JP3976994B2 - Silicon heater - Google Patents

Description

【００３４】
表１の結果を見れば明らかなように、実施例１〜３はいずれも、比較例１〜３と比較して歩留りが向上している。
【００３５】
なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
【００３６】
【発明の効果】
以上説明したように、本発明では、シリコンヒータであって、少なくともシリコン板の一方の面は溝加工によりヒータパターンを形成した発熱部であり、他方の面は溝加工を施さないヒータ面内の温度を均一化するための均熱部で、これに通電するための給電部を設けたことにより、コンタミネーションの発生を抑え、ウェーハの温度制御が可能になる。従って、処理の均一化を実現し、半導体製造の歩留りの向上を図ることができる。
【図面の簡単な説明】
【図１】プラズマドライエッチング装置の一例を示す概略図である。
【図２】本発明のシリコンヒータの一例を示した図である。
（ａ） 本発明のシリコンヒータのヒータパターンの一例を示す平面図、
（ｂ） （ａ）のＡ−Ａ線縦断面図、
（ｃ） （ｂ）のＢ部分の拡大図。
【符号の説明】
１…上部電極、 ２…シリコンウェーハ、 ３…シリコンリング、
４…下部電極、 ５…チャンバ、 ６…均熱部、
７…発熱部、 ８…給電部、 ９…シリコンヒータ。
ａ…均熱部の板厚、 ｂ…発熱部の板厚、
ｃ…発熱部のパターンの最小幅。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silicon heater mainly used in a plasma apparatus for manufacturing a semiconductor device.
[0002]
[Prior art]
As a semiconductor manufacturing apparatus, as represented by a plasma dry etching apparatus, a first electrode (hereinafter referred to as a lower electrode) on which a silicon wafer as an object to be processed is placed and a second electrode at a position facing the wafer. (Hereinafter referred to as an upper electrode) is known.
FIG. 1 is a schematic view showing an example of such a parallel plate type plasma dry etching apparatus. In this apparatus, a wafer 2 as an object to be processed is placed on a lower electrode 4 and a processing gas is ejected from the upper electrode 1 provided with a large number of fine holes for rectifying the processing gas through the fine holes. By connecting the upper electrode 1 to a high frequency power source, plasma is generated between the two electrodes to perform a desired process.
[0003]
In recent years, when semiconductors are required to have improved reliability and productivity at manufacturing sites, it is required to process wafers more uniformly.
However, in the actual process, due to the temperature rise due to the plasma processing, the temperature of the wafer and the temperature in the wafer surface are different at the beginning and end of the processing, resulting in a difference in the etching rate, making it unusable as a device. There was also.
[0004]
Therefore, recently, a heater is disposed on the lower electrode side to control the temperature of the wafer. This is to hold the wafer at a desired temperature in advance, thereby achieving a uniform etching rate.
[0005]
If the wafer is heated with a heater as described above, the temperature difference between the start and end of the process and the temperature difference within the wafer surface caused by the temperature rise associated with the plasma process can be reduced, but further miniaturization and higher integration are possible. Since semiconductors that are becoming more advanced require further highly uniform processing, there is a problem that the occurrence of contamination must also be controlled.
[0006]
For example, Japanese Patent Application Laid-Open No. 2000-54141 discloses a method in which a heater is embedded in a substrate mounting table (lower electrode) to form a heater. In this method, the wafer held on the substrate mounting table can be heated by the embedded heating element.
According to this method, the wafer can surely be heated. However, in Japanese Patent Laid-Open No. 2000-54141, the substrate mounting table itself is made of ceramics, and contamination occurs when the wafer and the substrate mounting table come into contact with each other when the wafer is held and taken out. It is not considered at all that it causes contamination when exposed to plasma. When such contamination occurs, there is a problem in that the yield of the circuit of the device to be manufactured is reduced, such as disconnection, short circuit, and insulation failure.
[0007]
[Problems to be solved by the invention]
Therefore, the present invention has been made in view of such problems, and in the semiconductor device manufacturing process, a silicon heater capable of suppressing the occurrence of contamination and controlling the temperature of the wafer is provided, and the yield of semiconductor manufacturing The main purpose is to improve this.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a silicon heater, wherein at least one surface of a silicon plate is a heat generating portion in which a heater pattern is formed by grooving, and the other surface is a heater surface not subjected to grooving. A silicon heater characterized in that it is a soaking part for equalizing the temperature inside and provided with a feeding part for energizing it .
