JP2006148143A - Holder for semiconductor-manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holder for a semiconductor-manufacturing apparatus, which is superior in burning ability of a wafer-holding surface and can be properly used for the thermal curing of resin for photolithography in a coater developer and the heat baking of a semiconductor insulating film of low dielectric constant, such as Low-k, and in which the apparatus as a whole can be miniaturized. <P>SOLUTION: The holder for the semiconductor-manufacturing apparatus consists of a wafer-holding part 1 which has a resistor heating element 2 and is made of ceramics, and a support element 4 which supports the wafer-holding part 1. The thermal conductivity of the support element 4 is lower than the thermal conductivity of the wafer-holding part 1, and the wafer-holding portion 1 and the support element 4 are not jointed. Preferably, the wafer holding part 1 has AlN as the main component, and the supporting element 4 is composed mainly of mullites. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a holder used in a semiconductor manufacturing apparatus, and is particularly suitable for heat curing of a resin film for photolithography in a coater developer and heat baking of a low dielectric constant insulating film such as Low-k. The present invention relates to a semiconductor manufacturing apparatus holder.

  In semiconductor manufacturing, Al circuits and Cu circuits on silicon wafers are formed by Al sputtering, Cu plating, etc., but with the recent high integration and miniaturization of semiconductors, the wiring width and inter-wiring width become smaller year by year. It is coming.

  The wiring pattern of the Al circuit or the Cu circuit is formed by a photolithography technique. For example, after a resin is evenly applied on an Al film, a pattern is imprinted on the resin film using an exposure device called a stepper, and the resin film is heated and cured to remove unnecessary portions, thereby removing the resin film on the Al film for wiring. A pattern resin film is formed. Thereafter, the Al film is etched along the cut pattern portion with an etching apparatus, and the resin film is removed to obtain a patterned Al wiring.

  Further, since the signal interaction between the wirings occurs when the wirings are close to each other, it is necessary to eliminate the interaction between the wirings by filling the wirings and the laminated layers with an insulating material having a low dielectric constant. Conventionally, silicon oxide has been used as an insulating material for this purpose, but a material called Low-k has come to be used as an insulating film having a lower dielectric constant. The low-k insulating film is made by dissolving the material into a slurry and spin-coating it to form a uniform film. After the patterning is performed by the photolithography technique in the same manner as described above, the film is solidified by heating and baking with a heater. It is formed by the method of making it.

  For example, a SUS foil as a resistance heating element is sandwiched between quartz plates as a heater used for heat curing of a resin film for photolithography as described above, or for heating and baking a low dielectric constant insulating film such as a low-k film. A heater was used. However, since there is a problem with the soaking property and durability of the heater, a heating device with excellent soaking property and high durability has been desired.

On the other hand, in a CVD apparatus used for forming various thin films, a ceramic heater in which a Mo coil is embedded in AlN or Si ₃ N ₄ having high thermal conductivity and high corrosion resistance is used. This ceramic heater is supported by bonding one end of a cylindrical AlN support to the back side of the wafer holding surface and sealing the other end with an O-ring. Moreover, the electrode terminal with low corrosion resistance and the lead wire for supplying the electrode are accommodated inside the cylindrical AlN support so as not to be exposed to the corrosive gas used in the chamber.

  In order to reduce costs in semiconductor manufacturing, the size of silicon wafers has been increased, and in recent years, the size has shifted from 8 inches to 12 inches. For this reason, there is an increasing demand for improvement in thermal uniformity for a heater used for heat curing of a resin film for photolithography and for heat baking of a low dielectric constant insulating film such as Low-k. Specifically, it is desired that the thermal uniformity on the wafer holding surface of the heater is within ± 1.0%, and preferably within ± 0.5%.

  In general, in a ceramic heater, there is a case where a wafer holding part and a support are joined in order to stabilize the wafer holding part or protect the electrode terminal from the atmosphere in the chamber. In this case, if the thermal expansion coefficients of the wafer holding part and the support are different, thermal stress is generated due to the difference in thermal expansion coefficient between the materials during the heating and cooling process, and cracking occurs in the ceramic, which is a brittle material. The wemi holding part and the support were joined using the same material.

