JPH10112277A - Ion-implanting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion-implanting device, capable of extracting an ion beam of uniform energy even at the time of a low output. SOLUTION: A high-output power supply 132 and a low-output power supply 134, connected in parallel are connected in series to an input rectification section 130, to form an ion extracting power supply 128. The high-output power supply 132 is constituted of a first inverter section 138, a first boost section 140, and a first output rectification section 142. The low-output power supply 134 is constituted of a second inverter section 144, a second boost section 146, and a second output rectification section 148, and both power supplies 132, 134 can be switched respectively. The required DC power of a high output or a low output can be properly outputted, and the occurrence of the so-called ripples can be prevented even at the time of the low output. Uniform DC power can be extracted and applied between an extracting electrode 124 and an ion source 112, and the desired ion beam can be extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an ion implantation apparatus.

[0002]

2. Description of the Related Art A conventional ion implantation apparatus has been generally described. First, a predetermined gas is converted into plasma in an ion source such as an arc chamber, and positive ions in the plasma are extracted by a predetermined electrode by an electrode. An ion beam is obtained by extracting with an energy. The ion beam is subjected to mass analysis by a mass analyzer to separate desired ions, and further, ion separation is completely performed by a decomposition slit. After the ion beam of the separated desired ions is accelerated to the final energy through the accelerator, the object is irradiated with the ions to introduce desired impurities into the surface of the object to be processed such as a semiconductor wafer. be able to.

Here, extraction of positive ions in plasma generated in an ion source, that is, generation of an ion beam will be described. A filament is provided in the ion source, and a gas source is connected to the ion source via a gas introduction pipe communicating with the filament. An opening is provided on the surface of the ion source in the ion extraction direction, and an extraction electrode is provided at a position facing the opening.

At the time of the ion implantation process, first, a predetermined gas is introduced into the ion source, and a predetermined high current, for example, 150 A DC power is supplied from a power supply for generating thermoelectrons to the filament provided in the ion source. Apply.
Further, a predetermined negative voltage, for example, -100 V DC power is applied from a power supply for generating arc discharge. Due to these DC powers, a discharge occurs between the filament in the ion source and the arc chamber, a predetermined processing gas is dissociated, and plasma is generated. At this time, a predetermined high voltage, for example, 80 kV, is applied between the ion source and the extraction electrode from a power source for ion extraction.
Is applied, only the positive ions in the plasma generated in the ion source are extracted toward the extraction electrode by the predetermined DC power. Then, the extracted ions, that is, the ion beam, are brought into a desired state through various processes such as passing through a mass spectrometer or a separation slit portion, and then irradiated to the object to be processed.

Incidentally, an ion extraction power supply for outputting a predetermined DC power to the ion source and the extraction electrode is configured as follows. That is, for example, an input rectifying unit including a diode bridge or the like that converts predetermined AC power into desired DC power, an inverter unit that converts the DC power into AC power controlled to a desired state, and converts the AC power into a desired AC power. A booster for boosting to high voltage and an output rectifier for converting high-voltage AC power to desired high-voltage DC power for extracting ions are sequentially connected.

[0006] Therefore, through this ion extraction power supply, it is possible to obtain a desired high voltage DC power for ion extraction in the ion implantation apparatus from the generally supplied AC power.

[0007]

However, since the above-mentioned power supply for extracting ions is used for extracting an ion beam of relatively high energy, a recent object to be processed, for example, an ultra-high integration of a semiconductor device is required. The ion implantation process with relatively low energy required for ultra-fine processing accompanying miniaturization cannot be coped with much.

That is, the predetermined high-voltage DC power applied to the ion source and the extraction electrode from the output rectifier of the ion extraction power supply actually contains a slight AC component, so-called ripple component. However, when extracting a relatively high energy ion beam, that is, when the voltage of the DC power is relatively high, the ratio of the voltage of the AC component to the voltage of the DC power is very small. It is almost constant. Therefore, the object can be efficiently subjected to ion implantation without disturbing the irradiation direction of the ion beam.

However, when a relatively low-energy ion beam is extracted, that is, when the DC power voltage is relatively low, the ratio of the AC component voltage to the DC power voltage increases. As a result, the disturbance of the voltage of the DC power, that is, the so-called ripple becomes remarkable. As a result, the extraction energy of the ions changes with the change in the voltage of the AC component, and the irradiation direction of the ion beam is disturbed. This leads to a longer injection processing time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of a conventional ion implantation apparatus. Provided is a new and improved ion implantation apparatus capable of providing a power supply and appropriately switching each power supply as needed to extract a desired ion beam and efficiently perform processing on an object to be processed. It is intended to be.

