JPH053107B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ion implantation apparatus used for manufacturing semiconductors or compound semiconductors or for modifying the surface of substances.

(Prior Art) A conventional ion implantation apparatus of this type has, for example, a first
As shown in the figure, a workpiece b such as a wafer is placed in an ion implantation chamber a held by a platen f, and a Faraday flag d is placed in the path of the ion beam c in front of it, and a Faraday box e is placed on the side of the path. The current of the ion beam c is measured using a Faraday flag d, and after adjusting the beam scanning system to uniformly implant ions into the workpiece b, the flag d is moved to the side. , the ion beam c is irradiated onto the workpiece b, and at this time, the Faraday box e is used to convert the secondary electrons ejected from the surface of the workpiece b by ion bombardment into a beam current in order to accurately measure the dose of ions implanted into the workpiece b. It works to prevent leakage from the measurement system.

(Problems to be Solved by the Invention) As mentioned above, conventional ion implantation equipment does not have a means to perform ion implantation processing while controlling the temperature of the workpiece in the range of -170°C to 500°C, for example, and is subject to temperature rise due to heat generation associated with ion implantation, and ion implantation cannot be performed at a predetermined temperature state. In addition, in conventional ion implantation equipment, the implantation chamber is opened to the outside each time a workpiece is taken out or taken out of the ion implantation chamber, which causes the inside of the implantation chamber to become contaminated, and the workpiece itself is also exposed to the atmosphere and is easily contaminated. When this happens, there is a difference between the temperature of the workpiece and the atmospheric temperature, which has the disadvantage that the quality of the workpiece changes.

It is an object of the present invention to eliminate these disadvantages and drawbacks of conventional ion implanters.

(Means for Solving the Problems) In the present invention, a wafer or other workpiece is placed in a vacuum ion implantation chamber, and the front surface thereof is irradiated with an ion beam to perform ion implantation processing. A work holder moving device is provided in the ion implantation chamber to hold a work holder with a work attached thereto and move freely back and forth, and is provided behind the work holder and comes into contact with the back surface of the work holder when the work holder moving device retreats. A tank into which a low-temperature medium such as liquid nitrogen is introduced is installed, an infrared heater or other first radiant heating device for heating the workpiece is installed in front of the workpiece, and a transparent window of the ion implantation chamber is accessed from outside the ion implantation chamber. The first radiant heating device is connected to a radiation thermometer that measures the surface temperature of the workpiece through the ion implantation chamber to control the first radiant heating device, and the ion implantation chamber is connected to the side of the ion implantation chamber through a gate valve and is connected to a vacuum pressure A load lock chamber that can control the pressure and atmospheric pressure is provided, and inside it,
a work holder transport device that reciprocates the work holder to the work holder moving device via the gate valve; a second radiant heating device such as an infrared heater that heats the work from the front of the work holder; A workpiece cooling device that can be brought into and out of contact with the back surface and a lid moving device that is movable to removably hold a lid that seals the workpiece between it and a work holder and to bring the lid into and out of contact with the work holder are provided. By doing so, the above problem was solved.

(Operation) A work holder carrying a work to be ion implanted is carried from the evacuated load lock chamber through the gate valve into the vacuum ion implantation chamber by a work holder transfer device, and is held by the work holder transfer device. Then, depending on the ion implantation conditions, the work holder moving device moves back to bring the work holder into contact with the tank, or the first radiant heating device in front of the work is activated to cool or heat the work.
When the temperature of the workpiece reaches a predetermined value, the front surface of the workpiece is irradiated with an ion beam, and when a predetermined amount of ions have been implanted, the gate valve is opened again, and the workpiece transfer device returns the workpiece together with the workholder to the vacuum load lock chamber. . The temperature of the processed workpiece is different from room temperature, and it takes a long time to return the workpiece temperature to room temperature in a vacuum.In order to shorten this time, when the workpiece temperature is high, the workpiece is placed on the back of the workpiece holder. A cooling device comes in contact to forcibly cool the workpiece, and when the workpiece temperature is low, a second radiant heating device heats the workpiece to return it to room temperature. Next, the lid moving device places a lid on the workpiece, which has returned to room temperature, to seal the space between it and the work holder. The workpiece is sealed in a vacuum state by making airtight contact with the workpiece. Therefore, the workpiece can be transferred from the load lock chamber for processing in the next step without being exposed to the atmosphere, thereby preventing deterioration in the quality of the workpiece.

When processing the next workpiece, the workpiece and workholder are held by the workpiece transfer device in the loadlock chamber, the lid is held by the lid movement device, and the partition is removed from the evacuated loadlock chamber again as described above. A work holder transport device transports the work to the ion implantation chamber via the valve, and the ion implantation process is repeated.

Note that the workpiece may be carried into the loadlock chamber after being sealed in a vacuum state between the workpiece holder and the lid body. In this case, when the loadlock chamber is evacuated, the pressure inside and outside the lid body will be reduced. is balanced, the lid can be easily removed from the work holder using the lid moving device, and the work can be carried into the ion implantation chamber together with the work holder.

