JP3172627B2 - Vacuum forming method and vacuum forming apparatus - 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 forming method and a vacuum forming apparatus used when loading or unloading a substrate into or from a process chamber. The present invention relates to a vacuum forming method and a vacuum forming apparatus for setting a state.

[0002]

2. Description of the Related Art In a process of forming a film or etching a semiconductor, it is necessary to maintain a relatively high degree of vacuum in a process chamber in order to prevent particles from adhering to the wafer surface. For example, the reaction chamber is evacuated by a vacuum pump, and the degree of vacuum in the reaction chamber is set to 10 Torr or less, preferably about 10 ^-3 to 10 ^-9 Torr. In addition, a load lock chamber is provided to prevent air and particles from directly entering the process chamber. The load lock chamber needs to be in a normal vacuum state at the same temperature as the process chamber.

In order to generate a high degree of vacuum in the load lock chamber, the load lock chamber is evacuated using a rotary pump, a dry pump, a turbo molecular pump or the like. Also,
After unloading the wafer, the load lock chamber is returned to the atmospheric pressure by filling it with nitrogen gas. As described above, since the atmospheric pressure state and the high vacuum state are repeated in the load lock chamber, particles existing in the chamber soar up and adhere to the wafer surface. Most of such particles have already been deposited on the inner wall of the chamber.

On the other hand, various gas molecules such as moisture, carbon monoxide, carbon dioxide or hydrogen are adsorbed on the surface of the semiconductor wafer or the inner wall of the chamber, and these gas molecules are separated from the wafer and the inner wall of the chamber under reduced pressure. Easier to do. Therefore, when evacuation including the gas molecules separated from the semiconductor wafer by the above-described vacuum pump is performed, the evacuation time may be long, or the desired degree of vacuum may not be reached.

[0005] Therefore, a radiator-like trap device is sometimes used to make the load lock chamber a high vacuum. This trap device has a common passage for both the refrigerant and the warm medium. When trapping gas molecules in the chamber, the refrigerant flows through the passage, and when returning to atmospheric pressure in the chamber, the refrigerant is discharged from the passage. After that, a hot medium is allowed to flow.

[0006]

However, in the conventional trap device, first, it takes a long time to exchange the refrigerant and the warm medium in the passage.

Second, thermal fatigue occurs in the constituent material of the passage due to repetition of cooling and heating, resulting in a short life.

Thirdly, when air is supplied as a heating medium into the passage, moisture in the air condenses on the inner wall of the passage shortly after the start of supply, and the condensed water becomes ice. The passage is clogged, and heat exchange between the refrigerant and the components of the trap device is hindered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vacuum forming method and a vacuum forming apparatus which can effectively prevent particles from flying up and can make a high vacuum in a chamber in a short time.

It is another object of the present invention to provide a vacuum forming method and a vacuum forming apparatus which are excellent in heat exchange property and durability.

[0011]

In order to solve the above-mentioned problems, the invention according to the first aspect is intended to directly or indirectly load or unload a substrate from or in each of an air atmosphere and a vacuum atmosphere. A chamber that defines a space, and an exhaust unit that exhausts the inside of the chamber,
Means for filling a gas having a vapor pressure of 1 atm or more at ambient temperature and 10 Torr or less at a temperature lower than the environmental temperature into the chamber space, and capturing gas molecules existing in the chamber space; Trapping means, the trapping means comprising a member having a surface on which gas molecules are to be solidified, a refrigerant passage communicating with a refrigerant supply source for supplying a refrigerant for cooling the member, and a temperature for heating the member. has a heating medium passage communicating hot fluid supply source for supplying a medium, the prior
The trap means moves between the chamber and the regeneration chamber.
And a trap means is located in the chamber.
The refrigerant is supplied to the refrigerant passage,
When the trap means is located in the room,
A heating medium is supplied .

[0012]

According to a second aspect of the present invention, in the first aspect, there is provided a gas purifying device for separating at least two gases having different coagulation temperatures, and the gas purifying device accommodates the two gases. A trap room, and cooling means provided in the trap room, through which a refrigerant having a temperature lower than a high coagulation temperature of the two gases flows.
When the gas having a high solidification temperature is cooled and solidified by the cooling means, the gas having a higher solidification temperature is carbon dioxide gas, the gas having a lower solidification temperature is nitrogen gas or oxygen gas, The refrigerant is liquid nitrogen.