[0011]

SUMMARY OF THE INVENTION According to the present invention, ions extracted from an ion source by an extraction electrode are subjected to mass analysis to select predetermined ions, and the selected ions are accelerated and implanted into an object to be processed. It is applied to an injection device. The extraction power supply for applying an output voltage to the extraction electrode has a configuration in which at least a high-output power supply and a low-output power supply connected in parallel are connected in series to an input rectifier. The high-power dedicated power supply includes at least a first inverter, a first booster, and a first output rectifier. The low-power dedicated power further includes at least a second inverter, a second booster, and a second booster. And an output rectifier.

Further, the first inverter section and the second inverter section
The inverter unit is selectively switchable with each other. The turns ratio of the first booster unit is higher than the turns ratio of the second booster unit, and the capacitance of the first smoothing capacitor of the first output rectifier unit is increased. Is set smaller than the capacity of the second smoothing capacitor of the second output rectifier. With this configuration, during the ion implantation process, when a high output is required, a high output voltage is applied to the extraction electrode from the high output dedicated power supply, and when a low output is required, It is possible to apply a low output voltage to the extraction electrode from a low output power supply.

As described above, according to the present invention, since the extraction power supply is composed of the mutually switchable high-output power supply and the low-output power supply, a relatively high-energy ion beam is extracted by easy switching. It is possible to cope with both the high output required at the time, that is, the output of the high-voltage DC power, and the low output required at the time of extracting the ion beam of relatively low energy, that is, the output of the low-voltage DC power.

Further, particularly when low-voltage DC power is required, the power is output via a low-power dedicated power supply, and the low-power dedicated power supply buffers the influence of AC components mixed in the DC power. can do. Therefore, a desired DC power having a very small ripple content can be applied between the ion source and the extraction electrode, so that the ion beam can be extracted from the ion source with uniform energy. As a result, mass spectrometry becomes stable,
The object can be efficiently irradiated with the ion beam in a desired state.

Further, in the extracted power supply, a high output power supply and a low output power supply are connected in series to the input rectifier,
Each of the high-output power supply and the low-output power supply includes an inverter, a booster, and an output rectifier. Therefore, the circuit design of the high-output dedicated power supply and the low-output dedicated power supply can be separately performed according to the required high-output DC power or low-output DC power.

Further, the turns ratio of the first booster is equal to the second turns ratio.
Since it is higher than the turns ratio of the booster, a high-output dedicated power supply can output higher-voltage DC power than a low-output dedicated power supply. Since the capacity of the smoothing capacitor of the second output rectifying unit is larger than the capacity of the smoothing capacitor of the first output rectifying unit, the DC power is mixed even at the time of low output, that is, at the time of outputting low voltage DC power. The voltage of the AC component can be buffered to prevent so-called ripples from occurring.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment in which the ion extraction power supply according to the present invention is applied to an ion implantation apparatus will be described in detail. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals,
A duplicate description will be omitted.

First, an overall configuration of an ion implantation apparatus 100 according to the present embodiment will be schematically described with reference to FIG. The ion implantation apparatus 100 includes an ion beam generation chamber 102, a mass analyzer 104, an ion separation chamber 10
6. The accelerator 108 and the processing chamber 110 are sequentially connected.

The ion beam generating chamber 102, the mass analyzer 104, the ion separating chamber 106, the accelerator 108, and the processing chamber 110 communicate with each other and are airtightly constructed. ,
The inside of the ion beam generation chamber 102 and the like are configured to be maintained at a predetermined reduced-pressure atmosphere, for example, 5 × 10 ⁻⁶ Torr.

Hereinafter, the ion beam generating chamber 102 will be described in order. Inside the ion source 112, an ion source 112 having a substantially rectangular parallelepiped housing structure and including an arc chamber or the like is provided.
Is provided. The ion source 112 is connected to the substantially disk-shaped support plate 1 via four substantially bar-shaped support bars 114, for example.
16 supported. The ion source 112 is configured to be detachable together with the support plate 116. When the ion source 112 is mounted, the ion source 112 is disposed at a predetermined location in the ion beam generation chamber 102, and the ion beam generation chamber 10
The second inner wall is not in contact with the second inner wall.

