KR20050106712A - Faraday system and ion implanter having the same - Google Patents

Abstract

In a Faraday system and an ion implantation apparatus having the same, which are used in an ion implantation process for doping a semiconductor substrate, the main control unit moves the Faraday cup assembly to block the ion beam when an error occurs in the ion implantation process. The control signal generated from the main controller is configured to be transmitted through the PDC or directly to the solenoid valve of a solenoid valve of an air line providing compressed air to a pneumatic cylinder for moving the Faraday cup assembly. By using the simplified command delivery scheme as described above, the moving speed of the Faraday cup assembly may be improved, and thus the time difference from stopping the scanning of the ion beam to blocking of the ion beam may be reduced.

Description

Faraday system and ion implanter having same {Faraday system and ion implanter having the same}

The present invention relates to a Faraday system and an ion implantation apparatus having the same. More specifically, the present invention relates to a Faraday system for blocking the ion beam when an error occurs in an ion implantation process for doping a semiconductor substrate and an ion implantation apparatus having the same.

In general, semiconductor devices are manufactured by sequentially, selectively and repeatedly performing unit processes such as deposition, photolithography, etching, ion implantation, polishing, cleaning, and drying on a semiconductor substrate. Recently, in order to meet a series of requirements for semiconductor devices such as larger storage capacity, higher processing speed, and higher reliability, active researches on the formation of fine patterns, metal wiring technologies, and the like have been conducted.

Among the unit processes, an ion implantation process is a process of implanting the ions by irradiating an ion beam made of desired ions to a specific region of the semiconductor wafer, the number and implantation depth of ions implanted in the specific region, compared to the thermal diffusion technology There is an advantage that can be adjusted. As an example of an apparatus for performing the ion implantation process, US Pat. Nos. 5,343,047 (issued to Ono, et al.) And 5,641,969 (Cooke, et al.) Disclose ion implantation devices and ion implantation systems. .

Conventional ion implantation apparatus largely includes an ion source, a beam line chamber, an end station chamber. The ion source ionizes the source gas using the release of hot electrons, the beam line chamber directs ions provided from the ion source to an end station chamber, and at least one semiconductor substrate is located in the end station chamber.

Specifically, the ion beam provided from the ion source is accelerated to a high energy through the beam line chamber and then focused, and the focused ion beam scans the semiconductor substrates by the rotation of a rotating disc holding the beam deflection mechanism and the semiconductor substrates. The beam line chamber includes an ion extractor that extracts ions from an ion source and forms an ion beam, a first polarity converter for converting the polarity of the extracted ion beam, a mass spectrometer for passing only specific ions from the ion beam with the converted polarity, An accelerator for accelerating the ions selected by the mass spectrometer, a second polarity converter for once again changing the polarity of the ion beam passing through the accelerator, a focusing mastnet for focusing the accelerated ion beam, and the ion beam being a semiconductor And a beam deflector that deflects the ion beam to scan the substrate as a whole.

The ion beam induced from the ion source to the mass spectrometer is converted from positive to negative by a first polarity transducer, and an injector for primarily measuring the ion current of the ion beam between the mass spectrometer and the accelerator. An Faraday cup assembly is provided, and the injector Faraday cup assembly measures the ion current of the negative ion beam selected by the mass spectrometer.

Meanwhile, a high voltage for accelerating the ion beam is applied to the accelerator, and a second acceleration for accelerating the positive ion beam in which the polarity is changed from negative to positive by the first acceleration unit and the second polar converter for accelerating the negative ion beam. Contains wealth. The second polar converter uses a stripping gas to convert the negative ion beam into a positive ion beam. The accelerated ion beam is directed to semiconductor substrates located inside the end station through a focusing mastnet and beam deflector. At this time, the High Energy Faraday cup assembly measures the ion current of the focused ion beam. In other words, by measuring the focusing degree, acceleration and ion current of the ion beam having a high energy by the accelerator, it is possible to determine the state of the ion beam before being guided to the semiconductor substrate.

The end station chamber is provided with a rotating disk for supporting and rotating a plurality of semiconductor substrates in the circumferential direction, and chucks for holding the plurality of semiconductor substrates and an opening for passing the ion beam are provided on the rotating disk. have. In addition, a disk Faraday cup assembly for counting ions implanted into the semiconductor substrate is disposed behind the rotating disk.

