JPH04121940A - Ion implanting apparatus - Google Patents

Abstract

PURPOSE:To obtain highly accurate implantation quantity by providing respective electrodes exclusively used for both preventing effectively secondary electrons generated upstream from Faraday system from entering the Faraday system and also preventing secondary ions generated inside the Faraday system from flowing outside the system. CONSTITUTION:An ion beam 10 is accelerated before being implanted into a wafer 1 and irradiated through a mask 6 and bias electrodes 5 and 4. Secondary electrons 12, subjected to energy exchange with the beam 10 upstream of the mask 6, are suppressed to move downstream of the electrode 5, due to the electrode 5 supplied with voltage from a bias power supply 8, subjected to tracking by a high voltage power supply 13. By irradiation of the beam 10 on the wafer 1, secondary ions 11 and the secondary electrons 12 are generated. The ions 11 are absorbed to the bias electrode 4 supplied with negative voltage by a bias power supply 7, and fed back to the Faraday system. The electrons 12 are returned to the Faraday system by the power supply 7, to which a negative voltage is impressed. Only current of the beam 10 flows into a current integrator 9, and thus measurement error of implantation quantity by the ions 11 and the electrons 12 can be prevented.

Description

[Detailed description of the invention]

[Industrial Application Field] This invention can be applied to, for example, an MO5 integrated circuit device (MO5IC).
The present invention relates to an ion implantation device commonly used in the manufacturing process. [Prior Art] Figures 2 and 3 are schematic cross-sectional views for explaining a conventional ion implantation device and ion implantation. The anode of the bias electrode source is shown connected to ground. In the figure, tilt! wafer, +21i platen,
+31 [7 Alade one cage% f4 + ld bias electrode, 161 id mask, 17) id bias power supply, (9)
Nicurrent integrator, [101fl ion beam, (]1iii secondary ion, Iziq secondary electron, αization j
It is a secondary electron of energy. Next, the operation will be explained. The ion beam (101 [accelerated upstream, determines the implantation area, and directs the ion beam (lO
) masks to prevent hitting (61 o and 150
0V is applied, the electrons pass through the bias electrode 14), enter the Faraday system, and are injected into the platen (21) and the wafer TL on the platen (21). By irradiating the above location with the ion beam (lO), secondary electrons are generated. Oz and secondary ions (11) are generated. These charged particles are driven by the electric field distribution within the Faraday system.

