JP3222899B2 - Coaxial plasma processing equipment - Google Patents
Coaxial plasma processing equipmentInfo
- Publication number
- JP3222899B2 JP3222899B2 JP26884591A JP26884591A JP3222899B2 JP 3222899 B2 JP3222899 B2 JP 3222899B2 JP 26884591 A JP26884591 A JP 26884591A JP 26884591 A JP26884591 A JP 26884591A JP 3222899 B2 JP3222899 B2 JP 3222899B2
- Authority
- JP
- Japan
- Prior art keywords
- plasma processing
- heater
- gas
- processing method
- plasma
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Photosensitive Polymer And Photoresist Processing (AREA)
- Drying Of Semiconductors (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は半導体ウェハ表面のレジ
スト膜のアッシング等に用いるプラズマ処理方法に関す
る。 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method used for ashing a resist film on a semiconductor wafer surface.
You.
【０００２】[0002]
【従来の技術】外部電極と内部電極とを筒状チャンバー
を挟んで同軸状に配置したプラズマ処理装置として特公
昭５３−３３４７１号公報に開示される装置がある。2. Description of the Related Art An apparatus disclosed in Japanese Patent Publication No. 53-33471 is a plasma processing apparatus in which an external electrode and an internal electrode are coaxially arranged with a cylindrical chamber interposed therebetween.
【０００３】同軸型プラズマ処理装置の一般的な構造
は、図４に示すように合成石英等からなる縦長の筒状チ
ャンバー１００の上下の開孔をチャンバープレート１０
１，１０２で閉塞し、筒状チャンバー１００の内外に筒
状の内部電極１０３及び筒状の外部電極１０４を夫々配
置し、この外部電極１０４の外方にプレヒータ１０５を
配置してなる。[0003] A general structure of a coaxial plasma processing apparatus is as shown in FIG. 4, in which upper and lower openings of a vertically long cylindrical chamber 100 made of synthetic quartz or the like are formed by a chamber plate 10.
The cylindrical internal electrode 103 and the cylindrical external electrode 104 are arranged inside and outside the cylindrical chamber 100, respectively, and a preheater 105 is arranged outside the external electrode 104.
【０００４】一方、合成石英等のロッドを起立してなる
ウェハー保持体１０６に、予め５０〜１００枚のウェハ
ー１０７を段積み収納したものを、図中矢印の如くに
プラズマ処理装置に下から挿入する。筒状チャンバー１
００内を真空引きし、減圧下でＯ2（酸素）を投入し、
プレヒータ１０５に通電して装置全体をある程度暖め
て、プラズマの発生条件を整えるとともに、高周波発振
器１０８により、外部電極１０４と内部電極１０３との
間に酸素プラズマを発生せしめる。On the other hand, 50 to 100 wafers 107 previously stacked and stored in a wafer holder 106 having a rod made of synthetic quartz or the like standing upright are inserted from below into a plasma processing apparatus as indicated by arrows in the figure. I do. Cylindrical chamber 1
00 is evacuated, O 2 (oxygen) is added under reduced pressure,
By energizing the preheater 105 to warm the whole apparatus to some extent, the conditions for plasma generation are adjusted, and oxygen plasma is generated between the external electrode 104 and the internal electrode 103 by the high-frequency oscillator 108.
【０００５】この酸素プラズマによって、ウェハー１０
７…表面のホトレジストを灰化処理（アッシング）す
る。The oxygen plasma causes the wafer 10
7: Ashing the photoresist on the surface.
【０００６】図５はアッシングレートの温度依存性を示
す図であり、ｘ軸はウェハーの端部−中心−端部を示
し、ｙ軸はアッシングレートを示す。パラメータｔ０，
ｔ１，ｔ２は処理温度であって、ｔ０＜ｔ１＜ｔ２の関
係にある。同図によれば、ウェハーの中心より端部の方
がアッシングレートは高く、また、処理温度が高いほど
アッシングレートは高くなる。FIG. 5 is a graph showing the temperature dependence of the ashing rate. The x-axis indicates the edge-center-edge of the wafer, and the y-axis indicates the ashing rate. Parameter t0,
t1 and t2 are processing temperatures, and have a relationship of t0 <t1 <t2. According to the figure, the ashing rate is higher at the end portion than at the center of the wafer, and the ashing rate increases as the processing temperature increases.
