JP4681756B2 - Exposure apparatus and device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD.
[0002]
[Prior art]
In recent years, in an exposure apparatus for semiconductor manufacturing and the like, there has been a demand for higher productivity and higher functionality in response to the demand for higher integration and higher integration in order to respond to the rapid increase in demand. Development of an exposure apparatus having higher throughput and higher transfer performance is desired.
[0003]
In such an exposure apparatus, a substrate holding apparatus that holds a substrate such as a wafer includes a wafer chuck that sucks a wafer as a substrate by a predetermined vacuum suction force, and the wafer chuck is separated from a focus position of the exposure apparatus. The process of receiving the wafer from the transfer hand at the wafer supply position, sucking and holding the wafer by the vacuum suction force and moving it to the focus position, and after the exposure is completed, the process of moving from the focus position to the wafer recovery position and collecting the wafer is repeated. Do.
[0004]
In a conventional exposure apparatus, there is only one suction line that generates a vacuum suction force for sucking a wafer onto the wafer chuck, and only a constant vacuum suction force is generated by switching ON / OFF. The vacuum suction force for sucking the wafer on the wafer chuck was the same in any sequence from receiving the wafer from the hand, carrying it to the focus position, finishing exposure, and moving it to the wafer collection position.
[0005]
[Problems to be solved by the invention]
However, according to the above conventional technique, the vacuum suction force of the wafer onto the wafer chuck is controlled only by ON / OFF switching, so that the supplied wafer is exposed and transported to the wafer recovery position. A large vacuum adsorption force will be maintained. However, there is a difference in the required vacuum suction force in each sequence from the wafer supply position to the focus position until the exposed wafer is transported to the wafer recovery position. While the wafer is received from the transfer hand and moved to the focus position, and while the wafer is moved from the focus position to the wafer recovery position, the wafer is attracted to the wafer chuck with an excessive vacuum suction force, and the wafer is transferred. In the work, the suction confirmation time and the pressure confirmation time when releasing the vacuum suction force to release the wafer become longer, and the throughput is lowered.
[0006]
In addition, the vacuum suction force cannot be controlled optimally by the sequence, and the burden on the vacuum source as a whole apparatus is large, affecting other vacuum systems.
[0007]
The present invention aims to provide an advantageous exposure apparatus in terms of throughput.
[0008]
[Means for Solving the Problems]
To achieve the above object, an exposure apparatus of the present invention, the retaining disc having a holding surface for holding a substrate, a variable mechanism for varying the vacuum suction force generated in the holding surface of the holding plate, the holding plate The stage moves between a supply position for holding the substrate supplied from the transport system on the holding plate and a focus position for exposing the substrate held on the holding plate. An exposure apparatus comprising:
The vacuum suction force is increased by the variable mechanism while the stage moves from the supply position to the focus position .
[0016]
[Action]
The vacuum chucking force generator of a holding plate such as a wafer chuck can be selectively connected to, for example, two suction lines, and the process of transporting a wafer as a substrate from the wafer supply position to the focus position, In the process of transporting wafers to the wafer collection position, the wafer is sucked and held with a weak vacuum suction force that does not cause the wafer to fall from the wafer chuck. At the focus position, strong vacuum suction is used for flattening the wafer and for stable holding during exposure. The vacuum suction force is switched in at least two stages so as to suck the wafer by force.
[0017]
Since the wafer is sucked with a weak vacuum suction force, the suction holding confirmation time is shortened, the vacuum suction force is switched while moving to the focus position, and the wafer is flattened with a strong vacuum suction force during wafer exposure. Thus, the wafer can be stably held and the positioning can be performed with high accuracy.
[0018]
In addition, a weak vacuum suction force is switched while the exposed wafer is moved from the focus position to the wafer recovery position, thereby shortening the time required for vacuum break for releasing the suction.
[0019]
In this way, the time spent for turning on / off the vacuum suction force can be greatly shortened, and the throughput of the exposure apparatus can be improved.
[0020]
In addition, since the time for maintaining a strong vacuum suction force is shortened, there is also an advantage that the burden on the vacuum source of the entire apparatus can be reduced.