(Example) An example of the present invention will be described with reference to the attached drawings.
In FIG. 2, reference numeral 1 denotes an ion implantation chamber that is evacuated by a vacuum pump, 2 an ion beam introduced into the ion implantation chamber 1, and 3 an ion implantation chamber whose front surface is irradiated with the ion beam 2. Si applied
A workpiece such as a wafer is shown, and the workpiece 3 is closely attached to the front surface of a plate-shaped workholder 4 by an electrostatic chuck or by mechanical means. The work holder 4 is removably held by a work holder moving device 8 consisting of, for example, an air cylinder 5 introduced from outside the ion implantation chamber 1 and a clamp 7 provided at the tip of the rod 6. The work holder 4 is moved back and forth in the direction of the ion beam 2 by the movement. 9 is a tank placed behind the work holder 4 and is supplied with a low-temperature medium such as liquid nitrogen or liquid helium from outside the ion implantation chamber 1 via a supply pipe 10; 11 is a workpiece held in the work holder moving device 8; This is a first radiant heating device consisting of an infrared heater installed so as to irradiate the front surface of the device 3 from the front. The first radiation heating device 11 is configured by, for example, a halogen lamp equipped with a reflector, and the amount of heat is controlled by a radiation thermometer 13 that measures the surface temperature of the workpiece 3 through a transparent window 12 provided in the ion implantation chamber 1. I made it so that it would be done.
14 is a converter that linearizes the electric signal outputted from the radiation thermometer 13 by analyzing the wavelength of light from the workpiece 3; 15 is a converter in which the signal from the converter 14 is input so that the workpiece 3 reaches a set temperature; The temperature regulator 16 is a power controller that receives the control output from the temperature regulator 15 and adjusts the power to the first radiant heating device 11.

Reference numeral 17 indicates a load lock chamber provided on the side of the ion implantation chamber 1 so as to communicate through a gate valve 18, and the internal pressure is increased by evacuation through the vacuum exhaust hole 19 and introduction of air and other gases. Controlled by vacuum pressure and atmospheric pressure. The load lock chamber 1
Inside the workpiece 7, a workpiece holder 4 with a workpiece 3 attached thereon is mechanically or electrically held detachably and transferred between the load lock chamber 17 and the workpiece holder moving device 8 in the ion implantation chamber 1. A holder conveyance device 20, a second radiation heating device 21 such as an infrared heater that heats the work 3 from the front of the work holder 4, a cooling device 22 such as a cooling plate that can be freely attached to and separated from the back of the work holder 4, and the work. 3 and the work holder 4 is held removably by a magnet or mechanical means, and the lid 23 is moved reciprocally to move the lid 23 toward and away from the work holder 4 using a cylinder or the like. A device 24 is provided. The cooling device 22 includes a rod 26 inserted through a door 25 on the side of the load lock chamber 17 that can be opened and closed.
When the door 25 is opened and the fixing pin 29 at the intermediate part of the work holder transfer device 20 is removed, the tip 20a moves along the chain line around the rotating shaft 27. The work holder 4 is bent as shown in the load lock chamber 1.
Moved to outside of 7. 28 is the lid body 2
This is a vacuum sealing gasket provided on the front end periphery of No. 3.

To explain its operation, first, load lock chamber 1
7 opens the door 25 and causes the work holder transport device 20 to hold the work holder 4 with the work 3 attached thereto, and causes the lid moving device 24 to hold the lid 23;
The door 25 is closed and the inside thereof is evacuated from the vacuum exhaust hole 19. Next, the work holder transfer device 20 is advanced into the vacuum ion implantation chamber 1 by opening the gate valve 18, and the work holder 4 and work 3 held therein are transferred to the work holder transfer device 8, and then the gate valve 18 is moved back. Close. When ion implantation into the workpiece 3 is scheduled to be performed at a high temperature, the first radiation heating device 11 that is linked to the radiation thermometer 13 is operated to heat the front surface of the workpiece 3 to a set temperature of, for example, 500°C, and then the ion beam is implanted. If ions are to be implanted in a low temperature state, the work holder moving device 8 is moved backward, and the back of the work holder 4 is brought into contact with the tank 9, so that the work 3 is irradiated by heat conduction.
After cooling to, for example, -170℃, ion beam 2
irradiate. When the predetermined amount of ion implantation is completed, if the work holder moving device 8 is moving, it is returned to its original position, the gate valve 18 is opened again, and the work holder transfer device 20 moves the work 3 and work holder 4 from the load lock chamber 17. The work holder is advanced to be received from the work holder moving device 8, received, and returned to the load lock chamber 17, where the gate valve 18 is closed. The work 3 and work holder 4 are in a high or low temperature state depending on the ion implantation conditions, and it takes time in a vacuum to return them to room temperature.
7 to heat the low-temperature workpiece 3 to room temperature, or the cooling device 2
This can be done in a short time by bringing the workpiece 2 into contact with the work holder 4 and cooling the high-temperature workpiece 3 to room temperature by heat conduction. When the work 3 returns to room temperature, the lid moving device 24 brings the lid 23 into contact with the work holder 4 so as to cover the work 3, and the load lock chamber 17
The inside is returned to atmospheric pressure. As a result, the lid body 23
Since the inside is under vacuum pressure and the outside is under atmospheric pressure, the workpiece 3 is brought into sealing pressure contact with the workpiece holder 4, and if the workpiece holder 4 is taken out from the load lock chamber 17 in this state, the workpiece 3 is exposed to the atmosphere. It can be transferred to the next processing step without exposure, and there is no deterioration in the quality of the ion-implanted workpiece.