【０００７】[0007]
【発明が解決しようとする課題】前記プレヒータ１０５
は装置温度を一定値に保ってアッシングレートをある程
度高めることを目的として付設されている。しかし、同
軸型プラズマ処理装置でプラズマが発生すると、そのプ
ラズマの熱により筒状チャンバー１００内の温度が徐々
に上がる傾向にある。そして、同軸型プラズマ処理装置
の筒状チャンバー１００は、ウェハー １０７を５０〜
１００枚段積み収納する関係から、縦長である。その為
にドラフト作用によって筒状チャンバー１００の上部が
下部に対して高温になることが分かった。その結果、図
５に示した通り上方のウェハー１０７は、ウェハーの中
心と端部のアッシングレートの差が著しくなり好ましく
ない。SUMMARY OF THE INVENTION The pre-heater 105
Are provided for the purpose of maintaining the device temperature at a constant value and increasing the ashing rate to some extent. However, when plasma is generated in the coaxial plasma processing apparatus, the temperature in the cylindrical chamber 100 tends to gradually increase due to the heat of the plasma. The cylindrical chamber 100 of the coaxial plasma processing apparatus stores the wafer 107 in 50 to
It is vertically long because 100 sheets are stacked and stored. Therefore, it was found that the temperature of the upper portion of the cylindrical chamber 100 became higher than that of the lower portion by the draft action. As a result, as shown in FIG. 5, the difference between the ashing rate at the center of the wafer and the ashing rate at the end of the upper wafer 107 is not preferable.
【０００８】そこで本発明の目的は同軸型プラズマ処理
装置におけるアッシングレートの均一性を改善すること
にあり、具体的にはプレヒータの分割による改善策と、
雰囲気ガスによる改善策とを提示するものである。Accordingly, an object of the present invention is to improve the uniformity of an ashing rate in a coaxial plasma processing apparatus, and specifically, an improvement by dividing a preheater,
It proposes an improvement measure by the atmospheric gas.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成すべく本
発明者は、縦長の筒状チャンバ−の外方に外部電極を配
置し、更にその外側に少なくとも高さ方向に２分割され
たされたヒ−タを配置した同軸型プラズマ処理装置を用
い、プラズマ発生前は上部及び下部ヒ−タで加熱し、プ
ラズマ発生後は上部ヒ−タを先にＯＦＦとして下部ヒ−
タのみで加熱し、プラズマ処理中のチャンバ−内の温度
を一定とすることで例えばアッシングレ−トの均一性を
改善するようにした。 In order to achieve the above object, the present inventor has arranged an external electrode outside a vertically long cylindrical chamber.
And further divided into at least two parts in the height direction
Using a coaxial plasma processing device with a heater
Before plasma generation, heat with upper and lower heaters,
After plasma occurs, the upper heater is turned off first and the lower heater is turned off.
Temperature in the chamber during plasma processing
Makes the ashing rate uniform, for example,
I tried to improve.
【００１０】また、前記筒状チャンバ−内に注入される
処理ガスとしては、酸素とヘリウムの混合ガスが好まし
く、ト−タルガス流量に対するヘリウム流量で示される
混合比を２０〜３０％の範囲とすることが更に好まし
い。 In addition, the gas is injected into the cylindrical chamber.
As a processing gas, a mixed gas of oxygen and helium is preferable.
Helium flow rate with respect to the total gas flow rate
More preferably, the mixing ratio is in the range of 20 to 30%.
No.
【００１１】[0011]
【００１２】[0012]
【作用】準備段階で上部ヒータ及び下部ヒータに通電
し、基本的には上部ヒータを先にＯＦＦして、下部ヒー
タのみで加熱する。雰囲気ガスを、酸素のみでなく酸素
とヘリウムの混合ガスとすることにより、アッシングレ
ートの均一性が飛躍的に向上する。In the preparatory stage, the upper heater and the lower heater are energized, and basically the upper heater is turned off first and the lower heater alone is used for heating. By using not only oxygen but also a mixed gas of oxygen and helium as the atmosphere gas, the uniformity of the ashing rate is remarkably improved.
