JPH0338835Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vacuum suction device that is used in the manufacturing process of semiconductor devices and chucks a semiconductor wafer (hereinafter abbreviated as wafer) by vacuum suction.

[Conventional technology]

2. Description of the Related Art In the manufacturing process of semiconductor devices, a method of vacuum suctioning a wafer and subjecting it to various treatments is often used. Among these, in photolithography as a patterning means, the surface flatness of the wafer during exposure has a large effect on patterning accuracy. For example, in a reflective projection mask aligner using a batch exposure method, if the wafer has a warpage of about 20 to 40 μm due to the depth of focus of the projection lens, the wafer is vacuum-adsorbed onto a flat support surface to smooth out the surface irregularities. It is necessary to suppress the thickness to about 8 μm or less.

If dust or the like is present between the wafer and its supporting surface,
If a portion having irregularities larger than about 8 μm occurs on the wafer surface, normal patterning will not be performed at this portion, resulting in variations in the pitch of the semiconductor element arrangement. Therefore, during exposure, the wafer must be in complete contact with the support surface.

In addition, the method of processing wafers by vacuum suction is
It is also used for single-fed baking. In this single-wafer baking method, a method is generally adopted in which the temperature of the supporting surface is kept constant and heat is uniformly conducted to the wafer. In this case, if a portion of the wafer has poor adhesion, heat conduction decreases at this portion, resulting in loss of uniformity of temperature distribution within the wafer. Since the pattern dimensions of semiconductor devices require high accuracy, processed wafers often become defective even if minute temperature fluctuations occur during baking.

FIG. 2 shows a conventional example of a wafer vacuum suction device (see Japanese Patent Laid-Open No. 59-3945).
In the figure, grooves 1 are carved approximately concentrically on the support surface (vacuum suction surface) 4 of the wafer. In addition, at the bottom of this groove 1, there is a suction hole 2 of the same size.
For example, a predetermined number of holes are provided at equal intervals so that a suction amount proportional to the bottom area of the holes can be obtained. Each suction hole 2 is connected to the center hole 3 inside the disc 6,
Furthermore, it is connected to a vacuum pump (not shown) via a vacuum line 5. Note that this vacuum suction device was processed as necessary for transportation in an automated line, etc. In addition, as a means for detecting whether or not the wafer is in close contact with the vacuum suction surface 4, a pressure gauge (not shown) is provided in the vacuum line 5, and the state of close contact is determined based on the pressure P detected by the pressure gauge. There were also things being done.

In such conventional wafer vacuum suction equipment,
As shown in FIG. 3a, when the edge of the wafer 9 is relatively far away from the vacuum suction surface 4 due to the presence of protrusions or dust 7, the
Because air flows in from the space 8, the vacuum line 5
The pressure P was higher than normal, and it was possible to determine that there was poor adhesion between the wafer 9 and the vacuum suction surface 4.

[Problem that the invention attempts to solve]

However, in the conventional wafer vacuum suction device, as shown in FIG. 3b, protrusions or dust 7
If there is a gap inside the vacuum suction surface 4, no new air will flow into the gap 8, so the pressure P in the vacuum line 5 will not increase, and poor adhesion cannot be detected. It was impossible. As the diameter of wafers increases, if the wafer is bent due to poor adhesion, high-precision processing cannot be performed in the above-mentioned processes such as exposure and baking, resulting in a decrease in the precision of semiconductor element arrangement. However, this has been a major problem in improving productivity since it results in the production of defective wafers.

Therefore, an object of the present invention is to provide a vacuum suction device for semiconductor wafers, which can determine adhesion failure regardless of the location where the adhesion failure occurs, and which can be applied to large-diameter wafers.

[Means for solving problems]

The vacuum suction device for semiconductor wafers according to the present invention includes:
Adjacent to the concentric suction grooves, leak grooves are carved approximately concentrically on the supporting surface of the disc, and the positions of the suction holes equally spaced in the suction grooves are balanced. A large number of leak holes are formed at equal intervals at the bottom of the leak groove, and the leak holes are connected to the leak center hole inside the disk.

[Effect]

In the present invention, a large number of leak holes are branched from the leak center hole and arranged in each leak groove, so each leak groove is connected to the leak center hole and the leak hole. It is possible to uniformly fill leak gas to a predetermined pressure.

In addition, since the leakage grooves are carved approximately concentrically on the support surface so as to be adjacent to the suction grooves, protrusions may be interposed at arbitrary points between the wafer and the support surface, resulting in If a gap occurs, this 〓
The leak gas flows from the leak groove adjacent to the gap to the adjacent suction groove over a substantially shortest distance.