[0021]
By using such an exposure apparatus, it is possible to contribute to improving the productivity of semiconductor devices and the like.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 1 illustrates a first embodiment. As shown in FIG. 1A, a wafer chuck 1 which is a holding disk mounted on a wafer stage such as an XY stage of an exposure apparatus, and its holding A suction part having pipes 2a and 2b, which are vacuum suction force generating parts for generating a vacuum suction force for sucking a wafer as a substrate, on a suction surface 1a as a face, and a pressure sensor 3 for detecting the pressure in the pipe. 10 is provided.
[0024]
The negative pressure of the pipes 2a and 2b for generating a vacuum suction force on the suction surface 1a of the wafer chuck 1 is supplied via a suction force variable mechanism 20 shown in FIG. The suction force variable mechanism 20 divides the vacuum pressure supplied from the vacuum source 4 of the apparatus into two suction lines 21a and 21b, and the controller 5 operates one of the lines to operate the electromagnetic valve 22 serving as switching means. Thus, the vacuum suction force on the wafer chuck 1 is changed in two stages. The vacuum suction force by each suction line 21a, 21b is adjusted to a predetermined two-stage vacuum suction force by the regulators 23a, 23b.
[0025]
In the exposure apparatus, when the wafer is supplied to the wafer chuck 1 on the wafer stage from the transfer system, the wafer transferred onto the wafer chuck 1 is sucked by the first suction line 21a with a weak vacuum suction force. At this time, it is determined whether the wafer is attracted to the wafer chuck 1 while monitoring the vacuum attracting force by the pressure sensor 3, and the process proceeds to the next sequence. During this time, the vacuum suction force for sucking the wafer on the wafer chuck 1 is sufficient if it can withstand the driving of the wafer stage, so the weak vacuum suction set in the first suction line 21 a of the suction force variable mechanism 20. Use power.
[0026]
Thus, when the wafer is attracted onto the wafer chuck 1 with an attracting force sufficient to withstand the stage drive, the wafer stage starts driving and moves from the wafer supply position to the focus position. In the meantime, the electromagnetic valve 22 is operated so as to switch the vacuum suction force that sucks the wafer on the wafer chuck 1 to the strong vacuum suction force of the second suction line 21 b of the suction force variable mechanism 20. The vacuum suction force by the second suction line 21b set as the suction force at the time of exposure is set to be larger than the suction force set at the time of wafer supply and recovery in consideration of wafer flatness correction.
[0027]
After the exposure is completed, the first suction line 21a of the suction force variable mechanism 20 is switched again while moving to the wafer collection position.
[0028]
As described above, the vacuum pressure from the vacuum source 4 is set to a necessary value for the two suction lines 21a and 21b by the regulators 23a and 23b in the suction force variable mechanism 20, and these two systems are set to solenoid valves. Since it is switched by 22, the vacuum suction force can be changed instantaneously. That is, it is possible to change the vacuum suction force to an appropriate value without generating an extra time lag.
[0029]
According to the present embodiment, when the wafer is transferred at the wafer supply position and the wafer recovery position, the wafer is sucked with a vacuum suction force lower than the vacuum suction force at the focus position. The time required to confirm the release can be greatly reduced. That is, since it is sufficient to generate a low vacuum suction force at the time of supplying the wafer, the time required for generating the vacuum suction force can be shortened, and similarly, the time required for the vacuum break can be shortened when collecting the wafer.
[0030]
By switching the suction line while moving to the focus position, the throughput of the exposure apparatus can be greatly improved. In addition, the time required for high vacuum pressure is shortened, which can contribute to reducing the burden on the vacuum source.
[0031]
FIG. 2 shows a second embodiment. In the suction force variable mechanism 30, the vacuum pressure supplied from the vacuum source 4 outside the apparatus is first divided into two suction lines 31 a and 31 b by an electromagnetic valve 32. By selecting either line by operating the electromagnetic valve 32, the vacuum suction force of the suction portion 10 of the wafer chuck 1 is changed. The vacuum suction force by each suction line 31a, 31b is adjusted to a two-stage vacuum suction force by the regulators 33a, 33b. The control of the vacuum suction force by switching the suction lines 31a and 31b is the same as in the first embodiment.