[0014] invention as set forth in claim 3, in claim 2, which is connected via a valve to the trap room, characterized in that it further comprises a large auxiliary room volume than the trap room.

According to a fourth aspect of the present invention, in the first aspect, a CO 2 gas is used as a filling gas.

[0016]

According to the present invention, the equilibrium vapor pressure in the load lock chamber can be set to 10 Torr or less only by solidifying the CO ₂ gas in the load lock chamber by cooling it to a temperature lower than the ambient temperature. Alternatively, the pressure in the load lock chamber can be set to the atmospheric pressure or higher by setting it to a value higher than that.

According to the present invention, the medium passage for cooling and heating the above-mentioned gas such as CO ₂ gas is made independent as a separate passage, so that the rise of the temperature change is made steep so that the solidification is performed. And the time to vaporization can be shortened.

That is, when the pump is evacuated in the load lock chamber, the gas flow in the chamber is largely disturbed, and in the load lock chamber located behind the reaction chamber, the gas inside the chamber is filled with nitrogen gas. The flow is greatly disturbed, and as a result, particles that have accumulated or adhered to the bottom surface or wall surface of the room are rolled up and scattered, and fall and adhere to the semiconductor wafer surface. In particular, this phenomenon becomes remarkable when quick evacuation or return to atmospheric pressure is performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, a description will be given of a case where a vacuum forming method according to an embodiment of the present invention is used in a load lock chamber of an etching system.

As shown in FIG. 1, a sender 6 is provided on the upstream side of the etching system, and a receiver 10 is provided on the downstream side thereof. A process chamber 8 and two loads are provided between the sender 6 and the receiver 10. Lock chambers 16 and 18 are provided. In the sender 6 and the receiver 10, a wafer cassette 5 and a wafer transfer device (not shown)
Is provided, and a plurality of semiconductor wafers W
Is housed.

A gate valve G1 is mounted on the entrance side of the first load lock chamber 16, and the first load lock chamber 1
6 is provided with a gate valve G2 on the outlet side. A gate valve G3 is attached to the entrance side of the second load lock chamber 18, and a gate valve G4 is attached to the exit side of the second load lock chamber 18. further,
A regeneration chamber 19 is provided in each of the first and second load lock chambers 16 and 18 via a gate valve G5.

Next, the gas purifier will be described with reference to FIGS.

The gas purifier 2 has a trap room 34 for containing at least two gases having different condensing temperatures. The cooling means 36 is provided in the trap chamber 34, and allows a refrigerant having a temperature lower than a higher condensing temperature of the two gases to flow. Here, the “condensation temperature” refers to a concept including a condensation point at which a gas changes to a liquid and a freezing point at which a gas changes to a solid.

An auxiliary room 42 communicates with the trap room 34 through a communication passage 40. The communication passage 40 is provided with a valve 38. The auxiliary room 42 has a larger volume than the trap room 34.

Each of the chambers 34 and 42 is formed of, for example, stainless steel or the like. The capacity of the trap room 34 is, for example, about 10 liters, while the capacity of the auxiliary room 42 is, for example, about 1000 liters. And 1
It is set to be 00 times larger. These capacities are not limited to those described above. For example, the trap room 34 is in the range of 1 to 10 liters, and the auxiliary room 42 is in the range of 10 to 10 liters.
It can be set within the range of 0 to 1000 liters, and this volume ratio indicates the degree of impurity gas dilution as described later.

A gas source 44 communicates with the auxiliary chamber 42 via a pipe 46. The pipe 46 is provided with a valve 47. The gas source 44 contains C having a purity of 99.999 vol%.
O ₂ gas is filled at high pressure.

A pressure gauge 48 is attached to the auxiliary room 42 so that its internal pressure can be detected. Further, a pipe 51 is attached to the auxiliary chamber 42, and the pipe 51 is provided with an on-off valve 50, a turbo molecular pump 52, and a rotary pump 54 in order from the upstream side.

As shown in FIG. 4 and FIG.
6 has a cooling plate 58 and a meandering pipe 60.
The cooling plate 58 is made of a material having good thermal conductivity such as an aluminum plate. The meandering pipe 60 meanders in a radiator shape and is attached to the cooling plate 58. The introduction side passage of the meandering pipe 60 is branched. One branch path 62 is connected to the refrigerant source 6 via an on-off valve 64.
6 is connected. The coolant source 66 contains liquid nitrogen. The other branch 68 is connected to a heating source 72 via an on-off valve 70. The heating source 72 is connected to a heating source 72 that stores a heating medium such as a normal temperature nitrogen gas or air.

