JPS63111174A - Method and apparatus for treating surface of substrate in vacuum vessel - Google Patents

Abstract

PURPOSE:To change DC bias generated on the surface of a substrate with high reproducibility by relatively changing the distance from electrode members to a support member supporting the substrate. CONSTITUTION:AC voltage is impressed to electrode members insulated electrically from the wall of a vacuum vessel 1 to generate plasma in the vessel 1 by glow discharge. A substrate to be surface-treated with the plasma is supported on a support member 9 and the distance from the support member 9 to the electrode members is mechanically changed to change DC bias generated on the surface of the substrate with respect to the AC voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for surface treatment of a substrate in a vacuum chamber, such as a CVD apparatus.

[Conventional technology and its problems]

Figure 9 shows the first conventional inversion, in which wafers (9■ indicates a case where multiple wafers are mounted, but one
The same thing applies when only one sheet is mounted. The stage body [F]D on which the wafer field is mounted is rotationally driven together with the earth shield by a rotation transmission mechanism (by motor □□□ via 911). The stage body SD and the earth shield (8z are electrically insulated by an insulator 9, and the stage body!813 has DC or R
DC or RF power is applied to the F power introduction section (there are methods such as a rotary contact type and a capacitor coupling type). Vacuum sealing during rotation and prevention of vibration of the rotation shaft are achieved by a vacuum rotary seal fitted into an opening in the vacuum chamber wall. (O-ring seals, Wilson seals, magnetic fluid seals, etc. are used as sealing methods).

The stage main body is provided with both or one of a heater and a cooling waterway, and the heater power and cooling water are introduced through an introduction part G31 (rotary stage, etc.) K.

Figure 10 shows the second conventional example arc', while the conventional example in Figure 9 (
The difference from 801 is that the heater mechanism (92) is separated from the stage main body and fixed to a vacuum chamber, and the mechanisms related to rotation are the same.

Note that parts corresponding to those in FIG. 9 are given the same reference numerals.

However, in the mechanism shown in Figure 9 or Figure 10 with an earth shield mechanism, if RFi power is applied to the stage body glue and plasma is generated by glow discharge in the vacuum chamber, the wafer (90) surface (stage body surface Although the DC bias generated on the wafer surface and the DC bias generated on the wafer surface mounted on the wafer surface are strictly speaking slightly different, in this specification, the explanation will proceed assuming that they are the same). The only way to do this is to change the RFt force itself, or to change it electrically, such as by providing a mechanism (capacitor, coil, resistor, etc.) that changes the impedance of the entire stage mechanism in the RF power transmission circuit. Furthermore, a mechanism for supplying power to the rotating body must be employed in the DC or RF power introduction section (c), which poses difficulties in terms of maintenance and inspection. Furthermore, if there are characteristic changes in the capacitors, coils, and resistors that are the elements of the mechanism that changes impedance, delicate adjustment of the DC bias becomes difficult.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method and apparatus for surface treatment of a substrate in a vacuum chamber, which can change the DC bias applied to a wafer in a purely mechanical manner, extremely simply, and with good reproducibility. do.

[Means for solving problems]

According to the first aspect of the present invention, the above object is to provide an electrode member that is electrically insulated from the wall of a vacuum chamber and to which an alternating current voltage is applied to generate plasma due to gua discharge in the vacuum chamber; The AC voltage generated on the surface of the support member (or the surface of the substrate mounted on the surface of the support member) by changing the distance between the support member and the support member for supporting the substrate to be surface-treated by the plasma. This is achieved by a method for surface treatment of a substrate in a vacuum chamber, which is characterized in that the DC bias for the substrate is varied.

Further, according to a second aspect of the present invention, an electrode member that is electrically insulated from a wall of a vacuum chamber and to which an alternating current voltage is applied to generate plasma by glow discharge in the vacuum chamber; or a drive shaft that slidably passes through the electrode member; a support member that is fixed to the end of the drive shaft on the vacuum chamber side and that supports the substrate to be surface-treated by the plasma; a drive mechanism for driving the shaft along its axial direction; and by driving the drive mechanism, the distance between the electrode member and the support member is changed, and the distance between the support member surface or the support member is changed. This is achieved by a surface treatment apparatus for a substrate in a vacuum chamber, characterized in that the DC bias with respect to the AC voltage generated on the surface of the substrate mounted on the surface of the support member is changed.