Furthermore, since a large number of leak holes are opened at equal intervals at the bottom of the leak groove in balance with the suction hole position, when the leak gas inflow occurs, new leak gas can be inflowed and sucked efficiently. It is done.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG. In addition, in this example, a leak groove 10, a leak hole 11, and a leak center hole 12 are newly provided in the conventional wafer vacuum suction device, and the same parts as in the conventional example are provided. A code is attached. In the figure, there are suction grooves 1 and leakage grooves 1 on the wafer support surface (vacuum suction surface) 4.
0 are engraved adjacently and approximately concentrically. There are two suction holes 2 of the same size in the first suction groove 1 from the center, and two suction holes 2 in the second and third suction grooves 1 located on two orthogonal center lines. A total of four locations have been opened. Leak holes 11 of the same size are formed at positions on the bisector of the center line of each leak groove 10, and each leak hole 11 is connected to a leak center hole 12 inside the disk 6. has been done. Although air is generally allowed to flow in through the leak center hole 12, an inert gas such as N ₂ may also be used as the leak gas.

In addition, in accordance with the technical idea of the present invention, the leak holes 11 are arranged equally in each leak groove 10 in balance with the position of the suction holes 2 so that poor adhesion at any position on the support surface 4 can be reliably determined. We plan to open multiple locations at regular intervals. Therefore, as described in the conventional example, when a large number of suction holes 2 are provided at equal intervals at the bottom of each suction groove 1 so as to obtain a suction amount proportional to the bottom area, If the leak holes 11 are of the same size, the number of them is increased and they are opened at equal intervals as the diameter of the leak grooves 10 increases, in order to balance the position of the suction holes 2 and increase the accuracy of determining poor adhesion. I can do things.

Next, a mechanism for determining poor adhesion will be described. Now, at an arbitrary point on the vacuum adsorption surface (supporting surface) 4, dust 7 is present between the wafer 9 and the space 8.
is occurring. In this case, the air newly flowing in through the path of leak center hole 12→leak hole 11→leak groove 10 is transferred to the gap 8→adjacent suction groove 1→suction hole 2→center hole 3. It is sucked into the vacuum line 5 via the path. Therefore, since the pressure P in the vacuum line 5 is higher than when the wafer 9 is normally suctioned, it is possible to reliably determine with good reproducibility that there is a poor adhesion between the wafer 9 and the vacuum suction surface 4. I can do it.

Note that it is desirable to provide a filter means in the leak center hole 12.

In addition to the exposure and baking steps, for example, when applying resist, the wafer 9 is held on the vacuum suction surface 4.
After being chucked by vacuum suction, the disc 6 is urged to rotate by a drive motor (not shown).

Therefore, the present invention can be applied to all devices that require close contact between the wafer 9 and the vacuum suction surface 4, such as a wafer exposure device, a baking device, a photoresist coating/developing device, and a grinder.

[Effect of idea]

As described in detail above, according to the present invention, the leak groove 10 is carved approximately concentrically on the support surface 4 of the wafer adjacent to the suction groove 1, and the leak groove 10 is formed adjacent to the suction groove 1. Since the main structure has a large number of leak holes 11 at equal intervals in balance with the position of the suction holes 2 on the bottom, it is possible to easily prevent poor adhesion at any location between the wafer 9 and the support surface 4. This has the effect of allowing reliable judgment.

In addition, since poor adhesion can be sufficiently prevented for large-diameter wafers, in processes that require close contact between the wafer 9 and the support surface 4, such as exposure and baking,
It also has the effect of enabling high-precision processing and improving the quality and yield of semiconductor devices using large-diameter wafers.

[Brief explanation of the drawing]

Fig. 1a is a plan view of the main part showing an embodiment of the present invention, Fig. 1b is a sectional view of the main part illustrating the mechanism for determining poor adhesion in the same embodiment, and Fig. 2a is a main part showing the conventional example. Fig. 2b is a sectional view of the main part thereof, Fig. 3a is a sectional view of the main part explaining the adhesion failure determination mechanism in the conventional example, and Fig. 3b is a sectional view of the main part explaining the defect. It is. 1... Suction groove, 2... Suction hole, 4... Support surface (vacuum suction surface), 6... Disk, 9... Wafer,
10...Leak groove, 11...Leak hole, 12
...Leak center hole.

Claims (1)

[Scope of utility model registration request] In a vacuum suction device for semiconductor wafers, the upper surface of a disk is used as a support surface, and the support surface has substantially concentric suction grooves in which a large number of suction holes are opened at equal intervals at the bottom of the support surface. a leak groove formed substantially concentrically on the support surface adjacent to the groove; a large number of leak holes formed at equal intervals at the bottom of the leak groove in balance with the suction hole position; A vacuum suction device for semiconductor wafers, comprising a leak center hole connecting the leak hole inside the disk.