It is preferable that the meandering pipe 60 and the cooling plate 58 have a surface area commensurate with the capacity of the room. A plurality of fins 74 are provided on the outer peripheral surface of the pipe 60 as shown in FIG. ing.

Further, cooling means 36 provided with the cooling plate 58, the trap room not only one side of 34, it is possible to provide all aspects as necessary, condensation of the refrigerant also CO ₂ gas supplied Any refrigerant may be used as long as the temperature is lower than -70 to -80 ° C. In particular, the vapor pressure of CO ₂ gas at the temperature of the refrigerant is considerably lower than 1 atm, and the temperature of the refrigerant is an impurity gas. Is preferably higher than the setting temperature.

When the concentration of the impurity gas is considerably low, it is only necessary that the vapor pressure can be maintained such that the impurity temperature is not trapped even at a refrigerant temperature equal to or lower than the condensing temperature of the impurity gas. The trap room 34 is provided with a pressure gauge 48 for detecting the internal pressure.

The trap chamber 34 is connected to a relatively large-capacity purified gas storage chamber 82 via a transfer path 80. The supply path 83 from the gas storage chamber 82 is branched into two, and each branch pipe is connected to the first and second load lock chambers 16,
18 respectively. On-off valve 84 for each branch pipe
And a mass flow controller (MFC) 86 are provided.

Incidentally, as shown in FIG.
May be directly connected to the gas source 44, and the trap room 34 may be directly evacuated by the vacuum pump 90.

As shown in FIGS. 8 and 9, a trap device 20 is provided in the regeneration chamber 19. The main part of the trap device 20 is composed of a pair of meandering aluminum pipes 22b and 22c, and has a radiator structure. These pipes 22b and 22c are fixed on the base 22a by fins 22d and wires 92. The trap device 20 has substantially the same structure as that of a radiator of a passenger car, and has a small size and a large surface area. The pipes 22b and 22c have an outer diameter of 5 mm and an inner diameter of 4 mm
It is. The trap device 20 can enter and exit the load lock chambers 16 and 18 via the gate valve G5. The regeneration chamber 19 is evacuated by a turbo molecular pump 26.

As shown in FIG. 6, a reflection plate 380 is provided outside the trap device 20. The detection end of the pressure detector 37 is provided inside the trap device 20.
Further, a vent valve 39 is provided at an appropriate position in the chamber 16.

As shown in FIG. 10, the pipes 22b and 22
c is stacked on the base 22a by the fins 22d. Fin 22d is brazed (brazing)
It is fixed to each of the pipes 22b and 22c and the base 22a by the like. The meandering pipes 22b, 22c
The roll bonding method is adopted for the formation. The roll bonding method is a kind of a cold press forming method in which an aluminum plate is partially pressed and a non-pressed portion serves as a fluid passage.

The trap device 20 is moved by a horizontal moving device 90. The operation rod 97 of the horizontal moving device 90 is connected to the trap device 20. The proximal end (not shown) of the operating rod 97 is connected to a rod (not shown) of the hydraulic cylinder. Guides (not shown) attached to the trap device 20 are slidably engaged with the pair of rails 91, respectively. Two flexible tubes 21 are provided in parallel with the rail 91. One flexible pipe 21 communicates with the refrigerant passage 22b. Liquid nitrogen is supplied to the refrigerant passage 22b.

The other flexible pipe 21 has a heating medium passage 22
It communicates with c. Supply pipe 9 communicating with heating medium passage 22c
3 is supplied with hot water and air.
The switching valve 94 switches between hot water and air.

As shown in FIG. 11, one refrigerant passage 22b
A plurality of heating medium passages 22c may be provided around the periphery. The pipes forming the passages 22b and 22c are connected to each other by fins 22d.

As shown in FIG. 12, a plurality of refrigerant passages 2
2b and the heating medium passage 22c may be arranged in a lattice. That is, the two refrigerant passages 22b are arranged side by side at the center position of the lattice arrangement, and the heating medium passages 22c are arranged around the two refrigerant passages 22b.

As shown in FIGS. 11 and 12, in the case of a structure in which the number of the heating medium passages 22c is larger than that of the refrigerant passage 22b, the time required for regeneration of the trap device 20 is reduced.