The ion current of the ion beam measured from the disk Faraday cup assembly is transmitted to a main controller, which controls the ion implantation process as a whole according to the ion current. Specifically, the main controller controls the operation of the scan motor to rotate the rotating disk in accordance with the ion currents measured by the plurality of Faraday cup assemblies and performs control functions for the ion source and the plurality of components.

For example, if an error occurs in the ion counting by the disk Faraday cup assembly, the main control unit stops the ion counting and the scan operation by sending a control signal to the scan system, and drives the high energy Faraday cup assembly by the accelerator. Block the accelerated ion beam.

In more detail, a main control unit called a process control computer (PCC) may include an output digital command when an error occurs in a measurement signal input through a dose control controller (hereinafter, referred to as a 'pdc'). The digital command signal is transmitted to the facility general purpose interface board (GPI) for signal control, which is referred to as 'ODC', and the GPI transmits the air controller and solenoid valve. It drives a pneumatic cylinder to move the high energy Faraday cup assembly.

However, the pressure of the compressed air supplied to the pneumatic cylinder is about 45 PSI, and the high energy Faraday cup assembly, as described above, has to go through several stages of command to move the actual high energy from the error occurrence of the ion implantation process. It takes a long time to move the Faraday cup assembly, which results in the concentration of ions at specific sites. That is, a problem arises in that ions are intensively implanted in a predetermined portion of the semiconductor substrate for a period from when the counting operation by the ion counting and the scan motor is stopped until the actual high energy Faraday cup assembly blocks the ion beam. In particular, with the recent high integration of semiconductor devices, the size of a die formed on a semiconductor substrate is reduced, and when the electrical margin is small, the above-described problems serve as a major factor in reducing the yield of semiconductor devices.

A first object of the present invention for solving the above problems is to provide a Faraday system for blocking an ion beam having a simplified command scheme and improved operation speed.

A second object of the present invention is to provide an ion implantation apparatus having the Faraday system as described above.

According to an aspect of the present invention for achieving the first object, a Faraday system, Faraday cup assembly for receiving an ion beam guided to a semiconductor substrate, and is connected to the Faraday cup assembly and for moving the Faraday cup assembly And a control unit directly connected to the driving unit and controlling the operation of the driving unit so that the Faraday cup assembly blocks the ion beam according to the measured value of the ion current of the ion beam.

According to another aspect of the present invention for achieving the second object, the ion implantation apparatus, an ion source for providing ions to be implanted into the semiconductor substrate, and extracts the ions generated from the ion source to form an ion beam And a beam line chamber for directing the ion beam to the semiconductor substrates, an end station chamber in which the semiconductor substrates are located, and a Faraday system for blocking the ion beam. Here, the Faraday system is provided in the beam line chamber and the Faraday cup assembly for receiving the ion beam, the drive unit is connected to the Faraday cup assembly, and for moving the Faraday cup assembly, and is directly connected to the drive unit and the ion beam And a control unit for controlling the operation of the driving unit so that the Faraday cup assembly blocks the ion beam according to a measured value of the ion current.

According to an embodiment of the present invention, the driving unit is installed in a pneumatic cylinder connected to the Faraday cup assembly, and an air line for supplying compressed air to the pneumatic cylinder and the air line in accordance with a control signal of the controller. It may include a solenoid valve for opening and closing, the pressure of the compressed air is preferably set at about 60 to 70PSI. The drive unit further includes a link mechanism for connecting between the pneumatic cylinder and the Faraday cup assembly, and pendulum motion the Faraday cup assembly by extension and expansion of the pneumatic cylinder.

On the other hand, the Faraday system may further include a shock absorber for limiting the amplitude of the link mechanism by the extension of the pneumatic cylinder, and for cushioning the shock applied to the link mechanism and the Faraday cup assembly. .

As described above, since the operation of the driving unit is directly controlled by the control signal generated from the control unit by directly connecting the control unit and the driving unit, defects in ion implantation due to the delay of movement of the Faraday cup assembly may be reduced as in the conventional apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram for explaining a Faraday system according to an embodiment of the present invention, Figure 2 is a side view for explaining the driving unit shown in FIG.

1 and 2, the illustrated Faraday system 100 is used in an ion implantation process to dope a semiconductor substrate 10 with desired ions, and has a high energy Faraday cup assembly 110 and the high energy. It includes a drive unit 120 for moving the Faraday cup assembly 110, and a main control unit 130 for controlling the operation of the drive unit 120.

