JP4546303B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus that performs an etching process on a substrate to be processed.

  In a manufacturing process of a semiconductor device, a flat panel display (FPD) or the like, a plasma processing apparatus such as a plasma etching apparatus is used to perform an etching process on a target substrate such as a semiconductor wafer or a glass substrate (LCD substrate). .

  In this type of plasma processing apparatus, as shown in FIG. 6, the processing apparatus 101 is an apparatus for performing a predetermined process on an LCD glass substrate, and here, a capacitively coupled parallel plate plasma etching apparatus is taken as an example. .

  The plasma etching apparatus 101 has a processing chamber 102 formed in a square tube shape made of, for example, aluminum. A prismatic insulating plate 103 made of an insulating material is provided at the bottom of the processing chamber 102, and an LCD glass substrate G, which is a substrate to be processed, is placed on the insulating plate 103. A susceptor 104 is provided. In addition, an insulating member 108 is provided on the outer periphery of the substrate 104a of the susceptor 104 and on the peripheral edge where the upper layer 105 and the dielectric material film 106 are not provided.

  Further, a power supply line 123 for supplying high frequency power is connected to the susceptor 104, and a matching unit 124 and a high frequency power source 125 are connected to the power supply line 123.

  A shower head 111 that functions as an upper electrode is provided above the susceptor 104 so as to face the susceptor 104 in parallel. The shower head 111 is supported on the upper portion of the processing chamber 102, has an internal space 112 inside, and has a plurality of discharge holes 113 for discharging a processing gas on the surface facing the susceptor 104. The shower head 111 is grounded and forms a pair of parallel plate electrodes together with the susceptor 104.

  A gas inlet 114 is provided on the upper surface of the shower head 111, and a processing gas supply pipe 115 is connected to the gas inlet 114. The processing gas supply pipe 115 has a valve 116 and a mass flow controller 117. A processing gas supply source 113 is connected via the.

  An exhaust pipe 119 is connected to the bottom of the side wall of the processing chamber 102, and an exhaust device 120 is connected to the exhaust pipe 119. The exhaust device 120 includes a vacuum pump such as a turbo molecular pump. As a result, the inside of the processing chamber 102 can be evacuated to a predetermined reduced pressure atmosphere. Further, a substrate loading / unloading port 121 and a gate valve 122 for opening and closing the substrate loading / unloading port 121 are provided on the side wall of the processing chamber 102, and a load lock adjacent to the substrate G with the gate valve 122 opened. It is designed to be transported between rooms.

  In the plasma etching apparatus 101 configured as described above, first, the substrate G as the object to be processed is loaded into the processing chamber 102 from the load lock chamber via the substrate loading / unloading port 121 after the gate valve 122 is opened. Then, it is placed on the convex portion 107 of the dielectric material film 106 formed on the susceptor 104. Thereafter, the gate valve 122 is closed, and the inside of the processing chamber 102 is evacuated to a predetermined degree of vacuum by the exhaust device 120.

  After that, the valve 116 is opened, and the flow rate of the processing gas from the processing gas supply source 118 is adjusted by the mass flow controller 117, while passing through the processing gas supply pipe 115 and the gas inlet 114 to the internal space 112 of the shower head 111. Introduced and further uniformly discharged onto the substrate G through the discharge holes 113, and the pressure in the processing chamber 102 is maintained at a predetermined value.

  In this state, high-frequency power is applied from the high-frequency power source 125 to the susceptor 104 via the matching unit 124, whereby a high-frequency electric field is generated between the susceptor 104 as the lower electrode and the shower head 111 as the upper electrode. Is dissociated into plasma, and the substrate G is etched (see Patent Document 1).

However, in such a conventional plasma processing apparatus, when the processing chamber of the plasma processing apparatus increases in area with the increase in the size of the substrate to be processed, the uniformity of plasma in the processing chamber varies. Therefore, uniform plasma processing cannot be performed on the substrate to be processed by the generated plasma.
JP 2002-313898 A

  The problem to be solved by the present invention is the non-uniformity of plasma in the processing chamber of the plasma processing apparatus.

  In the present invention, a partition member is inserted in a region where the plasma density in the processing chamber is locally high, and the plasma is deactivated by collision of ions and electrons with the member, and the plasma is made uniform over the entire surface of the substrate to be processed. Is a plasma processing apparatus.

  According to the plasma processing apparatus of the present invention, a partition member having a very simple structure is inserted into a region where the plasma density between the substrate to be processed and the inner wall surface of the processing container is locally high, and the plasma is deactivated. The uniformity of the etching rate can be achieved by making the plasma uniform.