The support plate 116 is connected to the ion beam generating container 12 via a bushing 118 which is an insulating member.
Connected to 0. Since these members are configured to be detachable, maintenance of the ion source 112 and the bushing 118 connected to the support plate 116 can be appropriately performed. The support plate 11
A handle 116a is provided on the surface opposite to the surface on the side of the ion beam generation chamber 102 of FIG.
6 is configured to be easily attached and detached.

Incidentally, a gas introduction pipe (not shown) is connected to the ion source 112, and electrodes (not shown) made of, for example, filaments are respectively provided on the opposed surfaces of the inner wall surfaces. In addition, a power supply for plasma generation (not shown) is connected to this electrode via a first wiring member 122. Accordingly, a predetermined processing gas, for example, arsine gas is introduced into the ion source 112 from the gas introduction pipe, and a predetermined high current, for example, 150 A, is supplied to the filament from the power supply for plasma generation (not shown) via the first wiring member 122. And a predetermined negative voltage, for example, -10
When a DC power of 0 V is applied, the processing gas is dissociated and the plasma is excited.

The mass analyzer 104 of the ion source 112
An opening is provided on the side surface, and an extraction electrode 124 is provided at a predetermined position between the opening and the mass analyzer 104. Further, an ion extraction power supply 128 is electrically connected to the extraction electrode 124 and the ion source 112 via a second wiring member 126. Therefore, when a predetermined high-voltage DC power is applied to the ion source 112 and the extraction electrode 124 from the ion extraction power supply 128 via the second wiring member 126, positive ions in the plasma excited in the ion source 112 Only the ions are extracted toward the mass analyzer 104, and the extracted ions become an ion beam.

Here, the configuration of the ion extraction power supply 128 according to the present embodiment will be described in detail with reference to FIG. The ion extraction power supply 128 includes a high-output power supply 132 and a low-output power supply 1
34 are connected in series.

First, the input rectification unit 130 includes a first rectifier D1 composed of, for example, a diode bridge, a filter choke part F composed of, for example, a coil, and, for example, 0.22 μm.
The first smoothing capacitor section C1 of FIG.
Therefore, when a predetermined voltage, for example, 208 V AC power is output from the external AC power supply 136 to the input rectifier 130, the AC power is converted into DC power by the first rectifier D1, and further the filter choke F and the smoothing filter The DC power is rectified through the capacitor unit C1.

The predetermined DC power output from the input rectifier 130 is output to a high-output power supply 132 and a low-output power supply 134. First, the configuration of the high-output power supply 132 will be described. The first inverter 138, the first booster 140, and the first output rectifier 142 are arranged from the input side.
Are sequentially connected.

The first inverter unit 138 includes, for example, four N-channel field effect transistors N11 to N11.
The first step-up unit 140 includes a first transformer unit T1 having a larger coil turns ratio than a second transformer T2 of a low-output power supply 134 described later.

Further, the first output rectifying unit 142 includes, for example, a second rectifier D2 formed of a diode bridge, and a second smoothing capacitor of 0.015 μF, for example, having a smaller capacitance than a third smoothing capacitor unit C3 described later. The section C2 is composed of a first resistor R1 of, for example, 60 MΩ and an output resistor R2 of, for example, 10 kΩ.

Therefore, the predetermined DC power output from the input rectifier 130 to the high-output power supply 132 is turned on / off in the first inverter 138 controlled by a controller (not shown), so that a desired state is obtained. , For example, 20 kHz
Is converted to AC power. The first inverter unit 13
While the on / off control of the power supply 8 is being performed, the second inverter 144 of the low-output power supply 134 described below is always off.

The AC power is supplied to the first booster 14.
0 in the first transformer section T1,
Is boosted to a desired high voltage higher than the boosted voltage in the second booster 146, for example, 80 kV.
2 is output.

The high-voltage AC power output to the first output rectifier 142 is first converted to DC power in the second rectifier D2, and then rectified by the second smoothing capacitor C2, and the output resistor R2 The signal is output between the ion source 112 and the extraction electrode 124 via the second wiring member 126.

On the other hand, the low-output power supply 134 according to the present embodiment is configured such that the second inverter 144 and the second
The booster 146 and the second output rectifier 148 are sequentially connected. First, the second inverter unit 144
Has substantially the same configuration as the first inverter unit 138, and includes, for example, four N-channel field effect transistors N21 to N2.
4 and the second booster 146 includes a second transformer section T2 having a smaller turns ratio than the first transformer section T1 of the high-output power supply 132.

Further, the second output rectifier 148 has a larger capacitance, for example, 1, than the second rectifier D2 composed of a diode bridge and the second smoothing capacitor C2.
A third smoothing capacitor section C3 of μF, for example, a third resistor R3 of 1 MΩ is connected to the first output rectifying section 142.

