JP3362525B2 - Ion implanter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for implanting an ion beam having a large area in section from a beam extraction electrode system of an ion source into a target without mass separation. The present invention relates to an ion implantation apparatus that achieves a uniform implantation dose distribution without rotating a target. FIG. 15 shows an apparatus for implanting ions into a target (substrate to be implanted) with an ion beam having a large cross section.
For example, a thin film transistor (T
FIG. 2 is a configuration diagram of an ion implantation apparatus that forms an FT) array. The plasma generation chamber 2 in the high-frequency ion source 1 is formed by a cylindrical container member 3 and a high-frequency flange member 4 attached thereto via an insulating material. The cylindrical container member and the high-frequency flange member are connected to a high-frequency power source 5. ing. The beam extraction electrode system 6 of the ion source has, for example, four electrodes.
A plasma grid (electrode) 7, an extraction electrode 8, a suppression electrode 9 and a ground electrode 10. The plasma grid is biased to a positive potential by an acceleration power supply 11 together with the cylindrical container member 3, and the extraction electrode is a plasma grid by an extraction power supply 12. , And the suppression electrode 9 is biased to a negative potential by the suppression power supply 13. The ion beam extracted from the beam extraction electrode system 6 is injected into the target 14 without mass separation. As shown in FIG. 16, each electrode in the extraction electrode system 6 is constituted by a multi-hole electrode having a hole 15 through which a large number of beams pass on the xy plane. . The plasma distribution in the plasma generation chamber 2 of the ion source is uniform over the entire surface of the beam extraction surface.
Therefore, the intensity of each beam finally obtained from each hole 15 of the ground electrode 10 is equal. The beam from each hole 15 of this ground electrode spreads and reaches the target 14, but with each hole provided at an interval, the beam is located at the x-axis position passing through the center of a row of holes in FIG. The corresponding beam intensity i on the target surface is shown in FIG.
It pulsates as shown in FIG. Therefore, target 14
Is held by the target rotation / holding mechanism 16 and the target is rotated to make the injection amount D in the arbitrary radius r direction from the center of the target uniform as shown in FIG. 17B. However, rotating the target 14 requires a target rotation / holding mechanism 16, which is complicated and needs to be provided in a vacuum injection chamber. By eliminating the need for such a target rotation mechanism, the cost of the target holding mechanism can be reduced. An object of the present invention is to provide an ion implantation apparatus which realizes a uniform implantation amount without rotating a target. According to the present invention, there is provided an ion implantation apparatus for injecting an ion beam having a large area in section from a beam extraction electrode system of an ion source into a target without mass separation. A beam extraction electrode system is formed by a multi-slit electrode, and a scan electrode for scanning a beam in a slit direction adjacent to the multi-slit electrode is provided in the beam extraction electrode system. Since the distribution of plasma in the plasma generating chamber of the ion source is uniform over the entire surface of the beam extraction surface, the intensity distribution of the beam extracted from each slit of the beam extraction electrode system is in the longitudinal direction of the slit. Is uniform. These one-dimensional, having a uniform intensity distribution in the longitudinal direction, the beam from each of a plurality of slits having the same intensity is scanned by a scan electrode in the direction of the adjacent slit, and the position of each slit and a portion between the slits is scanned. The beam intensity on the corresponding target surface is made uniform over time. Therefore, uniform implantation is realized on a large-area two-dimensional surface on the target. An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment. In the following description, the same reference numerals as those in FIG. 15 indicate the same or equivalent parts.
The plasma generation chamber 2 in the high-frequency ion source 1 is formed by a cylindrical container member 3 and a high-frequency flange member 4 attached to the cylindrical container member 3 with an insulating material interposed therebetween. It is connected to the.
The beam extraction electrode system 6 of the ion source includes a plasma grid (electrode) 7, an extraction electrode 8, a suppression electrode 9, and a ground electrode 1.
