JPH0575956U - Ion implanter - Google Patents

Abstract

(57) [Summary] [Structure] Around the platen 3 that holds the wafer 1,
A Farade 4 is provided, and a platen hood 9 is provided on the platen 3 and a guide plate 11 is provided on the Farade 4 in order to prevent leakage of charged particles such as secondary electrons emitted from the beam irradiation surface. . The platen hood 9 includes a movable portion 19 rotatably attached by a hinge 19c.
a. When the wafer 1 is attached or detached, the platen 3 is in a substantially vertical state, and the movable portion 19a is in a vertical state by its own weight. When the platen 3 rotates and enters the injection state (substantially vertical state), the tip of the movable portion 19 a contacts the guide plate 11. [Effect] Since no gap is created between the platen hood 9 and the guide plate 11 in the injection state, there is no leakage of charged particles, and the current measuring device 13 enables accurate beam current measurement.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ion implantation apparatus for implanting impurity ions into an ion irradiation target such as a wafer, and in particular, a holding member for holding the ion irradiation target is provided between a mounting position (horizontal position) and an implantation position. The present invention relates to an ion implantation apparatus in which a beam current of an ion beam applied to a holding member is measured by rotating the.

[0002]

[Prior Art]

 The ion implanter ionizes the impurities to be diffused, selectively extracts these impurity ions by mass spectrometry using a magnetic field, accelerates them by an electric field, and irradiates the ion irradiation target to irradiate the ion irradiation target. Impurities are injected into. Since this ion implanter can implant impurities that determine the characteristics of the device in the semiconductor process to an arbitrary amount and depth with good controllability, it is an important device for manufacturing the present integrated circuits. There is.

There is an electrostatic scanning type of ion implanter that electrostatically scans an ion beam in a X direction (for example, horizontal direction) and a Y direction (for example, vertical direction) with a high frequency voltage. As shown in FIG. 5, an ion irradiation target, for example, a wafer 51 is held in a substantially vertical state by a holding member (hereinafter, referred to as a platen) 53 in a target chamber 52 that is evacuated, and the above-mentioned X / Y Upon receiving the irradiation of the ion beam 62 scanned in both directions, the implantation process is performed.

When the implanted wafer 51 is removed from the platen 53 or the unimplanted wafer 51 is mounted on the platen 53, the position where the wafer 51 is in a horizontal state is normally set as shown in FIG. After the platen 53 is moved up to, the wafer 51 is attached and detached by a wafer exchanging mechanism (not shown).

Therefore, the platen 53 is driven by a platen driving mechanism (not shown) so that the wafer 51 is in a vertical state during the implantation process and is in a horizontal state when the wafer is attached or detached (see FIG. 6). ) And the attachment / detachment position (see FIG. 5).

By the way, a current measuring device (not shown) is connected to the platen 53.

A Faraday 54 for collecting charged particles such as secondary electrons or reflected beams emitted from the beam irradiation surface of the wafer 51 or the platen 53 is provided around the platen 53. The current measuring device is also connected to.

Then, the beam current during the implantation process is counted by the current measuring device connected to the platen 53 and the Faraday 54, and the implantation dose amount is controlled by the implantation controller (not shown) based on the measured current value. It is supposed to be done.

In order to prevent secondary electrons generated when the overscanned beam is applied to the platen 53 from leaking without being collected by the farad 54, the platen 53 is provided with a platen hood 59 and a farad. Guide plates 61 are provided at the lower portions, respectively.

[0010]

[Problems to be solved by the device]

 Since the platen hood 59 and the guide plate 61 described above are can-made products, a high degree of manufacturing precision cannot be expected. For this reason, it is difficult to design the platen hood 59 so that the platen hood 59 contacts the guide plate 61 without difficulty when the platen 53 rotates and reaches the injection position (see FIG. 6). Further, in the variable injection angle type in which the injection angle can be adjusted by the stop position of the rotating platen 53, the positional relationship between the platen hood 59 and the guide plate 61 differs depending on the injection angle. It is not possible for 59 to contact guide plate 61 comfortably. Therefore, in order to prevent the platen hood 59 from coming into contact with the guide plate 61 during the rotation of the platen 53, it is normally designed so that the track of the end portion 59a of the platen hood does not enter the guide plate 61 side. .. Therefore, in the above conventional configuration, when the platen 53 is at the injection position, a slight gap is generated between the platen hood 59 and the guide plate 61.