If some inert gas is introduced into the chamber before returning the load lock chamber 17 to atmospheric pressure, the work 3 can be sealed between the work holder 4 and the lid 23 in an inert gas atmosphere.

Reference numeral 30 in FIG. 2 indicates a Faraday flag for measuring the ion current of the ion beam 2, and the Faraday flag 30 is moved to the side during ion implantation.

In order to control the cooling speed and temperature of the work 3 during ion implantation, the retraction force of the work holder moving device 8 is changed in conjunction with the radiation thermometer 13, and the pressure contact force between the work holder 4 and the tank 9 is adjusted, for example, from 0 to 5.
The rate of temperature drop of the workpiece ³ may be changed by providing an inclusion such as rhenium, aluminum, brass, or vacuum grease between the work holder 4 and the tank 9. It is also possible to variably control the temperature reached.

Further, the work 3 carried into the load lock chamber 1 for ion implantation may be sealed with the work holder 4 and the lid body 23 at another location in advance, and in this case, the work holder 4 is transported by the work holder. The lid moving device 24 is moved forward and brought into contact with the lid 23 to hold it. When the inside of the load lock chamber 17 is evacuated, the pressure inside and outside of the lid 23 becomes balanced, and the lid 23 that was in close contact with the work holder 4 is easily removed, and the lid moving device that holds the lid 23 is removed. When 24 is moved backward, the work 3 and work holder 4 can be carried into the ion implantation chamber 1 shown in the second figure.

(Effects of the Invention) As described above, according to the present invention, a tank into which a low-temperature medium is introduced is provided in the ion implantation chamber, and the back surface of the work holder held by the work holder moving device can be brought into contact with the tank, and the work A first radiant heating device linked to a radiation thermometer is installed in front of the radiant thermometer to control the heating of the workpiece, so the temperature of the workpiece during ion implantation can be maintained at the set temperature, allowing ion implantation with the desired surface quality. A load lock chamber in which a workpiece can be manufactured and which can freely control vacuum pressure and atmospheric pressure is provided on the side of the ion implantation chamber via a gate valve, and a workpiece holder with a workpiece attached to the ion implantation chamber is transported back and forth to the ion implantation chamber. a second radiation heating device and a cooling device for returning the work and the work holder to normal temperature after returning from the ion implantation chamber; and a lid moving device for sealing the work and the work holder. Since I set it up,
It is possible to quickly return the ion-implanted workpiece to room temperature and seal it with a lid, which has the effect of preventing deterioration and contamination of the ion-implanted workpiece.

[Brief explanation of the drawing]

Figure 1 is a cutaway side view of a conventional ion implanter.
FIG. 2 is a cutaway side view of an embodiment of the invention. 1...Ion implantation chamber, 2...Ion beam, 3
... Work, 4 ... Work holder, 8 ... Work holder moving device, 9 ... Tank, 11 ... First radiation heating device, 12 ... Transparent window, 13 ... Radiation thermometer, 17 ... Load lock chamber , 18...gate valve,
20...Work holder transport device, 21...Second radiation heating device, 22...Cooling device, 23...Lid body,
24...Lid moving device.

Claims (1)

[Claims] 1. When a wafer or other workpiece is placed in a vacuum ion implantation chamber and the front surface of the workpiece is irradiated with an ion beam to perform ion implantation processing, the workpiece holder with the workpiece attached is placed inside the ion implantation chamber. A work holder moving device that can hold and move back and forth is provided, and a tank containing a low-temperature medium such as liquid nitrogen that comes into contact with the back surface of the work holder when the work holder moving device retreats is installed behind the work holder. , a radiation thermometer that measures the surface temperature of the workpiece from outside the ion implantation chamber through a transparent window of the ion implantation chamber, with an infrared heater or other first radiation heating device installed in front of the workpiece to heat the workpiece; is connected to control the first radiant heating device, and further includes a load lock chamber on the side of the ion implantation chamber that communicates with the ion implantation chamber via a gate valve and can control vacuum pressure and atmospheric pressure. , a work holder transport device that reciprocates the work holder to the work holder moving device via the gate valve, and an infrared heater or other second radiant heating device that heats the work from the front of the work holder. , a workpiece cooling device that can be moved toward and away from the back of the work holder, and a lid that removably holds a lid that seals between the work and the work holder, and that is movable to bring the lid toward and away from the work holder. An ion implantation device characterized by being provided with a body movement device.