The high energy Faraday cup assembly 110 is used by an accelerator (not shown) to receive an ion beam with high energy and to measure the ion current and focusing degree of the ion beam. In addition, when an error occurs in the ion implantation process, the ion beam is blocked so that the ion beam is no longer guided to the semiconductor substrate 10. The error of the ion implantation process can be detected by the ion current measured from the disk Faraday cup assembly 204 disposed behind the rotating disk 202 supporting the semiconductor substrates 10. That is, the main controller 130 controls the operation of the driving unit 120 so that the high energy Faraday cup assembly 110 blocks the ion beam according to the ion current measurement value of the ion beam.

In detail, the main controller 130 is connected to the high energy Faraday cup assembly 110 and the disk Faraday cup assembly 204 through the PDC 132. In addition, although not shown, the main control unit 130 is connected to the injector Faraday cup assembly (not shown) through the PDC 132, and is connected to the driving unit 120 for moving the high energy Faraday cup assembly 110. do.

The driving unit 120 is installed in the pneumatic cylinder 122 for moving the high energy Faraday cup assembly 110, and the air line 124 for supplying compressed air to the pneumatic cylinder 122, the air line ( 124 includes a solenoid valve 126 for opening and closing.

The PDC 132 is connected to the Scan Spin Tilt (SST) interface 134 for controlling the operation of the rotating disk 202, and the SST interface 134 is connected to the Scan Servo Controller (136). The scan servo controller 136 is connected to the scan motor 140 through an amplifier 138. The scan motor 140 rotates the rotating disk 202 such that the ion beam scans the plurality of semiconductor substrates 10 supported in the circumferential direction on the rotating disk 202. In addition, the rotation speed and rotation speed of the scan motor 202 are measured by the encoder 142 and the measurement signal is fed back to the scan servo controller 136. In addition, the rotation position of the rotating disk 202 is transmitted to the main controller 130 by a position transducer 144 connected to the encoder 142.

The main controller 130 analyzes the ion current measured from the disk Faraday cup assembly 204 and information about the rotation of the rotating disk 202, and controls the ion implantation process as a whole based on this. Here, when an error occurs in the ion implantation process, the main controller 130 stops the ion counting through the disk Faraday cup assembly 204 and at the same time stops the rotation of the scan motor 140, and at the same time An energy Faraday cup assembly 110 generates a control signal to block the ion beam.

The control signal is delivered to the solenoid valve 126 in the form of a driving voltage for driving the solenoid valve 126 through the PDC 132, the solenoid valve 126 is a pneumatic cylinder 122 in accordance with the control signal Open air line 124 to provide compressed air for elongation). For example, a drive voltage of about 12V is applied to the solenoid valve 126, which causes the solenoid valve 126 to open the air line 124.

As shown, the control signal is provided from the main controller 130 to the solenoid valve 126 through the PDC 132, but is more preferably transmitted directly from the main controller 130 to the solenoid valve 126. Do.

On the other hand, the drive unit 120 connects between the pneumatic cylinder 122 and the high energy Faraday cup assembly 110 for moving the high energy Faraday cup assembly 10, the expansion and expansion of the pneumatic cylinder 122 And further includes a link mechanism 150 for pendulum motion of the high energy Faraday cup assembly 110. Here, the pneumatic cylinder 122 is hinged to one end of the link mechanism 150, high energy Faraday cup assembly 110 is coupled to the other end of the link mechanism 150. Thus, the pneumatic cylinder 122 is extended by the compressed air supplied through the solenoid valve 126, the high energy Faraday cup assembly 110 is moved on the path of the ion beam to block the ion beam.

At this time, the pressure of the compressed air is preferably about 60 to 70 PSI, more preferably about 65 to 67 PSI. This is a very high pressure in the prior art compared to the pressure of the compressed air is about 45 PSI, which makes the moving speed of the high-energy Faraday cup assembly 110 much faster than in the prior art.

On the other hand, the blocking plate 152 for limiting the extension distance of the pneumatic cylinder 122 is arranged spaced apart a predetermined distance in the extension direction of the pneumatic cylinder 122. On the other hand, when the moving speed increases as described above, the impact energy transmitted to the link mechanism 150 and the high-energy Faraday cup assembly 110 increases, so that the shock absorber 154 for damping the blocking plate 152 is provided. Is coupled to.