In this case, during the implantation process, charged particles such as secondary electrons leak from the gap between the platen hood 59 and the guide plate 61, and the measurement error of the beam current becomes large. .. In this case, the implantation controller controls the implantation dose amount different from the set dose amount, and the desired implantation amount cannot be obtained.

The present invention has been made in view of the above, and an object thereof is to perform ion implantation capable of preventing leakage of charged particles emitted from a beam irradiation surface during an implantation process and performing accurate beam current measurement. To provide a device.

[0013]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the ion implantation apparatus of the present invention includes a holding member that is rotatably provided and holds an ion irradiation target, and the holding member when the ion irradiation target is attached to or detached from the holding member. Holding member driving means for rotating the holding member so that the holding member is in a substantially vertical state during injection processing while the member is in a substantially horizontal state, and a beam irradiation surface provided around the holding member. Charged particle collecting member that collects charged particles such as secondary electrons and reflected beams emitted from the device, a hood member provided on the holding member to prevent leakage of charged particles, and leakage of charged particles. In order to prevent this, an ion implantation equipped with a guide plate provided below the charged particle collecting member, and a beam current measuring means connected to the holding member and the charged particle collecting member to measure the beam current. In the device, it has taken the following means.

That is, the hood member includes a hood member main body portion fixed to the holding member and a movable portion rotatably attached to the hood member main body portion by a hinge. When in the vertical state, the tip of the movable portion comes into contact with the guide plate.

[0015]

[Action]

 According to the above configuration, the charged particle collecting member that collects the charged particles such as the secondary electrons and the reflected beam emitted from the beam irradiation surface is arranged around the holding member that holds the ion irradiation target. Has been done. Further, in order to prevent leakage of the charged particles, a hood member is provided on the holding member, and a guide plate is provided below the charged particle collecting member. The hood member has a movable portion rotatably attached to a hood member main body portion fixed to a holding member by a hinge.

After holding the ion irradiation target in a substantially horizontal state, the holding member is driven by the holding member driving means to rotate and is brought into a substantially vertical state. When the holding member is in a substantially horizontal state, the movable portion is in a vertical state due to its own weight. Then, when the holding member is rotated to be in a substantially vertical state, the tip of the movable portion is in contact with the guide plate, and there is no gap between the hood member and the guide plate. In this case, since the movable part is rotatably attached by the hinge, an unreasonable force is not applied to the contact point where the tip of the movable part contacts the guide plate. In addition, in the variable implantation angle type ion implanter having the function of adjusting the implantation angle by the stop position of the rotating holding member, the stop position of the holding member (implantation position) is not constant, but the stop position of the holding member is Even if it changes, the contact state between the tip of the movable part and the guide plate is maintained. Therefore, the leakage of charged particles emitted from the beam irradiation surface is significantly reduced, and the beam current can be accurately measured by the beam current measuring means.

[0017]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS.

The ion implantation apparatus according to the present embodiment is an electrostatic scanning type that electrostatically scans an ion beam in the X direction (eg, horizontal direction) and the Y direction (eg, vertical direction), and FIG. As shown in FIG. 5, an ion source part 21 for ionizing the implanted elements and extracting it as an ion beam 12, a mass separation part 22 for selecting and extracting only predetermined implanted ions, and an ion beam 12 for transporting the ion beam 12 as necessary. Beam line section 23 including the function of accelerating the beam with an electrostatic accelerating tube 25, shaping and focusing the beam shape with a Q lens 26, and scanning the beam in both X and Y directions with the scanning electrodes 27, 27, an ion irradiation target It is composed of an end station section 24 for setting the wafer 1 as described above and performing an implantation process.

As shown in FIG. 3, the end station section 24 is provided with a target chamber 2, and the inside of the target chamber 2 is kept in a vacuum state. A holding member (hereinafter, referred to as a platen) 3 that holds the wafer 1 is provided inside the target chamber 2. The platen 3 includes a platen base 3a and a clamper 3b that holds the wafer 1 between the platen base 3a.

The platen 3 is held by a platen holding arm 5. An arm shaft 7 is provided at an end of the platen holding arm 5 via an insulating member 6, and the arm shaft 7 is supported by a vacuum seal bearing 8 attached to a side wall 2 a of the target chamber 2. It is supported. A gear 10a is attached to the arm shaft 7, and the gear 10a is meshed with a gear 10b rotated by a motor 10c. A platen drive mechanism 10 is configured by the gear 10a, the gear 10b, and the motor 10c, and the platen 3 is driven by the platen drive mechanism 10 to rotate in the A direction in the drawing.

