JP2003152061A - Substrate sucking and fixing table and exposure system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate sucking and fixing table wherein influence of foreign matters on a back of a semiconductor wafer which is sucked and held on a substrate sucking and fixing table and influence of unevenness of the back are improved simultaneously. SOLUTION: This substrate sucking and fixing table is used for sucking and holding flatly the semiconductor wafer 11 retained by a retaining pin 15, by making pressure of a sucking chamber 13 surrounded with an outer peripheral wall 12 negative. In the table, the length of a long edge 17 of a shape of a contact surface of the retaining pin 15 is different from that of a short edge 18, and the edge 17 is made longer than the period of the unevenness of the back of the semiconductor wafer 11 without excessivively increasing contact ratio, so that influence is not exerted from both the foreign matter on the back of the semiconductor wafer 11 and the unevenness of the back of the semiconductor wafer 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate suction-fixing base for sucking and holding a semiconductor wafer, and more particularly to a technique for maintaining a highly accurate flat surface of a semiconductor wafer held on the substrate suction-fixing base.

[0002]

2. Description of the Related Art For example, exposure for forming a predetermined resist pattern on a semiconductor wafer by applying a resist on a semiconductor wafer and exposing and developing a circuit pattern for one layer formed on a reticle, which is a master. In the apparatus, the flatness of the semiconductor wafer becomes an important issue in order to prevent a resolution defect due to the fact that an image is not formed within the depth of focus and form a sharp circuit pattern.
For this reason, a flat state is realized by vacuum suction from the back surface by a substrate suction fixing base having a good flatness, and an exposure process is performed on this.

As an example in which such an exposure apparatus is described in detail, for example, published by the Industrial Research Board, "1999.
For example, there is a "VLSI Manufacturing / Testing Equipment Guidebook" (published on November 20, 1998), and the substrate adsorption and fixing base is used as shown in Fig. 1. Here, the shape of this substrate suction fixing base is as shown in FIG. 2 or FIG. 3, but there are advantages and disadvantages.

That is, since the substrate suction fixing base having the shape shown in FIG. 2 is contacted by the minute support pins, the contact rate with respect to the semiconductor wafer is low, and the foreign matter on the back surface of the semiconductor wafer is less likely to be caught. It is effective in reducing the exposure failure that is the cause. However, when the state of the back surface of the semiconductor wafer is uneven, the flatness of the front surface side of the semiconductor wafer may be affected depending on whether the tip of the support pin contacts the projection or the recess.

On the other hand, since the substrate adsorption / fixing base of FIG. 3 contacts the semiconductor wafer on a continuous surface, the irregularities on the back surface of the semiconductor wafer are always in contact with the projections, which is flat on the front surface side of the semiconductor wafer. Hard to affect the degree. But,
Since the contact rate with the back surface of the semiconductor wafer becomes large, and there is a high probability that foreign matter on the back surface of the semiconductor wafer will be caught, exposure failure due to this is likely to occur.

As an invention relating to this, Japanese Patent Laid-Open No.
There are 163848 and Japanese Patent Application No. 1-319965, and certain effects can be obtained from each viewpoint.

[0007]

However, the flatness obtained by the above-described substrate suction fixing base is not sufficient. That is, in the above invention, reduction of exposure failure due to the influence of foreign matter on the back surface of the semiconductor wafer and reduction of influence of flatness of the semiconductor wafer surface due to unevenness on the back surface of the semiconductor wafer are alternatives, and both problems are solved at the same time. I can't.

Therefore, an object of the present invention is to simultaneously achieve both reduction of the influence of foreign matter on the back surface of the semiconductor wafer and reduction of the influence of unevenness on the back surface of the semiconductor wafer by optimizing the shape of the support pins of the substrate suction fixing base. Thus, it is to provide a technique capable of maintaining a highly accurate flat surface.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0010]

The typical ones of the inventions disclosed in the present subject matter will be outlined below.

That is, in the substrate suction fixing base according to the present invention, the length of the long side of the shape of the upper surface of the support pin is set to a certain length or more so as to have a sufficient distance with respect to the cycle of the unevenness of the semiconductor back surface. By making the length of the side as short as possible, the semiconductor wafer is held flat by suction without increasing the contact area with the semiconductor wafer as much as possible.

An exposure apparatus according to the present invention is characterized in that it is constructed by using the above-mentioned substrate suction fixing base.

The semiconductor manufacturing method according to the present invention is for manufacturing a semiconductor by exposing a semiconductor wafer using the above-mentioned substrate suction / fixing stand or the exposure apparatus.

In the semiconductor substrate processing method and semiconductor manufacturing method according to the present invention, a semiconductor wafer is polished by using the above-described substrate suction fixing base to manufacture a semiconductor.