Configuration of Plasma Processing Apparatus As shown in FIG. 1 attached, a plasma processing apparatus 1 of the present invention includes a processing container 2 that is electrically conductive and hermetically held (inner dimensions of the processing container, width direction: 2,890 mm, longitudinal Direction: 3,100 mm, height 600 mm), and the processing chamber 3 is formed in the processing container 2. In the processing chamber 3, a processing target substrate G (for example, a glass substrate having an outer shape of 1,870 mm × 2,200 mm) having a rectangular shape in plan view such as a glass substrate carried in / out of the gate valve 14 is placed. A conductive lower electrode 4 that also serves as a mounting table is disposed. The lower electrode 4 is connected to a 13.56 MHz high frequency power supply unit and a 3.2 MHz high frequency power supply unit via a 13.56 MHz matching circuit 7 and a 3.2 MHz matching circuit 8, respectively. Further, the upper electrode 5 is disposed in parallel with the lower electrode 4 at a position facing the substrate mounting surface of the lower electrode 4, and impedance adjustment circuits 9 and 10 (13.56 MHz impedance adjustment circuit 9, 3 .2 MHz impedance adjustment circuit 10). Other configurations are almost the same as those of the conventional parallel plate type plasma etching apparatus.

  As described above, by configuring the plasma processing apparatus 1 of the present invention, the upper substrate 5 and the lower electrode 4 are applied with high-frequency power in a superimposed manner to generate plasma and process the substrate G to be processed. By providing an impedance adjustment circuit 9 (for 13.56 MHz) including a capacitive component and an impedance adjustment circuit 10 (for 3.2 MHz) between the electrode 5 and the processing container 2, the plasma from the lower electrode 4 and the upper part The impedance value from the upper electrode 5 to the return conductive path through the electrode 5 and the wall of the processing vessel 2 is the impedance value from the upper electrode 5 to the return conductive path through the wall of the processing vessel 2. Can be smaller. Therefore, it is possible to suppress the generation of plasma between the lower electrode 4 and the wall portion of the processing container 2, generate a highly uniform plasma in the processing chamber 3, and achieve in-plane uniformity with respect to the substrate G to be processed. High plasma treatment can be performed.

  However, as described above, when the processing chamber 3 is increased in area with the increase in the size of the substrate G to be processed, the plasma uniformity in the processing chamber of the plasma processing apparatus still varies.

Aspect of the shielding member where, in the plasma processing apparatus 1 of the present invention, the processing chamber in the 3 plasma density shielding member 11 is made larger to (etching rate) at a high as possible contact area between the plasma (11a, 11b, 11c, 11d) (or a convex portion is integrally formed on the inner wall surface 2a of the processing vessel 2), and the plasma in the processing chamber 3 is made uniform.

  For example, in the plasma etching apparatus 1 for a glass substrate (FPD), when the etching rate is high only at the center of the long side of the substrate G to be processed, it opposes the center of the long side a as shown in FIGS. The partition member 11 is disposed on the inner wall surface 2 a of the processing container 2.

  That is, the inner wall surface 2a of the plasma etching apparatus 1 for processing a substantially rectangular target substrate such as a glass substrate is a flat surface substantially parallel to the long side a and the short side b of the target substrate G. Yes.

  Therefore, as shown in FIGS. 1 and 2, a baffle plate 5 is attached between the inner wall surface 2a of the processing vessel 2 and the lower electrode 4 so as to be parallel to the long side and the short side of the lower electrode 4, respectively. A partition member 11 (for example, a height of about 150 mm or more) is disposed as close as possible to the substrate G to be processed so as to contact the baffle plate 5 and the inner wall surface 2a. That is, in the embodiment of FIG. 1 and FIG. 2, as shown in FIG. 2, it is a rectangular shape in plan view and has a predetermined height so as to oppose substantially the center of the long side a and the short side b of the substrate G to be processed. A partition member 11 is disposed. The partition member 11 may be attached to the baffle plate 5 with a separate leg attached, or by any other attachment method.

  In the embodiment shown in FIG. 3A, the partition member 11a is a hollow box-shaped member having a predetermined length or a solid box-shaped member.

  The constituent material of the partition member may be a conductor such as a metal (for example, a 5 mm thick steel plate) or an insulator. In short, in the plasma processing apparatus of the present invention, in order to ensure the uniformity of the plasma etching process, the partition member 11a is inserted in a place where the plasma density is high, and ions and electrons collide with the member 11a to lose the plasma. You just have to make use of it. A partition member is selectively inserted between the substrate to be processed G and the inner wall surface 2a of the processing container 2 to improve the uniformity of the etching rate, thereby enabling uniform plasma processing.