  However, if a material with high thermal conductivity is used for the wafer holding part in order to increase the thermal uniformity of the wafer holding surface, it is necessary to use the same material with high thermal conductivity for the support, and this occurs in the resistance heating element of the wafer holding part. Heat escapes very efficiently through the support with high thermal conductivity. For this reason, the temperature of the wafer holding part is greatly lowered at the joint portion with the support, and the heat uniformity of the wafer holding part has to be lowered.

  In addition, in order to prevent the thermal uniformity of the wafer holding part from deteriorating due to heat escaping to the joined support, if a support having a low thermal conductivity and a different thermal expansion coefficient from that of the wafer holding part is joined, the difference in thermal expansion coefficient There was a problem that cracks were formed in the ceramic wafer holding part, which is a brittle material, due to the thermal stress caused by.

  Furthermore, in order to lower the temperature of the place where the support is placed in the chamber and prevent thermal deterioration of the material on the chamber side, it is common practice to cool the vicinity of the support placement part of the chamber with water or the like. In this case, if the support is short, the temperature gradient becomes tight, so that the support is easily broken by the thermal shock. In order to prevent cracking due to thermal shock, it is usually necessary to lengthen the support to about 300 mm. Therefore, the height of the chamber for housing the support must be increased, and there is a restriction on downsizing of the entire apparatus.

  In view of such a conventional situation, the present invention is excellent in heat uniformity of a wafer holding surface, heat curing of a resin film for photolithography in a coater developer, and heating of an insulating film having a low dielectric constant such as Low-k. An object of the present invention is to provide a holding body for a semiconductor manufacturing apparatus that can be suitably used for firing and can be downsized as a whole.

  In order to achieve the above object, a holding body for a semiconductor manufacturing apparatus provided by the present invention includes a ceramic wafer holding part having a resistance heating element and a supporting body that supports the wafer holding part. The rate is lower than the thermal conductivity of the wafer holder, and the wafer holder and the support are not joined.

In the holding body for a semiconductor manufacturing apparatus according to the present invention, the wafer holding portion is mainly composed of at least one ceramic selected from AlN, Al ₂ O ₃ , SiC, and Si ₃ N ₄ , In particular, the wafer holding part is preferably AlN.

  In the holding body for a semiconductor manufacturing apparatus of the present invention, the support is mainly composed of mullite, and it is particularly preferable that the support is a composite of mullite and alumina.

  Furthermore, this invention provides the semiconductor manufacturing apparatus using either of the above-mentioned holding bodies for semiconductor manufacturing apparatuses. The semiconductor manufacturing apparatus provided by the present invention is an apparatus used for heat curing of a resin film for photolithography or heat baking of an insulating film having a low dielectric constant.

  According to the present invention, there is provided a holding body for a semiconductor manufacturing apparatus in which the thermal uniformity of the wafer holding surface can be made within ± 1.0%, preferably within ± 0.5%, and the entire apparatus can be miniaturized. can do. This holding body for a semiconductor manufacturing apparatus can be suitably used for heat curing of a resin film for photolithography in a coater developer and heat baking of a low dielectric constant insulating film such as Low-k.

In the semiconductor manufacturing process, heat curing of a resin film for photolithography used for a coater developer and low-k baking are different from a CVD apparatus and an etching apparatus using a corrosive gas containing a halogen element, such as He, Ar, N _2. , H ₂ or the like is used as an atmosphere, so that an electrode mainly composed of a material that is easily corroded by halogen is not corroded, and problems such as contamination to the chamber do not occur.

  Therefore, in a semiconductor manufacturing apparatus using these non-corrosive atmospheres, the support body is necessarily formed in a cylindrical shape, and the heater electrode terminals and lead wires provided in the wafer holding portion are accommodated therein, and completely sealed from the atmosphere in the chamber. There is no need to separate them. For this reason, it is not essential to hermetically bond the wafer holding unit and the support, and the wafer holding unit can be supported only by being placed on the support, for example, without being bonded to the support.

  As described above, when the wafer holding unit and the support are not bonded, the heat generated by the resistance heating element of the wafer holding unit can be prevented from escaping through the support. Therefore, in the present invention, the thermal conductivity of the support is the wafer holding unit. Combined with the lower thermal conductivity, the heat uniformity of the wafer holder can be greatly improved. Moreover, since the wafer holding part and the support are not joined, no thermal stress due to the difference in thermal expansion coefficient is applied, and there is no possibility that the ceramic wafer holding part will break.

