JP3200668B2 - Exhaust method in cryopump and micromachining equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system in a fine processing apparatus provided with a load lock chamber in a process chamber.
And a cryopump that can be used for this type of exhaust system .

[0002]

2. Description of the Related Art FIG. 4 shows the structure of an ion implantation apparatus using a conventional exhaust system. In this apparatus, a semiconductor wafer 200 is loaded into a load lock chamber 204 through a gate valve 202 by a wafer transfer mechanism (not shown) such as a turntable, and is moved through a gate valve 206 by a hand arm in the load lock chamber 204. Loaded into the process chamber 208. The semiconductor wafer 200 having undergone the ion implantation process is carried out of the process chamber 208 via the load lock chamber 204 by the operation opposite to the above.

A process chamber 208 is connected to a cryopump 212 via a gate valve 210, and is always in a vacuum state suitable for an ion implantation process, for example, 1 × 1.
It is evacuated to a pressure of about 0 ^-6 Torr.

The load lock chamber 204 is connected to a rotary pump 218 via a pipe 214 and to a cryopump 224 via a pipe 220. In the middle of the pipes 214 and 220, solenoid valves 216 and 2
22 are provided. The load lock chamber 204 is evacuated (evacuated) from atmospheric pressure to a pressure of about several tens of mm Torr each time the semiconductor wafers 200 are loaded one by one. Under the vacuum condition, a hand arm in the load lock chamber 204 loads / unloads the semiconductor wafer 200 into / from the process chamber 208.

In order to evacuate the load lock chamber 204, first, the electromagnetic valve 214 is turned on while the electromagnetic valve 222 is turned off, and the load lock chamber 204 is roughly evacuated to about several hundred mmTorr by the rotary pump 218. Normal,
When the degree of vacuum exceeds about 100 mmTorr, oil flows backward from the rotary pump to the exhaust chamber.
When the pressure reaches about rr, the solenoid valve 216 is turned off.

Next, the electromagnetic valve 222 is turned on, and the load lock chamber 204 is evacuated by the cryopump 224. The evacuation evacuates the load lock chamber 204 to a high vacuum of several tens of mm Torr or less .

As described above, in the load lock chamber 204, first, several hundred mm
A rough evacuation (rough evacuation) is performed to about Torr, and then a desired vacuum state (several tens of mm
Vacuum to about rr). Since the cryopump is a vacuum pump of a type that condenses gas molecules on an extremely cooled surface and exhausts the same, there is no backflow of oil or the like, and the load lock chamber 204 can be in a clean high vacuum state.

[0008]

As described above, conventionally, while the process chamber 208 is constantly evacuated to a high vacuum suitable for the ion implantation process by the cryopump 212, the load lock chamber 204 is periodically rotated by the rotary pump. After roughing by 218, cryopump 22
4 was evacuated to a suitable high vacuum. That is, a dedicated cryopump 212 is applied to the process chamber 208, while a dedicated cryopump 224 is applied to the load lock chamber 204, and a total of two cryopumps are used.

Although the above example relates to an ion implantation apparatus, a sputtering apparatus, a vapor deposition apparatus, a CVD apparatus,
The same applies to other semiconductor manufacturing apparatuses such as a PVD apparatus and an epitaxial apparatus. According to the conventional method, a dedicated cryopump is used for each of the process chamber and the load lock chamber. Therefore, a large number of cryopumps are required in the entire semiconductor manufacturing line, which is problematic in terms of cost, space, maintenance, and the like.

[0010] The present invention has been made in view of such conventional problems, simultaneously and individually a plurality of the exhaust chamber in one
Cryopo that can be evacuated to a high vacuum state efficiently
The purpose is to provide a pump. In addition, the present invention
Micro processing equipment with load lock chamber attached to process chamber
The number of cryopumps used
Also process chamber and load lock chamber at the same time
Evacuate individually and efficiently to high vacuum
The purpose of the present invention is to provide an improved exhaust system.