As described above, when an error occurs in the ion implantation process, the control signal generated from the main controller 130 is transmitted to the solenoid valve 126 through the PDC 132 or directly to the solenoid valve 126. . In addition, by mounting the shock absorber 154 it is possible to use a higher pressure compressed air than in the prior art it is possible to move the high energy Faraday cup assembly 110 in a faster time.

In fact, when the pressure of the compressed air is adjusted to about 65 to 67 PSI, the total travel time of the high energy Faraday cup assembly 110 is faster from 684 ms to 72 ms, compared to the case of using the conventional compressed air of about 45 PSI, and the scan stop It was confirmed through experiment that the time from the expansion of the high-energy Faraday cup assembly 110 to about 306ms to 24ms. In addition, when the ion implantation process is performed under the above conditions, the ion implantation uniformity was confirmed to be improved to about 0.42% from 3.18%. The ion implantation uniformity can be confirmed by measuring the sheet resistance of the semiconductor substrate 10.

FIG. 3 is a schematic diagram illustrating an ion implantation apparatus having a Faraday system shown in FIG. 1, and FIG. 4 is a side view illustrating the rotating disk illustrated in FIG. 3.

3 and 4, the illustrated ion implantation apparatus 200 includes an ion source 210, a beam line chamber 220, an end station chamber (), and a Faraday system 100.

The ion source 210 includes an arc chamber 212 and a filament 214 for emitting hot electrons. The source gas supplied to the arc chamber 212 may be ionized by the collision with the hot electrons. In addition, an ion source 210 such as a radio frequency type duoplasmatron, a cold cathode type, a sputter type, or a penning ionization type may be used.

The beam line chamber 220 includes an ion extractor 222 for extracting the ion beam from the ion source 210, a first polarity converter 224 for converting the polarity of the ion beam extracted by the ion extractor 222, and Mass spectrometer 226 for sorting specific ions from the polarized ion beam, injector Faraday cup assembly 228 for measuring the ion current of the ion beam consisting of the selected ions, and for accelerating the ion beam of the sorted ions An accelerator 230, a second polarity transducer 232 connected to the accelerator 230 to change the polarity of the ion beam passing through the accelerator 230, a focusing magnet 234 to focus the accelerated ion beam, and the like. do.

The first polar converter 224 includes a solid magnesium and a heater used as the electron donating material. A high heat of about 450 ° C. is provided to the solid magnesium from the heater, and gaseous magnesium molecules are released from the solid magnesium to collide with the extracted ion beam. The ion beam then obtains electrons from the magnesium molecule and converts it to an ion beam having negative properties.

As described above, the ion beam having negative properties is provided to the accelerator 230 by selecting only specific ions from the mass analyzer 226.

As the accelerator 230, a tandetron chamber including a plurality of electrodes to which a high voltage is applied may be used. The positive ion beam converted by the first accelerator 230a and the second polar converter 232 to accelerate the negative ion beam may be used. It includes a second acceleration unit 230b for accelerating. The second polarity converter 232 is disposed between the first accelerator 230a and the second accelerator 230b and converts the negative ion beam into a positive ion beam by using a stripping gas such as nitrogen gas.

The positive ion beam accelerated through the accelerator 230 is focused through the focusing magnet 234 and is incident on the semiconductor substrate 10. In this case, a scanner (not shown) may be further provided to inject ions into the semiconductor substrate 10 as a whole. On the other hand, when converted into a positive ion beam by the second polar converter 232, the positive ion beam includes ions having various energy levels. An ion filter (not shown) may be further provided to select ions having a specific energy from among ions having various energy levels included in the positive ion beam.

The end station chamber 240 includes a rotating disk 202 for supporting and rotating a plurality of semiconductor substrates 10, and a plurality of chucks for supporting the semiconductor substrates 10 on the rotating disk 202. (Not shown) and an opening 202a for passing the ion beam are provided in the circumferential direction. The rotating disk 202 is connected to a vertical driver (not shown), and a scan motor 140 for rotating the rotating disk 202 is connected to the rear surface of the rotating disk 202. More specifically, the rotating disk 202 has a disk shape, a plurality of semiconductor substrate 10 is disposed along the edge. During the ion implantation process, the rotating disk 202 may be vertically moved and rotated by the vertical driver and the scan motor 140 such that the positive ion beam is entirely injected into the semiconductor substrates 10. In addition, a disk Faraday cup assembly 204 is disposed at the rear of the rotating disk 202 for measuring the ion current of the ion beam passed through the opening 202a at every rotation, and the ion implanted into the semiconductor substrate 10 is disposed. Counting can be done by the ion current measurement.

