JPH08195183A - Ion implanting device and ion implanting method - Google Patents

Abstract

PURPOSE: To provide an ion implanting device increasing conductance when an ion implantation chamber is exhausted and capable of evacuating it in a short time. CONSTITUTION: This ion implanting device is provided with an ion implantation chamber 46 having a holding plate 50 holding a processed body W in it, an end station chamber 48 communicated with the ion implantation chamber 46, and a high vacuum pump 86 connected to the end station chamber 48. The ion beam B1 extracted from an ion source 36 is implanted on the surface of the processed body held on the holding plate 50 in the ion implanting device, and an auxiliary exhaust passage 88 for increasing exhaust conductance is formed between the high vacuum pump 86 and the ion implantation chamber 46. At the time of ultra-evacuation, the atmosphere in the ion implantation chamber 46 is exhausted via the end station chamber 48 and discharged via the auxiliary exhaust passage 88, the whole exhaust conductance is increased, the time required for evacuation is shortened, and the throughput is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus and an ion implantation method.

[0002]

2. Description of the Related Art Generally, as an apparatus for introducing impurities in a semiconductor device manufacturing process, an ion implantation apparatus is used because the amount of impurities introduced can be precisely controlled and the number of ions can be grasped for processing. Has been.

In this ion implantation system, a dopant gas containing arsenic (As), phosphorus (P), etc. is brought into a plasma state,
Ion is extracted by applying an electric field by an electrode provided in the middle of this, and a predetermined magnetic field is applied to the extracted ion beam to exclude impurity ions and perform mass spectrometry to extract only predetermined ions, Further, the energy of the extracted ions is increased or decreased to be injected into the object to be processed.

This will be specifically described with reference to FIG. FIG. 8 is a schematic configuration diagram showing a conventional ion implantation apparatus. As shown in the figure, the ion implantation apparatus 2 has an ion source 4 for converting a supply gas into a plasma, and this ion source is connected to a gas box (not shown) for supplying a dopant gas and the like required for the ion source. ing.

An extraction electrode 6 for extracting plasma ions from the ion source 4 is provided on the exit side of the ion source 4, and the extracted ion beam B1 is accelerated and has a mass analyzer 8 having a strong electromagnetic magnet. And the direction of travel thereof is bent, and here, only predetermined necessary ions are taken out and unnecessary ions are eliminated. The extracted ions are introduced to the end station module side, where the advancing direction is changed by the deflection coil 12 or the ions are horizontally scanned.

In the ion implantation chamber 14 of the end station, a plurality of semiconductor wafers W, for example, 13 semiconductor wafers W are provided at the peripheral edge portion.
A disc-shaped holding plate 16 capable of holding the rotatably supported is rotatably supported. The ion implantation chamber 14 is composed of a bowl-shaped casing portion 18 whose one side is opened and a lid portion 20 which hermetically covers the opened portion, and the holding plate 16 is provided with the lid portion 2.
It is rotatably supported at the center of 0 and is rotated by a rotary motor 22. The lid 20 is tilted up and down by an actuator (not shown), and the ion implantation chamber 14
The inside can be opened and closed. Tilt the lid 20 to hold the holding plate 16
Wafers are transferred by a transfer arm (not shown) in a state where the wafer is kept horizontal.

On a part of the front side of the casing portion 20,
An ion introducing port 24 for introducing the ion beam B1 is provided, and a wafer W for accurately counting the charges of the ion beam B1 is provided in the vicinity of the introducing port 24.
A Faraday ring 28 for electrically pushing back the secondary electrons that have collided with and ejected to the wafer side is arranged. A small-capacity end station chamber 26 is provided on the beam introduction side of the ion beam introduction port 24, and the ion beam B1 previously deflected passes through the end station chamber 26 and the Faraday ring 28. , Is injected onto the surface of the wafer held by the holding plate 16.

This ion implantation operation is performed by the ion beam B1.
In order to assure the progress of the above, the vacuum must be performed under a high vacuum of, for example, 10 ⁻⁶ Torr, and therefore, in the end station chamber 26, a roughing pump 30 and a high vacuuming cryopump 32 are respectively installed in the valve 31. , 33, and is connected to the roughing pump 3 up to a predetermined pressure.
After evacuating at 0, the cryopump 32 is used to evacuate the ion implantation chamber 14 and the end station chamber 26 to the above-described high degree of vacuum.
The exhaust on the beam line module side is evacuated by a separately provided pump similar to the one described above.