[0011]

In order to achieve the above object, a cryopump according to the present invention comprises an end portion of a cylindrical case.
To form the main air intake and
A sub intake port is provided near the end, and inside the case,
Forward from the middle part of the case toward the first air inlet
A main condensing portion extending in a longitudinal direction of the case;
From the middle part of the case toward the sub intake port.
A sub-condensation portion extending in the longitudinal direction is provided;
The main condensed part and the sub-condensed part are extremely low on the end side, respectively.
Cooling means for cooling to a predetermined temperature,
Rabbit extending longitudinally of the case facing the condensate
A labyrinth having a rinsing plate
The gas molecules entering the case are kept extremely low at the main condensation part.
Attached to the warm surface, freeze-exhausted, and
The gas molecules that enter the source into the labyrinth
A structure for adhering to the cryogenic surface of the sub-condensation part and for freezing and exhausting
And In the cryopump of the present invention, the case
An air passage for communicating the sub-condensed part and the main condensed part with each other
Is also possible. Also, the exhaust system of the present invention
Is a process chamber for performing a predetermined process under vacuum.
A substrate to be processed into the process chamber under vacuum.
Load lock chamber for loading or unloading
This is an exhaust system in a micromachining device equipped with
In the cryopump of the present invention, the process port
While allowing the chamber to communicate with the cryopump.
The load lock chamber communicates with the sub intake port.
System.

[0012]

In the cryopump of the present invention, the first exhausted chamber is provided.
Into the case through the main air inlet at one end of the case
Gas molecules adsorb on the cryogenic surface of the main condensate and freeze-exhaust
And at the same time, near the other end of the case from the second exhausted chamber.
Gas molecules entering the case through the sub intake port
Adsorbed to the cryogenic surface of the sub-condensation part while being guided by the virinth
Freeze and exhaust. In the main condensing part, the freezing means is behind
Large space on the front side of the main air intake.
The size of the main intake port.
Freeze and exhaust individual and effective gas molecules
it can. On the other hand, in the sub-condensation part, near the other end of the case
Space is limited due to the existence of freezing means
Effective area in contact with gas molecules by the action of labyrinth
Is large, so it came in through the secondary intake even in a small space
Gas molecules can be individually and effectively frozen and evacuated. Departure
In the clear exhaust system, the process chamber and load
The main condensing part and sub-condensing part of the cryopump with one lock chamber
The condensing part evacuates simultaneously and efficiently.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a cryopump according to this embodiment will be described with reference to FIGS. The cryopump case 10 is made of stainless steel and has a cylindrical side surface. The upper end is open to form an opening 12, and the lower end is closed by a bottom plate 14. The opening 12 forms a main intake port and is connected to a first exhaust chamber (not shown) via a gate valve (not shown) or the like. Around the main intake port 12, a flange 16 for attaching and fixing the present cryopump to the first exhaust chamber is formed integrally with the case 10.

Inside the case 10, a case bottom plate 1
4, a refrigeration cylinder 18 is erected at the center of the refrigeration cylinder 18, and first and second condensed portions 20, 22 made of a material having high thermal conductivity, for example, aluminum.
Is arranged.

The first condensing portion 20 has a substantially cup-like shape, and is attached to the refrigeration cylinder 18 toward the main intake port 12, that is, with the cup opening facing the main intake port 12.
A gap 24 for heat insulation is provided between the first condensed portion 20 and the case 10. The second condensing part 22 is a cylindrical body having a smaller diameter than the first condensing part 20, and is attached to the refrigeration cylinder 18 inside the first condensing part 20. Activated carbon for effectively adsorbing gas molecules such as hydrogen, oxygen, and argon is adhered to the surface of the second condensed portion 22. A plurality of annular cap-shaped baffles 15 for preventing backflow of gas are disposed concentrically at the main intake port 12.

The lower end of the freezing cylinder 18 is connected to the case bottom plate 14.
Is connected to the refrigerator 26 through the opening. The refrigerator 26 receives high-pressure helium from a compressor (not shown) from a high-pressure port 28, condenses the input high-pressure helium with a condenser, and then evaporates (adiabatic expansion) with an evaporator to generate cryogenic cold air. I do. Helium converted into low-pressure gas by the evaporator is sent out from the low-pressure port 30 to the compressor.

The cryogenic cold air generated in the refrigerator 26 passes through the refrigeration cylinder 18 to the first and second condensing portions 20 and 20.
22. Thereby, the surfaces of the first condensed portion 20 and the baffle 15 are cooled to, for example, 40 ° K, and the surfaces of the second condensed portion 22 are cooled to, for example, 15 ° K.

In order to discharge the gas molecules accumulated in both the condensing sections 20 and 22, a neutral gas, for example, nitrogen gas N2 is supplied from the purge port 32 to the case while the cryopump is shut off from each of the discharge chambers. 10 to vent the room. This vent causes gas molecules to evaporate from the surfaces of the condensed portions 20 and 22, and is exhausted from the out port 34 together with the neutral gas.