The platen 3 holds the wafer 1 substantially horizontally when the wafer 1 is attached and detached, and holds the wafer 1 substantially vertically during the pouring process. That is, the platen 3 is fixed at the attachment / detachment position where it becomes substantially horizontal as shown in FIG. 2 when the wafer 1 is attached / detached, and becomes substantially vertical as shown in FIG. 1 during the implantation process. Fixed in position. Further, the platen 3 is of a variable injection angle type, and the injection angle can be adjusted by the stop position of the platen 3.

The platen holding arm 5 is provided with a clamper drive mechanism 15 that drives the clamper 3b up and down when the platen 3 is at the attachment / detachment position. The clamper drive mechanism 15 moves the guide shaft 15a connected to the clamper 3b by an air cylinder or the like in the axial direction to drive the clamper 3b up and down.

Further, the target chamber 2 is provided with a wafer exchanging mechanism (not shown) composed of a robot arm or the like. This wafer exchanging mechanism conveys the wafer 1 in synchronism with the operation of the clamper driving mechanism 15 and attaches and detaches the wafer 1 when the platen 3 is at the loading / unloading position.

By the way, in order to measure the beam current during the implantation process, a current measuring device (beam current measuring means) 13 having one end grounded is connected to the platen holding arm 5 having the same potential as the platen 3. .. Around the platen 3, there is provided a farad (charged particle collecting member) 4 for collecting secondary electrons or reflected beams emitted from the beam irradiation surface of the wafer 1 or the platen 3. The current measuring device 13 is connected to the Farade 4 via a resistor 14.

The current measuring device 13 counts the beam current during the implantation process, and the implantation controller (not shown) controls the implantation dose amount based on the count of the beam current.

Further, in order to prevent charged particles such as secondary electrons or reflected beams emitted from the beam irradiation surface during the implantation process from leaking between the platen 3 and the Farade 4, the platen 3 is A platen hood (hood member) 9 is provided, and a guide plate 11 is provided below the Farade 4.

The platen hood 9 is made of stainless steel, and has a first hood 17 provided around the platen base 3 a, a second hood 18 connected to the first hood 17 and covering the platen holding arm 5, and a second hood. When the platen 3 is in the injection state, the third plate 19 is in contact with the guide plate 11 to prevent leakage of charged particles such as secondary electrons.

The third hood 19 has a structure in which a movable portion 19 a whose tip portion contacts the guide plate 11 is rotatably attached to a fixed portion 19 b by a hinge 19 c, and the movable portion 19 a is attached to the guide plate 11. When not in contact, the movable portion 19a is always in a vertical state due to its own weight. The hood member main body described in the utility model registration claim is composed of a first hood 17, a second hood 18, and a fixing portion 19b of the third hood 19.

A block 11 a is provided on the contact surface of the guide plate 11 with the movable portion 19 a of the third hood 19. This block 11a insulates between the platen hood 9 having the same potential as the platen 3 and the guide plate 11 having the same potential as the Farade 4 and prevents particles from being generated when the movable part 19a made of metal comes into contact with the platen hood 9. In addition, it is formed of a synthetic resin having insulation and cushion such as polytetrafluoroethylene.

The operation of the end station section 24 of the ion implantation apparatus when the implantation process is performed in the above configuration will be described below.

First, the unimplanted wafer 1 is mounted on the platen 3 in the target chamber 2. Specifically, as shown in FIG. 2, the unimplanted wafer 1 carried by the wafer exchanging mechanism is placed on the upper surface of the platen base 3a of the platen 3 which is put on and taken off by the platen driving mechanism 10. Placed. After that, the clamper 3b pushed up is driven by the clamper drive mechanism 15 and displaced downward, so that the wafer 1 is pressed against the platen base 3a.

The platen 3 to which the wafer 1 is fixed as described above is rotated by being driven by the platen driving mechanism 10 and put into an implantation state in which the wafer 1 is substantially vertical as shown in FIG.

After that, the ion beam 12 scanned in both the X and Y directions by the scanning electrodes 27, 27 (see FIG. 4) is applied to the wafer 1, and the implantation process is performed.

During this implantation process, the beam current is counted by the current measuring device 13 connected to the platen 3 and the Farade 4. Then, the implantation controller controls the implantation dose amount based on the count of the beam current.