As shown in the configuration diagram of FIG. 2, each of these electrodes is configured as a multi-slit electrode in which a plurality of slits 17 are formed in parallel. A scan electrode 18 is provided between the extraction electrode 8 and the suppression electrode 9 in the extraction electrode system 6. As shown in FIG. 3, the scan electrode 18 is configured by attaching a required number of electrode rods 19 in parallel to an insulating support member 20 at intervals. Slit 21 formed between each electrode rod 19
Correspond to the positions of the slits 17 of the electrodes 7 to 10 in the extraction electrode system 6. The required number of electrode rods 19 is 1
The two pairs of electrode rods are connected to output terminals a and b of the beam scan power supply 22. The beam scan power supply 22 has two triangular wave power supplies 23 and 24. The potential of the output terminal a and the potential of the same b are the same in absolute value but different in polarity with respect to the reference potential terminal c to which both triangular wave power supplies are connected. Output terminals a to which two sets of electrode rods are connected,
The scan voltage Vs whose polarity changes to positive or negative as shown in FIG. FIG. 5 is an electric circuit configuration diagram of the extraction electrode system. The plasma grid 7, the extraction electrode 8, and the suppression electrode 9 are provided with necessary components by the acceleration power supply 11, the extraction power supply 12, and the suppression power supply 13 as in FIG. The potential is applied. The reference potential terminal c of the beam scan power supply 22 that applies the scan voltage Vs to the scan electrode 18 is connected to the same potential point as the extraction electrode 8. In FIG. 1, the target 14 is held in a non-rotating state by a target holding mechanism 25.
An ion beam is extracted from the plasma chamber 2 by an electric field between the plasma grid electrode 7 and the extraction electrode 8. When the beam from each slit 17 subsequently reaches the position of the scan electrode 18, an alternating electric field acting on the slit 21 between the electrode rods 19 by the beam scan power supply 22 causes the electrode rod 1 to move.
Scanning is performed at a constant amplitude in the direction of the y-axis orthogonal to 9 (FIG. 3) in the direction of the adjacent slit in the multi-slit electrode. The beam intensity of the ion beam extracted from each slit 17 in the multi-slit electrode of the beam extraction electrode system 6 is such that the plasma density distribution in the plasma generation chamber 2 is uniform, so that the slit longitudinal direction and x-axis direction (FIG. 2), and the intensity of the ion beam extracted from each slit is also uniform. The slit beam extracted from each of these slits is
The beam is scanned by the scan electrode 18 in the direction of the adjacent slit in the multi-slit electrode so that the light is injected into the surface of the multi-slit electrode. Each arrow s near the target 14 in FIG. 1 indicates the scanning state of the beam. By arranging the scan electrode 18 of the target 14 on the downstream side of the beam from the extraction electrode 8, the beam is scanned before the beam is sufficiently accelerated, so that the beam can be swung with a small scan voltage Vs. By doing so, the distribution of the beam current i in the y-axis direction as a time average becomes uniform as shown in FIG. 6A, and therefore, the distribution of the implantation amount D in the y-axis direction is the same. It can be made uniform as shown in FIG. Since the beam distribution of each slit is originally uniform in the x-axis direction, by performing scanning, the injection amount distribution in the y-axis direction is made uniform, so that both the x and y directions can be obtained without rotating the target 14. Axial direction, thus target 1
4 can be uniformly implanted over the entire surface. The longitudinal direction of the slits 17 and 21 may be either the horizontal direction or the vertical direction. As shown in the embodiments described below, the present invention can be implemented by changing the positions of the scan electrodes and the number of electrodes. Hereinafter, the same reference numerals as those in FIGS. 1 to 5 indicate the same or equivalent parts. FIG. 7A is a configuration diagram of another embodiment having an extraction electrode system 6 composed of five electrodes including scan electrodes, similarly to FIG. 1, and a scan electrode 18 is arranged downstream of the ground electrode 10 in the beam direction. In this way, the scan voltage does not affect the occurrence of breakdown between the extraction electrode 8 and the suppression electrode 9 which are the beam acceleration unit. FIG. 8 is a circuit configuration diagram of the beam extraction electrode system. The reference potential terminal c of the beam scan power supply 22 is grounded. Accordingly, the potential configuration in the beam extraction electrode system 6 is as shown in FIG. 7B, and the arrow indicates the amplitude range of the scan voltage Vs in the scan electrode 18. FIG. 9A is a configuration diagram of another embodiment having an extraction electrode system 6 of six electrodes including scan electrodes.