  In the embodiment of FIGS. 1 and 2, the partition members 11 are disposed at positions substantially opposite to the center of the long side a and the short side b of the substrate to be processed G. When the plasma etching rate is high, each of the four corners is provided with a triangular shape or a plate shape in plan view and a partition member having a predetermined height is disposed (see “Triangular shape partition member shown by hatching in FIG. 2). 11 ”).

  In addition, as shown in FIG. 2, when the partition member 11a is disposed so as to face the gate valve which is the loading / unloading of the substrate to be processed G, the lower electrode 4 on which the substrate to be processed G is placed is moved up and down. This prevents the substrate G to be loaded / unloaded from the gate valve 14 into the processing chamber 3. Further, when the substrate G is carried in and out by moving the partition member 11 up and down, it does not exist in the processing chamber 3 so as not to interfere with the loading and unloading of the substrate. You may make it take out.

  In addition, when many types of processes are performed in the same processing chamber, a partition member that functions as a plasma deactivation plate is selectively operated to generate an optimal plasma that matches each process condition in the same processing chamber. Make it possible.

  Further, the shape of the partition members may be varied according to the process conditions and types in the processing chamber, and the arrangement positions thereof may be varied.

  Further, as shown in FIG. 3B, a slope-shaped partition member 11 b may be disposed so as to lean against the inner wall surface 2 a of the processing chamber 2 and the outer edge of the lower electrode 4. In this case, the deactivation rate of the plasma decreases as the position is farther from the substrate G to be processed.

  Further, as shown in FIG. 3C, in order to make the etching rate of the process uniform, the upright plate-like partition member 11b may be attached to the baffle plate 5 as close as possible to the substrate G to be processed. Good.

  Furthermore, as shown in FIG. 3 (d), a partition member 11a having an L-shaped cross section may be provided on the inner wall surface 2a of the processing chamber 2 so as to be brought into contact with the plasma to make the plasma etching rate uniform.

Demonstration of Plasma Uniformity In the plasma processing apparatus of the present invention, since the plasma density in the processing chamber is locally high, a screen member is selectively inserted into a portion where the etching rate is locally increased and plasma is generated. It can be brought into contact and deactivated to make the plasma density uniform and improve the uniformity of the etching rate.

(I) Demonstration of plasma homogenization effect by plasma measurement First, as shown in FIG. 4 (plasma homogenization effect of screen member), the screen member is placed on the substrate to be processed in the processing chamber as in the plasma processing apparatus of the present invention. The difference in the plasma electron density between the adjacent device and the device without a screen member as in the conventional apparatus was measured by PAP (Plasma Absorption Probe).

That is, in the method for confirming the effect of the present invention by PAP, as shown in FIG. 5, the insulating tubes 17 are passed through both wall portions of the processing vessel 2 of the plasma processing apparatus, and the insulating tubes 17 are supported at both ends by an O-ring. After sealing, the coaxial probe 15 is inserted into the insulating tube 17, and only the coaxial probe 15 is slid, and an electromagnetic wave signal is applied from the network analyzer 16 to the coaxial probe 15 while being swept in frequency. The electron density of plasma was measured from 60 mm. Here, in the processing chamber 3 under the atmosphere of processing gas SF ₆ / N ₂ , RF power source 15,000 w, bias power source 7,000 w, electrostatic chuck adsorption voltage 3.0 kV, back pressure pressure 3.0 Torr, 70 mTorr. The electron density of the plasma was measured.

  According to PAP, when a certain frequency signal matches the plasma electron frequency fp, the electromagnetic wave is absorbed by the plasma. Using this characteristic, the electron density Ne is obtained from the equation (1).

従来の衝立部材を設けていないプラズマ処理装置とでは、図４から明白なように、プラズマの電子密度（Ｎｅ〔ｍ^-3〕）は、従来の衝立部材なしのものに比して、衝立部材の設置範囲で、大幅に低下し、これに伴いプラズマが大巾に均一化された。なお、本実験での衝立部材の設置範囲は、図４に示すように、被処理基板の中心から約６００ｍｍまでの位置であり、また、図４に示すように、処理室２の内壁から被処理基板Ｇの端部までの距離Ｌｐの１／２（図４では◆で示す）、１／３（図４では■で示す）であることを指す。また、幅０とは、衝立部材を内壁に接触させて設置した場合を示す（図４では×で示す）。

As is apparent from FIG. 4, in the plasma processing apparatus having no conventional partition member, the electron density (Ne [m ⁻³ ]) of the plasma is higher than that of the conventional one without the partition member. In the installation range, the plasma was greatly reduced, and the plasma was made more uniform. In addition, the installation range of the partition member in this experiment is a position from the center of the substrate to be processed to about 600 mm as shown in FIG. 4, and from the inner wall of the processing chamber 2 as shown in FIG. It indicates that the distance Lp to the end of the processing substrate G is 1/2 (indicated by ◆ in FIG. 4) and 1/3 (indicated by ■ in FIG. 4). The width 0 indicates a case where the partition member is placed in contact with the inner wall (indicated by x in FIG. 4).

