JP2588377B2 - Semiconductor wafer holder and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer holder used for manufacturing an LSI and a method for manufacturing the same.

[0002]

2. Description of the Related Art A semiconductor wafer used in general LSI manufacturing is subjected to 100 to 200 processes of depositing various materials, forming a pattern, removing unnecessary portions by etching, adding impurities, annealing, oxidizing, and cleaning. Is performed.
During this process, the wafer is generally held in various holders.

[0003] What has been most frequently used so far is a so-called boat or susceptor made of quartz (not shown) (first conventional example). As another alternative, there is a ceramic jig mainly composed of polycrystalline Si, SiC, or the like (second conventional example).

As another wafer holder, a jig 9 such as a so-called cassette or tray formed by molding a resin such as Teflon or polypropylene as shown in the perspective views (1) and (2) of FIG. Is commercially available (third conventional example).

There is another wafer holder which is used in LSI manufacturing and uses a semiconductor wafer itself. For example, a so-called branch holder is processed by processing a lowest-cost Si wafer as a semiconductor wafer using a lathe or the like (fourth conventional example).

[0006]

The jig used in the first conventional example has a high heat-resistant temperature of about 400 to 1150 ° C., and uses various high-temperature grown thin films (thermal oxide films, chemical vapor deposition techniques). Is used as a holder for attaching or growing a so-called CVD film on a wafer. However, this is easily affected by hydrofluoric acid and the like, and the processing accuracy is poor. There was a difficulty.

[0007] Also in the second conventional example, there is no great difference in gains and losses of interest, except for the improvement of chemical resistance, as compared with the quartz jig described above. Further, the third conventional example is excellent in chemical resistance unlike the above-mentioned quartz jig, but has low heat resistance of about 200 ° C. and cannot withstand a high temperature treatment of about 100 ° C., and thus its use is limited.

Further, the fourth conventional example can be said to be the most desirable in terms of heat resistance and cleanliness. However, the smoothness of the machined surface is poor. , Various debris originate from the wafer and wafer holder. These fragments are LS
This causes contamination and pattern defects at the I level, and is far from a general-purpose semiconductor wafer holder.

The present invention solves the above-mentioned conventional problems of using a wafer itself as a holder, and provides a semiconductor having characteristics such as low cost, high cleanliness, and high heat resistance required for a general wafer holder. It is an object to obtain a wafer holder and a method for manufacturing the same.

[0010]

According to the present invention, as shown in FIG. 1, a semiconductor wafer holder (1) for holding a semiconductor wafer (6) is composed of a single crystal plate and a semiconductor wafer (6) is placed thereon. (2) is formed by anisotropic etching, and the side wall has a forward taper so that the bottom (4) of the dent (2) and the side wall of the dent (2) are continuous. .

[0011]

For example, a recess (2) having a shape corresponding to the shape of the semiconductor wafer (6) is processed by anisotropic etching on a single crystal plate having a crystal surface (100) as a main surface, and the processed recess (2) is processed. ) Is placed and held on the semiconductor wafer (6).

[0012]

1 shows a semiconductor wafer holder according to a first embodiment of the present invention. FIG. 1 (1) is a plan view, and FIG. 1 (2) is a sectional view taken along line XX '(not to be complicated). Therefore, diagonal lines are omitted).

In FIG. 1, reference numeral 1 denotes a semiconductor wafer holder, which is mainly composed of single crystal Si having (100) as a main surface 11. Reference numeral 2 denotes a depression formed by anisotropic etching and serving as a holding portion of a wafer 6 shown by a broken line. Reference numeral 3 denotes a side wall thereof, and reference numeral 4 denotes a bottom portion. Reference numeral 5 denotes a hole for loading and unloading the wafer 6 from the holding portion of the holder.

The recess 2 has a single crystal silicon (anisotropically etched surface) formed by anisotropic etching of single crystal Si and another (100) main surface 11 ′ parallel to the main surface 11 having side walls. To form a continuous forward taper. Therefore, the main surface 11 ′ forms the bottom 4.

Here, the above-mentioned anisotropic etching surface is obtained by a difference in etching rate depending on the plane orientation of a crystal represented by an anisotropic etching solution such as a mixture of KOH, water and alcohol. Shows a low etching rate for this type of liquid.