[For production]

By simply moving the support member that supports the substrate (wafer) relative to the electrode member (to which a F voltage is applied) and changing the distance between them, the surface of the support member, and therefore the The DC bias generated on the substrate surface can be changed.

Since the DC bias can be changed depending on the distance,
The adjustment is easy, and it may be unnecessary to use a rotary joint mechanism in the RFg force section as in the conventional example.

Therefore, the overall configuration can be simplified and maintenance and inspection intervals can be lengthened.

〔Example〕

Hereinafter, a CVD apparatus according to an embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows the entire CVD apparatus of this embodiment. In the figure, a reactant gas introduction nozzle (2) is attached to the - side end wall of the vacuum chamber (1), and the bottom of the other end. There are exhaust holes on the wall (
3) is formed. The exhaust hole (3) is the exhaust pipe (4
) and a main duct (5) to an exhaust system (not shown). Further, an opening ff01 for taking out a wafer is formed in the other side wall, and this can be opened and closed by an airtight gate valve (not shown).

A vertical rotation drive mechanism (6) according to the present invention is disposed below the vacuum chamber (1), and a cover (7) covers this. These are fixed to the vacuum chamber (1) and are also fixed to the vacuum chamber (1).
1) is fixed to a frame -) (partially shown) with bolts 111.

As clearly shown in Figures 2 and 3, a disc-shaped susceptor (9) faces inside the vacuum chamber (1), and the stage body (8) is disposed directly below the susceptor (9). At the periphery, a bolt (a) runs straight through the insulating 7 langes συ to an earth shield body αQ arranged concentrically therewith in an airtight manner. The earth shield Q0 is airtightly attached to the bottom wall C14 of the vacuum chamber (1) by bolts (43) at the outer periphery.
) K is fixed. A quartz ring is attached to the upper surface of the earth shield body OQ.

A rotating shaft (A) is integrally fixed to the susceptor (9) at its center, and is inserted through the center hole (8a) of the stage body (8) to create a vacuum having a It is airtightly and rotatably supported by a rotary seal device (17). The vacuum rotary sealing device αη further has a pair of upper and lower bearings (tea) (tab), which support the rotating shaft (t).
The bearing case α9 into which the bearings sa) (xsb) are fitted is fixed to the intermediate mounting plate cutout at the lower end.

A boo IJ (zx) is fixed near the lower end of the rotating shaft (to), and a motor 4 is fixed to a lower mounting plate (2) located below this via a contact plate (8). The plate 100 is fixed to the motor ■ by bolts l511, and as shown in Fig. 5, the vertical part (27a) of the plate α is fixed to the angle member (120) by bolts (121). ) Fixed to the mounting base. Rotating shaft of motor (2
Goo on the tip of 41! Jc! 31 is the key (122)
and a hexagonal hole upper S' screw (123), and a timing belt ◎ is wound between this and the above-mentioned boot IJ211.

There is also a base plate c below the lower mounting plate C26+! A mark is provided, which is integrally fixed to the upper stage main body (8) by three guide shafts 4 arranged at equal angular intervals as clearly shown in FIGS. 3 to M5.

The threaded portion (38a) at the upper end of the guide shaft (to) is screwed into the screw hole of the stage body (8), and the screw (124) at the lower end is screwed and tightened. is fixed to the base plate (to). Upper mounting plate (39 and intermediate mounting base, lower mounting plate ■ has fixed linear ball bearing rigid mouth, guide shirt)
(351 is slidably guided, and the upper mounting plate, middle mounting plate, and lower mounting plate side are housed in the guide shaft C9 and can be moved up and down accurately. .

The air cylinder device is fixed to the base plate Q81, and the tip of the driving arad is fixed to the lower mounting plate (2e) by C311.The lower end of the rotating shaft (to) is inserted through the opening (26a) of the lower mounting plate ω, and the shaft water cooling introduction device 6Q is attached to this.

This mainly consists of an a-tally union, and although it is not shown in the figure, the refrigerant is introduced from this, passes through the hollow part of the rotating shaft (a), is supplied to the hollow part of the stage body (8), and then It circulates through the other hollow part of the rotating shaft (g). (The arrows indicate the introduction and extraction of refrigerant.) There is also a Ueno lift bin (4CJ) on the east side of the upper mounting plate.
As clearly shown in FIG. 4, three of them are screwed and fixed at their lower ends, and their upper ends are inserted through through holes (8b) formed in the peripheral edge of the stage body (3).