(Ii) Demonstration of plasma homogenization effect from etching process (a) When a partition member is arranged at a position facing the long side of the substrate to be processed A partition at a position facing the long side a of the substrate to be processed G shown in FIG. By arranging the member 11, the etching rate reduction by the partition member, that is, the uniformity of plasma, was compared with the conventional one without the partition member.

表１では、表１（ａ）は、衝立部材を配置しない場合の被処理基板の長辺方向（横軸）と短辺方向（縦軸）の所定個所でのエッチングデプスを、表１（ｂ）は、箱形の衝立部材（図３（ａ）参照）を配置し、その長さが電極寸法の１／２、巾Ｗｐがバッフル板の巾Ｗｂの２／３のものの（ここでは内壁と基板端部との距離Ｌｐの２／３の厚さのものが内壁から設置されている）エッチングデプスを、また、表１（ｃ）は、斜面状の衝立部材（図３（ｂ）符号１１ａ参照）を配置し、その長さＬｐが電極寸法の１／４、巾Ｗｐがバッフル板の巾と同じものの（ここでは内壁と基板端部との距離Ｌｐと同じ厚さのものが内壁から設置されている。すなわち、この実施例では、内壁と基板端部との間が衝立部材により埋没されている。）エッチングデプスを示している（いずれも短辺側には、衝立部材を配置していない）。

In Table 1, Table 1 (a) shows the etching depth at predetermined locations in the long side direction (horizontal axis) and the short side direction (vertical axis) of the substrate to be processed when no partition member is arranged. ) Has a box-shaped partition member (see FIG. 3A), whose length is 1/2 of the electrode dimension, and whose width Wp is 2/3 of the width Wb of the baffle plate (here, the inner wall and Etching depth (having a thickness of 2/3 of the distance Lp from the end of the substrate is installed from the inner wall), and Table 1 (c) shows a slope-shaped partition member (reference numeral 11a in FIG. 3 (b)). The length Lp is 1/4 of the electrode dimensions, and the width Wp is the same as the width of the baffle plate (here, the same thickness as the distance Lp between the inner wall and the substrate end is installed from the inner wall) That is, in this embodiment, the space between the inner wall and the end of the substrate is buried by a screen member.) Etching It shows the TOPS (both on the short side is not arranged the shielding member).

  As apparent from Table 1 (a), in the case where the partition member is not disposed, the etching depth of the central part of the long side and the short side of the substrate to be processed is high (2564, 2372), and the etching depth is uneven.

  On the other hand, in the case where the box-shaped partition members shown in Table 1 (b) are arranged, the effect of suppressing the etching rate is sufficiently recognized at the long side portion by arranging the partition members (2564 → 2291). 2779 → 2266).

  In addition, in the case where the slope-shaped partition members (see reference numeral 11b in FIG. 3B) shown in Table 1 (c) are arranged, the etching rate at the center of the long side is the same as that in which the box-shaped partition members are arranged. The inhibitory effect was sufficiently recognized (2564 → 2351, 2779 → 2383).

(B) When partitioning members are arranged at the four corners of the processing chamber Next, a triangular partitioning member shown by hatching in FIG. 2 is arranged at the four corners of the processing chamber to compare with a conventional one without a partitioning member. Thus, the etching depth was reduced, that is, the uniformity of the etching rate (plasma) by the screen member was compared.