  In the case where the wafer holding part and the support are not joined, in order to increase the thermal uniformity of the wafer holding part and shorten the length of the support, the wafer holding part should be made of at least a material having a high thermal conductivity, at least from the support. In addition, it is preferable to use a material having a low thermal conductivity as much as possible for the support while using a material having a high thermal conductivity.

Specifically, the material of the wafer holding part is preferably at least one ceramic selected from AlN, Al ₂ O ₃ , SiC, and Si ₃ N ₄ from the viewpoints of high thermal conductivity, heat resistance, and insulation. Among them, AlN having particularly high thermal conductivity and excellent heat resistance and corrosion resistance is more preferable.

When using the AlN wafer holder, the material of the support is mullite having a thermal expansion coefficient of 4.0 × ^{10 -6} / ℃ close to the thermal expansion coefficient of ^{AlN 4.5 × 10 -6 / ℃ (} 3Al It is preferable to use a material mainly composed of ₂ O ₃ .2SiO ₂ ). Mullite has a very low thermal conductivity of 4 W / mK and has a great effect of suppressing the escape of heat, so that the thermal uniformity of the wafer holder is further improved. In addition, even if the length of the support is shortened, the temperature gradient of the wafer holding part, the support part, and the container installation part is not tight, and the cracking of the support due to thermal shock can be suppressed, so that the reliability is improved. Further, alumina (Al ₂ O ₃ ) is added to mullite to adjust the thermal expansion coefficient of the support, and for example, the thermal expansion coefficient is adjusted to about 4.5 × 10 ⁻⁶ / ° C. to constitute the wafer holding unit. It is also possible to approximate the thermal expansion coefficient of AlN.

Example 1
0.5% by weight of yttria (Y ₂ O ₃ ) was added to the aluminum nitride (AlN) powder as a sintering aid, an organic binder was further added and dispersed and mixed, and then granulated by spray drying. Two pieces of this granulated powder were formed by uniaxial pressing into a size of 350 mm in diameter and 5 mm in thickness after sintering. This molded body was degreased in a nitrogen gas stream at a temperature of 800 ° C., and sintered in a nitrogen stream at a temperature of 1900 ° C. for 6 hours. The obtained AlN sintered body had a thermal conductivity of 180 W / mK. The surfaces of the two sintered bodies were polished using diamond abrasive grains.

  On one AlN sintered body, a resistance heating element circuit was printed using W slurry obtained by adding and kneading a sintering aid and an ethylcellulose binder to W powder, and degreased in a nitrogen stream at 900 ° C. Bake by heating at 0 ° C. for 1 hour. On the remaining sintered body, a slurry obtained by adding and kneading an ethylcellulose binder to glass for bonding was applied and degreased in a nitrogen stream at 900 ° C.

By superposing the bonding glass surface of these two AlN sintered bodies and the resistance heating element surface, and applying a load of 50 g / cm ² to prevent deviation, heating and bonding at 1800 ° C. for 2 hours, As shown in FIG. 1, an AlN wafer holder 1 having a resistance heating element 2 embedded therein was fabricated. An electrode terminal (not shown) connected to the internal resistance heating element 2 is joined to the back surface of the wafer holder 1, and the power supply leader 3 is electrically connected to an external power source. Were joined.

As a support for supporting the wafer holder consists of mullite _{(3Al 2 O 3 · 2SiO 2} ), was prepared cylindrical supporting body having an outer diameter of 100 mm × inner diameter 90 mm × length 100 mm. The thermal conductivity of this mullite support was 4 W / mK. As shown in FIG. 1, one end of the support 4 was clamped and fixed to the chamber 5, and the wafer holder 1 was placed on the support 4 without bonding. The lead wire 3 from the wafer holding unit 1 was housed in the support 4 and sealed between the chamber 5 and the O-ring 6.

The inside of the chamber 5 is depressurized to 0.1 torr in an N ₂ atmosphere, power is supplied from outside the system to the resistance heating element 2 and heated to 500 ° C., and the flange fixed to the chamber 5 of the support 4 is cooled with water When the temperature uniformity of the entire surface of the wafer holder 1 holding the wafer 7 was measured, it was 500 ° C. ± 0.39%. Ten of the same holders were prepared, and the heat cycle test was performed by raising and lowering the temperature between room temperature and 500 ° C. 500 times. However, all of the ten holders had no problem after the heat cycle.