Between the bottom of the stage body (8) and the upper mounting plate, there is a bellows (
411 is installed. For this, Ueno 1-.

The lift bin (40) is kept isolated from the atmosphere.

The base plate also has Ueno--vertical drive cylinder device 3.
z is fixed, and the tip of its driving Qrad W is connected to the upper mounting plate via a link pole (b).

As shown in FIG. 2, the susceptor (9) has three elongated holes (four holes) formed at equal angular intervals around the center circumference, and these holes are located around the circumference where the above-mentioned wafer lift bin T40 is arranged. Although they are on the same circumference and are not aligned in Figure 3,
By rotating the susceptor (9) relative to the stage body (3), the susceptor (9) is aligned as shown in FIG. 2. Although the wafer is not shown in each figure, the wafer placed on the susceptor (9) is in the cylinder device c3.
The drive rod 2 rises, and therefore the upper mounting plate C39 and the wafer lift bin lift up to push up the wafer. Susceptor (9)
) is rotated by the motor 4, and the elongated hole (positioning means (102) for stopping it in an upright position aligned with the wafer lift bin (4C)) is provided.
The pulley (2D) is placed below.

In addition, a sensor mounting column (the upper end of which is fixed) is attached to the outer periphery of the stage body (8).
451 F6Z is installed and the sensor (451
is the raised position of the lower mounting plate C61, and therefore the susceptor (9
) detects the rising position of the sensor! Reference numeral 621 indicates the upper mounting board, which is designed to detect the elevated position of the wafer lift bin (4G).

Note that, as schematically shown in FIG. 3, RFt power is supplied to the stage body (3) from an RF power supply section (100) via an electric line (101).

The embodiments of the present invention have been described above, and the functions, effects, etc. thereof will now be described.

It is assumed that a wafer or a substrate is placed on the susceptor (9) even though it is not shown. In addition, a vacuum chamber (1
) is evacuated to a desired pressure, and gas necessary for plasma generation by gummy discharge is introduced to a predetermined pressure.

When the cylinder device is driven, as the arad C01 rises, the lower mounting plate C61, the intermediate mounting plate, the bearing casing CL9, and the bearings (18a) (18b)
The integral rotation @α rises through . Therefore, the susceptor (9) integrated therewith also rises 1, and the distance d from the top surface of the stage body (8) increases.

Figure 8 shows the changes in d at this time and the susceptor (9) surface or the wafer W on it when plasma is generated.
FIG. 8 shows the relationship with the potential V generated on the surface. In humans, d is small, but the DC bias voltage Vdc is relatively large. As shown in Figure 8B, d becomes d, and so on! As the noise increases, the DC bias voltage Vd c2 further increases.
It gets colder. Next, as shown in FIG. 8C, when d becomes even smaller, the DC bias voltage Vdc3 becomes even smaller. That is, the potential generated therein and the DC bias voltage can be changed depending on the distance the susceptor (9) rises.

Generally, during sputtering, etching, P-CVD, etc., a wafer is applied with a F bias voltage, and an appropriate C bias voltage is applied to the wafer in order to achieve processing effects on film quality, step coverage, etching anisotropy, etc. Conventionally, this was done by electrical adjustment.

However, according to the non-embodiment, this DC bias voltage can be easily changed by moving the susceptor (9) up and down and changing the vertical distance d from the stage body (8).

Therefore, in this embodiment, the elevated position of the susceptor (9) is determined in consideration of the quality of the film formed on the surface of the wafer placed on the susceptor (9) and other characteristics. The intermediate mounting base and lower mounting plate (26) are guided by the guide shaft mechanism and raised. So rotate! 1II (a) rises along the guide shaft (to) accurately without deviation, and when it reaches a predetermined height, it moves to the sensor mounting column t.
A sensor attached to 44); 45) detects this and supplies this detection signal to cylinder C29'. As a result, the driving of the cylinder device is stopped, and the susceptor (9) stops at a height a predetermined distance from the stage body (8).

The motor (25) is then driven. This rotational force is transmitted to the transmission shaft α-j/C via the timing bell) [221 and Boo IJ f21J, and the susceptor (9) rotates. A reaction gas is introduced into the vacuum chamber (1) from a nozzle 2) containing four reaction gases, and a thin film made of the components of the reaction gas is uniformly spread on the surface of the wafer placed on the susceptor (9) by rotation. formed in thickness.

When a thin film of a predetermined thickness is formed, the introduction of the reaction gas is stopped, and the driving of the motor (2) is stopped. That is, the rotation of the susceptor (9) is stopped. Next, the cylinder device 4 is driven, the drive rod ω) is lowered, and the susceptor (
9) is lowered, and the cylinder device (291) is stopped by the detection signal of the sensor (49).

Therefore, the susceptor (9) assumes the position shown in FIG.

Note that when the motor is stopped, the positioning means (102
), the scissor receptor (9) stops rotating at an angular position where the seven elongated holes fQ are aligned with the wafer lift bin (40) below.

Next, the wafer vertical drive cylinder device C32 is driven, and the upper mounting plate C3e is raised. Therefore, the wafer lift bin (4 (1) rises together and the susceptor (9
) protrudes from the long holes (4 holes) and pushes up the wafer.

Although not shown, a transport fork introduced into the vacuum chamber (1) through the opening σα is inserted under the wafer, and then the fork rises slightly to remove the wafer from the lift bin (40). The wafer is then received and led out to the adjacent extraction chamber through an opening (701) formed in the side wall of the vacuum chamber (1).

In the unloading chamber, the next wafer is placed on the fork, transported into the vacuum chamber (1), stopped on the protruding wafer lift bin (40), and then the fork is lowered to place the wafer on the wafer lift pin book. After the fork descends a little further, it retreats from the opening σ0 to the extraction chamber.

Next, the cylinder device 6z is driven to lower the wafer and the lift bin (4CI to the position shown in FIG. 3).

The wafer is thus placed on the susceptor (9).

The lowered position is detected by a sensor (6?J), and the drive of the cylinder device 6z is stopped based on this detection signal.

Thereafter, the above-described operation is repeated again.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, a vacuum CVD apparatus has been described, but the present invention is not limited to this, and can be applied to a wide range of substrate surface treatment apparatuses such as sputtering, plasma etching, and P-CVD apparatuses.

〔Effect of the invention〕

As described above, according to the method and apparatus for surface treatment of a substrate in a vacuum chamber of the present invention, the DC bias generated on the substrate surface can be changed purely mechanically, and the It is possible to overcome the various drawbacks that things had.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a CVD apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of II-II Mlli in FIG.
! The direction cross-sectional view, FIG. 3, is lll-11 [ in FIG.
4 is a cross-sectional view in the IV-IV gland direction in FIG. 3, FIG. 5 is a cross-sectional view in the ■-v line direction, FIG. 6 is a cross-sectional view in the ■-■ line direction in FIG. 5, Fig. 7 is a partially exploded perspective view of the main parts of the present CVD apparatus, Fig. 8 is a graph showing the outline of the main parts and voltages showing the operation of this embodiment, and Fig. 9 is a conventional CVD apparatus. The side view of "a" and FIG. 10 are (iIj side views) of another conventional CVD apparatus.

Claims (2)

[Claims] (1) An electrode member that is electrically insulated from the wall of the vacuum chamber and to which an alternating current voltage is applied to generate plasma by glow discharge in the vacuum chamber, and supports the substrate to be surface-treated by the plasma. A vacuum chamber characterized in that a DC bias with respect to the AC voltage generated on the surface of the support member or the surface of a substrate mounted on the surface of the support member is changed by changing the distance between the vacuum chamber and the support member. A method for surface treatment of substrates. (2) an electrode member that is electrically insulated from the wall of the vacuum chamber and to which an alternating voltage is applied to generate plasma by glow discharge in the vacuum chamber; the wall or the electrode member is slidable; a drive shaft to be inserted; a support member fixed to an end of the drive shaft on the vacuum chamber side for supporting a substrate to be surface-treated by the plasma; and a support member for driving the drive shaft along its axial direction. and a drive mechanism for changing the distance between the electrode member and the support member by driving the drive mechanism to prevent generation of electricity on the surface of the support member or the surface of the substrate mounted on the surface of the support member. 1. An apparatus for surface processing a substrate in a vacuum chamber, characterized in that a DC bias with respect to the alternating current voltage is changed.