表２では、表２（ａ）は、衝立部材を配置しない場合の被処理基板の長辺方向（横軸）と短辺方向（縦軸）の所定個所でのエッチングデプスを、表２（ｂ）は、処理室内側隅から被処理基板の隅までの距離（図２に示すＷｔ）の２／３の位置に箱形の衝立部材（図３（ａ）参照）を処理室内側の四隅に配置したもののエッチングデプスを、また表２（ｃ）は、処理室内側の隅から基板の四隅一杯に（基板の四隅に接近させて）衝立部材を配置したもののエッチングデプスをそれぞれ示している。

In Table 2, Table 2 (a) shows the etching depth at predetermined locations in the long side direction (horizontal axis) and the short side direction (vertical axis) of the substrate to be processed when no partition member is arranged. ) Is a box-shaped partition member (see FIG. 3A) at two-thirds of the distance (Wt shown in FIG. 2) from the processing chamber side corner to the corner of the substrate to be processed at the four corners on the processing chamber side. Table 2 (c) shows the etching depth of the substrate in which the partition members are arranged from the corner on the processing chamber side to the four corners of the substrate (close to the four corners of the substrate).

  As apparent from Table 2 (b), it is recognized that the etching rate at the four corners of the processing chamber is suppressed by arranging the partition members at the four corners (2759 → 2476, 2868 → 2582, 2724 → 2472, 2753 → 2491, respectively).

  Furthermore, as shown in Table 2 (c), the etching rate at the four corners was more effectively suppressed by bringing the screen member closer to a position closer to the substrate to be processed.

  The plasma processing apparatus of the present invention is not limited to a plasma etching apparatus, but is various indispensable to improve plasma uniformity by preventing local increase in plasma density in plasma CVD and other plasma apparatuses. Applicable to processing equipment.

It is a schematic diagram (longitudinal section) of the plasma processing apparatus of the present invention, and is an embodiment in which a partition member is disposed in the processing chamber in the vicinity of the substrate to be processed. FIG. 2 is a horizontal cross-sectional view of the plasma processing apparatus of the present invention shown in FIG. 1. FIG. 2 is a partially enlarged vertical cross-sectional view of the plasma processing apparatus according to the present invention shown in FIG. 1, showing each embodiment in which a partition member is disposed in the processing chamber in the vicinity of the substrate to be processed. FIG. 3A is an embodiment in which a partition member having a box-shaped cross section is disposed in the processing chamber in the vicinity of the substrate to be processed, and FIG. 3B is an embodiment in which a partition member having a slope shape is disposed. FIG. 3C shows an embodiment in which an upright wall-shaped partition member is disposed, and FIG. 3D shows an embodiment in which an L-shaped partition member is disposed. FIG. 4 shows the change (decrease) in the plasma electron density from the center of the substrate to be processed to the edge of the substrate to be processed in the plasma processing apparatus of the present invention (with a partition member) and the conventional plasma processing apparatus (without the partition member). Indicates the placement position. The measurement method used for measuring the change of the plasma electron density shown in FIG. 4 is shown. The longitudinal cross-sectional view of the plasma processing apparatus which does not arrange | position the conventional partition member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 2 Processing container 3 Processing chamber 4 Lower electrode 5 Upper electrode 11 (11a-11d) Screen member 13 Baffle plate 14 Gate valve 15 Probe 16 Network analyzer 17 Insulation tube G Substrate to be processed (glass substrate)

Claims (9)

In a plasma processing apparatus provided with a processing chamber for processing a substrate to be processed, a partition member for deactivating plasma is provided between the side wall of the processing chamber surrounding the substrate to be processed and the periphery of the substrate to be processed. A plasma processing apparatus , which is disposed in the vicinity of a substrate and has a uniform plasma or etching rate with respect to the substrate to be processed. The portion of the partition member, the plasma processing apparatus according to claim 1, characterized in that it is arranged at a position facing the substrate to be processed around.   The plasma processing apparatus according to claim 1, wherein the partition member has a rectangular shape in plan view and has a box-shaped hollow rectangular cross section or a box-shaped solid rectangular cross section.   The plasma processing apparatus according to claim 1, wherein the partition member is an upright plate-like body.   The partition member is a plate-like body having a rectangular shape in a plan view, and is disposed obliquely with respect to a plasma irradiation direction in the vicinity of an inner wall surface of the processing chamber and the substrate to be processed. Item 2. The plasma processing apparatus according to Item 1.   The plasma processing apparatus according to claim 1, wherein the partition member has a rectangular shape in plan view, an L-shaped cross section, and is attached to an inner wall surface of the processing chamber.   The plasma processing apparatus according to claim 1, wherein the partition member has a triangular shape or a plate-like body in a plan view and is arranged at four corners of the processing chamber.   The plasma processing apparatus according to claim 1, wherein the partition member is selectively disposed or operable in accordance with a process condition in the processing chamber. The said partition member does not interfere with loading / unloading of the substrate when the substrate to be processed is loaded / unloaded into the processing chamber, and appears in the processing chamber only when processing the substrate to be processed. 2. The plasma processing apparatus according to 1.

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