Here, focusing on the movable part 19a of the platen hood 9, as shown in FIG. 2, when the platen 3 is at the attachment / detachment position, the movable part 19a rotatably provided by the hinge 19c is , It is in a vertical state due to its own weight. The movable portion 19a is kept in a vertical state until it comes into contact with the guide plate 11, and as the platen 3 rotates, the angle formed by the movable portion 19a and the fixed portion 19b gradually increases. The distance from the platen 3 at the tip of the portion 19a increases. Then, the tip of the movable part 19a contacts the block 11a of the guide plate 11 immediately before the platen 3 reaches the injection position, and when the platen 3 stops at the injection position as shown in FIG. The tip is in contact with the block 11a of the guide plate 11.

Since the movable portion 19a is rotatably attached by the hinge 19c, an unreasonable force is not applied to the contact point where the tip of the hinge 19c contacts the block 11a of the guide plate 11. Further, since the block 11a is made of a synthetic resin having a cushion such as polytetrafluoroethylene, particles are hardly generated from the contact point between the movable portion 19a and the block 11a.

Further, in the case of the ion implantation apparatus of variable implantation angle as in this embodiment, the stop position (implantation position) of the platen 3 is not constant depending on the implantation angle, but the stop position of the platen 3 changes. Also, the natural contact state between the tip of the movable portion 19a and the guide plate 11 is maintained.

As described above, when the platen 3 is at the injection position, the platen hood 9 and the guide plate 11 are in good contact with each other, and there is no gap between them, unlike the conventional case. Leakage of charged particles such as secondary electrons can be greatly reduced compared to the conventional case. As a result, it is possible to measure the beam current with a small error by the current measuring device 13, and the implantation controller controls the implantation amount substantially as set.

[0039]

[Effect of the device]

 As described above, in the ion implantation apparatus of the present invention, the hood member is rotatably attached to the hood member main body portion fixed to the rotatably provided holding member and the hood member main body portion. When the holding member is in a substantially vertical state, the tip of the movable portion comes into contact with a guide plate provided below the charged particle collecting member.

Therefore, when the holding member is in a substantially horizontal state, the movable portion is in a vertical state by its own weight, and when the holding member is rotated and is in a substantially vertical state, the tip of the movable portion is guided. Abut the plate. In this case, since the movable part is rotatably attached by the hinge, no unreasonable force is applied to the contact point where the tip of the movable part contacts the guide plate, and the injection position of the holding member changes. However, the contact between the tip of the movable part and the guide plate will be maintained. In this way, when the holding member is in the injection position, the hood member and the guide plate make contact with each other comfortably, and there is no conventional gap between them, so that the leakage of charged particles emitted from the beam irradiation surface is prevented. The beam current can be significantly reduced compared to the conventional method, and the beam current can be measured accurately.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic vertical cross-sectional view showing a state in a target chamber when a platen is rotated to an injection position.

FIG. 2 is a schematic vertical cross-sectional view showing a state in the target chamber when the platen is in a mounting / removing position.

FIG. 3 is a schematic cross-sectional view showing a state of an end station section of the ion implantation apparatus.

FIG. 4 is a schematic configuration diagram showing a main part of an ion implantation device.

FIG. 5 shows a conventional example, and is a schematic vertical cross-sectional view showing a state in the target chamber when the platen is at the attachment / detachment position.

FIG. 6 is a schematic vertical sectional view showing a state in the target chamber when the platen is rotated to an injection position.

[Explanation of symbols]

 1 Wafer (Ion Irradiation Target) 3 Platen (Holding Member) 4 Farade (Charged Particle Collection Member) 9 Platen Hood (Hood Member) 10 Platen Drive Mechanism (Holding Member Drive Means) 11 Guide Plate 11a Block 12 Ion Beam 13 Current Measuring device (beam current measuring means) 17 First hood 18 Second hood 19 Third hood 19a Movable part 19b Fixed part 19c Hinge

Claims (1)

[Scope of utility model registration request] 1. A holding member that is rotatably provided to hold an ion irradiation target, and the holding member is in a substantially horizontal state when the ion irradiation target is attached to or detached from the holding member. So that the holding member is in a substantially vertical state,
A holding member drive means for rotating the holding member, a charged particle collecting member provided around the holding member for collecting charged particles emitted from the beam irradiation surface, and a charged particle collecting member for preventing leakage of the charged particles. A hood member provided on the holding member, a guide plate provided below the charged particle collecting member for preventing leakage of charged particles, and a beam current measured by being connected to the holding member and charged particle collecting member In the ion implantation apparatus, the hood member includes a hood member body portion fixed to a holding member, and a movable portion rotatably attached to the hood member body portion by a hinge. The ion implantation apparatus, characterized in that, when the holding member is in a substantially vertical state, the tip of the movable portion comes into contact with the guide plate.