According to the substrate suction fixing base having the above-described structure, the distance between the long sides 17 of the support pins 15 is made longer than the distance of the repetition cycle of the unevenness of the back surface of the semiconductor wafer 11, so that the unevenness of the back surface The effect of repetition can be minimized, and an effect comparable to that in the case of continuous contact as shown in FIG. 3 can be obtained.

That is, as shown in FIG. 5, when the unevenness of the back surface of the semiconductor wafer 11 is measured by a surface roughness meter, the maximum unevenness is 0.3 mm although it depends on the type of the semiconductor wafer 11. In the following cases, 0.3 mm is sufficient for the long side 17 of the support pin 15, and the maximum period does not exceed 0.8 mm empirically even at the maximum, so it is sufficient for the long side 17 to be 0.8 mm at the maximum. is there. On the other hand, as shown in FIG. 12, the length of the short side 18 of the support pin 15 is not unnecessarily long, so that the area of the short side × the long side can be reduced, and the short side 18 and the long side 17 can be reduced. Long sides 17
By increasing, the area increases as the square of the long side 17, whereas according to the present invention, the area increases only by the square of the long side 17. Further, by shortening the short side 18 conversely, the difference can be further expanded. Short side 1
The length of 8 is due to processing problems or durability problems,
It is necessary to have a minimum of 0.05 mm or more, and it is necessary to set the maximum to 0.3 mm because the effect cannot be expected if it exceeds 0.3 mm which has been generally used conventionally. Further, if the ratio of the short side 18 to the long side 17 is too small, the effect cannot be expected, so at least 1.
2 or more is required. The area ratio of points of action is empirically 2%
The following are considered desirable, so it is necessary to determine the dimensions to satisfy all of them.

As a result, it is possible to realize a substrate suction-fixing stand which can simultaneously keep the influence of foreign matter on the back surface of the semiconductor wafer 11 and the influence of unevenness on the back surface of the semiconductor wafer 11 to a minimum, and to prevent defocusing. It is possible to prevent problems from occurring.

According to the exposure apparatus using such a substrate suction fixing base, even in a fine process with a shallow depth of focus,
A good circuit pattern can be transferred to the semiconductor wafer 11.

According to the semiconductor manufacturing method using such a substrate suction fixing base or the exposure apparatus, the semiconductor can be manufactured even in a fine process having a shallow depth of focus.

It is possible to polish the semiconductor wafer 11 by using such a substrate suction fixing base to form a highly accurate flat semiconductor or to manufacture a semiconductor.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic view showing an exposure apparatus in which a substrate suction / fixing base according to an embodiment of the present invention is used, and FIG. 2 shows the pin contact type substrate suction / fixing base and a semiconductor wafer 11. FIGS. 3 and 4 are a plan view and a sectional view of a ring contact type substrate suction fixing base.

As shown in FIG. 1, the exposure apparatus using the substrate suction fixing base according to the present embodiment uses, for example, an Hg lamp 2 as an exposure light source. The exposure light 3 from the Hg lamp 2 is converged by the elliptical mirror 4, and is then converged by the condenser lens 8 via the reflector 5, the relay lens 6, and the reflector 7. After passing through such an illumination system, the light is captured by the circuit pattern formed on the reticle 9, reduced by the reduction lens 10, and finally projected onto the semiconductor wafer 11 held on the substrate suction fixing base 1. The semiconductor wafer 1 coated with the resist by this
The circuit pattern will be transferred onto the surface 1.

Here, as shown in FIG. 2, the substrate suction fixing base 1 for holding the semiconductor wafer 11 is surrounded by the outer peripheral wall 12 in order to prevent deformation due to aging and thermal expansion, for holding the semiconductor wafer 11. The suction chamber 13 is formed in the substrate suction fixing base 1. Suction chamber 13
Is connected to an external exhaust pump or the like (not shown) via the suction hole 16. As shown in FIG. 3, the outer peripheral wall 12 is formed to be slightly smaller than the semiconductor wafer 11 to prevent the resist solution applied around the back surface of the semiconductor wafer 11 from adhering.

The conventional substrate suction fixing base is a semiconductor wafer 1.
In order to make it less likely to be affected by foreign matter on the back surface of No. 1, the support pin 15 having a small contact area often contacts the back surface of the semiconductor wafer 11. The shape of the contact portion of the support pin 15 is φ
Many of them are about 0.2 to φ0.3 (or about □ 0.2), and with respect to the surface roughness of the unevenness on the back surface of the semiconductor wafer 11 shown in FIG. Susceptible to.