The plane represented by (nn1) of single crystal Si shows a low etching rate. Here, n is an integer. Typical surfaces include (111) and (331).

In the present invention, (nn1), (n'n'1), (n "n" 1).
Are formed, and these mutually continuous portions generally form the side wall 3 of the wafer holding portion, and another (100) provided by processing as shown in the cross-sectional view of FIG.
The surface, or main surface 11 ', forms the bottom 4 of the wafer holding site.

At the center of the bottom 4 is a wafer holder 1.
Is provided. This hole 5 allows the wafer 6 to be held and moved by an arm or a manipulator (not shown) at the bottom when the wafer 6 is loaded or unloaded from the wafer holder 1, and contamination or defects on the wafer surface are prevented. Can be avoided.

Next, an example of a method for manufacturing the semiconductor wafer holder 1 shown in FIG. 1 will be described with reference to cross-sectional views showing a process sequence in FIG. As shown in FIG. 2A, a single crystal Si piece 101 having a (100) plane is oxidized, and a SiO ₂ film 102 is grown on the surface as a sub-member. Part Although SiO ₂ film is made of a mask for subsequent anisotropic etching is not limited to the SiO ₂ film, Si ₃ N ₄ film, SI
POS, polycrystalline Si or the like may be used, and these are collectively called a thin film layer.

The single-crystal Si piece 101 may be a small piece cut out of a single-crystal Si ingot, or a large-diameter Si wafer called a dummy wafer in consideration of the mass production effect.

Next, as shown in FIG. 2B, a mask 103 for processing the SiO ₂ film 102 is formed by photolithography (optical engraving), and the mask 103 is
The O ₂ film 102 is selectively removed.

Subsequently, as shown in FIG.
After removing 03, it is immersed in an anisotropic etching solution to process the single crystal Si piece 101. Due to the characteristics of the anisotropic etching solution, the single crystal Si piece 101 is formed as shown in FIGS.
(N1), (n'n'1) ...
Is processed to appear.

In the example of FIG. 2 (3), the right side of the drawing shows an example in which the single crystal Si piece 101 has been penetrated, and the left side has a part of the single crystal Si piece 101, and a new (10)
An example in which processing is performed up to the state where the 0) plane is formed is shown. In this case, the SiO ₂ film 102 on the back surface of the single-crystal Si piece 101 is left.
This is for preventing the processing, and may be removed after the desired processing.

When high precision is not required, the SiO ₂ film 102 on the back surface is unnecessary. According to the above steps (n
n1), (n'n'1) According to ... experimental result of forming the side wall 3 consecutive, the mask 103 is patterned into a circular shape, a single crystal of the SiO ₂ film 102 has been transferred as a mask When the Si piece 101 is processed, this single crystal S
An anisotropic etching surface of the i-piece appears, and FIG.
The processed shape as shown in FIG. In this experiment, processing was performed while maintaining a 20% aqueous solution of KOH at 80 ° C., and a small amount of isopropyl alcohol was added for the purpose of controlling anisotropic etching.

According to the above-described embodiment, L is used as the main member.
Since single crystal Si as the material of SI is used, a low-cost and high-quality material can be easily obtained. In addition, the same shape can be mass-produced by using the photolithography technology, so that the cost can be reduced, and the high precision processing quality of 1 μm or less possessed by the photolithography technology is also provided.

Further, since the holder is made of single-crystal Si, all the cleaning means in the usual LSI manufacturing process can be used, and the same level of cleanliness as the Si wafer to be held can be easily obtained. Further, it has necessary and sufficient heat resistance.

Further, since the holder has a high-accuracy surface for holding the wafer, there is no cause of dust such as projections and small holes, and the holder has low dust generation. Further, since the portion in contact with the wafer is limited to a part of (nn1) constituting the side wall, even if thin film deposition or growth is performed with the wafer 6 loaded as shown in FIG. 11 and the wafer 6 do not adhere.