The Faraday system 100 as shown in FIG. 1 is disposed between the focusing magnet 234 and the end station chamber 240, and an ion beam guided to the end station chamber 240 when an error occurs in an ion implantation process. To block. Further details of the Faraday system 100 have been described above with reference to FIGS. 1 and 2 and will be omitted.

According to the present invention as described above, when an error occurs in the ion implantation process, the main control unit transmits a control signal to the solenoid valve only through the PDC, or directly transmits the control signal to the solenoid valve. As such, the speed of movement of the high energy Faraday cup assembly for blocking the ion beam is improved through the transfer of control signals through a significantly simplified command delivery scheme over the prior art.

In addition, by mounting the shock absorber, compressed air having a higher pressure than the prior art can be used in the pneumatic cylinder, so that the moving speed of the high energy Faraday cup assembly can be further improved.

Therefore, since the time from the interruption of the scan motor to the blocking of the ion beam is significantly shortened, the ion implantation uniformity can be greatly improved, which can greatly improve the productivity of the semiconductor device.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1 is a schematic block diagram illustrating a Faraday system according to an embodiment of the present invention.

FIG. 2 is a side view illustrating the driving unit illustrated in FIG. 1.

FIG. 3 is a schematic diagram illustrating an ion implantation apparatus having a Faraday system shown in FIG. 1.

FIG. 4 is a side view illustrating the rotating disk shown in FIG. 3.

Explanation of symbols on main parts of drawing

10: semiconductor substrate 100: Faraday system

110: high energy Faraday cup assembly

120: drive unit 122: pneumatic cylinder

124: air line 126: solenoid valve

130: main controller 132: PDC

140: scan motor 202: rotating disk

204: Disc Faraday Cup Assembly

Claims (10)

A Faraday cup assembly for receiving an ion beam directed to a semiconductor substrate; A drive unit connected to the Faraday cup assembly and configured to move the Faraday cup assembly; And And a control unit directly connected to the driving unit and controlling the operation of the driving unit so that the Faraday cup assembly blocks the ion beam according to the measured value of the ion current of the ion beam. The method of claim 1, wherein the driving unit, A pneumatic cylinder connected with the Faraday cup assembly; And Faraday system is installed in the air line for supplying compressed air to the pneumatic cylinder, characterized in that it comprises a solenoid valve for opening and closing the air line in accordance with the control signal of the controller. The Faraday system of claim 2, wherein the pressure of the compressed air is 60 to 70 PSI. 3. The apparatus of claim 2, wherein the drive unit further connects the pneumatic cylinder and the Faraday cup assembly and further comprises a link mechanism for pendulum motion of the Faraday cup assembly by extension and expansion of the pneumatic cylinder. Faraday system, characterized in that. 5. The shock absorber of claim 4, further comprising a shock absorber for limiting the amplitude of the link mechanism by extension of the pneumatic cylinder and for damping shocks applied to the link mechanism and the Faraday cup assembly. Faraday system. The Faraday system of claim 1, further comprising a disk Faraday cup assembly connected to the control unit and configured to measure the ion current. An ion source for providing ions for implantation into the semiconductor substrates; A beam line chamber for extracting ions generated from the ion source to form an ion beam and directing the ion beam to the semiconductor substrates; An end station chamber in which the semiconductor substrates are located; And A Faraday cup assembly provided in the beam line chamber for receiving the ion beam, a drive unit connected to the Faraday cup assembly and moving the Faraday cup assembly, and directly connected to the drive unit and measuring an ion current of the ion beam And a Faraday system for blocking an ion beam, the Faraday cup assembly including a control unit for controlling an operation of the driving unit to block the ion beam. 8. The rotating disk of claim 7, wherein the end station chamber comprises: a rotating disk having an opening for supporting the semiconductor substrates, rotating the semiconductor substrates so that the ion beam scans the semiconductor substrates, and passing the ion beam; And a disk Faraday cup assembly disposed behind and measuring the ion current of the ion beam passed through the opening. The method of claim 7, wherein the beam line chamber comprises: an extractor for extracting ions from the ion source and forming an ion beam; a mass analyzer for selecting target ions from ions included in the ion beam; And an focusing magnet for focusing the accelerated ion beam and an accelerator for accelerating an ion beam of ions. 10. The ion implantation apparatus of claim 9, wherein the Faraday system blocks the focused ion beam.