Accordingly, predetermined DC power output from the input rectifier 130 to the low-output power supply 134 is turned on in the second inverter 144 controlled by a controller (not shown), like the first inverter 138. -It is turned off and converted to a desired state, for example, 20 kHz AC power. While the second inverter 144 is on / off controlled, the first inverter 138 of the high-output power supply 132 is always off.

The AC power is supplied to the second booster 14
6 in the second transformer section T2, the high-output power supply 132
After being boosted to a desired high voltage lower than the boosted voltage of the first booster 140, for example, 10 kV, the voltage is output to the second output rectifier 148.

The high-voltage AC power output to the second output rectifier 148 is first converted to high-voltage DC power in the third rectifier D3,
Rectification is performed by the third smoothing capacitor section C3 according to the present embodiment, which has a larger capacitance than the electrostatic capacity of the smoothing capacitor section C2.

Further, since the second output rectifier 148 is connected in series to the first output rectifier 142 of the high-output power supply 132, the output resistor R2 and the second wiring member 1 are connected.
26, the ion source 112 and the extraction electrode 12
4 is output.

As described above, the high-output power supply 13
2nd first inverter section 138 and low output power supply 134
Is controlled by a controller (not shown). Therefore, while the first inverter unit 138 is on / off controlled, the second inverter unit 144 is always in an off state, and a predetermined high-output DC power is output only from the high-output power supply 132, While the second inverter 144 is on / off controlled, the first inverter 138 is always off, and a predetermined low-output DC power is output only from the low-output power supply 134.

As described above, in the present embodiment, the high-output power supply 132 of the ion extraction power supply 128 and the low-output power supply 132 are connected to each other in accordance with the output required during the ion implantation process, that is, the output of the high-output or low-output DC power. The output power supply 134 can be switched between each other. Therefore,
Not only at the time of high output but also at the time of low output, it is possible to apply desired DC power in which no AC component is mixed, that is, no so-called ripple occurs between the ion source 112 and the extraction electrode 124. An ion beam can be extracted from inside with uniform energy.

Further, since the energy of the extracted ion beam is uniform even at the time of low output, for example, the transmittance at the separation slit 162 described later is improved, and the utilization efficiency is improved. As a result, the ion beam
It is possible to efficiently irradiate an object to be processed, for example, a semiconductor wafer (hereinafter, referred to as “wafer”) W. Further, the ion extraction power supply 128 is connected to a high output power supply 132.
And the power supply 134 for low output, it is possible to design a circuit according to a desired output.

Referring back to FIG. 1, a suppression electrode 150 is provided at a predetermined position between the opening of the ion source 112 and the extraction electrode 124. A variable DC power supply 154 is connected to the suppression electrode 150 via a third wiring member 152, and the variable DC power supply 154 is a second wiring member between the ion extraction power supply 128 and the ion extraction electrode 124. 126.

Therefore, when ions are extracted from the ion source 112, the secondary electrons emitted from the extraction electrode 124 toward the ion source 112 are converted to the suppression electrodes 15.
0 pushes back to the extraction electrode 124,
It is possible to prevent the output current of the extraction power supply 128 from increasing due to the next electron.

Further, between the extraction electrode 124 in the ion beam generation chamber 102 and the mass analyzer 104, that is, on the downstream side of the ion beam extracted by the extraction electrode 124, a variable slit section 1 capable of changing the width of the slit is provided.
In some models, 56 is provided. The variable slit section 156 is provided to adjust the amount of ions reaching the wafer W by changing the width of the slit.

Next, the mass analyzer 104 will be described. This mass analyzer 104 is connected to the ion beam generation chamber 102 through the gate valve G1 and is used for the ion beam generated in the ion beam generation chamber 102. It is located downstream. Inside the mass spectrometer 104, a gap 158 of the iron core of the mass spectrometer magnet 160 is provided, and the outer periphery of the outer wall of the mass spectrometer 104 in the direction curved to the concave of the gap 158 and in the vertical direction is provided. , And a mass spectrometer magnet 160.

Therefore, when the ion beam introduced from inside the ion beam generating chamber 102 passes through the gap 158, the mass analyzer 104
By bending the trajectory by the magnetic field generated from 60, it is possible to take out only desired ions using the difference in the degree of bending according to the mass of the ions.