[0009]
In this way, a silicon heater is of high purity because it is made of the same material as the silicon wafer that is the main object to be processed. Even if the silicon heater is in contact with the silicon wafer when it is held or taken out, it is contaminated. Can be suppressed. Further, even if the silicon heater itself is exposed to plasma, it does not cause new contamination.
[0010]
Further, by installing such a silicon heater in a plasma apparatus or the like to heat the wafer, it is possible to make the temperature uniform before and after the process and in the wafer surface.
In the heater of the present invention, the surface on which the heater pattern is formed by grooving the silicon plate is the heat generating portion, and the surface on which the grooving is not performed is the soaking portion. Is excellent in adhesion to the wafer, and the wafer can be efficiently heated. Furthermore, since the heater has a heat generating part and a soaking part integrated with a silicon plate, there is an advantage that the resistance of the heater can be easily adjusted and the manufacture is easy.
[0011]
In this case, it is preferable that 2a <b, where a is the thickness of the soaking part and b is the thickness of the heat generating part .
Thus, by making the plate thickness b of the heat generating portion thicker than twice the plate thickness a of the soaking portion (2a <b), the thickness of the heat generating portion is sufficiently thicker than the thickness of the soaking portion. Therefore, it is possible to prevent a large amount of current from flowing through the soaking part or a sufficient amount of heat generation from being obtained.
[0012]
Moreover, it is preferable that the minimum width of the pattern of the heat generating portion is 1 mm or more .
In this way, if the minimum width of the heat generating portion pattern is 1 mm or more, the influence on the heat generation amount due to a slight deviation in dimensions is reduced, so that the temperature unevenness of the heater does not occur and the mechanical strength is ensured. Therefore, it is possible to prevent damage during handling.
[0013]
In the present invention, the silicon is preferably single crystal silicon .
In this way, if the silicon material is single crystal silicon, it is the same material as the wafer to be processed, so that contamination of the wafer due to contamination can be prevented. In addition, it is superior to polycrystalline silicon in terms of mechanical strength, quality control, etc., and is advantageously used as a high-purity, long-life material.
[0014]
The silicon preferably has a specific resistance of 1 Ω · cm or less .
As described above, since those having a specific resistance of 1 Ω · cm or less are often used as wafers, they are easily available, the cost is kept low, and they are advantageous for adjusting the resistance for forming the heater.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.
As a result of various investigations and examinations in order to suppress the occurrence of contamination and control the temperature of the wafer in the heater used in the semiconductor device manufacturing process, the present inventors have used silicon as the heater material. The inventors have found that a heater may be formed by integrating a heat generating portion and a soaking portion on the silicon plate, and the present invention has been completed.
[0016]
Here, FIG. 2A is a plan view showing an example of a heater pattern of the silicon heater of the present invention used as a lower electrode of the plasma dry etching apparatus, and FIG. 2B is a plan view of FIG. FIG. 2A is a longitudinal sectional view taken along line AA, and FIG. 2C is an enlarged view of a portion B in FIG.
[0017]
The silicon heater of the present invention is used in, for example, a plasma dry etching apparatus as shown in FIG. 1. This apparatus includes a chamber 5, a silicon heater 9 installed as a lower electrode in the chamber 5, and the silicon heater. 9 includes a silicon ring 3 disposed around a silicon wafer 2 placed on the substrate 9 and an upper electrode 1 having a large number of fine holes for processing gas rectification. A processing gas is ejected from the upper electrode 1 through a fine hole, and the upper electrode 1 is connected to a high-frequency power source, thereby generating plasma between the two electrodes and etching the surface of the silicon wafer 2.
[0018]
Here, the silicon heater according to the present invention is characterized in that at least one surface of the silicon plate is a heat generating portion in which a heater pattern is formed by grooving, and the other surface has a uniform temperature within the heater surface without grooving. In other words, the heat equalizing section is provided with a power feeding section for energizing the soaking section.