[0032]
In this way, the vacuum pressure from the vacuum source 4 is set to a required value in the two suction lines 31a and 31b by the regulators 33a and 33b inside the variable suction force mechanism 30, and the two systems are switched by the solenoid valve 32. Therefore, the vacuum suction force can be changed instantaneously. That is, it is possible to arbitrarily change the vacuum suction force without generating an extra time lag.
[0033]
FIG. 3 shows a third embodiment. A negative pressure as a vacuum suction force on the wafer chuck 1 is supplied from a vacuum source 4 outside the apparatus, and a servo valve 40 constituting a suction force variable mechanism is provided. Thus, it is possible to change the pressure value by changing the vacuum suction force for sucking the wafer on the wafer chuck 1 steplessly.
[0034]
In a semiconductor exposure apparatus, when a wafer is supplied onto the wafer chuck 1 of the wafer stage from the transfer system, whether the wafer is attracted to the wafer chuck 1 while monitoring the vacuum attracting force for attracting the wafer onto the wafer chuck 1. Judge whether or not to proceed to the next sequence. At this time, the vacuum chucking force of the wafer chuck 1 need only be enough to drive the wafer stage, so the servo valve 40 is controlled to a low vacuum chucking force.
[0035]
When the wafer is sucked onto the wafer chuck 1 with a vacuum suction force sufficient to drive the stage, the wafer stage starts driving and moves to the focus position. Meanwhile, the vacuum suction force set to the suction force at the time of exposure is changed by controlling the servo valve 40. The vacuum suction force at the time of exposure is set to be larger than the vacuum suction force set at the time of wafer supply and recovery in consideration of wafer flatness correction.
[0036]
According to the present embodiment, by installing a servo valve that can be controlled to an arbitrary level, it is possible to freely control the vacuum suction force on the sequence, and to cope with a change in the pressure of the vacuum source 4 Is easy.
[0037]
Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 4 shows a manufacturing flow of a semiconductor device (a semiconductor chip such as an IC or LSI, or a liquid crystal panel or a CCD). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask production), a mask which is an original plate on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. 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. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (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, the semiconductor device is completed and shipped (step 7).
[0038]
FIG. 5 shows a detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is reduced by the projection lens system which is the exposure means of the exposure apparatus described above, and the wafer is printed and exposed. In step 17 (development), the exposed wafer is developed. 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 manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device that has been difficult to manufacture.
[0039]
【The invention's effect】
The present invention can provide an exposure apparatus that is advantageous in terms of throughput .
[Brief description of the drawings]
FIGS. 1A and 1B show a substrate holding device of an exposure apparatus according to a first embodiment, in which FIG. 1A is a diagram showing a configuration of a wafer chuck that is an adsorption unit, and FIG. It is.
FIG. 2 is a diagram showing a second embodiment.
FIG. 3 is a diagram illustrating a third embodiment.
FIG. 4 is a flowchart showing a semiconductor manufacturing process.
FIG. 5 is a flowchart showing a wafer process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wafer chuck 2a, 2b Piping 3 Pressure sensor 4 Vacuum source 5 Controller 20, 30 Suction force variable mechanism 21a, 21b, 31a, 31b Suction line 22, 32 Solenoid valve 23a, 23b, 33a, 33b Regulator 40 Servo valve

Claims (3)

Includes a retaining disc having a holding surface for holding a substrate, a variable mechanism for varying the vacuum suction force generated in the holding surface of the holding plate, and a stage for mounting the retaining disc, the stage is conveyed An exposure apparatus that moves between a supply position for holding a substrate supplied from a system on the holding plate and a focus position for exposing the substrate held on the holding plate,
An exposure apparatus, wherein the vacuum suction force is increased by the variable mechanism while the stage moves from the supply position to the focus position. A holding plate having a holding surface for holding a substrate; a variable mechanism for changing a vacuum suction force generated on the holding surface of the holding plate; and a stage on which the holding plate is mounted, the stage being a transfer system An exposure apparatus that moves between a supply position for holding the substrate supplied from the holding plate on the holding plate and a focus position for exposing the substrate held on the holding plate,
  An exposure apparatus, wherein the vacuum suction force is reduced by the variable mechanism while the stage moves from the focus position to the supply position. A step of exposing the substrate by the exposure apparatus according to claim 1 or 2 ,
Device manufacturing method characterized by having a step of developing the substrate exposed in the step.

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