The above-described trap device 20 has a gas filled in the load lock chambers 16 and 18. This filling gas has a vapor pressure of at least atmospheric pressure at normal temperature,
In addition, it is desirable that the alloy has a characteristic that the equilibrium vapor pressure at a cooling temperature lower than ordinary temperature reaches 10 Torr or less, preferably 10 ^-3 Torr or less, in which particles on the order of submicron do not soar.

In this embodiment, CO ₂ gas is used as the filling gas. As shown in Table 1, this CO ₂ gas has an equilibrium vapor pressure of 10 ⁻³ Torr at 105 ° K. This one
At 05 ° K, the moisture (H
_{Since the} equilibrium vapor pressure of ₂ O) is sufficiently lower than 10 ⁻³ Torr, water hardly adheres to the semiconductor wafer W.

[Table 1] As described above, even if moisture exists inside the first load lock chamber 16, the moisture does not adversely affect the evacuation. This is because at a temperature set for the CO ₂ gas (for example, 105 ° K), a H ₂ O vapor pressure can be obtained sufficiently higher than a vapor pressure of 10 ⁻³ Torr obtained with the CO ₂ gas. The load lock chambers 16, 18
In order to fill the inside with CO ₂ gas, it is desirable to adopt a structure that prevents the entry of other gases outside the atmosphere-side gate valves G1 and G4. For example, it is preferable to form a gas curtain by flowing CO ₂ gas in a laminar flow state from the outlet to the intake, or to fill the inside of the sender 6 and the receiver 10 with CO ₂ gas.

Next, the operation of generating a high vacuum in the load lock chambers 16 and 18 will be described with reference to FIGS.

First, the load lock chamber 16 and the spare chamber 1
9 is exhausted until it becomes 10 to 10 ^-3 Torr or less (step S1).

The exhaust valve 28 is closed (step S2),
The CO ₂ gas is supplied into the load lock chamber 16 (Step S3). It is determined whether or not the internal pressure of the load lock chamber 16 has reached the atmospheric pressure (1 atm) based on the pressure detection result (step S4). In this case, in order to prevent the entrainment of air, CO ₂ gas may be filled until the internal pressure of the load lock chamber 16 slightly exceeds 1 atm.

When the internal pressure of the load lock 16 exceeds 1 atm, the gate valve G1 is opened (step S5) and the sender 6
The wafer W in the cassette 5 on the side is carried into the load lock chamber 16 (step S6).

After the gate valve G1 is closed (Step S7), the gate valve G5 is opened and the cooling plate 22a of the trap device is carried into the load lock chamber. The cooling plate 22a of the trap device 20 is cooled and the CO ₂ gas is cooled.
is solidified on a (step S8). That is, liquid nitrogen is allowed to flow through the meandering pipe 22b, and the cooling plate is set to -19.
Cool to near 6 ° C. As a result, the CO ₂ gas condenses and solidifies on the cooling plate 22a to form dry ice.

Other component gases such as moisture in the load lock chamber are also cold trapped, and the internal pressure of the load lock chamber 16 is further reduced. At this time, as described later, the raw material C
O ₂ gas (gas used for the gas source 44) has a purity of 99.
999 vol%, and the purified CO ₂ gas
_The amount of impurities is reduced to about 1/100 of the _two gases. For this reason, since almost all of the charged CO ₂ gas is solidified, the internal pressure of the load lock chamber 16 becomes 10 ^-6 to 10 ^-7 To
A high vacuum of rr is reached. In addition, the trap means 22
When the amount of water or the like condensed in the meandering pipe 22b is saturated, the gate valve G5 is opened and the trap means 22 is pulled back into the regeneration chamber 19. And the meandering pipe 22
The supply of the refrigerant to b is stopped. Preferably, normal temperature nitrogen gas is supplied to the meandering pipe 22b instead of the refrigerant. At the same time, air or hot water is supplied to the other meandering pipe 22c as a hot medium. At this point, the reproduction room 19
The inside is evacuated by a turbo molecular pump. Therefore, the water and the like condensed in the meandering pipe 22b are removed from the fins 22.
The gas evaporates by heating from the heating medium through d and the base 22a, and is exhausted by a turbo molecular pump. Thereby, the trap means 20 is regenerated.

It is determined whether or not the internal pressure of the load lock chamber 16 has reached the process set pressure (step S9). When the internal pressure reaches the process set pressure, the gate valve G2 is opened (Step S10), and the wafer W is transferred from the load lock chamber 16 to the process chamber 8 (Step S11).

