the temperature of the wafer suction means, and a medium flowing in the medium flow path. A flow rate adjusting means for adjusting the flow rate of the medium, and a control means for controlling the flow rate adjusting means, the control means according to the time of exposure and non-exposure, the medium flow rate at the time of exposure than the medium flow rate at the time of non-exposure An exposure apparatus for controlling the flow rate adjusting means so as to reduce the flow rate. 2. The exposure apparatus according to claim 1, wherein the flow rate of the medium at the time of exposure is a flow rate within a range in which vibration accompanying the flow of the medium does not affect exposure accuracy. 3. A temperature sensor for detecting a temperature of said wafer suction means, wherein said control means controls said flow rate adjusting means in accordance with a detection signal from said temperature sensor. 2. The exposure apparatus according to claim 1, wherein: