JP2976314B2 - Vacuum processing equipment - Google Patents

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.

[0002]

2. Description of the Related Art When vacuum processing such as ion implantation is performed on a semiconductor wafer, if air enters a large vacuum processing chamber, it takes a long time to return to a high vacuum state again. Wafers are loaded and unloaded between the vacuum processing chamber and the outside (atmospheric pressure atmosphere) through the intermediary. In the load lock chamber, when loading a wafer into the vacuum chamber, the pressure in the load lock chamber is set to the atmospheric pressure to take in the wafer. Thereafter, the vacuum chamber is opened to open the vacuum chamber side. The atmosphere inside the lock chamber is released after returning to the atmospheric pressure.

[0003] When the atmosphere enters the load lock chamber, components in the atmosphere, particularly moisture, are adsorbed to the vessel wall, and when the pressure is reduced, the adsorbed components such as moisture desorb from the vessel wall. It takes a long time to exhaust.

[0004] For this reason, conventionally, when the load lock chamber is opened, the load lock chamber is set to an inert gas atmosphere with nitrogen gas or the like, and the pressure is set to be more positive than that of the atmosphere side. I try to blow out gas.

[0005]

The surface of the wafer carried into the load lock chamber adsorbs moisture contained in the air and hydrocarbons which are residual components during heat treatment. When the wafer is carried into the load lock chamber, the adsorbed components are desorbed from the surface of the wafer when the pressure is reduced. In addition, since the load lock chamber is formed in a size corresponding to the wafer, the ratio of the surface area of the wafer to the surface area of the wall of the load lock chamber is large. Therefore, as described above, the intrusion of the atmosphere into the load lock chamber is suppressed. However, the fact is that it is not so effective in increasing the speed of evacuation.

The present invention has been made in view of such circumstances, and an object of the present invention is to increase the speed of evacuation of a vacuum chamber and also to make the environment for vacuum processing cleaner. It is to provide a vacuum processing apparatus which can be achieved.

[0007]

According to the present invention, there is provided a vacuum processing apparatus for evacuating a vacuum chamber after the workpiece is carried into the vacuum chamber, the vacuum processing apparatus being provided in the vacuum chamber,
A holding table for holding a peripheral portion of the processing object; and a processing table for the processing object before the evacuation is completed after the processing object is carried into the vacuum chamber.
Means for applying energy for desorbing the adsorbed components on the surfaces of both surfaces to the surface of the object to be processed.

[0008]

[Function] The vacuum chamber is open to the atmosphere, for example.
Assuming that the object to be processed is carried into the vacuum chamber from the air atmosphere, energy such as plasma and light is applied to both surfaces of the object to be processed before the evacuation is completed, for example, immediately after the vacuum chamber is closed. As a result, moisture and the like adsorbed on both surfaces of the object to be processed are desorbed in a short time. Accordingly, the amount of adsorbed components desorbed from the entire vacuum chamber (including the object to be processed) after desorption according to the present method is extremely small, and a predetermined degree of vacuum is reached in a short time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a chamber constituting a load lock chamber as a vacuum chamber, for example, a vacuum process for performing ion implantation on a wafer. Gate valves G1 and G2 are provided between the chamber 10 and the outside (atmospheric atmosphere), and are provided on the outside and the vacuum processing chamber 10 side, respectively.

A gas introduction pipe 2 and an exhaust pipe 3 are connected to the chamber 1. The gas introduction pipe 2 is connected to a gas introduction valve V1 through a gas introduction valve V1, for example, hydrogen gas for generating plasma, which will be described later. The exhaust pipe 3 is connected to a supply source, for example, a supply source of helium gas for plasma stabilization, and a supply source of, for example, nitrogen gas for opening the inside of the chamber 1 to an inert gas atmosphere when the inside of the chamber 1 is opened to the outside. ,
It is connected to evacuation means such as a turbo molecular pump 31 and a rotary pump 32. Valves V2, V3, and V4 are connected in the middle of the exhaust pipe 3, and these valves V2, V3, and V4 are configured to be opened and closed according to a predetermined sequence in order to smoothly evacuate.

Further, a ring-shaped wafer holding table 11 for holding the peripheral portion of the wafer W is installed in the chamber 1, and the circumference of the holding table 11 is, for example, divided into three parts. A locking pin 11a is provided at the position,
The wafer W is prevented from being displaced and falling off during loading and unloading. The support 11 is provided with a support 1 supported on the bottom of the chamber 1 via a feedthrough 12 which is an insulator.
3 is fixed to the upper end.

Here, the chamber 1 itself constitutes one electrode in this example, and the holding table 11 and the support 1
Reference numeral 3 denotes the other electrode, and a power supply for plasma generation is connected between these electrodes. As this power supply,
For example, as shown by a solid line in FIG. 1, a DC power supply 41 having a positive electrode connected to the chamber 1 and the ground and a negative electrode connected to the column 13 may be used, or a high-frequency power supply 42 and a matching network 43 shown by a dotted line in FIG. May be used.

Next, the operation of the above embodiment will be described.
An unprocessed wafer is removed from the chamber 1 by the gate valve G2.
Is carried into the vacuum processing chamber 10 through the gate valve G
2 is closed, and the next wafer is to be loaded into the chamber 1 from the atmosphere side. First, the introduction valve V1 is opened, nitrogen gas is introduced into the chamber 1 from a nitrogen gas supply source (not shown) through the gas introduction pipe 2, and the inside of the chamber 1 is returned to the atmospheric pressure. Then, the gate valve G1 is opened. A nitrogen gas atmosphere at a positive pressure than the atmospheric pressure is set to suppress the intrusion of the atmosphere into the chamber 1.

Next, an unprocessed wafer W is loaded into the chamber 1 from outside by a transfer mechanism (not shown), and
On the gate valve G1 and the gas introduction valve V1.
, The pumps 31, 32 and valves V2, V
3. The inside of the chamber 1 is evacuated using V4. The pressure in the chamber 1 is, for example, 10 ⁻³ to 10 ⁻⁶ Torr.
r, the gas introduction valve V1 is opened, and hydrogen gas and helium gas are supplied from a hydrogen gas supply source and a helium gas supply source (not shown), for example, 10 to 500 SC, respectively.
It is introduced into the chamber 1 at a flow rate of CM, and the pressure between the electrodes, that is, between the wall of the chamber 1 and the wafer holding table 11 and the support 13 is controlled while controlling the pressure in the chamber 1 to several hundred milliTorr. For example, 100 to 100 by DC power supply 9
A DC voltage of 0 V is applied. In this case, high frequency power may be applied from the high frequency power supply 42 shown in FIG. As a result, plasma is generated on both sides of the wafer W, and the plasma discharge-cleans the wafer W.
The moisture and hydrocarbons adsorbed on the surface (both sides) of the surface are desorbed. Such discharge cleaning, for example,
After 300 seconds, the gas introduction valve V1 is closed, and after reaching a predetermined degree of vacuum, the gate valve G2 on the vacuum processing chamber 10 side
Is opened, the wafer on the holding table 11 is transferred into the vacuum processing chamber 10 by a transfer mechanism (not shown), and such operations are sequentially repeated to vacuum-process the wafer on the atmospheric side through the chamber 1 (load lock chamber). It is transported into the chamber 10.

According to the above embodiment, since the energy of the plasma is larger than the adsorption energy of moisture or the like on the wafer surface, the adsorbed components on the wafer surface are desorbed by the discharge cleaning of the plasma and exhausted from the exhaust pipe 3. Therefore, the amount of adsorbed components desorbed from the chamber 1 during evacuation is reduced, and the time required for evacuation of the chamber 1 is shortened. Since the discharge cleaning can be performed in a very short time, the time from when the inside of the chamber 1 is sealed to when a predetermined degree of vacuum is obtained can be considerably shortened even in consideration of this amount. If the adsorbed components on the surface of the wafer are desorbed in the load lock chamber, the amount of the adsorbed components evaporated from the wafer is extremely small when the wafer is carried into the vacuum processing chamber. High purity can be maintained.