The gate valve G2 is closed (step S1).
2) The dry ice is vaporized by heating the cooling plate 22a (step S13). That is, the gate valve G1,
With the G2 closed, a cooling medium 22a is heated by flowing a heating medium at room temperature or higher, such as nitrogen gas or air, through the meandering pipe 22c. As a result, all the dry ice is vaporized, and the internal pressure of the load lock chamber returns to 1 atm.

When it is determined that the internal pressure of the load lock chamber 16 has returned to 1 atm (step S14), the process returns to step S5, and the gate valve G1 is opened.
By repeating steps S14 to S14, the next wafer W is carried into the load lock chamber.

On the other hand, when the processed wafer W in the reaction chamber 8 is carried out to the receiver 10, the other load lock chamber 18 is used. The operation in the load lock chamber 18 is the same as the operation in the load lock chamber 16 described above. C
As the O ₂ gas repeatedly solidifies and vaporizes in the load lock chamber 18, the internal pressure of the load lock 18 changes from atmospheric pressure to high vacuum or from high vacuum to atmospheric pressure.

Next, the CO ₂ gas to be filled in the load lock chambers 16 and 18 is purified (by removing impurities to remove CO ₂ gas).
₍₂ Increase gas purity) will be described.

Commercially available industrial CO ₂ gas contains about 10 ppm of impurity components such as oxygen and nitrogen. Oxygen and nitrogen are liquefied at the solidification temperature of the CO ₂ gas, further fall to the bottom of the chamber, and vaporize again, which hinders achievement of a high vacuum.

First, the auxiliary room 42, the trap room 34,
Each of the purified gas storage chambers 82 has a vacuum pump 5
2 and 54 are sufficiently evacuated.

The on-off valve 78 is closed and the valve 38 is opened, and the on-off valve 47 is operated to reduce the gas supply pressure from the gas source 44 from approximately 50 atm to 1 atm (760 Torr) while the auxiliary room 42 and the trap room 34 Then, CO ₂ gas is introduced. In this case, CO ₂ gas may be introduced into each of the chambers 42 and 34 until the pressure becomes equal to the filling pressure of the gas source 44. The pressure at the time of gas introduction is detected by pressure gauges 48 and 76. Also, commercially available industrial CO ₂ gas always contains about 10 ppm of impurities (N ₂ gas, O ₂ gas, Ar gas, etc.) without fail. The component ratio of the impurity gas is N ₂
The gas is about 67%, the O ₂ gas is about 31%, and the Ar gas is about 1.2%.

Next, the meandering pipe 22 in the trap room 34
Liquid nitrogen is passed through b to cool the cooling plate 22a. Then, the CO ₂ gas is condensed and the cooling plate 22a
Adheres to the surface of In this case, since the valve 38 is in the open state, the trap room 34 and the auxiliary room 42 communicate with each other via the communication passage 40. Therefore, trap room 3
As the trapping of the CO ₂ gas in the chamber 4 progresses, the gas in the auxiliary chamber 42 also flows through the communication passage 40 to the trap chamber 34.
Flow into the interior. Such a trap has a CO ₂ gas pressure in the auxiliary chamber 42 and the trap chamber 34 of −19.
The process is performed at 6 ° C. until the vapor pressure becomes about 10 ⁻⁹ to 10 ⁻¹⁰ Torr. At this time, the impurity gas is dispersed almost uniformly in the trap room 34 and the auxiliary room 42 without being trapped, that is, without being condensed, depending on the impurity concentration (partial pressure). In this state, the communication valve 38 is closed. Then, the supply of the refrigerant to the meandering pipe 22b is stopped, and instead, a heating medium such as nitrogen gas or air is circulated through the meandering pipe 22c to vaporize the dry ice.

As a result, C in the trap room 34
The impurity concentration in the O ₂ gas is given by the following equation (1).

Impurity concentration = initial impurity concentration × capacity of trap room 34 / (capacity of auxiliary room 42 + capacity of trap room 34) (1) In this embodiment, the initial impurity concentration in the CO ₂ gas is Since the capacity is 10 ppm, the capacity of the auxiliary chamber 42 is 1000 liters, and the capacity of the trap chamber 34 is 10 liters, when these are substituted into the above equation (1), the impurity gas concentration becomes about 1/100. Therefore, the impurity concentration in the purified CO ₂ gas is about 0.1 ppm. By operating the on-off valve 78, the purified CO ₂ gas is stored in the purified gas storage chamber, and supplied to the load lock chambers 16 and 18 while controlling the flow rate as needed.

As described above, since the degree of dilution of the impurity gas concentration depends on the volume ratio between the auxiliary chamber 42 and the trap chamber 34, the dilution degree can be changed by appropriately selecting these volume ratios. Moreover, by using the large-capacity room 42 and the small-capacity room 34, the gas can be purified without using a mechanical pump.

The refrigerant is not limited to liquid nitrogen as long as the temperature is lower than the condensation temperature of the CO ₂ gas, and other types of gas such as liquid oxygen, liquid hydrogen, and liquid helium may be used.

The load lock chamber has a volume of 8 to 50 liters for a semiconductor wafer having a diameter of 6 to 12 inches and about 100 liters for an LCD substrate. Therefore, it is necessary to appropriately select a CO ₂ gas filling amount and an exhaust pump according to the chamber volume. Also,
In order to reduce the soaring of the particles, it is preferable that the particles are widely dispersed in the exhaust port chamber without being localized only in the chamber.

According to the above embodiment, when using the same CO ₂ gas (gas having a purity of 99.999 deposition%), the internal pressure of the chamber was 1.5 × 10
^-3 Torr is obtained, whereas when purified CO ₂ gas (higher purity gas) is used, the chamber internal pressure is 9.8 × 1
0 ^-5 Torr was obtained.

Further, according to the above embodiment, since the refrigerant passage and the heating medium passage are separately provided in the trap device, the thermal fatigue of the passage pipe is reduced, and the life of the pipe can be extended.

In the above embodiment, since the refrigerant passage is independent of the heating medium passage, the switching between the cooling and the heating of the trap device can be performed quickly in a short time (about 30 seconds).

Further, according to the above-described embodiment, since a supply / exhaust device such as a pump is not used for evacuating the load lock chamber and returning to the atmospheric pressure, a pressure loss at the time of supply / exhaust can be eliminated. Therefore, the pressure in the load lock chamber can be quickly converted.

Next, a case where the trap device is permanently installed in the load lock chamber will be described with reference to FIGS.

As shown in FIG. 16, the etching system of this embodiment has two senders 6 and one receiver 1.
0, the wafers W are transferred from each sender 6 to the process chamber 8 alternately. A load lock chamber 16 is provided between the sender 6, the receiver 10, and the process chamber 8.
Are provided respectively.

As shown in FIG. 17, each load lock chamber 1
A trap device 30 is installed in an upper region in the wafer 6, and the wafer W passes just below the trap device 30. The trap device 30 is a substrate 30a made of aluminum.
A coolant passage 30b is provided on the lower surface side of the substrate 30a, and a heating medium passage 30c is provided on the upper surface side of the substrate 30a.

When the trap means is regenerated in the load lock chamber 16 as described above, the wafer loading operation does not have to be stopped every time the regenerating operation is performed, so that the operation rate of the apparatus is improved.

As shown in FIG. 18, the load lock chamber 16 may be provided inside the outer shell chamber 42. Trap device 40
Is mounted on the outer wall of the load lock chamber 16 and is surrounded by the outer shell chamber 42. The trap device 40 is a structure combining serpentine pipes 40a and 40b,
The assembly composed of the meandering pipes 40a, 40b is substantially a pipe assembly 22b, 2 shown in FIG.
Same as 2c.

In this case, it is preferable to insulate the space between the outer shell chamber 42 and the load lock chamber 16, and it is desirable to provide vacuum insulation or insert a heat insulating material.
By doing so, the dry ice can be made to adhere to the wall surface of the load lock chamber 16, and the dry ice attachment area can be increased. Therefore, a high vacuum state can be quickly reached in the load lock chamber.

Next, the exhaust efficiency will be described with reference to FIG.

FIG. 15 shows the results obtained by taking the elapsed time on the horizontal axis and taking the internal pressure of the chamber on the vertical axis, and using a rotary pump to evacuate the chamber using three different methods. In the figure, a curve A represents an exhaust efficiency characteristic line when cooling and exhausting using high-purity CO ₂ gas (Example 1), and a curve B represents an exhaust efficiency characteristic line when performing ordinary exhaust by a rotary pump. Curve C represents an exhaust efficiency characteristic line (Comparative Example 2) when performing slow exhaust by a rotary pump (evacuation little by little in order to suppress soaring of particles). As is clear from the figure, the time required for the chamber internal pressure to reach 1 × 10 ^-2 Torr was about 1 in Example 1, 0.5 in Comparative Example, and about 12 in Comparative Example 2 (arbitrary units). ). On the basis of Comparative Example 1, the evacuation time of Example 1 is twice as long, and the evacuation time of Comparative Example 2 is 24 times as long. Although the exhaust time of Example 1 is longer than that of Comparative Example 1, the number of particles soared is significantly reduced in Example 1 compared to Comparative Example 1.

Next, a description will be given of the result of examining the number of particles adhered to the wafer W when each of the methods of Example 1 and Comparative Examples 1 and 2 is used.

0.2 μm diameter adhered to 6 inch wafer W
m or more particles were counted. The number of particles was counted by an optical measuring instrument, and the measurement was performed both before and after the exhaust. The number of adhered particles was 25,000 to 40000 in Comparative Example 1, and 25 in Comparative Example 2.
In Example 1, a result of 13 was obtained.

FIGS. 19 to 24 are schematic views showing various modified examples when the trap device is permanently installed in the chamber.

As shown in FIG. 19, a gas inlet 102 and an exhaust port 104 are formed in the chamber 100. The gas inlet 102 is connected to the C
It is in communication with an O ₂ gas supply source 130. Gas inlet 10
2 is formed on the ceiling of the chamber 100. Exhaust port 1
04 is the turbo molecular pump 1 via the flow control valve 141
It communicates with 40.

In the chamber 100, a wafer mounting table 106 supported by a spindle 107 is provided. The trap device 120 is provided immediately below the wafer mounting table 106. An internal passage 122 is formed in the substrate of the trap device 120, and the passage 122 communicates with a coolant supply source 126. Further, a heater 124 is provided on the substrate of the trap device 120.
Is embedded, and the heater 124 is connected to a power supply 128. The controller 110 controls the refrigerant supply source 12.
6, heater power supply 128, CO ₂ gas supply source 130, valve 1
31 and 141 are controlled.

According to such an apparatus, when the refrigerant is passed through the passage 122, the CO ₂ gas is solidified, and when the heater 124 is energized, the dry ice is vaporized.

In the apparatus shown in FIG. 20, the nozzle 132 is located in the middle of the chamber 100 so that the CO ₂ gas is supplied to a position near the wafer W and the trap device 120.

In the apparatus shown in FIG. 21, two nozzles 13
2 are respectively positioned in the middle of the chamber 100, and C
O ₂ gas is supplied to a place near the wafer W and the trap device 120. According to this device, the amount of CO ₂ gas injected from each nozzle 132 can be reduced, so that the soaring of particles is reduced.

In the apparatus shown in FIG.
3 is used to introduce CO ₂ gas into the chamber 100. The shower head 133 has a disk shape,
On the lower surface, 100 to 200 pores having a diameter of 1 to 2 mm are formed. The shower head 133 has a role of uniformly supplying gas to various parts inside the chamber. For this reason,
The soaring of particles in the chamber 100 can be suppressed.

In the device shown in FIG.
4 is used to introduce CO ₂ gas into the chamber 100. The diffusion filter 134 is made of a porous ceramic sintered body, and has a role of reducing the force of the ejected gas. For this reason, particles can be prevented from rising in the chamber 100.

In the apparatus shown in FIG.
0 is attached to the side wall of the chamber 100.

[0087]

According to the present invention, since the refrigerant passage and the heating medium passage provided in the trap means are provided as separate passages, it is not necessary to exchange the medium. Therefore, it is possible to reduce the thermal fatigue of the portion to which each medium is supplied, thereby obtaining a trap device with improved durability. Further, according to the present invention, since the path for supplying each medium is provided independently, the time required for collecting various gases and regenerating the trap device can be reduced by eliminating the poor temperature rise that occurs when replacing the medium. Can be further
Since the refrigerant and the heating medium are not supplied to the same path, it is possible to prevent a situation in which water in the heating medium is dewed and clogs the path. Therefore, since the efficiency of collecting various gases is not reduced and the efficiency of evacuation is not reduced without impairing the durability of the structural parts, various gases that lower the degree of vacuum in the vacuum chamber are removed favorably. It becomes possible.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing a semiconductor wafer processing system having a process chamber and two load lock chambers.

FIG. 2 is a block diagram showing a gas purification device for purifying CO ₂ gas introduced into a load lock.

FIG. 3 is a partial block diagram showing a part of the gas purification device.

FIG. 4 is a sectional view showing a trap room of the gas purification device.

FIG. 5 is a sectional view showing a cooling unit provided in the trap room.

FIG. 6 is a sectional view showing the trap device inside the load lock chamber by cutting out the load lock chamber.

FIG. 7 is a perspective view showing a trap device inserted into the load lock chamber.

FIG. 8 is a longitudinal sectional view showing a trap device in a reproduction chamber.

FIG. 9 is a cross-sectional view showing a trap device in a regeneration chamber.

FIG. 10 is a cross-sectional view showing a cooling pipe and a heating pipe attached to the trap device.

FIG. 11 is a sectional view showing a modified example of the cooling pipe and the heating pipe.

FIG. 12 is a sectional view showing another modification of the cooling pipe and the heating pipe.

FIG. 13 is a flowchart illustrating a vacuum forming method according to an embodiment of the present invention.

FIG. 14 is a timing chart showing the operation of the trap device.

FIG. 15 is a characteristic diagram showing the exhaust efficiency in the chamber according to the method of the present invention in comparison with that according to the conventional method.

FIG. 16 is an overall schematic diagram showing a semiconductor wafer processing system having a process chamber and three load lock chambers.

FIG. 17 is a cross-sectional view illustrating a trap device according to another embodiment in which a load lock chamber is cut away.

FIG. 18 is a cross-sectional view showing a trap device according to another embodiment in which a load lock chamber is cut away.

FIG. 19 is a schematic sectional view showing a basic configuration of a load lock chamber having a wafer mounting table and a trap device.

FIG. 20 is a schematic sectional view of a load lock chamber showing a CO ₂ gas introduction unit.

FIG. 21 is a schematic sectional view of a load lock chamber showing a modification of the CO ₂ gas introduction means.

FIG. 22 is a schematic sectional view of a load lock chamber showing another modification of the CO ₂ gas introduction means.

FIG. 23 is a schematic sectional view of a load lock chamber showing still another modified example of the CO ₂ gas introduction means.

FIG. 24 is a schematic cross-sectional view showing a load lock chamber of a modified example in which a mounting position of a cooling plate is changed.

[Explanation of symbols]

 16, 18 Load lock chamber 22a forming a chamber Cooling plate forming a cooling member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-31585 (JP, A) JP-A-61-142374 (JP, A) JP-A-2-294573 (JP, A) JP-A-62-294 157282 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/3065 B01J 3/02 C23C 16/44

Claims (4)

(57) [Claims] 1. A chamber that defines a space in which a substrate is to be loaded or unloaded directly or indirectly from or in each of an air atmosphere and a vacuum atmosphere, exhaust means for exhausting the inside of the chamber, Means for filling the space of the chamber with a gas having a pressure of 1 atm or more at a temperature and not more than 10 Torr at a temperature lower than the ambient temperature; and a trap means for capturing gas molecules existing in the space of the chamber. The trap means comprises: a member having a surface on which gas molecules are to be solidified; a refrigerant passage communicating with a refrigerant supply source for supplying a refrigerant for cooling the member; and a temperature for supplying a heating medium for heating the member. A heating medium passage communicating with a medium supply source, wherein the trapping means moves between the chamber and the regeneration chamber.
Movably provided , and when the trap means is located in the chamber,
Refrigerant is supplied to the refrigerant passage, and a trap
A vacuum forming device, wherein a warming medium is supplied to the warming medium passage when the step is located . 2. The gas purifying apparatus according to claim 1, further comprising a gas purifying device for separating at least two gases having different coagulation temperatures, the gas purifying device comprising: a trap room accommodating the two gases; And a cooling means through which a refrigerant having a temperature lower than a higher solidification temperature of the two gases is passed. The cooling means cools and solidifies the gas having a higher solidification temperature, The vacuum forming apparatus, wherein the higher temperature gas is carbon dioxide gas, the lower coagulation temperature gas is nitrogen gas or oxygen gas, and the refrigerant is liquid nitrogen. 3. The vacuum forming apparatus according to claim 2, further comprising an auxiliary chamber having a larger volume than the trap chamber , connected to the trap chamber via a valve. 4. The vacuum forming apparatus according to claim 1, wherein CO2 gas is used as the filling gas.