[0009]

By the way, in a general semiconductor manufacturing apparatus, it is always required to improve its productivity (throughput), and this ion implantation apparatus is no exception. Normally, in this type of ion implantation apparatus, although depending on the processing conditions, wafer loading,
It takes about 15 minutes for one batch to perform a series of operations such as evacuation, ion implantation, and wafer unloading. Of these, the time required for evacuation is about 7 minutes, which is a relatively long time. Which caused a decrease in throughput.

The reason why the evacuation requires a relatively long time is not only that the opening area of the ion introduction port 24 that connects the ion implantation chamber 14 and the end station chamber 26 cannot be made very large. This is because the Faraday ring 28 is arranged so that the gas easily flows, that is, the exhaust conductance is considerably reduced, and the gas does not smoothly flow from the ion implantation chamber 14 side to the end station chamber 26 side.

Further, in order to improve the throughput, two ion implantation chambers 14 and an end station chamber 26 are separately provided, and when the ion implantation operation is performed in one ion implantation chamber, the other ion implantation chamber is in the other ion implantation chamber. Wafers are also loaded and unloaded to improve processing efficiency, but as mentioned above, it takes a lot of time to evacuate, so the waiting time is long and the expected results are sufficient. I can't do it.

The present invention focuses on the above problems,
It was created to solve this effectively. An object of the present invention is to provide an ion implantation apparatus and an ion implantation method that can increase the conductance of the ion implantation chamber during evacuation to evacuate to a predetermined high vacuum level in a short time.

[0013]

In order to solve the above-mentioned problems, the present invention has an ion implantation chamber having a holding plate for holding an object to be processed, and an end station chamber communicating with the ion implantation chamber. A high-vacuum pump connected to the end station chamber, wherein an ion beam extracted from an ion source is injected into the surface of the object to be processed held on the holding plate, An auxiliary exhaust passage for increasing exhaust conductance is formed between the pulling pump and the ion implantation chamber.

[0014]

Since the present invention is constructed as described above, during the evacuation, the atmosphere in the end station chamber is directly sucked by the high evacuation pump attached to the end station chamber, for example, the cryopump, and the ion is removed. The atmosphere in the injection chamber is sucked by the cryopump through the newly provided auxiliary exhaust passage.

Therefore, the atmosphere in the ion implantation chamber is exhausted through the end station chamber and simultaneously sucked directly by the cryopump through the auxiliary exhaust passage, so that the conductance with respect to the gas flow is increased. Therefore, vacuuming can be performed in a short time, and the throughput can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ion implantation apparatus and the ion implantation method according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a partially cutaway schematic plan view showing an ion implantation apparatus according to the present invention, FIG. 2 is a perspective view showing an end station module side of the ion implantation apparatus shown in FIG. 1, and FIG. 3 is a sectional view showing the end station module. 4 is a sectional view showing an auxiliary exhaust passage newly provided between the cryopump and the ion implantation chamber, FIG. 5 is an exploded view showing a joint portion of the auxiliary exhaust passage shown in FIG. 4, and FIG. 6 is an auxiliary shown in FIG. It is a figure which shows the alignment adjustment means provided in the junction part of an exhaust passage.

In the present embodiment, a so-called dual end station type ion implantation apparatus provided with two ion implantation chambers will be described as an example. As shown in the figure, the ion implantation apparatus 34 has an ion source 36 for converting the supply gas into plasma, and this ion source is connected to a gas box (not shown) for supplying the dopant gas required for ion implantation. ing.

An extraction electrode 38 for extracting plasma ions from the ion source 36 is provided on the exit side of the ion source 36, and the extracted ion beam B1 is accelerated to have a mass spectrometer 40 having a strong electromagnetic magnet. And the direction of travel thereof is bent and only predetermined ions necessary for doping are taken out. The extracted ions leave the terminal station and are introduced to the end station module side, and the deflection coil 44 provided here
The traveling direction can be changed by, and the scanning can be performed in the horizontal direction, for example. Since the apparatus of this embodiment has two ion implantation chambers 46, 46,
In the deflection coil 44, the ion beam B1 is selectively bent toward either one of the ion implantation chambers.