[0019]
As described above, since the silicon heater of the present invention is made of the same material as the silicon wafer that is the object to be processed, it does not become an impurity and has high purity. Even if it contacts, generation | occurrence | production of contamination can be suppressed. In addition, there is an advantage that contamination is not caused even if the silicon heater itself is exposed to plasma and its surface is attacked.
[0020]
Further, as shown in FIG. 2, the silicon heater 9 has a heat generating portion 7 in which a heater pattern is formed by groove processing on at least one surface of a silicon plate, and a temperature in the heater surface where no groove processing is performed on the other surface. A heat equalizing section 6 for making uniform and a power feeding section 8 for energizing the heater are provided, and a power source is connected to the power feeding section 8 to function as a heater by energizing.
[0021]
By installing such a silicon heater 9 in a plasma device or the like and heating the wafer, the temperature of the wafer and the temperature in the wafer surface can be made uniform at the beginning and end of processing, so that the etching rate is uniform. Can be achieved. And if the wafer 2 is mounted on the upper surface of the flat soaking part 6 which has not performed groove processing, it will be excellent in adhesiveness with a wafer and can be heated efficiently. Furthermore, since the heater is obtained by integrating the soaking part 6 and the heat generating part 7 on the silicon plate, it is advantageous for adjusting the resistance as a heater.
[0022]
As shown in FIG. 2C, when the thickness of the soaking part 6 of the silicon heater 9 is a and the thickness of the heat generating part 7 is b, it is preferable that 2a <b.
In the silicon heater of the present invention, since the soaking part 6 and the heating part 7 are integrally formed on the silicon plate, the thickness of the heating part 7 is equal to the soaking part as long as the relationship (2a <b) is satisfied. Since it has a sufficient thickness with respect to the plate thickness of 6, it is possible to prevent a large amount of current from flowing through the soaking part or a sufficient amount of heat generation from being obtained. Therefore, the temperature difference between the soaking part 6 and the heat generating part 7 can be reduced and soaking can be achieved.
[0023]
Moreover, it is preferable that the minimum width c of the pattern of the heat generating portion 7 is 1 mm or more.
In this way, if the minimum width c of the pattern of the heat generating portion 7 is 1 mm or more, the influence on the heat generation amount due to a slight deviation in dimensions is reduced, so that the temperature unevenness of the heater does not occur and the mechanical strength is ensured. Therefore, it is possible to prevent damage during handling.
[0024]
In the present invention, the silicon material is preferably single crystal silicon.
Here, if the silicon material is single crystal silicon, it can be made of the same material as the wafer to be processed, so that it does not cause contamination. In addition, it is superior to polycrystalline silicon and amorphous silicon in terms of mechanical strength, quality control, etc., and is advantageously used as a high-purity and long-life material.
[0025]
This single crystal silicon is usually manufactured by the Czochralski method, and according to this method, single crystal silicon having a large diameter is inexpensive and manufactured. If this single crystal silicon is used as a silicon heater, the strength and resistance are controlled with high precision, and a silicon wafer on which a device to be processed is manufactured is manufactured by the Czochralski method. In most cases, the same material is used and is most preferable.
[0026]
Further, the silicon preferably has a specific resistance of 1 Ω · cm or less.
Silicon, by its nature, has an electrical resistance value that depends on temperature. In particular, in silicon having a specific resistance exceeding 1 Ω · cm, the electrical resistance value varies greatly depending on the temperature, so that it is difficult to use it stably as a heater.
On the other hand, with silicon having a specific resistance of 1 Ω · cm or less, the change in electrical resistance value due to this temperature is small, and a stable heater can be produced. In addition, since silicon having such specific resistance is often used as a wafer, it is easily available, the cost is kept low, and it is advantageous for adjusting the resistance for forming the heater.
[0027]
Here, the case where the silicon heater of the present invention is used in the plasma etching apparatus has been described as an example, but the silicon heater of the present invention can be applied to all processing apparatuses using plasma, such as a plasma CVD apparatus and a sputtering apparatus. It is.
Further, the silicon heater of the present invention can be used for heating a wafer when forming a thin film in a device process, and is useful for various semiconductor device manufacturing apparatuses.
[0028]
【Example】
Examples of the present invention and comparative examples are shown below.