Two ground electrodes 10 ₁ and 10 ₂ are provided, and a scan electrode 18 is arranged between them. Sputter particles from the target 14 can be prevented from adhering to the scan electrode 18. FIG. 10 is a circuit configuration diagram of the beam extraction electrode system. The reference potential terminal c of the beam scan power supply 22 is grounded. FIG. 9B shows the potential configuration of the beam extraction electrode system. The average voltage of the scan voltage Vs is zero, but since the amplitude changes as indicated by the arrow, the function of suppressing the negatively charged particles from entering the beam extraction electrode system may be reduced. In this case, the reference potential terminal c of the scan power supply is biased to a negative potential by the bias power supply 26 shown by a dotted line in FIG. An example of the potential configuration at this time is shown in FIG. FIG. 11A is a structural view of another embodiment having an extraction electrode system 6 also including five electrodes including a scan electrode. A scan electrode 18 is arranged between a suppression electrode 9 and a ground electrode 10. I do. As in the embodiment of FIG. 7, there is no possibility of the occurrence of breakdown of the beam accelerating portion due to the scan electrode, and it is possible to prevent the sputter particles from the target 14 from adhering to the scan electrode 18 as in the embodiment of FIG. . FIG. 12 is a circuit configuration diagram of the beam extraction electrode system. The reference potential terminal c of the scan power supply 22 is connected to the same potential point as the suppression electrode 9. FIG. 11 (b) shows the potential configuration of the beam extraction electrode system due to this. FIG. 13A is a configuration diagram of an embodiment having a four-electrode extraction electrode system 6 including scan electrodes. The scan electrode 18 is on the beam downstream side of the plasma grid 7,
It is provided almost at the position of the extraction electrode, so that it also has the function of the extraction electrode. Thus, even when the scan electrodes are provided, the number of electrodes can be reduced, and the occurrence of breakdown in the beam acceleration unit can be suppressed. FIG. 14 is a circuit diagram of the beam extraction electrode system. The reference potential terminal c of the scan power supply 22 is connected to the negative terminal of the extraction power supply 12, and the potential configuration in this case is shown in FIG. According to the present invention, as described above, uniform ion implantation can be performed on the entire surface of a target without rotating a target having a large area. Therefore, the target rotating mechanism can be omitted from the target holding mechanism, the structure of the target holding mechanism is simplified, and the mechanism can be manufactured at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an embodiment of the present invention. FIG. 2 is a configuration diagram of a multi-slit electrode in an extraction electrode system. FIG. 3 is a configuration diagram of a scan electrode and a scan power supply in an extraction electrode system. FIG. 4 is a waveform diagram of a scan voltage applied to a scan electrode. FIG. 5 is an electric circuit configuration diagram of an extraction electrode system. FIG. 6 is a characteristic diagram of a beam current and an injection amount distribution. FIG. 7 is a configuration diagram of an embodiment in which a scan electrode is arranged downstream of a ground electrode, and a potential configuration diagram of an extraction electrode system. 8 is a circuit configuration diagram of an extraction electrode system in the embodiment of FIG. FIG. 9 is a configuration diagram of an embodiment in which a scan electrode is arranged between two ground electrodes, and a potential configuration diagram of an extraction electrode system. FIG. 10 is a circuit configuration diagram of an extraction electrode system in the embodiment of FIG. FIG. 11 is a configuration diagram of an embodiment in which a scan electrode is arranged between a suppression electrode and a ground electrode, and a potential configuration diagram of an extraction electrode system. 12 is a circuit configuration diagram of an extraction electrode system in the embodiment of FIG. FIG. 13 is a configuration diagram of an embodiment in which a scan electrode has a function of an extraction electrode, and a potential configuration diagram of an extraction electrode system. FIG. 14 is a circuit configuration diagram of an extraction electrode system in the embodiment of FIG. FIG. 15 is a configuration diagram of a conventional ion implantation apparatus using a beam having a large cross section. FIG. 16 is a configuration diagram of a multi-hole electrode in a conventional beam extraction electrode system. FIG. 17 shows beam intensity in a conventional ion implantation apparatus;
FIG. 4 is an explanatory diagram illustrating an example of an injection amount characteristic. [Description of Signs] 1 Ion source 2 Plasma generation chamber 6 Extraction electrode system 7 Plasma grid 8 Extraction electrode 9 Suppression electrode 10 Ground electrode 14 Target 17 Electrode slit 18 Scan electrode 19 Electrode rod 20 Insulating support member 21 Scan electrode slit 22 Beam scan power supply 25 Target holding mechanism

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-107118 (JP, A) JP-A-2-65230 (JP, A) JP-A-5-67450 (JP, A) JP-A-7-107 176290 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 37/317 H01J 37/08 H01J 37/147 C23C 14/48 H01L 21/265

Claims (1)

(57) [Claim 1] In an ion implantation apparatus for injecting an ion beam having a large area from a beam extraction electrode system of an ion source into a target without performing mass separation, the beam extraction is performed. An ion implantation apparatus, wherein the electrode system is formed by a multi-slit electrode and includes a scan electrode for scanning a beam in a slit direction adjacent to the multi-slit electrode.