Support pins 15 of the substrate suction fixing base 1 of the present invention.
As shown in FIGS. 6 and 12, the shape of the contact portion is not the same in length and width, but is a rectangular shape in which the short side 18 is 0.1 mm and the long side 17 is 0.4 mm. . When the rectangular action points are arranged in a grid pattern with a pitch of 2 mm, the contact area ratio is 1%, which is a sufficient value against the influence of the foreign matter sandwiched on the back surface of the semiconductor wafer 11. Moreover, since the long side 17 is 0.4 mm, the cycle of the unevenness on the back surface of the semiconductor wafer 11 is 0.
For those having a thickness of 4 mm or less, the support pins 15 do not intervene, and the effect of unevenness is less likely to appear on the surface of the semiconductor wafer.

As a result, both the foreign matter on the back surface of the semiconductor wafer 11 and the unevenness on the back surface of the semiconductor wafer 11 are less likely to be affected, and a focus margin can be secured for exposure and the like. (Embodiment 2) In the substrate adsorption / fixing base 1 of Example 1, even when the support pin 15 has an oval shape or an elliptical shape as shown in FIG. 7, a difference between the long side and the short side is provided. The same effect can be obtained by the thing. The same applies to a shape in which the corners of a rectangle are chamfered. (Third Embodiment) In the substrate suction fixing base 1 of the first or second embodiment, it may be necessary to dispose the support pins 15 having different long sides 17 and short sides 18 in consideration of the directivity.

That is, when the irregularities on the back surface of the semiconductor wafer 11 have a certain directionality (for example, when the surface shape is like a hairline finish), the effect of the length in the direction of the long side 17 is not effective. There are cases.

In this case, it is effective that the direction of the long side 17 is different for each support pin.

FIG. 8 shows a change in directionality in the case of a grid arrangement, and FIG. 9 shows a change in directionality in the case of a polar coordinate arrangement.
FIG. 10 shows the change in directionality in the case of the staggered arrangement.

In the case of FIGS. 8 and 9, the direction is changed by 90 degrees, and in the case of FIG. 10, the angle 20 of the support pin of the middle stage 19 is alternately switched to +60 degrees and -60 degrees.

As a result, the influence of the directionality of the unevenness can be reduced. (Embodiment 4) The substrate adsorption / fixing base 1 according to Embodiments 1 to 3.
The exposure apparatus in which is used as shown in FIG. 1 is less likely to be affected by foreign matter on the back surface of the semiconductor wafer 11 and less likely to be affected by unevenness on the back surface of the semiconductor wafer 11, and thus is less likely to cause defects. In addition, the yield can be improved by the semiconductor manufacturing method using this manufacturing method. (Embodiment 5) A polishing apparatus for a semiconductor wafer 11 using the substrate adsorption / fixing bases of Embodiments 1 to 3 as shown in FIG. When polishing is performed while the front surface of the semiconductor wafer 11 is in contact with the polishing table 21 in the state where the wafer 11 is straightened, the influence of foreign matter on the back surface of the semiconductor wafer 11 is less likely, and the influence of unevenness on the back surface of the semiconductor wafer 11 is also affected. Since it is hard to receive, the semiconductor wafer 11 can be processed into a highly accurate flat surface. In addition, the yield can be improved by a semiconductor manufacturing method using this manufacturing method.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

In the above description, the invention mainly made by the present inventor has been described with respect to an optical exposure apparatus which is a field of application which is the background of the invention. However, the invention is not limited thereto, and an electron beam exposure apparatus, and The present invention can be applied not only to these exposure apparatuses but also to various semiconductor manufacturing apparatuses and semiconductor inspection apparatuses that need to hold a semiconductor wafer in a flat state.

Then, it is possible to manufacture a semiconductor by using the method described above. Manufacturing a semiconductor can include manufacturing a liquid crystal as well.

[0035]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. (1). That is, according to the substrate suction fixing base of the present invention,
By keeping the contact rate of the support pins 15 small when the semiconductor wafer 11 is sucked,
Of the back surface of the semiconductor wafer 11 and the back surface of the semiconductor wafer 11 are less likely to be affected by irregularities. (2). Therefore, according to the exposure apparatus using the substrate suction fixing base according to the present invention, the held semiconductor wafer 11
Since the flatness of the exposed surface side of the semiconductor wafer 1 is improved, a circuit pattern having a good resolution can be obtained without changing the focal length.
It becomes possible to transfer to 1. (3). By the above (2), good semiconductor chips can be manufactured even in the entire area of the semiconductor wafer 11, and production with a good yield can be performed. (4). Further, according to the substrate suction fixing base according to the present invention,
In polishing the semiconductor wafer 11 adsorbed to it,
Due to the effect of (1), a highly accurate surface can be processed, and when used in combination with the exposure device of (2), a better focus can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an exposure apparatus in which a substrate suction fixing base according to a first embodiment of the present invention is used.

FIG. 2 is a perspective view showing a structure of a conventional pin contact type substrate suction fixing base.