(Examples 1-3)
A single crystal silicon ingot was cut and peripherally ground to produce a disc having a diameter of 200 mm and a thickness of 20 mm. With a machining center, a 15 mm deep groove is machined on one side of this disc using a diamond tool to form a heat generating part, and a 5 mm thick surface that is not grooved is used as a soaking part. 2 were formed, and a heater pattern as shown in FIG. 2 was prepared so that the overall resistance would be 2Ω. And the electric power feeding part was made to connect with a terminal via aluminum foil.
[0029]
The silicon heater thus obtained was installed in the chamber of the plasma etching apparatus as the lower electrode. Next, a silicon wafer is placed on the silicon heater, a processing gas is ejected from the upper electrode through a fine hole, and the upper electrode is connected to a high-frequency power source, thereby generating plasma between the two electrodes, thereby forming a surface of the silicon wafer. Etched.
At this time, the wafer was heated by energizing the power supply part of the silicon heater. By controlling the temperature of the wafer by connecting a temperature controller to the silicon heater, it was possible to hold the wafer with an accuracy of 200 ° C. ± 2 ° C. within the wafer surface. Table 1 shows the yield when processing 500 wafers in this state was repeated three times.
[0030]
In Examples 1 to 3 in which a wafer was processed using a silicon heater, contamination of the silicon wafer was maintained even when the wafer was in contact with the silicon heater when the wafer was held and taken out, or even if the silicon heater itself was exposed to plasma. Occurrence could be suppressed and yield could be improved.
[0031]
(Comparative Examples 1-3)
Except for using the lower electrode made of ceramics instead of the silicon heater in the example, the surface of the silicon wafer was etched in the same manner as in the example, and the yield when repeating 500 wafers three times was obtained. This is also shown in Table 1.
[0032]
In Comparative Examples 1 to 3 where the wafer was processed using the ceramic lower electrode, contamination occurred due to contact between the silicon wafer and the ceramic lower electrode or exposure of the ceramic lower electrode to the plasma. Yield decreased.
[0033]
[Table 1]

[0034]
As is clear from the results of Table 1, the yields of Examples 1 to 3 are improved as compared with Comparative Examples 1 to 3.
[0035]
The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
[0036]
【The invention's effect】
As described above, in the present invention, a silicon heater, at least one surface of the silicon plate is a heat generating portion in which a heater pattern is formed by grooving, and the other surface is in the heater surface where no grooving is performed. By providing a heat equalizing part for equalizing the temperature and supplying a power supply part for energizing this, the occurrence of contamination can be suppressed and the wafer temperature can be controlled. Accordingly, it is possible to achieve uniform processing and improve the yield of semiconductor manufacturing.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a plasma dry etching apparatus.
FIG. 2 is a view showing an example of a silicon heater according to the present invention.
(A) The top view which shows an example of the heater pattern of the silicon heater of this invention,
(B) AA line longitudinal sectional view of (a),
(C) The enlarged view of B part of (b).
[Explanation of symbols]
1 ... upper electrode, 2 ... silicon wafer, 3 ... silicon ring,
4 ... lower electrode, 5 ... chamber, 6 ... soaking part,
7 ... Heat generating part, 8 ... Power feeding part, 9 ... Silicon heater.
a ... plate thickness of soaking part, b ... plate thickness of heating part,
c: Minimum width of the heat generating part pattern.

Claims (4)

  A silicon heater for placing a silicon wafer in a plasma processing apparatus, wherein at least one surface of a silicon plate is a heat generating portion in which a heater pattern is formed by grooving, and the other surface is in a heater surface that is not subjected to grooving A heating section for equalizing the temperature of the heating pattern, and a power feeding section for energizing the heating section is provided at both ends of the heater pattern. The thickness of the heating section is a, A silicon heater for mounting a silicon wafer in a plasma processing apparatus, wherein 2a <b, where b is a plate thickness.   2. The silicon heater for mounting a silicon wafer in a plasma processing apparatus according to claim 1, wherein a minimum width of the pattern of the heat generating portion is 1 mm or more. 3. The silicon heater for mounting a silicon wafer in the plasma processing apparatus according to claim 1, wherein silicon of the silicon heater is single crystal silicon. 4. The silicon heater for mounting a silicon wafer in a plasma processing apparatus according to claim 1, wherein the silicon of the silicon heater has a specific resistance of 1 Ω · cm or less. 5.

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