【００１３】[0013]
【実施例】本発明の実施例を添付図面に基づいて以下に
説明する。図１は本発明に係る同軸型プラズマ処理装置
の断面図であり、同軸型プラズマ処理装置１は合成石英
等からなる縦長の筒状チャンバー２の上下開口をチャン
バープレート３，４で閉塞し、筒状チャンバー２の内外
に同心円状に内部電極５と外部電極６を夫々配置し、こ
の外部電極６の外方に上部ヒータ７と下部ヒータ８を段
積み配置してなる。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a coaxial plasma processing apparatus according to the present invention. In the coaxial plasma processing apparatus 1, the upper and lower openings of a vertically long cylindrical chamber 2 made of synthetic quartz or the like are closed by chamber plates 3 and 4. An inner electrode 5 and an outer electrode 6 are arranged concentrically inside and outside the chamber 2, and an upper heater 7 and a lower heater 8 are stacked outside the outer electrode 6.
【００１４】上部ヒータ７は上部コントローラ９を介し
て給電され、上部コントローラ９は上部熱電対１０の測
温値に基づいて上部ヒータ７をＯＮ／ＯＦＦ制御する。The upper heater 7 is supplied with power via an upper controller 9, and the upper controller 9 controls ON / OFF of the upper heater 7 based on a temperature measurement value of an upper thermocouple 10.
【００１５】又、下部ヒータ８は下部コントローラ１１
を介して給電され、下部コントローラ１１は下部熱電対
１２の測温値に基づいて下部ヒータ８をＰＩＤ制御す
る。ＰＩＤ制御は比例−積分−微分制御をいい、測温値
が設定値から十分に離れていればヒータ出力を高め、測
温値が設定値に近づくほどヒータ出力を絞り、オーバー
シュートやハンチングを防止する制御方式である。The lower heater 8 is connected to the lower controller 11.
, And the lower controller 11 performs PID control of the lower heater 8 based on the temperature measurement value of the lower thermocouple 12. PID control refers to proportional-integral-differential control. If the measured temperature value is sufficiently far from the set value, the heater output is increased, and the heater output is reduced as the measured temperature value approaches the set value, preventing overshoot and hunting. Control method.
【００１６】なお、本実施例では上部ヒータ７、下部ヒ
ータ８ともに赤外線ヒータである。図中、１４はガス導
入管であり、配管を介して酸素（Ｏ2）とヘリウムガス
（Ｈｅ）が所定の混合比で導入される。１５は排気管で
あり図示せぬ真空ポンプで排気され、筒状チャンバー２
内を所定の圧力に減圧するものである。１６は酸素ボン
ベ、１７は流量計、１８は定流量弁、１９はヘリウムボ
ンベ、２０は流量計、２１は定流量弁、２２は流量コン
トローラである。In this embodiment, both the upper heater 7 and the lower heater 8 are infrared heaters. In the figure, reference numeral 14 denotes a gas introduction pipe through which oxygen (O 2 ) and helium gas (He) are introduced at a predetermined mixing ratio. An exhaust pipe 15 is evacuated by a vacuum pump (not shown), and
The inside is reduced to a predetermined pressure. 16 is an oxygen cylinder, 17 is a flow meter, 18 is a constant flow valve, 19 is a helium cylinder, 20 is a flow meter, 21 is a constant flow valve, and 22 is a flow controller.
【００１７】以上の構成からなる同軸型プラズマ処理装
置の作用を次に述べる。排気管１５において筒状チャン
バー２内を１０ -3 Ｔｏｒｒ（トール）程度まで真空排気
した後に酸素ヘリウム混合ガスをガス導入管１４から補
給して、筒状チャンバー２内を０．５〜１．０ Ｔｏｒ
ｒに保つ。The operation of the coaxial plasma processing apparatus having the above configuration will be described below. After evacuating the inside of the cylindrical chamber 2 to about 10 −3 Torr (Torr) in the exhaust pipe 15, a mixed gas of oxygen and helium is supplied from the gas introducing pipe 14, and the inside of the cylindrical chamber 2 is 0.5 to 1.0. Tor
r.
【００１８】一方、上部ヒータ７及び下部ヒータ８にて
装置温度を８０℃に保ち、外部電極６と内部電極５との
間にプラズマを発生せしめてウェハーＷのアッシングを
開始する。アッシング処理時間は約１５分であるが、こ
の間にチャンバー２内の温度が徐々に上昇するので、上
部ヒータ７は上部コントローラ９によりＯＦＦされ、下
部ヒータ８も下部コントローラ１１により徐々に絞ら
れ、チャンバー２内の温度上昇を抑制する。On the other hand, the apparatus temperature is maintained at 80 ° C. by the upper heater 7 and the lower heater 8, plasma is generated between the external electrode 6 and the internal electrode 5, and the ashing of the wafer W is started. The ashing processing time is about 15 minutes. During this time, the temperature inside the chamber 2 gradually rises, so that the upper heater 7 is turned off by the upper controller 9 and the lower heater 8 is also gradually squeezed by the lower controller 11. suppressing the temperature rise in 2.