Two ion implantation chambers 46, 46 and end station chambers 48, 48 provided in communication therewith.
1 are symmetrically provided in FIG. 1 with these joints as the center lines and have the same configuration. Therefore, one ion implantation chamber and end station chamber will be described below as an example.

In the ion implantation chamber 46 of the end station, a disk-shaped holding plate made of, for example, aluminum capable of holding a plurality of, for example, 13 semiconductor wafers W to be processed at one time at the peripheral portion. 50 is rotatably supported. The ion implantation chamber 46 has a bowl-shaped casing portion 52, for example, made of aluminum, which is open on one side.
And a lid 54 made of, for example, aluminum that covers the open portion in an airtight manner, and a sealing member 56 such as an O-ring is interposed between these joints to hermetically seal the inside. The support shaft of the holding plate 50 is rotatably supported at the center of the lid 54 via, for example, a magnetic seal member 58, and is rotated by a rotary motor 60.

As shown in FIG. 3, the lid portion 54 is fixed to the other end of an arm 62 which is rotatable around a fulcrum supported by a fixed object (not shown), and the arm 62 is not shown. The lid 54 can be tilted up and down by being rotated by an actuator. Then, as shown by the chain double-dashed line in FIG. 3, the wafer is transferred to and from the holding plate 50 by the articulated arm 64 provided outside while the lid 54 is tilted and kept horizontal. I'm supposed to get it.

An ion introduction port 66 having a diameter larger than the diameter of the wafer is provided at a part of the front peripheral edge of the casing 52, and inside the ion implantation chamber 46 near the ion introduction port 66. Is provided with a Faraday ring 68 for electrically pushing back the secondary electrons jumping out from the wafer surface at the time of ion implantation to the wafer side. The deflected beam B1 is transmitted to the end station chamber 48 and the ion introduction port. After being introduced into the ion implantation chamber 46 via 66, it is implanted into the wafer surface held by the holding plate 50.

The partition wall of the end station chamber 48 is made of, for example, stainless steel and is firmly attached and fixed to the casing portion 52 side. Of course, the two end station chambers 48 are separated from each other. On the ion beam entrance side of the end station chamber 48, for example, a beam passage port 72 provided with a first gate valve 70 is provided, and by opening and closing the first gate valve 70 as necessary. The inside of the end station room 48 can communicate with the terminal station side.

A rough evacuation port 76 having a rough evacuation valve 74 is provided on, for example, the bottom wall of the ion implantation chamber 46, and the exhaust port 76 is used, for example, for rough evacuation of a rotary pump or the like. A pump 78 is connected via an exhaust passage 80.

Further, an exhaust port 84 is provided on, for example, one side wall of the end station chamber 48, and the exhaust port 84 is a high vacuum evacuation pump via a high vacuum evacuation gate valve 82, for example. The cryopump 86 is connected. Therefore, in order to exhaust the atmosphere in the ion implantation chamber 46, a main exhaust passage leading to the cryopump 86 via the ion introduction port 66 and the end station chamber 48 is formed.

An auxiliary exhaust passage 88, which is a feature of the present invention, is provided so that the cryopump 86 and the ion implantation chamber 46 can be directly connected to each other, and the gas flow resistance at the time of evacuation is reduced. The exhaust conductance is increased to make it smaller. In particular,
As shown in FIG. 1, an auxiliary exhaust port 90 is provided in the casing part 52 that partitions the front of the ion implantation chamber 46, and an auxiliary gate valve 92 as an opening / closing valve is provided in the exhaust port 90 to make an auxiliary device made of, for example, stainless steel. The exhaust passage 88 is connected.

The other end of the auxiliary exhaust passage 88 is connected to the cryopump 86 via the alignment adjusting means 94. Here, the configuration of the alignment adjusting means 94 will be described with reference to FIGS. 4 to 6. As shown in the figure, the auxiliary exhaust passage 88 is bent and formed in a substantially L shape, and when the tip and the exhaust pipe 96 on the side of the cryopump 86 are connected, the X direction is the Z direction and the horizontal direction in FIG.・ Positioning in Y direction is required.