  In addition, the conventional support has a length of 300 mm, and the height of the chamber for housing it needs to be about 450 mm. On the other hand, in Example 1, even if the length of the support 4 was shortened to 100 mm, it could be used without any problem, and the height of the chamber 5 could be reduced to 250 mm.

Example 2
2% by weight of magnesia (MgO) was added to the aluminum oxide (Al ₂ O ₃ ) powder as a sintering aid, and a binder was further added, dispersed and mixed, and granulated by spray drying. Two pieces of this granulated powder were formed by uniaxial pressing into a size of 350 mm in diameter and 5 mm in thickness after sintering.

A sintering aid and an ethylcellulose binder were added to the W powder and kneaded, and a resistance heating element circuit was printed on one of the molded bodies. This was degreased in an air stream at 700 ° C., heated at 1600 ° C. for 3 hours, and simultaneously sintered. The obtained Al ₂ O ₃ sintered body had a thermal conductivity of 20 W / mK. The surface of this sintered body was polished using diamond abrasive grains.

  The remaining molded body was sintered in the same manner as described above, and a slurry obtained by adding and kneading an ethylcellulose binder to glass for bonding was applied onto the sintered body and degreased in an air stream at 900 ° C. The glass surface for bonding and the resistance heating element surface of these two sintered bodies were superposed and bonded in the same manner as in Example 1 to obtain a wafer holding part. The electrode terminal was joined to the back surface of the wafer holding part in the same manner as in Example 1, and the lead wire was further joined.

The Al ₂ O ₃ wafer holder was placed on the same mullite support as in Example 1. One end of the mullite support was clamped to the chamber. When the thermal uniformity of the entire holding surface of the wafer holder was measured under the same conditions as in Example 1, the thermal uniformity was 500 ° C. ± 0.7%. Moreover, ten same holders were produced, and a heat cycle test was conducted in the same manner as in Example 1. However, there was no problem.

Example 3
To the silicon carbide (SiC) powder, 2% by weight of boron carbide (B ₄ C) was added as a sintering aid, a binder was further added, dispersed and mixed, and granulated by spray drying. Two pieces of the granulated powder were formed by uniaxial pressing into a size of 350 mm in diameter and 5 mm in thickness after sintering.

  A sintering aid and an ethylcellulose-based binder were added to the W powder and kneaded, and a resistance heating element circuit was printed on one molded body. This was degreased in a nitrogen stream at 900 ° C., heated at 1900 ° C. for 5 hours, and co-fired. The obtained SiC sintered body had a thermal conductivity of 150 W / mK. The surface of the sintered body was polished using diamond abrasive grains.

  The remaining molded body was sintered in the same manner as described above, and a slurry obtained by adding and kneading an ethylcellulose-based binder to glass for bonding was applied onto the sintered body and degreased in a nitrogen stream at 900 ° C. The glass surface for bonding and the resistance heating element surface of these two sintered bodies were superposed and bonded in the same manner as in Example 1 to obtain a wafer holding part. The electrode terminal was joined to the back surface of the wafer holding part in the same manner as in Example 1, and the lead wire was further joined.

  The SiC wafer holder was placed on the same mullite support as in Example 1. One end of the mullite support was clamped to the chamber. When the thermal uniformity of the entire holding surface of the wafer holder was measured under the same conditions as in Example 1, the thermal uniformity was 500 ° C. ± 0.5%. Moreover, ten same holders were produced, and a heat cycle test was conducted in the same manner as in Example 1. However, there was no problem.

Example 4
2 wt% yttrium oxide (Y ₂ O ₃ ) and 2 wt% aluminum oxide (Al ₂ O ₃ ) are added to the silicon nitride (Si ₃ N ₄ ) powder as a sintering aid, and a binder is further added. The mixture was dispersed and granulated by spray drying. Two pieces of the granulated powder were formed by uniaxial pressing into a size of 350 mm in diameter and 5 mm in thickness after sintering.

A sintering aid and an ethylcellulose-based binder were added to the W powder and kneaded, and a resistance heating element circuit was printed on one molded body. This was degreased in a nitrogen stream at 900 ° C., heated at 1900 ° C. for 5 hours, and co-fired. The obtained Si ₃ N ₄ sintered body had a thermal conductivity of 20 W / mK. The surface of the sintered body was polished using diamond abrasive grains.