【００１９】即ち、ドラフト作用により上方程高温とな
るので、プラズマ発生後は下部ヒータ８のみで保温を図
ることに特徴があり、これによってアッシングレートの
悪化は効果的に阻止される。That is, since the temperature rises upward as a result of the draft action, it is characterized in that the temperature is maintained only by the lower heater 8 after the plasma is generated, thereby effectively preventing the ashing rate from deteriorating.
【００２０】そして、本発明はヒータ分割の他に、酸素
にヘリウムガスを混入させたことを特徴とする。図２は
混合ガス比とアッシングレートの関係を示す図、図３は
混合ガス比と均一性の関係を示す図である。なお、ｘ軸
は混合比（ヘリウム流量／トータルガス流量）である。The present invention is characterized in that helium gas is mixed with oxygen in addition to the heater division. FIG. 2 is a diagram showing the relationship between the mixed gas ratio and the ashing rate, and FIG. 3 is a diagram showing the relationship between the mixed gas ratio and the uniformity. The x-axis is the mixing ratio (helium flow rate / total gas flow rate).
【００２１】図２によればヘリウムガスの比率が高まる
ほど、アッシングレートが減少する。そして、図３に示
す通りウェハー１枚における、端部と中央部のアッシン
グレートの比であるところの、面内均一性は酸素のみの
場合に約３０％であったものが、混合比５０％で約１０
％に大幅改善されている。According to FIG. 2, the ashing rate decreases as the helium gas ratio increases. As shown in FIG. 3, the in-plane uniformity, which is the ratio of the ashing rate between the edge and the center of one wafer, was about 30% when only oxygen was used, but the mixing ratio was 50%. About 10
% Has been greatly improved.
【００２２】又、同一チャージにおける複数のウェハー
間のアッシングレートの比であるところのウェハー間均
一性は酸素のみの場合に約１５％であったものが、混合
比２０〜３５％（中央値３０％）では約３．５％に大幅
に改善されている。従って、混合比が２０〜３５％にお
いて、ウェハー間均一性が最良となり、このときに面内
均一性は１１〜１４％で、酸素のみの場合の均一性に対
しそれぞれ２倍以上改善されている。The uniformity between wafers, which is the ratio of the ashing rate between a plurality of wafers at the same charge, was about 15% when only oxygen was used, but the mixing ratio was 20 to 35% (median value: 30). %), Which is greatly improved to about 3.5%. Therefore, the mixing ratio of the 20 to 35%, between wafer uniformity is the best, with 11 to 14% in-plane uniformity at this time are respectively improved twice or more with respect to the uniformity of the case of oxygen only .
【００２３】尚、図１に示した実施例においてプレヒー
タは上部ヒータ７及び下部ヒータ８での２分割構成とし
たが、これに限るものではなく上中下等３分割以上とし
てもよい。In the embodiment shown in FIG. 1, the pre-heater is divided into two parts by the upper heater 7 and the lower heater 8. However, the present invention is not limited to this.
【００２４】[0024]
【発明の効果】以上に述べた通りプレヒータを上下に分
割することで上方のヒータを先行してＯＦＦすることが
出来、筒状チャンバーの高さ方向の温度差の拡大を抑制
することが出来るのでウェハーのアッシングレート均一
性は改善される。As described above, by dividing the preheater into upper and lower parts, the upper heater can be turned off in advance and the increase in the temperature difference in the height direction of the cylindrical chamber can be suppressed. The ashing rate uniformity of the wafer is improved.
【００２５】又、雰囲気ガスを酸素にヘリウムを加えた
混合ガス（好ましくは混合比が２０〜３５％）とするこ
とにより、酸素のみの場合に比較してアッシングレート
の均一性が格段に改善される。Further, by setting the atmosphere gas to a mixed gas obtained by adding helium to oxygen (preferably at a mixing ratio of 20 to 35%), the uniformity of the ashing rate is remarkably improved as compared with the case of using only oxygen. You.