In the present cryopump, two intake ports 36 and 38 facing each other are provided on the side surface of the lower end of the case 10. These intake ports 36 and 38 are auxiliary intake ports, and are respectively connected to second and third exhaust chambers (not shown) via pipes (not shown).

In the case 10, a third condensed portion 40 is provided integrally with the first condensed portion 20 and extends vertically from the bottom plate 20a toward the lower end of the case. The third condensed portion 40 includes an outer cylindrical condensed portion 42 having the same diameter as the first condensed portion 20 and an inner cylindrical condensed portion 44 having a smaller diameter than the outer cylindrical condensed portion 40. The surfaces of these outer and inner cylindrical condenses 42, 44 are cooled to approximately the same temperature (40 ° K) as the surface of the first condensate 20.

An annular horizontal support plate 46 is attached and fixed to the inner surface of the case 10 below the third condensing portion 40. The outer cylindrical condensing portion 42 and the inner cylindrical condensing portion are attached to the horizontal supporting plate 46. An outer cylindrical labyrinth plate 48 interposed between the inner cylindrical labyrinth plate 44 and the inner cylindrical labyrinth plate 50 interposed between the inner cylindrical condensed portion 44 and the freezing cylinder 18 are erected.
Further, a large number of ventilation holes 52 are formed in the outer peripheral portion of the bottom plate 20a of the first condensed portion 20 in the circumferential direction.

In the cryopump having such a configuration, the gas from the first exhaust chamber flows into the baffle 15 and the inside of the first condensing portion 20 from the main intake port 12, where:
Water vapor is frozen and exhausted on the surface of the baffle 15 and the inner surface (40 ° K) of the first condensing portion 20, and hydrogen, oxygen, argon, etc. are frozen or adsorbed on the surface of the second condensing portion 22 (15 ° K). Exhausted. The water vapor that has entered the gap 24 between the first condensed portion 20 and the case 10 is dissipated by the first condensed portion 2.
It is frozen and evacuated on the outside surface of the zero (40 ° K).

On the other hand, the case 1
The gas molecules flowing from the second and third exhausted chambers into the inside of the second condensing portion 40 are outside and inside the third condensing portion 40 and the inside cylindrical condensing portion 4.
2,44 and outer and inner cylindrical labyrinth plates 48,50
The steam enters the labyrinth 54 which is defined by the following formulas. In the labyrinth 54, the water vapor is supplied to the inside and outside surfaces (40 ° K) of the inner cylindrical condensing portion 44 and the inner side surface (40
It is frozen and evacuated at ゜ K). In addition, hydrogen, oxygen, argon, and the like enter the inside of the first condensed portion 20 from the labyrinth 54 through the vent hole 52, and enter the surface (15) of the second condensed portion 22.
凍結 K) freezes or adsorbs and exhausts. The water vapor that cannot be completely exhausted by the labyrinth 54 enters the inside of the first condensed portion 20 through the vent hole 52, or
Through the gap 2 between the first condensed portion 20 and the case 10
4 and is frozen and evacuated on the inner surface or the outer surface of the first condensed portion 20.

As described above, in the cryopump of this embodiment, the gas from the first chamber to be evacuated is introduced into the inside of the substantially cup-shaped first condensing section 20, and the steam is supplied to the first condensing section 20. And while condensing and exhausting by the baffle 15, hydrogen, oxygen, argon and the like are condensed and exhausted by the second condensing part 22, while gas from the second and third exhausted chambers is transferred to the back side of the first condensing part 20. Third coagulation part 40 and labyrinth plate 4
The steam is condensed and exhausted in the labyrinth 54 formed by the first and second condensing portions 20, and hydrogen, oxygen, argon and the like are provided on the bottom plate of the first condensing portion 20. The air was further guided to the inside of the first condensed portion 20 through the ventilation hole 52 and condensed and exhausted by the second condensed portion 22. Thus, the first, second, and third chambers to be evacuated can be simultaneously evacuated (evacuated) to a clean ultra-vacuum state of, for example, about 1 × 10 ⁻⁹ Toor.

