KR100799382B1 - Plasma treatment system - Google Patents

Abstract

A partition member is inserted into a region where the plasma density in the processing chamber of the plasma processing apparatus is locally high to deactivate the plasma, thereby making the plasma uniform. In the plasma processing apparatus 1, the partition member 11 which inactivates a plasma is provided in the site | part where the plasma density in a process chamber 3 is locally high, and the plasma etching rate with respect to the to-be-processed substrate G is equalized. It is characterized by.

Description

Plasma Treatment Equipment {PLASMA TREATMENT SYSTEM}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view (vertical section view) of a plasma processing apparatus of the present invention, showing an embodiment in which a partition member is disposed in a processing chamber in proximity to a substrate to be processed;

FIG. 2 is a cross sectional plan view of the plasma processing apparatus of the present invention shown in FIG. 1;

3A to 3D are enlarged longitudinal cross-sectional views of an arrow A portion of the plasma processing apparatus of the present invention shown in FIG. 1, showing respective embodiments in which a partition member is disposed in the processing chamber in proximity to the substrate to be processed. ,

3A is a view showing an embodiment in which a partition member having a box-shaped cross section is disposed in a processing chamber in proximity to a substrate to be processed;

3B is a view showing an embodiment in which a partition member having an inclined surface shape is disposed;

3C is a view showing an embodiment in which a wall partition member of an upright position is arranged;

3D is a view showing 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 the substrate to be processed and the partition member in the plasma processing apparatus (with the partition member) of the present invention and the conventional plasma processing apparatus (without the partition member). Drawing showing the placement position of,

FIG. 5 is a view showing a measurement method used to measure a change in plasma electron density shown in FIG. 4;

6 is a longitudinal sectional view of a plasma processing apparatus in which no conventional partition member is disposed;

Explanation of symbols for the main parts of the drawings

1: plasma processing apparatus 2: processing vessel

3: process chamber 4: lower electrode

5: upper electrode 11 (11a to 11d): partition member

13: baffle plate 14: gate valve

15: Probe 16: Network Analyzer

17: insulated tube G: substrate to be processed (glass substrate)

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

In manufacturing processes, such as a semiconductor device and a flat panel display (FPD), plasma processing apparatuses, such as a plasma etching apparatus, are used in order to etch a to-be-processed substrate, such as a semiconductor wafer and a glass substrate (LCD substrate).

In this kind of plasma processing apparatus, as shown in FIG. 6, the processing apparatus 101 is an apparatus which performs predetermined | prescribed process of an LCD glass substrate, and is comprised here using a capacitively coupled parallel plate plasma etching apparatus as an example.

This plasma etching apparatus 101 has a processing chamber 102 formed into a box shape made of aluminum, for example. The columnar insulating plate 103 made of an insulating material is disposed on the bottom of the processing chamber 102, and the susceptor 104 for mounting the LCD glass substrate G, which is a substrate to be processed, is disposed on the insulating plate 103. Is arranged. In addition, an insulating member 108 is disposed at the periphery where the layer 105 and the dielectric material film 106 on the outer circumference and upper surface of the substrate 104a of the susceptor 104 are not arranged.

A susceptor 104 is connected with a feed line 123 for supplying high frequency power, and a matcher 124 and a high frequency power supply 125 are connected to the feed line 123.

Moreover, above the susceptor 104, the shower head 111 which functions as an upper electrode facing parallel to this susceptor 104 is arrange | positioned. The shower head 111 is supported at the upper portion of the processing chamber 102, and has a plurality of discharge holes 113 having an internal space 112 therein and discharging the processing gas on a surface facing the susceptor 104. Formed. This shower head 111 is grounded and comprises a pair of parallel flat electrodes with the susceptor 104.

A gas inlet 114 is disposed on an upper surface of the shower head 111, and a process gas supply pipe 115 is connected to the gas inlet 114, and a valve 116 and a process gas supply pipe 115 are connected to the process gas supply pipe 115. The process gas supply source 118 is connected via a mass flow controller (MFC) 117.