First, an expanded step portion 98 is provided at the end of the auxiliary exhaust passage 88, and a thread 100 is cut on the outer surface thereof. A ring-shaped seal groove 102 is formed on the end face of the step portion 98, and a first seal member 104 such as a ring-shaped O-ring is provided therein. A wide ring-shaped cushioning ring 106 made of, for example, stainless steel is interposed on the end surface of the step portion 98 in which the first seal member 104 is fitted, and an O-ring or the like is formed on the inner side surface of the ring 106. A second seal member 108 is provided. Further, a ring-shaped pressing member 110 having a substantially rectangular cross section is provided to sandwich the second seal member 108 and the pressing ring 106, and the pressing member 11 is provided.
At the inner end portion of 0, the taper portion 11 for pushing the second seal member 108 toward the passage center side to improve airtightness
2 is formed.

Then, in order to press the above members, a ring-shaped tightening jig 114 having a U-shaped cross section is attached. On the inner surface of the tip of the tightening jig 114, a screw thread 116 that is screwed into the screw thread 100 of the step 98 is formed, and the other end of the jig 114 abuts the side surface of the pressing member 110. It is like this. The outer diameter of the tip of the exhaust pipe 96 on the side of the cryopump 86 is set to be slightly smaller than the inner diameters of the buffer ring 106 and the pressing member 110. Therefore, as shown in FIG. 4 or FIG. By tightening and fixing with a tightening jig 114 in a state in which the tip of 96 is inserted into the stepped portion 98, the exhaust passage is axially (Z direction) and radially (X direction).
・ They are coupled in an airtight manner while absorbing the displacement of both in the Y direction).

A limiter screw 118 for preventing the auxiliary exhaust passage 88 and the exhaust pipe 96 from coming too close to each other during evacuation is provided on the outer periphery of the exhaust pipe 96 so as to be retractable in the axial direction of the pipe. .

In this embodiment, the diameters of various valves and the inner diameter of the auxiliary exhaust passage 88 are, for example, 8 inches, and the capacities of the ion implantation chamber 46 and the end station chamber 48 are about 90 liters and 50 liters, respectively. belongs to.

Next, the operation of this embodiment configured as described above will be described. First, when a wafer is transferred to and from the holding plate 50 provided on the lid portion 54, the first gate valve 70 that connects the end station chamber 48 and the terminal station side is completely closed to connect them. The arm 62 is swung to tilt the lid 54 by driving an actuator (not shown) that opens and closes the lid 54 that partitions the ion implantation chamber 46, as shown by the chain double-dashed line in FIG. This lid 54 is maintained in a horizontal state. In this state, the disc-shaped holding plate 50 rotatably supported by the lid portion 54 is also in a horizontal state, and the inside of the ion implantation chamber 46 and the end station chamber 48 communicating therewith are also open to the atmosphere. There is.

In this state, the plurality of wafers W stored in the wafer cassette (not shown) are placed in the articulated arm 6
4 is used to transfer to the peripheral portion of the holding plate 50 and hold it. In this case, the holding plate 50 can hold, for example, 13 wafers in total. When the transfer of the wafer is completed, the actuator (not shown) is driven again to erect the lid portion 54, and the lid portion 54 is joined to the caging 52 to make the inside of the ion implantation chamber 46 airtight.

After the ion implantation chamber has been sealed in this manner, the vacuum evacuation operation is next performed. First, in order to perform roughing, the roughing valve 7 provided at the roughing exhaust port 76
4 is opened to drive the roughing pump 78. This allows
The atmosphere in the ion implantation chamber 46 is directly evacuated by the pump 78, and the atmosphere in the end station 48 flows into the ion implantation chamber 46 through the ion introduction port 66 which communicates the both, whereby the atmosphere as described above is obtained. It is discharged by the roughing pump 78.

In such a roughing operation, the pressure in the end station chamber 48 and the ion implantation chamber 46 is, for example, 0.
The process is repeated until it reaches 1 to 0.05 Torr. The time required for this rough evacuation is about 1 minute, although it depends on the capacity of the device. When the rough evacuation operation is completed in this way, the rough evacuation valve 74 is closed, and at the same time, the high vacuum evacuation gate valve 82 that connects the cryopump 86 is opened and the auxiliary exhaust passage 88 is closed. 92
Is opened to connect the ion implantation chamber 46 and the cryopump 86 to each other through the auxiliary exhaust passage 88.
Exhaust at 6.