Here, in the present invention, discharge cleaning may be performed with the inside of the chamber 1 sealed. However, since there is a possibility that a part of the desorbed components may adhere to the surface of the wafer W again, as in the embodiment. It is desirable to carry out the process while allowing the gas to flow into the chamber 1, and for the gas introduced into the chamber 1,
In order to prevent moisture from adsorbing to the vessel wall (inner wall) of the chamber 1, it is preferable to introduce a dry gas from which the moisture content has been removed to the order of ppb, for example.

As described above, in the present invention, the energy of the activation energy for desorbing the adsorbed component may be applied to the surface of the wafer. As a means for this, as described above, the helium or hydrogen gas supply source is used. The present invention is not limited to plasma generating means including a power supply unit and the like, but may be means for irradiating the surface of the wafer with ultraviolet light or laser light, for example.

Specifically, for example, as shown in FIG. 2, the upper surface and the lower surface of the chamber 1 are constituted by light transmitting windows 51 and 52, respectively, and an ultraviolet lamp 53
54, for example, immediately after closing the gate valve G1 on the atmosphere side, the ultraviolet lamps 53,
Ultraviolet rays may be applied to both surfaces of the wafer W in the chamber 1 through the first and the second 52 to desorb adsorbed components on the wafer surface by the energy.

As shown in FIG. 3, both upper and lower surfaces of the chamber 1 are constituted by laser light transmitting windows 61 and 62,
The laser light path from the laser light source 6 is branched into upper and lower sides of the chamber 1 by the half mirror M1 and the reflection mirror M2,
Reflection mirrors M3 and M arranged on these branch optical paths, respectively.
The laser beam may be irradiated over the entire surface of the wafer by changing the incident angle by rotating the drive unit 4 by a drive unit (not shown). 2 and 3, the gas introduction pipe is not shown.

The means for applying energy necessary for desorbing the adsorbed component to the wafer is not limited to the above-mentioned means, but as the temperature rises, the vapor pressure of the adsorbed component increases, and the Since the amount of gas components in the chamber 1 increases, it is preferable that the temperature does not increase.

Further, the present invention is not limited to a single wafer type apparatus, but may be applied to a system for carrying a large number of wafers at once into a load lock chamber. Is an amount corresponding to the number of wafers, and it is very effective to desorb it.

The present invention is not limited to desorbing adsorbed components on the surface of the object in the load lock chamber, but the vacuum processing chamber is evacuated every time a wafer is loaded or unloaded. In this case, the adsorbed components may be desorbed in the vacuum processing chamber.

[0023]

As described above, according to the present invention, after the object to be processed is carried into the vacuum chamber, energy such as plasma or light is applied to the surface of the object to remove the adsorbed components on the surface of the object. Since the desorption is performed, the desorption amount of the adsorbed components in the entire vacuum chamber (including the object to be processed) after desorption becomes extremely small, and as a result, a predetermined degree of vacuum is reached in a short time. Furthermore, even after reaching a predetermined degree of vacuum, since the amount of adsorbed components desorbed from the surface of the object to be processed is small, the environment in the vacuum processing atmosphere can be maintained at high purity.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing another embodiment of the present invention.

FIG. 3 is an explanatory view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chamber 2 Gas introduction pipe 3 Exhaust pipe 41 DC power supply 42 High frequency power supply 53, 54 Ultraviolet lamp 6 Laser light source 31 Turbo molecular pump 32 Rotary pump 12 Feedthrough 13 Column 11 Wafer support 11a Lock pin 10 Vacuum processing chamber 51 Light transmission Window 52 Light transmission window 61 Light transmission window 62 Light transmission window

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01J 3/00-3/08 H01L 21/205 H01L 21/265 H01L 21/285 H01L 21/302 H01L 21 / 31 H01L 21/68

Claims (1)

(57) [Claims] 1. A vacuum processing apparatus for evacuating a vacuum chamber after a workpiece is carried into a vacuum chamber and provided in the vacuum chamber to hold a peripheral portion of the workpiece.
A holding table which, prior to the evacuation ends after the workpiece has been carried into the vacuum chamber, the energy for desorbing the adsorbed components of the both sides of the surface of the object - in the surface of the object to be processed Means to give ,
A vacuum processing apparatus comprising: