JP2003264224A - Vacuum treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce carriage abnormality by releasing a wafer safely without causing dislocation by the rear pressure of the wafer, in a vacuum treatment device which is equipped with a mechanism for holding the wafer by electrostatic adsorptive force. <P>SOLUTION: This vacuum treatment device monitors the pressure of a vacuum chamber and a heat conductive gas line until it shifts from the termination of wafer treatment to static elimination, and stops electrostatic adsorption and performs the static elimination after the relation between the upward force (Fup) to the wafer and the downward force (Fdw) to the wafer comes to |Fdw|>|Fup| thereby fulfilling the pressure of the gas line. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum processing apparatus having a structure in which a heat transfer gas is flown to the back surface of a wafer fixed by electrostatic attraction.

[0002]

2. Description of the Related Art In semiconductor manufacturing equipment such as dry etching and sputtering, a wafer is fixed by electrostatic attraction on a stage, and a heat transfer gas is caused to flow on the back surface of the wafer to accurately control the temperature of the wafer. It is used.

Regarding the detachment of the wafer, if the wafer is detached by the push-up pin in a state where the suction force after processing is high, there is a possibility that the wafer is broken or the wafer is displaced. A treatment is provided to weaken the electrostatic attraction force.

FIGS. 3 (a) to 3 (c) show an outline of a conventional vacuum processing apparatus from general wafer processing to desorption. 1 is a vacuum processing chamber, 2 is a wafer, 3 is a stage equipped with an electrostatic adsorption mechanism, 4 is a heat transfer gas supply line, 5 is a plasma state during wafer processing, 6 is a plasma state during static elimination processing, and 7 is a lift pin. Is.

FIG. 3A shows a wafer being processed.
The wafer 2 is electrostatically adsorbed on the stage 3, and gas is supplied from the heat transfer gas supply line 4 to the back surface of the wafer for temperature control. The pressure in the processing chamber is generally 0.1 to 100 Pa.
Conditions are used and the heat transfer gas pressure on the backside of the wafer is several kP.
a.

After the wafer processing, electrostatic attraction is stopped, static elimination processing for removing the residual attraction force is executed (FIG. 3B), and the lift pins 7 lift the wafer up to the transfer position (FIG. 3 ( c)).

[0007]

However, in the above-mentioned conventional technique, when electrostatic attraction is stopped and static elimination processing is performed, the wafer is weakened in attraction force due to the residual gas pressure in the heat transfer gas line. Force of. In FIG. 4, the vertical axis represents forces | Fup | and | Fdw |
The horizontal axis shows time, and the end of wafer processing is 0.
I am trying. In the conventional technique, after the wafer processing is completed,
Since the static elimination processing is started immediately after the static elimination processing conditions are satisfied, the static elimination processing start point is t1 in FIG. Therefore, the wafer is blown up and deviates from the stage, which causes an abnormality in the transportation.

An object of the present invention is to provide a vacuum processing apparatus which solves the problems such as a wafer shift that occurs when the conventional static elimination processing is executed.

[0009]

A vacuum processing apparatus according to the present invention for solving the above-mentioned problems monitors a processing chamber pressure and a heat transfer gas supply line pressure, and compares the pressures and conditions (|
Fdw |> | Fup |) is provided and a control means for outputting a signal is provided, and the wafer can be safely removed without causing the positional deviation of the wafer and the transfer abnormality due to the backside pressure of the wafer, which have been problems in the past. Can be separated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the charge removal processing start point according to the present invention. The vertical axis represents the forces | Fup | and | Fdw | applied to the wafer, the horizontal axis represents time, and 0 is set at the end of wafer processing. By performing the static elimination process after the upward force Fup on the wafer exceeds the point (point t2 in FIG. 1) that is smaller than the downward force Fdw, the wafer from which the electrostatic adsorption force is removed is blown up by the back surface pressure. Without being safely removed from the stage.