Since the auxiliary exhaust passage 88 is not provided in the conventional apparatus, the atmosphere in the ion implantation chamber 46 once enters the end station chamber 48 through the ion introduction port 66 having a small opening area. It flowed in and was then discharged by the cryopump 86. Therefore, when the atmosphere in the ion implantation chamber 46 passes through the ion introduction port 66, a large fluid resistance is exerted, and the exhaust conductance is reduced. In particular, since the Faraday ring 68 that blocks the flow of gas is arranged near the ion inlet 66, the exhaust conductance is further reduced, and therefore, a predetermined high vacuum degree, for example, up to 1 × 10 ⁻⁵ Torr. It took a relatively long time to evacuate, for example, about 7 minutes after the start of evacuation of the cryopump.

On the other hand, in the device of the present invention, the auxiliary exhaust passage 88 is separately provided as described above, and the atmosphere in the ion implantation chamber 46 is exhausted through the passages of two systems together with the conventional passage. By doing so, the exhaust conductance can be greatly improved, and it is possible to evacuate to a predetermined high vacuum degree in a short time as compared with the conventional device. In this embodiment, the exhaust conductance could be improved by about 60% by using the valve size and piping size of 8 inches as described above. FIG. 7 is a graph comparing the time required for high vacuum drawing of the device of the present invention and the conventional device. Here, the target high vacuum degree is 1 × 10 ⁻⁵ Tor.
r is set, and the horizontal axis represents the elapsed time after the start of the cryopump exhaust.

As is apparent from this graph, the conventional device,
After the exhaust of the cryopump is started together with the device of the present invention, the target 1 × 10 ⁻⁵ To is obtained within a short time of about 30 seconds to 1 minute.
Although the pressure sharply drops to near rr, the rate of pressure decrease thereafter sharply drops and the pressure in the ion implantation chamber only gradually decreases. Nevertheless, in the case of the device of the present invention, the exhaust conductance was increased as described above, so the pressure reduction rate was larger than that of the conventional device, and as a result, the target value was reached in about 3 minutes after the start of driving the cryopump. On the other hand, in the case of the conventional device, the target value was reached in about 7 minutes, and the time required for vacuuming could be improved by about 4 minutes.

Considering that a series of flows of wafer loading, vacuum evacuation, ion implantation, and wafer unloading is about 15 minutes, the improvement amount for 4 minutes is relatively large, and the throughput is correspondingly increased. It is possible to improve. That is, while the wafer loading operation is being performed, the ion implantation operation is being performed in the other adjacent ion implantation chamber, but as described above, the time required for vacuuming is short. Since the waiting time is reduced as much, the throughput can be improved accordingly.

When the predetermined high vacuum level is reached as described above, the first gate valve 70 is opened and the ion beam is communicated with the end station side which is always maintained in the high vacuum state during operation. The passage will be opened and the ion implantation operation will be started. As described above, when the implantation is performed in one ion implantation chamber, the wafer loading / unloading operation is performed in the other ion implantation chamber, and these operations are alternately and continuously performed.

By the way, the auxiliary exhaust passage 8 as described above is used.
When 8 is separately provided, the cryopump 86 and the ion implantation chamber 4 are actually used in the actual machine due to the request for downsizing of the apparatus.
The distance L1 between the casing portion 6 and the casing portion 20 is, for example, several c
m is very narrow (see FIG. 1), and it is a very difficult work to align the other end of the auxiliary exhaust passage 88 connected to the casing 20 and connect it to the cryopump 86.
However, in the device of the present invention, since the alignment adjusting means 94 as shown in FIGS. 4 to 6 is provided,
It is possible to easily assemble while adjusting the position even in a small gap portion that is difficult to assemble. That is, the screw thread 116 of the tightening jig 114 is screwed into the screw thread 100 provided on the step 98 at the end of the auxiliary exhaust passage to tighten the screw thread 100, whereby the pipe axial direction (Z direction) and the pipe radial direction (X / Y direction). It is possible to connect these in an airtight manner while permitting a positional deviation to (). For example, if there is a displacement in the pipe axis direction, the tip of the exhaust pipe 96 enters the inside of the step portion 98 as shown in FIG. 6, and if there is a displacement in the pipe radial direction, the exhaust pipe 96 will Any shift can be absorbed by shifting slightly in the direction. In this case, since the first seal member 104 is pressed by the buffer ring 106, the space between them is completely airtightly sealed, and the second seal member 108 is formed by the tapered portion 112 of the pressing member 110. Since it is pressed against the buffer ring 106 side and the outer peripheral surface side of the exhaust pipe 96, a complete air-tight seal between them can be achieved.