In addition, 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, and the exhaust device 120 uses a vacuum pump such as a turbo molecular pump. It is comprised so that vacuum suction to the predetermined pressure-reduced atmosphere can be carried out in the process chamber 102 by this. Further, a substrate loading / exiting outlet 121 and a gate valve 122 for opening / closing the substrate loading / exiting outlet 121 are disposed on the sidewall of the processing chamber 102, and the substrate ( G) is to be conveyed between adjacent load lock chambers.

In the plasma etching apparatus 101 configured as described above, the substrate G, which is the object to be processed, is first loaded into the processing chamber 102 from the load lock chamber via the substrate loading / unloading opening 121 after the gate valve 122 is opened. 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 vacuum sucked up to a predetermined vacuum degree by the exhaust device 120.

Thereafter, the valve 116 is opened so that the flow rate of the process gas from the process gas supply source 118 is adjusted by the mass flow meter 117, and the shower head is provided through the process gas supply pipe 115 and the gas inlet 114. It is introduced into the internal space 112 of 111 and is discharged uniformly with respect to the board | substrate G through the discharge hole 113, and the pressure in the process chamber 102 is maintained at a predetermined value.

In this state, a high frequency electric power is applied to the susceptor 104 from the high frequency power supply 125 via the matching unit 124, thereby providing a high frequency electric field between the susceptor 104 as the lower electrode and the shower head 111 as the upper electrode. , The processing gas decomposes into plasma, and the etching treatment is performed on the substrate G (see Japanese Patent Laid-Open No. 2002-313898).

However, in such a conventional plasma processing apparatus, as the area of the processing chamber of the plasma processing apparatus increases with the increase in size of the substrate to be processed, an unbalance occurs in the uniformity of the plasma in the processing chamber. Therefore, a uniform plasma process cannot be performed with the generated plasma with respect to a to-be-processed substrate.

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

According to the present invention, a partition member is inserted into a region having a high plasma density in a processing chamber, ions and electrons collide with the member to deactivate the plasma, and uniformize the plasma over the entire surface of the substrate to be treated. It is a plasma processing apparatus characterized by the above-mentioned.

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, thereby inactivating the plasma and making the plasma uniform, thereby etching. Uniformity of speed can be achieved.

plasma  Configuration of the processing unit

As shown in FIG. 1, the plasma processing apparatus 1 of the present invention has a conductive, airtightly held processing container 2 (in the inner dimension of the processing container, width direction: 2,890 mm, length direction: 3,100 mm, Height: 600 mm), and the processing chamber 3 is formed in this processing container 2. And in this process chamber 3, the to-be-processed board | substrate G (for example, the glass substrate of external shape 1,870 mm x 2,200 mm) is mounted in planar view, such as a glass substrate carried in and out from the gate valve 14, and so on. A conductive lower electrode 4 serving as a mounting table is provided. The lower electrode 4 is connected to a 13.56 MHz high frequency power supply section and a 3.2 MHz high frequency power supply section via a 13.56 MHz matching circuit 7 and a 3.2 MHz matching circuit 8, respectively. At the position opposite the substrate mounting surface of the lower electrode 4, the upper electrode 5 is disposed in parallel with the lower electrode 4, and the impedance adjusting circuit 9, 10 [impedance adjusting circuit for 13.56 MHz] is provided. (9) and impedance adjusting circuit 10 for 3.2 MHz]. In addition, the other structure is substantially the same as the conventional parallel plate type plasma etching apparatus.

In this way, by configuring the plasma processing apparatus 1 of the present invention, the plasma is generated by applying high frequency power superimposed between the upper electrode 5 and the lower electrode 4 to process the substrate G to be processed. In this case, between the upper electrode 5 and the processing container 2, an impedance adjusting circuit 9 (for 13.56 MHz) and an impedance adjusting circuit 10 (for 3.2 MHz) containing a capacitor component are provided, thereby providing a lower electrode ( The plasma value from 4) and the impedance value until reaching the return conductive path through the upper electrode 5 and the wall of the processing container 2 are converted into the plasma and processing container 2 from the upper electrode 5. It can be made smaller than the impedance value until it reaches a return conductive path through a wall part. For this reason, it is possible to suppress the generation of plasma between the lower electrode 4 and the wall portion of the processing container 2, and to generate a high uniformity plasma in the processing chamber 3, thereby in-plane uniformity with respect to the substrate G to be processed. This high plasma process can be performed.