FIG. 2 is a sectional view of a vacuum processing apparatus equipped with a mechanism for comparing the pressure in the processing chamber with the pressure of the heat transfer gas line according to the present invention. 1 is a vacuum processing chamber, 2 is a wafer, 3 is a stage equipped with an electrostatic adsorption mechanism, 4 is a heat transfer gas supply line, 8 is a pressure gauge for the heat transfer gas line 4, 9 is a pressure gauge for the processing chamber 1, and 10 is a pressure gauge. Is a control means, compares the pressure gauges 8 and 9,
It is equipped with a mechanism for outputting a signal.

FIG. 2 shows a state immediately after wafer processing, in which the wafer 2 is electrostatically adsorbed on the stage 3. Exhaust of the heat transfer gas line 4 is started, and the processing chamber 1 is controlled to have a pressure of the static elimination processing condition after exhaust. The values detected by the pressure gauges 8 and 9 at this time are calculated by the control means 10. The control means 10 compares the values of the pressure gauge 8 and the pressure gauge 9, detects the value of the pressure gauge that satisfies the condition | Fdw |> | Fup |, and then outputs a signal. When the upward force Fup on the wafer becomes smaller than the downward force Fdw
(Point t2 in FIG. 1) is the timing when the control means 10 outputs a signal.

Since Fup and Fdw are given by Fup = P1 × S1 Fdw = P2 × S2 + gw respectively, the control means 10 outputs signals by monitoring the values of P1 and P2, that is, the pressure gauges 8 and 9. You can Upon receipt of this signal, the processing sequencer in the vacuum processing chamber 1 stops electrostatic attraction and starts static elimination processing.

The wafer 2 which has been subjected to the static elimination processing is safely blown up by the pressure of the heat transfer gas and is safely transferred to the stage 3
Be detached from.

[0015]

[Table 1]

Table 1 compares the transfer test results using the wafer desorption method and the vacuum processing apparatus according to the present invention with those of the prior art. A transfer test of 1000 wafers was performed, and the number of transfer deviations due to the wafer backside pressure is shown. The transfer deviation, which has occurred 30 times in the conventional technique, does not occur in the transfer test using the vacuum processing apparatus according to the present invention, and safe wafer detachment is possible.

[0017]

As described above, according to the present invention, the positional deviation of the wafer and the abnormal conveyance are caused by executing the static elimination process after satisfying the condition (| Fdw |> | Fup |) that the wafer is not blown up. The wafer that has been electrostatically adsorbed can be safely released.

Further, according to the present invention, the position shift of the wafer is performed by performing the static elimination processing by using the vacuum processing apparatus equipped with a mechanism for comparing and calculating the pressure in the processing chamber and the pressure of the heat transfer gas line and outputting a signal. Also, the electrostatically adsorbed wafer can be safely detached without causing a conveyance abnormality.

[Brief description of drawings]

FIG. 1 is a graph showing charge removal processing start points in the present invention.

FIG. 2 is a sectional view of a device according to an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional vacuum processing apparatus in a wafer processing state.

FIG. 4 is a graph showing charge removal processing start points in the related art.

[Explanation of symbols]

1 vacuum processing chamber 2 wafers 3 Stage equipped with electrostatic adsorption mechanism 4 Heat transfer gas supply line 5 Plasma state during wafer processing 6 Plasma state during static elimination 7 lift pins 8 Pressure gauge for heat transfer gas supply line 4 9 Pressure gauge in processing chamber 1 10 Control means

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5F004 BA04 BB22 BB25 BC03                 5F031 CA02 HA16 HA33 HA35 HA39                       JA10 JA21 JA47 MA29 MA32                       NA05 PA30

Claims (2)

[Claims] 1. In a vacuum processing apparatus having a structure in which a heat transfer gas is caused to flow to the back surface of a wafer fixed by electrostatic attraction, the pressure of a processing chamber and the pressure of a heat transfer gas supply line are compared, and after a desired condition is satisfied, A vacuum processing apparatus comprising a control means for executing static elimination processing. 2. The vacuum processing apparatus according to claim 2, wherein the desired condition is that the upward force on the wafer is smaller than the downward force on the wafer.