  The remaining molded body was sintered in the same manner as described above, and a slurry obtained by adding and kneading an ethylcellulose-based binder to glass for bonding was applied onto the sintered body and degreased in a nitrogen stream at 900 ° C. The glass surface for bonding and the resistance heating element surface of these two sintered bodies were superposed and bonded in the same manner as in Example 1 to obtain a wafer holding part. The electrode terminal was joined to the back surface of the wafer holding part in the same manner as in Example 1, and the lead wire was further joined.

The Si ₃ N ₄ wafer holder was placed on the same mullite support as in Example 1. One end of the mullite support was clamped to the chamber. When the thermal uniformity of the entire holding surface of the wafer holding part was measured under the same conditions as in Example 1, the thermal uniformity was 500 ° C. ± 0.8%. Moreover, ten same holders were produced, and a heat cycle test was conducted in the same manner as in Example 1. However, there was no problem.

Example 5
The same AlN wafer holder as in Example 1 was placed on a SUS support having an outer diameter of 100 mm, an inner diameter of 90 mm, and a length of 100 mm without bonding. In addition, the electrode terminal and the lead wire of the resistance heating element edge part were joined to the back surface of the wafer holding part similarly to Example 1. The thermal conductivity of this SUS was 15 W / mK.

  When this holder was evaluated in the same manner as in Example 1, the thermal uniformity of the wafer holding surface was 500 ° C. ± 0.42%. Moreover, ten same holders were produced, and a heat cycle test was conducted in the same manner as in Example 1. However, there was no problem.

Comparative Example 1
A wafer holding unit was produced in the same manner as in Example 1. The support was made of the same AlN as the wafer holder and had an outer diameter of 100 mm, an inner diameter of 90 mm, and a length of 300 mm. Both the wafer holder and the support were made of AlN, and the thermal conductivity was 180 W / mK. The wafer holder was placed on this support without bonding.

  When the same evaluation as Example 1 was performed about the obtained holding body, the soaking | uniform-heating property was 500 degreeC +/- 1.2%. Moreover, ten same holders were produced, and a heat cycle test was conducted in the same manner as in Example 1. However, there was no problem.

Comparative Example 2
A wafer holder made of AlN was produced in the same manner as in Example 1. As the support, a Cu support having an outer diameter of 100 mm, an inner diameter of 90 mm, and a length of 300 mm was prepared. The wafer holder had a thermal conductivity of 180 W / mK, and the support had a thermal conductivity of 393 W / mK. An end portion of the support was polished, and a wafer holder was placed on the end without bonding to form a holder.

  When the same evaluation as Example 1 was performed about the obtained holding body, the soaking | uniform-heating property was 500 degreeC +/- 2.5%. Moreover, ten same holders were produced, and a heat cycle test was conducted in the same manner as in Example 1. However, there was no problem.

It is general | schematic sectional drawing which shows the state which fixed the holding body of this invention in the chamber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wafer holding part 2 Resistance heating element 3 Leader 4 Support body 5 Chamber

Claims (7)

  It comprises a ceramic wafer holding part having a resistance heating element and a support that supports the wafer holding part. The thermal conductivity of the support is lower than the thermal conductivity of the wafer holding part. A holding body for a semiconductor manufacturing apparatus, which is not bonded. _{2. The} holding body for a semiconductor manufacturing apparatus according to claim 1, wherein the wafer holding portion is mainly composed of at least one ceramic selected from AlN, Al ₂ O ₃ , SiC, and Si ₃ N _4. .   The holding body for a semiconductor manufacturing apparatus according to claim 2, wherein the wafer holding portion is AlN.   The said support body has a mullite as a main component, The holding body for semiconductor manufacturing apparatuses in any one of Claims 1-3 characterized by the above-mentioned.   5. The holding body for a semiconductor manufacturing apparatus according to claim 4, wherein the support is a composite of mullite and alumina.   The semiconductor manufacturing apparatus using the holding body for semiconductor manufacturing apparatuses in any one of Claims 1-5. The semiconductor manufacturing apparatus according to claim 6, wherein the semiconductor manufacturing apparatus is used for heat curing of a resin film for photolithography or heat baking of an insulating film having a low dielectric constant.

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