The (nn1) plane makes a specific angle (θ in FIG. 1 (2), for example, about 54 ° in the case of (111)) with the (100) plane. The angle is easy to do. That is, the width of the opening of the side wall 3 is increased by “2 × dtan (90−θ)”,
The displacement of the wafer 6 at the time of loading can be absorbed. Note that d is the height of the main surface 11 and the main surface 11 '.

Next, a second embodiment of the present invention is shown in FIG.
This is because the wafer holder 1 obtained by the method shown in FIG.
This is a wafer holder having a composite structure in which another material 8 is embedded between the two. Bonding of the two wafers holder 1, 1 'are bonded by flaky SiO ₂ obtained by oxidizing and reducing gas of the low-melting glass and SiH ₄ based (so-called soot).

This bonding is performed with high precision as described above.
The method is not limited to a method for assuring high purity, and can be fixed as much as possible by using an adhesive as needed or simply by pressing (for example, van der Waals force).

This embodiment can be applied to the detection of the position of the wafer holder 1 by using a material 8 of a different material from the wafer holders 1 and 1 '. For example, when relatively high-resistance Si is used, infrared rays and the like are well transmitted, but when a metal is used, infrared rays are blocked, so that the position of the wafer holder 1 can be detected with high accuracy by infrared rays. Moreover, if it is a metal, an eddy current can be generated by an external alternating magnetic field, and the metal can play a role of a heater.
If a magnetic material is used instead of metal, drive control such as movement and holding of the wafer holder 1 using magnetic force can be performed.

FIG. 1 shows an application example of the present invention.
Multiple leaf holders using the above bonding technology
It can be. The wafer holder 1 is a single crystal
Since Si is used as the main member, SiO _Two, Si_Three
N_Four, SiO_xN_ySo-called SIPOS film, polycrystalline S
i-film or a sub-member of these composite films
1 because it can be deposited on the surface of
There is. For example, if the surface is SiO_Two, Upper layer S
i_ThreeN _FourWhen a two-layer film consisting of
1 is resistant to contamination despite being Si, and
And high performance as a holder in a high temperature atmosphere
Performance and high reliability. The surface is made of SiO_TwoCover with membrane
This makes it difficult for contaminants to enter the wafer holder 1.
Thus, high-purity characteristics can be maintained for a long time.

[0033]

As described above, according to the present invention, low cost, high cleanliness, high heat resistance, and high reliability can be obtained for practical use.

The wafer holder in the case of the composite structure can perform drive control such as position detection, movement, and holding of the wafer holder by a material embedded therein.
It is advantageous for further automation and cost reduction when used in the SI manufacturing process.

[Brief description of the drawings]

FIG. 1 shows a plan view (1) and a sectional view (2) of a first embodiment of the present invention.

FIG. 2 shows an example of a method for manufacturing a semiconductor wafer holder according to the present invention.

FIG. 3 shows a sectional view of a second embodiment of the present invention.

FIG. 4 is a perspective external view showing an example of a conventional wafer holder.

[Explanation of symbols]

1 semiconductor wafer holder 2 recess 3 side wall 4 bottom 5 hole 6 wafer 7 adhesive 8 Stock 9 jigs 11, 11 'main surface 101 monocrystalline Si piece 102 SiO ₂ film 103 mask

Claims (2)

(57) [Claims] 1. A semiconductor wafer holder for holding a semiconductor wafer, comprising a single crystal plate having a depression for holding the semiconductor wafer, wherein the depression formed on the single crystal plate has a bottom surface formed by a crystal. A semiconductor wafer holder, wherein the side wall of the recess is formed so as to form a forward taper in which a lower end of the side wall is continuously connected to the bottom surface. 2. A method of manufacturing a semiconductor wafer holder having a depression for holding a semiconductor wafer, comprising: a single crystal plate having one crystal surface as a main surface; A first step of forming a thin film layer forming a mask, and after forming a mask for processing the thin film layer on the thin film layer, using the mask to make the thin film layer correspond to the shape of the depression. A second step of selectively removing the single crystal plate by anisotropic etching using the selectively removed thin film layer after removing the mask used in the second step. A third step of forming a bottom surface of the dent and a side wall of the dent after being removed by a depth, wherein the first to third steps are sequentially performed; Method of manufacturing a Ehahoruda.