In particular, in the cryopump of this embodiment, the third condensing portion 40 has a large effective area in contact with gas molecules by the action of the labyrinth 54, and can effectively exhaust water vapor even with a relatively small size. . Also,
Since hydrogen, oxygen, argon, and the like from the second and third exhausted chambers are guided to the second condensed section 22 through the ventilation holes 52 provided in the bottom plate of the first condensed section 20, all the exhausted chambers are provided. The second condensing part 22 is shared with the exhaust gas.

FIG. 3 shows a structure of a cryopump according to a modification. This modified example is different from the above-described embodiment in that the intake ports 60 and 62 are attached to the bottom plate 14 of the case 10 as auxiliary intake ports, and the third condensed portion is formed as the first condensed portion.
A single cylindrical condensed portion 64 having the same diameter as the condensed portion 20 of
The labyrinth 68 is constituted by one cylindrical labyrinth plate 66, and means for guiding hydrogen, oxygen, argon and the like from the intake ports 60 and 62 to the second condensing portion 22 is not provided.

As described above, the sub intake port can be provided at an arbitrary position near the case end opposite to the main intake port 12. Further, the number of sub intake ports is not limited to two, but may be one, or may be three or more. The labyrinth means may be any as long as it increases the contact area of the gas molecules with the third condensed part, and an arbitrary structure can be selected.

In some cases, a cryopump is used mainly for exhausting water vapor, such as a load lock chamber in a semiconductor manufacturing apparatus. In such a case, only the third condensate is sufficient. Therefore, as in this modification, it is possible to omit a vent for guiding hydrogen, oxygen, argon, and the like from the sub-intake port to the second condensing portion side. Further, the structure of the second condensed portion is not limited to the cylindrical shape as in the above-described embodiments and modified examples. For example, a large number of cap-shaped plate members may be arranged at regular intervals.

Next, an embodiment in which the exhaust system according to the present invention is applied to an ion implantation apparatus will be described with reference to FIG. In this ion implantation apparatus, 100 is a process chamber for performing ion implantation, 102 and 104 are load lock chambers, 10
6 is a cryopump according to the above embodiment,
Is a gate valve, 118 is a rotary pump, 122-1
28 is a solenoid valve, and 130 to 136 are pipes.

The semiconductor wafer 300 is transferred to the gate valve 10 by a wafer transfer mechanism (not shown) such as a turntable.
8 is carried into the load lock chamber 102 through the gate valve 11 by the hand arm in the load lock chamber 102.
0 is loaded into the process chamber 100.
Similarly, the semiconductor wafer 300 is loaded into the process chamber 100 from the load lock chamber 104 side. After the ion implantation process is completed, the semiconductor wafer 300 is moved from the process chamber 100 to the load lock chamber 10 by the hand arm in the opposite operation.
2,104 unloaded, then load lock chamber 1
02 and 104 are carried out.

The process chamber 100 is provided with a cryopump 1 through a gate valve 116 as a first chamber to be evacuated.
06 is connected to the main intake port (12). Accordingly, the process chamber 100 is constantly evacuated to a clean ultra-high vacuum suitable for the ion implantation process, for example, about 1 × 10 ⁻⁶ by the cryopump 106.

The load lock chambers 102 and 104 are connected to the pipe 1
30 and 132, and is connected to a rotary pump 118, and a pipe 134,
136, the sub intake port of the cryopump 106 (3
6, 38). Each load lock chamber 102, 1
In step 04, the chamber must be evacuated (evacuated) from atmospheric pressure to a high vacuum of about several tens of mm Torr each time one semiconductor wafer 300 is loaded.

In order to perform this evacuation, first, the electromagnetic valve 12
When the load lock chambers 2 and 128 are turned on, the load lock chambers 102 and 104 are roughly evacuated to about several 100 mmTorr by the rotary pump 118. Normally, when the degree of vacuum exceeds about 100 mmTorr, oil flows backward from the rotary pump to the chamber to be evacuated.
22 and 128 are turned off.

Next, the solenoid valves 124 and 126 are turned on, and the two load lock chambers 1 are driven by the cryopump 106.
Evacuate 02,104. Since almost no water vapor remains in each of the load lock chambers 102 and 104 due to the rough evacuation by the rotary pump 118, the air holes (5
2) Even a pump having a pump structure like the modified example of FIG. 2 without it can be used. The pressure in each of the load lock chambers 102 and 104 is evacuated to a high vacuum of several tens mmTorr or more by evacuation by the cryopump 106.