As described above, by using the above-mentioned alignment adjusting means 94, the auxiliary exhaust passage can be easily attached to the conventional device having a limited installation space. In the above embodiment, the case where one auxiliary exhaust passage is provided for one ion implantation chamber has been described, but the present invention is not limited to this, and a plurality of auxiliary exhaust passages may be provided.

In the present embodiment, a so-called dual type ion implantation apparatus having two ion implantation chambers has been described as an example, but the present invention is not limited to this, and one ion implantation chamber is provided. Of course, it can be applied to a so-called single type ion implanter.

[0044]

As described above, according to the ion implantation apparatus of the present invention, the following excellent operational effects can be exhibited. Since the auxiliary exhaust passage is provided between the ion implantation chamber communicating with the end station chamber and the high vacuum pump, the exhaust conductance during high vacuum can be significantly improved. Therefore, the time required for vacuuming can be shortened, and the product throughput can be improved. Further, by using the alignment adjusting means, it is possible to easily attach the auxiliary exhaust passage while aligning the auxiliary exhaust passage without making a large design change to the conventional device.

[Brief description of drawings]

FIG. 1 is a partially cutaway schematic plan view showing an ion implantation apparatus according to the present invention.

FIG. 2 is a perspective view showing an end station module side of the ion implantation apparatus shown in FIG.

FIG. 3 is a cross-sectional view showing an end station module.

FIG. 4 is a sectional view showing an auxiliary exhaust passage newly provided between a cryopump and an ion implantation chamber.

5 is an exploded view showing a joint portion of the auxiliary exhaust passage shown in FIG.

FIG. 6 is a view showing a position adjusting means provided at a joint portion of the auxiliary raw exhaust passage shown in FIG.

FIG. 7 is a graph comparing the time required for high vacuum drawing of the device of the present invention and the conventional device.

FIG. 8 is a schematic configuration diagram showing a conventional ion implantation apparatus.

[Explanation of symbols]

 34 Ion implantation device 36 Ion source 38 Extraction electrode 40 Mass analyzer 44 Deflection coil 46 Ion implantation chamber 48 End station chamber 50 Holding plate 52 Casing portion 54 Lid portion 66 Ion introduction port 68 Faraday ring 78 Roughing pump 82 For high vacuum Gate valve 86 Cryopump (high vacuum pump) 88 Auxiliary exhaust passage 90 Auxiliary exhaust port 92 Auxiliary gate valve 94 Alignment adjusting means 96 Exhaust pipe B1 Ion beam W Semiconductor wafer (processing target)

Claims (6)

[Claims] 1. An ion implantation chamber having a holding plate for holding an object to be processed therein, an end station chamber communicating with the ion implantation chamber, and a high vacuum pump connected to the end station chamber. In an ion implantation apparatus, which is configured to inject an ion beam extracted from an ion source into a surface of an object to be processed held by the holding plate, enhancing exhaust conductance between the high vacuum pump and the ion implantation chamber. An ion implantation apparatus characterized in that it is configured to form an auxiliary exhaust passage for. 2. The ion implanter according to claim 1, wherein the auxiliary exhaust passage can be opened and closed by an on-off valve. 3. The ion implantation apparatus according to claim 1, wherein a position adjusting means is provided at a joint between the auxiliary exhaust passage and the high vacuum pump. 4. The ion implantation chamber and the end station chamber are respectively provided in plurality, and the ion beam is configured to be selectively supplied into the ion implantation chamber. Item 3. The ion implanter according to any one of items 1 to 3. 5. The ion implantation apparatus according to claim 1, wherein the high vacuum pump is a cryopump. 6. An ion implantation chamber having a holding plate for holding an object to be processed, an end station chamber communicating with the ion implantation chamber, and a high vacuum pump connected to the end station chamber. An ion implantation method in which an ion beam extracted from an ion source is injected into a surface of an object to be processed held by the holding plate, and an exhaust conductance is increased between the vacuum pump and the ion implantation chamber. And an auxiliary exhaust passage for forming an auxiliary exhaust passage is formed, and the ion implantation operation is performed after the ion implantation chamber is evacuated by using the two systems of the end station chamber side and the auxiliary exhaust passage side. Ion implantation method.