【００２６】よって、プレヒータの分割とヘリウム混合
ガスの使用の一方若しくは双方を採用することにより、
同軸型プラズマ処理装置におけるウェハーのアッシング
レートの均一性を十分に改善することが出来る。Therefore, by adopting one or both of the division of the preheater and the use of the helium mixed gas,
The uniformity of the ashing rate of the wafer in the coaxial plasma processing apparatus can be sufficiently improved.
【図１】本発明に係る同軸型プラズマ処理装置の断面図FIG. 1 is a sectional view of a coaxial plasma processing apparatus according to the present invention.
【図２】本発明の混合ガス比とアッシングレートの関係
を示す図FIG. 2 is a diagram showing a relationship between a mixed gas ratio and an ashing rate according to the present invention.
【図３】本発明の混合ガス比と均一性の関係を示す図FIG. 3 is a diagram showing a relationship between a mixed gas ratio and uniformity according to the present invention.
【図４】従来の同軸型プラズマ処理装置の断面図FIG. 4 is a cross-sectional view of a conventional coaxial plasma processing apparatus.
【図５】アッシングレートの温度依存性と面内均一性を
示す図FIG. 5 is a diagram showing the temperature dependency and in-plane uniformity of an ashing rate.
１…同軸型プラズマ処理装置、２…筒状チャンバー、５
…内部電極、６…外部電極、７…上部ヒータ、８…下部
ヒータ、９…上部コントローラ、１１…下部コントロー
ラ、１４…ガス導入管、Ｗ…ウェハー。DESCRIPTION OF SYMBOLS 1: Coaxial plasma processing apparatus, 2: Cylindrical chamber, 5
... internal electrode, 6 ... external electrode, 7 ... upper heater, 8 ... lower heater, 9 ... upper controller, 11 ... lower controller, 14 ... gas introduction pipe, W ... wafer.
フロントページの続き (56)参考文献 特開 平３−109722（ＪＰ，Ａ) 特開 平２−213482（ＪＰ，Ａ) 特開 平２−14522（ＪＰ，Ａ) 実開 昭61−38932（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 21/3065 G03F 7/42 Continuation of the front page (56) References JP-A-3-109722 (JP, A) JP-A-2-213482 (JP, A) JP-A-2-14522 (JP, A) JP-A-61-38932 (JP) , U) (58) Field surveyed (Int.Cl. 7 , DB name) H01L 21/3065 G03F 7/42
Claims (3)
部電極及び外部電極を配置し、この外部電極の外方に高
さ方向に２分割されたヒータを配置した同軸型プラズマ
処理装置によるプラズマ処理方法において、プラズマ発
生前は上部及び下部ヒ−タで加熱し、プラズマ発生後は
上部ヒ−タを先にＯＦＦとして、下部ヒ−タのみで加熱
することを特徴とするプラズマ処理方法。 1. A coaxial plasma in which a cylindrical internal electrode and an external electrode are arranged inside and outside a vertically long cylindrical chamber, and a heater divided into two in the height direction is arranged outside the external electrode.
In a plasma processing method using a processing apparatus,
Heat before and after heating with upper and lower heaters, and after plasma generation
Turn off the upper heater first and heat only with the lower heater
A plasma processing method.
いて、アッシング用の処理ガスとして酸素とヘリウムの
混合ガスを用いることを特徴とするプラズマ処理方法。 2. The plasma processing method according to claim 1,
And oxygen and helium as processing gas for ashing
A plasma processing method using a mixed gas.
いて、前記アッシング用の処理ガスは、ト−タルガス流
量に対するヘリウム流量で示される混合比を２０〜３０
％の範囲としたことを特徴とするプラズマ処理方法。 3. The plasma processing method according to claim 2, wherein
The ashing process gas is a total gas flow.
The mixing ratio indicated by the helium flow rate to the
%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26884591A JP3222899B2 (en) | 1991-09-20 | 1991-09-20 | Coaxial plasma processing equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26884591A JP3222899B2 (en) | 1991-09-20 | 1991-09-20 | Coaxial plasma processing equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0590222A JPH0590222A (en) | 1993-04-09 |
| JP3222899B2 true JP3222899B2 (en) | 2001-10-29 |
Family
ID=17464072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26884591A Expired - Fee Related JP3222899B2 (en) | 1991-09-20 | 1991-09-20 | Coaxial plasma processing equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3222899B2 (en) |
-
1991
- 1991-09-20 JP JP26884591A patent/JP3222899B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0590222A (en) | 1993-04-09 |
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