FIG. 3 is a plan view showing a structure of a conventional ring contact type substrate suction fixing base.

FIG. 4 is a cross-sectional view showing a structure of a conventional ring contact type substrate suction fixing base.

FIG. 5 is a diagram of surface roughness on the back surface of the semiconductor wafer according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing the shape of the pin according to the first embodiment of the present invention.

FIG. 7 is a plan view showing the shape of a pin according to the second embodiment of the present invention.

FIG. 8 is a plan view showing an arrangement of pins in a board array according to a third embodiment of the present invention.

FIG. 9 is a plan view showing the arrangement of pins in the polar coordinate array according to the third embodiment of the present invention.

FIG. 10 is a plan view showing an arrangement of pins in a staggered arrangement according to a third embodiment of the present invention.

FIG. 11 is an explanatory diagram for flattening a substrate according to the fifth embodiment of the present invention.

FIG. 12 is a perspective view showing a structure of a substrate suction fixing base having a pin shape according to the first embodiment of the present invention.

[Explanation of symbols]

1 ... Substrate adsorption fixing base, 2 ... Hg lamp, 3 ... g line (light), 4 ... Elliptical mirror, 5 ... Reflector, 6 ... Integrator, 7 ... Reflector, 8 ... Condenser lens, 9
... reticle, 10 reduction lens, 11 semiconductor wafer, 12 ring, 13 suction chamber, 15 support pin, 1
6 ... suction hole, 17 ... long side, 18 ... short side, 19 ... middle stage, 2
0 ... angle, 21 ... polishing machine.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasushi Matsuda             5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Stock             Ceremony Company within Hitachi Semiconductor Group (72) Inventor Koichi Koyanagi             3-3 Fujibashi, Ome City, Tokyo 2 Hitachi Higashi             Inside Kyo Electronics Co., Ltd. (72) Inventor Teruo Honda             3-3 Fujibashi, Ome City, Tokyo 2 Hitachi Higashi             Inside Kyo Electronics Co., Ltd. F term (reference) 3C058 AA01 AB04 CA01 CB01                 5F031 CA02 CA05 FA01 FA02 FA07                       HA08 HA13 MA22 MA27 PA14                 5F046 CC08 CC10

Claims (10)

[Claims] 1. A fixing table for vacuum-adsorbing a substrate, wherein the area ratio of the points of action in contact with the substrate is 2% or less, the surface shape of the points of action is rectangular, and the long side distance of the rectangle is 0.3.
mm or more and 0.8 mm or less, and the distance of the short side is 0.0
5 mm or more and 0.3 mm or less, and the long side is the short side 1.
A substrate suction fixing base having a support pin that is more than twice as large. 2. A fixing table for vacuum-adsorbing a substrate, wherein the area ratio of the points of action in contact with the substrate is 2% or less, the surface shape of the points of action is oval, and the distance between the long sides of the oval is 0. .3
mm or more and 0.8 mm or less, and the distance of the short side is 0.0
5 mm or more and 0.3 mm or less, and the long side is the short side 1.
A substrate suction fixing base having a support pin that is more than twice as large. 3. A fixing base for vacuum-adsorbing a substrate, wherein the area ratio of the points of action contacting the substrate is 2% or less, the surface shape of the points of action is elliptical, and the distance between the long sides of the ellipse is 0. .3
mm or more and 0.8 mm or less, and the distance of the short side is 0.0
5 mm or more and 0.3 mm or less, and the long side is the short side 1.
A substrate suction fixing base having a support pin that is more than twice as large. 4. When arranging the support pins having the surface shape according to claim 1, claim 2 or claim 3 in a grid pattern, the long side direction is arranged so as to be alternately changed by 90 degrees. Substrate adsorption fixing base with supporting pins. 5. When arranging the support pins having the surface shape of claim 1, claim 2 or claim 3 in polar coordinates, it is arranged so that the direction of the long side is alternately changed by 90 degrees. A substrate suction fixing base having a supporting pin to be. 6. When the support pins having the surface shape of claim 1, claim 2 or claim 3 are arranged in a staggered manner,
A substrate adsorption fixing base having a support pin characterized by repeating a row arranged so that the direction of the long side is alternately changed by 90 degrees and a row in which the direction of the long side is alternately repeated +60 degrees and -60 degrees. . 7. A method of manufacturing a semiconductor by performing exposure using a substrate suction fixing base having a support pin according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6. 8. A semiconductor exposure apparatus having a substrate suction fixing base having the support pin according to claim 1, claim 2, claim 3, claim 4, claim 5, or claim 6. 9. A method of polishing a semiconductor wafer by using a substrate suction fixing base having a support pin according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6. 10. A method of polishing a semiconductor wafer by using a substrate suction fixing base having a support pin according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6. Method of manufacturing a semiconductor.