However, as described above, if the area of the processing chamber 3 increases with the enlargement of the processing target substrate G, there is still an imbalance in the uniformity of the plasma in the processing chamber of the plasma processing apparatus.

Shape of the partition member

Therefore, in the plasma processing apparatus 1 of the present invention, the partition members 11 (11a, 11b, 11c, 11d) in which the contact area with the plasma is as large as possible in a place where the plasma density (etching speed) in the processing chamber 3 is high. Is disposed so that some or all of them are at a position higher than the substrate G (or the convex portions are integrally formed on the inner wall surface 2a of the processing container 2) to form the plasma in the processing chamber 3. Equalize.

For example, in the plasma etching apparatus 1 of the glass substrate FPD, when etching speed is high only in the center of the long side of the to-be-processed substrate G, as shown to FIG. 1 and FIG. 2, the long side ( The partition member 11 is arrange | positioned at the inner wall surface 2a of the processing container 2 which opposes the center of a).

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

Therefore, as shown in FIGS. 1 and 2, a baffle plate 13 is disposed between the inner wall surface 2a of the processing container 2 and the lower electrode 4, and the long side of the lower electrode 4. And the partition member 11 (e.g., height of about 150 mm) as close as possible to the substrate to be processed G so as to be parallel to each of the short sides and in contact with the baffle plate 13 and the inner wall surface 2a. Or more). That is, in the embodiment of Fig. 1 and Fig. 2, as shown in Fig. 2, the shape is rectangular in plan view as opposed to the central portion of the long side a and the short side b of the substrate G to be processed. The partition member 11 of predetermined height is arrange | positioned. Mounting of the partition member 11 to the baffle plate 13 can be performed by attaching a separate leg or by any other mounting method.

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

In addition, the constituent material of the partition member may be a conductor such as a metal (for example, a steel plate having a thickness of 5 mm) or an insulator. In short, in the plasma processing apparatus of the present invention, in order to ensure uniformity of the plasma etching treatment, the partition member 11a is inserted at a high plasma density, and ions and electrons collide with the member 11a to deactivate the plasma. I want you to. A partition member is selectively inserted between the substrate G to be processed 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 addition, in the Example of FIG. 1 and FIG. 2, although the partition member 11 was arrange | positioned in the position which opposes substantially center of the long side a and the short side b of the to-be-processed substrate G, respectively, When the plasma etching rate of the four corners of the substrate G is high, the partition members having a predetermined height are arranged in the four corners in the form of a triangle or a plate in plan view ("triangular" shown by hatching in FIG. 2). Partition member 11].

In addition, as shown in FIG. 2, when the partition member 11 is arrange | positioned facing the gate valve which is a carrying-in / out port of the to-be-processed substrate G, the lower electrode 4 which mounts the to-be-processed substrate G is carried out. Is raised and lowered so as not to interfere with carrying in and taking out of the processing target substrate G from the gate valve 14 to the processing chamber 3. Further, the partition member 11 itself is lifted up and down so as not to interfere with the loading and unloading of the substrate to be processed, so that the partition member 11 itself is not present in the processing chamber 3 and into the processing chamber 3 only during processing. You can make it appear.

In addition, when several kinds of processes are performed in the same process chamber, the partition member which functions as a plasma deactivation plate is selectively operated, and it is set as the structure which can generate the plasma suitable for each process condition in the same process chamber.

In addition, the shape of a partition member may be changed according to the process conditions and types in a process chamber, and each arrangement place thereof may also be changed.

In addition, as shown in FIG. 3B, the inclined partition member 11b may be disposed so as to lean against the inner wall surface 2a of the processing chamber 2 and the outer edge of the lower electrode 4. In this case, the deactivation rate of the plasma decreases by a portion spaced from the substrate G.

In addition, as shown in FIG. 3C, in order to make the etching speed of the process uniform, the upright plate-shaped partition member 11c may be attached to the baffle plate 13 as close to the substrate G as possible. .