[Direction is restricted. Configure the 77 RAD system and install the current integrator (91
The charged particles connected to and trapped by the pole at t' are measured by the current integrator (9) and flow into the ground. [Problem to be solved by the invention] Since the conventional ion implantation device is configured as described above, high-energy ions generated upstream of the Faraday system are
Since secondary electrons (500 eV or more) cannot be suppressed and are measured using a current integrator, the injection amount exceeds the setting. Further, there is a problem in that secondary ions cannot be measured by the current-in aggregator due to the bias connected to the ground as shown in FIG. 2, and the implantation amount exceeds the setting as described above. This invention was made to solve all of the above problems, and the secondary electrons of high varnish and lugie generated upstream of the Faraday system enter the Faraday system to prevent crushing of V press-fitting 1] fixed error. It is an object of the present invention to provide an ion implanter which can prevent errors in determining the implantation amount due to secondary ions generated by ion beam irradiation flowing out of the Faraday system. [Means for Solving the Problems] The ion implantation apparatus according to the present invention has the effect that the 7'c secondary electron gold generated in the Faraday system, which is the conventional role of the bias electrode, returns to the 7 Alladay system. To prevent high-energy secondary electrons generated upstream from the Faraday system from entering the Faraday system, and to prevent secondary ions generated within the Faraday system by ion beam irradiation from flowing out of the 7Araday system. Each has its own dedicated bias electrode. [Operation] An appropriate voltage is supplied to the two independent bias electrodes of the present invention by a bias power source that is tracked with a high voltage power source for the upstream bias electrode, and the high energy 2 that is generated upstream of the Faraday system is Prevent secondary electrons from entering the Faraday system. In addition, 1100V is applied to the downstream bias electrode to the secondary electrons and secondary ions generated in the Faraday system, and by connecting the anode of the isolated bias power supply to the 7Araday system, they are returned to the Faraday system. be done. [Embodiment] Hereinafter, all drawings of an embodiment of the present invention will be described. 1st
In the figure; 1) to +41, +6+, +7)
, t91 to (121) are the same as those shown in the conventional example of FIG. 2, so a complete explanation will be omitted.
, +8+ bias t! which supplies voltage to bias electrode 2 L51! 2. j+a) is a high voltage power supply for accelerating ions and at the same time varying the output of the bias power supply 2 (8). Mask (61 grounded and ion beam
The implantation area of ot is determined, and the ion beam (lO) is prevented from flowing into the bias electrode (4) and the bias electrode 2t61. Bias power supply (7) supplies electrons to the habia scissor (41). Next, the operation will be explained. Ion beam (10) i'! is accelerated before being implanted into the wafer t1+, and is connected to the mask [6] and the bias electrode 2t51.
．． It is irradiated through the bias electrode 14). Mask (6
) On the upstream side of the ion beam (10+), the bias power supply 2 (8) is tracked with the secondary electrons (I force, especially high-energy secondary electrons, high-energy piezoelectric!03) and the secondary electrons exchange energy with the ion beam (10+). Bias N T42 powered by
Movement downstream from the bias electrode 2 (5) is inhibited by +a+. In addition, the ion beam (1
By irradiation of 01, secondary ions (11) and secondary electrons α
2. occurs. Secondary ions (bias power supply (11+)
7), the bias electrode (4+VC) supplied with a voltage of -]00V is absorbed and returned to the Faraday system.The secondary electron α21 is returned to the Faraday system by the bias power supply (7) to which a voltage of -100V is applied. Since the exit from the 7-Alade system is prevented, a current of only the ion beam (!0) flows through the current integrator (9), and the amount of implantation by secondary ions fl11 and secondary electrons f12) is measured. It is possible to prevent errors from occurring. In addition, bias electrode (4) and bias electrode 2 (
51k is provided, and the bias electrode (41) can be set to a low voltage of 1100V, and the bias electrode 41 (bias electrode close to 3) can be set to a low voltage of 1100V, and the high voltage side bias 1 [pole 2 (6) is connected to the Faraday cage (
3) By separating it from the bias i! The exchange of charges between the bias electrode 2 (6) and the 7-Araday system due to pressure is alleviated, and errors in measuring the injection amount can be prevented. [Effects of the Invention] As described above, according to the present invention, there are two bias electrodes, and the bias voltage on the upstream side completely prevents energy-controlled secondary electrons from entering the Faraday system, and the downstream one completely prevents the energy from entering the Faraday system.
By connecting a low voltage bias power supply of V to the Faraday system, it is possible to prevent secondary ions from flowing out of the 7Araday system.
Since the charge measured by the current integrator is 6 times that of the ion beam, it is effective to obtain a highly accurate injection mold.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an ion implanter according to an embodiment of the present invention, and FIGS. 2 and 3 are schematic IIT side views showing a conventional ion implanter. FIG. 3 shows a device connected to a Faraday system, and FIG. 3 shows a device in which the anode of the bias power source is connected to ground. In the figure, 1lli wafer, (2: Ni platen, +3
'lU Faraday cage, (41 (1 bias electrode, 1
5) H bias electrode 2, +6) mask, (7) bias power supply, (8 bias power supply 2, +s+H current integrator, [101ttlI:t:/Heat
m, l1l) fl secondary ion, 112)-1l secondary heptad, 1. I3'1 is a high pressure '1iif source. fl, in the figure, the same numbers are the same, and (1 equivalent part is 0)

Claims (1)

[Claims] Bias for returning low-energy secondary electrons and secondary ions generated by ion beam irradiation to the wafer and platen into the Faraday system, and suppressing high-energy secondary electrons that try to enter the Faraday system from upstream. An ion implanter characterized by having separate bias for the purpose of ion implantation.