The ion beam passed through the mass analyzer 104 is guided by the mass analyzer 104 in a predetermined direction.
Only the ion beam of the desired ions is
Is introduced into the ion separation chamber 106 connected to
In the ion separation chamber 106, a separation slit portion 162 is provided, and unnecessary ions which are close to each other in mass and are not separated in the mass analyzer 104 are introduced into the ion beam. It is configured to be excluded from.

The ion beam which has been converted into the desired ions only through the above steps is introduced into the accelerator 108 connected to the ion separation chamber 106. The accelerator 108 is configured to apply a predetermined acceleration voltage to an ion beam to be introduced and accelerate the ion beam.

The accelerated ion beam is supplied to the processing chamber 11 connected to the accelerator 108 via the gate valve G2.
Introduced in 0. Incidentally, a rotary mounting table 164 for mounting the wafer W is provided in the processing chamber 110. The rotary mounting table 164 has a plurality of wafers W arranged in the circumferential direction, and is rotatable via a rotary shaft 166 by operating a rotation drive mechanism (not shown). The beam is configured to be deflected (scanned) on the circumference on which the plurality of wafers W are placed.

Further, at a position surrounding the ion beam introduced into the processing chamber 110 at a position facing the rotary mounting table 164, secondary electrons generated during ion implantation are confined so as not to flow outside. A Faraday cup 168 for accurately measuring the ion beam current is provided. Further, a beam gate 170 is provided in a direction in which the ion beam is introduced into the Faraday cup 168. The beam gate 170 is connected to the Faraday cup 16
Unnecessary irradiation of the ion beam on the side 8 is prevented, and it is configured as a measuring device for adjusting the ion beam introduced into the wafer W before irradiation.

As described above, a preferred embodiment of the present invention has been described with reference to the accompanying drawings, but the present invention is not limited to this configuration. Within the scope of the technical idea described in the claims, those skilled in the art can come up with various modified examples and modified examples, and these modified examples and modified examples are also within the technical scope of the present invention. It is understood that it belongs to.

For example, in the above-described embodiment, the configuration in which the ion extraction power supply 128 includes the high-output power supply 132 and the low-output power supply 134 has been described as an example. However, the present invention is not limited to such a configuration. Depending on the required output power, the extracted power supply can be further composed of a plurality of power supplies.

In the above embodiment, the input rectifier 130 of the ion extraction power supply 128 and the high-output power supply 1
When describing the internal configuration of the power supply 32 and the low-output power supply 134, the number and connection order of the respective components have been specifically described. However, the present invention is not limited to such a configuration, and the present invention is applied. Modifications and changes can be made as appropriate depending on the device.

[0053]

As described above, according to the present invention,
Since the draw-out power supply is composed of a high-output power supply and a low-output power supply that can be switched each other, it is possible to cope with both required high-output and low-output DC power output. Also, when low-power DC power is output from a low-power dedicated power supply, it is possible to prevent so-called ripples, which are particularly noticeable at low power, and to apply uniform DC power to the ion source and the extraction electrode. can do. As a result, the ion beam can be extracted from the ion source with uniform energy not only at the time of high output but also at the time of low output, and the object can be efficiently irradiated with the ion beam.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of an ion implantation apparatus to which the present invention can be applied.

FIG. 2 is a schematic explanatory view showing a configuration of an ion extraction power supply in the ion implantation apparatus shown in FIG.

[Explanation of symbols]

 Reference Signs List 102 ion beam generation chamber 110 processing chamber 112 ion source 124 extraction electrode 128 ion extraction power supply 130 input rectification unit 132 high output power supply 134 low output power supply 138 first inverter unit 140 first booster unit 142 first output rectification unit 144 2 inverter section 146 second boost section 148 second output rectification section

Claims (1)

[Claims] 1. An ion implantation apparatus for injecting ions extracted from an ion source by an extraction electrode into an object to be processed, wherein an extraction power supply for applying an output voltage to the extraction electrode is a high-output power supply connected at least in parallel. And a low-output dedicated power supply connected in series to an input rectifier. The high-output dedicated power supply comprises at least a first inverter, a first booster, and a first output rectifier. At least a second inverter, a second booster, and a second output rectifier are provided. The first inverter and the second inverter are selectively switchable with each other, and a turns ratio of the first booster is provided. Is higher than the turns ratio of the second booster, the capacity of the first smoothing capacitor of the first output rectifier is smaller than the capacity of the second smoother of the second output rectifier, and When a power request is made, a high output voltage is applied to the extraction electrode from the high output dedicated power supply, and a low output voltage is applied to the extraction electrode from the low output dedicated power supply when a low output request is made. , Ion implantation equipment.