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

plasma  Demonstration of equalization

In the plasma processing apparatus of the present invention, since the plasma density in the processing chamber is locally high, a partition member is selectively inserted into a portion where the etching rate is locally increased, and brought into contact with the plasma to inactivate the plasma, thereby uniformizing the plasma density. The uniformity of can be improved.

(i) Demonstration of plasma uniformity effect by plasma measurement

First, as shown in FIG. 4 (plasma equalization effect of the partition member), the partition member is disposed in the processing chamber in close proximity to the substrate to be processed, as in the plasma processing apparatus of the present invention, and the partition member is disposed as in the conventional apparatus. The difference of the electron density of the plasma of not placing was measured by PAP (Plasma Absorption Probe).

That is, in the confirmation method of the effect of this invention by PAP, as shown in FIG. 5, the insulated pipe 17 is made to penetrate the both wall parts of the processing container 2 of a plasma processing apparatus, and the insulated pipe 17 is carried out by O-rings. ) Is supported at both ends and vacuum-sealed, and the coaxial probe 15 is inserted into the insulated tube 17, and only the coaxial probe 15 is slid, so that the electromagnetic signal from the network analyzer 16 to the coaxial probe 15 is frequency-swept. It was applied while scanning, and the electron density of the plasma was measured from 60 mm immediately above the lower electrode 4. Here, the electron density of the plasma in the processing chamber 3 in the atmosphere of the processing gas SF ₆ / N ₂ , RF power 15,000 W, bias power 7,000 W, electrostatic chuck adsorption voltage 3.0 kPa, back pressure 3.0 Torr, 70 mTorr Measured.

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

[Equation 1]

m _e = weight of electron e = electron

ε ₀ = dielectric constant of vacuum ε _r = dielectric constant

f _p = plasma electron frequency

As is apparent from FIG. 4 in the plasma processing apparatus which does not arrange the conventional partition member, the electron density Ne [m- ³ ] of plasma falls significantly in the range of arrangement | positioning of a partition member compared with the absence of the conventional partition member. In connection with this, the plasma was substantially uniform. In addition, the arrangement | positioning range of the partition member in this experiment is a position from the center of a to-be-processed board | substrate to about 600 mm, as shown in FIG. 4, and, as shown in FIG. 4, from the inner wall of the process chamber 2 It shows that it is 1/2 (shown with ◆ in FIG. 4), and 1/3 (shown with ■ in FIG. 4) of the distance Lp to the edge part of the to-be-processed substrate G. FIG. In addition, the width | variety zero shows the case where the partition member is arrange | positioned in contact with an inner wall (it shows with x in FIG. 4).

(ii) Demonstration of Plasma Uniformity Effect from Etching Process

Ⓐ In the case where the partition member is disposed at the position opposite to the long side of the substrate to be processed

By arranging the partition member 11 at a position opposite to the long side a of the substrate G shown in FIG. 2, the etching speed of the conventional partitionless member and the partition member is reduced, that is, plasma. Uniformity was compared.

TABLE 1

(a) Gate side etching depth

(b) Gate side etching depth

(c) Gate side etch depth

In Table 1, Table 1 (a) shows the etching depth in predetermined each position of the long side direction (horizontal axis) and short side direction (vertical axis) of a to-be-processed substrate, when a partition member is not arrange | positioned, Table 1 ( b) is provided with a box-shaped partition member (see FIG. 3A), the length of which is 1/2 of the electrode dimension and the width Wp of 2/3 of the baffle plate width Wb [herein the inner wall and substrate end of The thickness of 2/3 of the distance Lp is arranged from the inner wall. The etching depth is shown. In addition, Table 1 (c) arranges the partition member having an inclined surface shape (see reference numeral 11b in FIG. 3B), and the length thereof. (Lp) is one quarter of the electrode dimension and the width Wp is equal to the width of the baffle plate (in this case, the one having the same thickness as the distance Lp between the inner wall and the substrate end is disposed from the inner wall). That is, in this embodiment, the partition wall is buried between the inner wall and the substrate end portion.] The etching depth is shown (all of the partition members are not disposed on the short sides).