While the load lock chambers 102 and 104 are evacuated, the cryopump 106 continuously exhausts the process chamber 100. That is, the cryopump 106 simultaneously evacuates the process chamber 100 communicating with the main exhaust port 12 to a high vacuum state (for example, about 1 × 10 ⁻⁶ mmTorr) suitable for the process, and at the same time,
The load lock chambers 102 and 104 are evacuated from a roughly evacuated state (for example, several hundred mmTorr) to an appropriate high vacuum state (for example, a high vacuum state of several tens mmTorr or less ) as a spare chamber.

In this ion implantation apparatus, the volume of the process chamber 100 is, for example, about 100 liters, while the volume of each of the load lock chambers 102, 104 is, for example, about 0.3 liters. Load lock chambers 102, 1 for exhaust air
The addition of the exhaust of 04 has almost no effect on the exhaust capacity of the cryopump 106.

As described above, according to the exhaust system of this embodiment, the process chamber 100 and the two load lock chambers 1
02 and 104 can be handled by one cryopump 106. In addition to ion implantation equipment, sputtering equipment, vapor deposition equipment, CVD equipment, P
A load lock chamber is generally used in various semiconductor manufacturing apparatuses such as a VD apparatus and an epitaxial apparatus, and the exhaust system of the present invention can be applied to these various apparatuses. In such a case, the number of cryopumps used in the entire semiconductor manufacturing line is greatly reduced, which not only reduces costs, but also increases working space and piping, and reduces the time and labor required for cryopump management and maintenance. Advantages such as halving are obtained.

[0038]

As described above, the present invention has a
According to the pump, gas molecules from the first exhaust chamber are
To a relatively large capacity or size in the case
Fill the possible main condensate with gas molecules from the second evacuated chamber
Large effective condensation area due to labyrinth action
By allocating the sub-condensation part that can be held,
Simultaneously, individually, and efficiently create high vacuum
Can be exhausted. In addition, the evacuation method of the present invention
According to the process chamber and the fine processing device
The load lock chamber is connected to the main intake port of the cryopump of the present invention.
And the sub intake port to communicate with each other.
One process pump and one load pump
The lock chambers are simultaneously and individually and efficiently vacuumed
Can be exhausted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ion implantation apparatus to which an exhaust system according to an embodiment of the present invention is applied.

FIG. 2 is a schematic cross-sectional view showing a structure of a cryopump according to an embodiment for use in the exhaust system of the present invention.

FIG. 3 is a schematic sectional view showing a structure of a cryopump according to a modification for use in the exhaust system of the present invention.

FIG. 4 is a block diagram showing a configuration of an ion implantation apparatus to which a conventional exhaust system is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Case 12 Main intake port 36 Sub intake port 38 Sub intake port 60 Sub intake port 62 Sub intake port 100 Process chamber 102 Load lock chamber 104 Load lock chamber 106 Cryopump 124 Solenoid valve 126 Solenoid valve 134 Pipe 136 Pipe

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI H01L 21/3065 H01L 21/302 B (58) Investigated field (Int.Cl. ⁷ , DB name) H01L 21/265 603

Claims (3)

(57) [Claims] An opening at one end of the cylindrical case to open a main air inlet;
And a sub-inlet near the other end of the case.
Is provided inside the case from the intermediate portion of the case.
A main extending in the longitudinal direction of the case toward the vent
Condensation part and the auxiliary intake port from the middle part of the case
And a sub-condensed portion extending in the longitudinal direction of the case toward
The main condensation portion and the sub-condensation portion are provided on the other end side of the case.
Cooling means for cooling each to a very low predetermined temperature
And extends in the longitudinal direction of the case facing the sub-condensed portion.
A labyrinth having a labyrinth plate is provided, and gas molecules entering the case from the main intake port are removed.
Attached to the cryogenic surface of the main condensed part and evacuated by freezing,
The gas molecules entering the case from the sub intake port are
Lead to the labyrinth and adhere to the cryogenic surface
A cryopump characterized by freezing and exhausting. 2. The apparatus according to claim 2 , wherein said sub-condensation portion and said main condensate portion are provided in said case.
A ventilating path for communicating with the joint.
The cryopump according to claim 1. 3. A process for performing a predetermined process under vacuum.
Process chamber and the process chamber under vacuum.
Load loader for loading or unloading processing substrates
This is an exhaust method in a micromachining device with a lock chamber.
And the main inlet of the cryopump according to claim 1 or 2
The process chamber is connected to the
Connects the load lock chamber to the sub intake port of Io pump
Exhaust method characterized by at least.