As can be seen from Table 1 (a), when the partition member is not disposed, the etching depths of the center portions of the long side and the short side of the substrate to be processed are deep (2564, 2372), and unevenness occurs in the etching depth.

On the other hand, in the case where the box-shaped partition member shown in Table 1 (b) is arranged, the effect of suppressing the etching rate is sufficiently recognized in the long side portion by disposing the partition member (reduced from 2564 to 2291 and 2779 to 2266).

In addition, when arranging the inclined partition member (refer to reference numeral 11b in FIG. 3B) shown in Table 1 (c), the effect of suppressing the etching rate is sufficiently recognized in the long side center portion similarly to the arrangement of the box-shaped partition member. (2564 → 2351, 2779 → 2383).

Ⓑ When partition members are arranged at four corners of the treatment chamber

Next, by arranging the triangular partition members shown by hatching in FIG. 2 at four corners of the processing chamber, the etching depth is reduced compared to the conventional one without the partition members, that is, the uniformity of the etching rate (plasma) by the partition members. I made a gender comparison.

TABLE 2

(a) Gate side etching depth

(b) Gate side etch depth

(c) Gate side etching depth

In Table 2, Table 2 (a) shows the etching depth in the predetermined location of the long side direction (horizontal axis) and short side direction (vertical axis) of a to-be-processed substrate, when a partition member is not arrange | positioned, Table 2 (b) Denotes an etching depth in which a box-shaped partition member (see FIG. 3A) is disposed at four corners inside the processing chamber at a position 2/3 of the distance from the inner corner of the processing chamber to the corner of the substrate to be processed (Wt shown in FIG. 2). In addition, Table 2 (c) has shown the etching depth which arrange | positioned the partition member closely to the four corners of a board | substrate from the corner inside a process chamber (close to the corner of a board | substrate).

As can be seen from Table 2 (b), by arranging the partition members at the four corner portions, it can be seen that the etching rates at the four corner portions of the processing chamber are suppressed (2759 → 2476, 2868 → 2582, 2724). → 2472, 2753 → 2491, respectively).

In addition, as shown in Table 2 (c), by bringing the partition member closer to the position closer to the processing target substrate, the etching rates at the four corner portions were more effectively suppressed.

The plasma processing apparatus of the present invention is not limited to the plasma etching apparatus, and in various types of processing apparatuses in plasma CVD or other plasma apparatuses, it is essential to prevent the plasma density from increasing locally and improve the uniformity of the plasma. Applicable

Claims (9)

In the plasma processing apparatus, A partition member for inactivating the plasma is disposed in a region where the plasma density in the processing chamber is locally high, so that the plasma or etching rate with respect to the substrate to be treated is uniform. The partition member is disposed between the inner wall surface of the processing chamber and the substrate to be processed in close proximity to the substrate to be processed, and part or all of the partition member is disposed at a position higher than the substrate to be processed. Plasma processing apparatus. delete The method of claim 1, The partition member has a rectangular shape in plan view and has a hollow hollow rectangular cross section or a rectangular solid rectangular cross section. Plasma processing apparatus. The method of claim 1, The partition member is an upright plate-like body, characterized in that Plasma processing apparatus. The method of claim 1, The partition member is a plate-shaped body having a rectangular shape in plan view, and is disposed inclined with respect to the plasma irradiation direction in proximity to the inner wall surface of the processing chamber and the substrate to be processed. Plasma processing apparatus. The method of claim 1, The partition member has a rectangular shape in plan view, has an L-shaped cross section, and is mounted on an inner wall surface of the processing chamber. Plasma processing apparatus. The method of claim 1, The partition member is triangular or plate-like in plan view, and is disposed at four corners of the processing chamber. Plasma processing apparatus. The method of claim 1, The partition member is selectively arranged or operatively arranged according to the process conditions in the processing chamber. Plasma processing apparatus. The method of claim 1, The partition member is exhibited into the processing chamber only during the processing of the substrate to be processed without interfering with the loading and unloading of the substrate when the substrate is loaded into or taken out of the processing chamber. Plasma processing apparatus.

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