JP4566352B2 - High current ion implanter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the structure of an ion beam current measuring device (flag Faraday) in a large current ion implantation device.
[0002]
[Prior art]
Conventionally, an ion beam current measuring device (Flag Faraday) in a large current ion implanter has the following configuration.
[0003]
FIG. 3 is a perspective view showing the configuration of the flag Faraday in the conventional high current ion implantation apparatus.
[0004]
In this figure, 1 is a fixed portion, 2 is a guide plate fixed to the fixed portion 1, 3 is a drive shaft, and 4 is a flag Faraday that can be moved on the guide plate 2 by the drive shaft 3.
[0005]
Therefore, as shown in FIG. 3A, in the ion beam setup state, the flag Faraday 4 blocks the ion beam 5 and measures the beam current by a built-in Faraday cup sensor.
[0006]
Thereafter, when the implant process is started, the flag Faraday 4 is moved to the position shown in FIG. 3B by driving the drive shaft 3, passes through the slit 6 a of the decomposition aperture 6, passes the ion beam 5, and the wafer (not shown). ) Get to the top. Here, the surface 4A adjacent to the ion beam 5 of the flag Faraday 4 has a planar shape.
[0007]
While this operation is repeated, the surface 4A adjacent to the ion beam 5 of the flag Faraday 4 is sputtered with its constituent base material (stainless steel) by the ion beam 5, and in the worst case, it is implanted or adhered as an impurity onto the wafer.
[0008]
[Problems to be solved by the invention]
As a method for suppressing the dust generation described above, a method of shielding a portion sputtered with an ion beam using a carbon plate or the like is generally used. However, since the shielding method using a carbon plate or the like does not suppress the basic ion beam spattering phenomenon, the base material (stainless steel) as the carbon contamination on the wafer or the sputtering progresses by sputtering the carbon plate itself. ) Is exposed, and heavy metal contamination such as Fe, Cr, Ni, etc., which are the main components of stainless steel, occurs, causing fatal defects in the transistor characteristics of the LSI and significantly reducing the product yield. There is sex.
[0009]
Therefore, the present invention eliminates the above problems, changes the flag Faraday shape, reduces the area of the sputtered portion, or changes the shape of the carbon plate or the like used as a cover, and reduces the area of the sputtered portion. An object of the present invention is to provide a structure of an ion beam current measuring device that can be made small.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides
[1] and have contact to the high current ion implanter, comprising an ion beam current measuring device with a structure to reduce the area of the shape of the surface adjacent the ion beam configured to R-shaped, contact with the ion beam.
[0011]
[2] a large current Oite an ion implantation apparatus, an ion beam current measuring apparatus, a surface close to the ion beam of the ion beam current measuring apparatus protects, constituting the shape of the surface adjacent the ion beam R type and a shield structure to reduce the area of contact with vertebral Onbimu.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0013]
FIG. 1 is a perspective view showing the configuration of a flag Faraday in the high current ion implantation system according to the first embodiment of the present invention. The same parts as those in the conventional example are denoted by the same reference numerals, and the description thereof is omitted.
[0014]
First, as shown in FIG. 1A, in the ion beam setup state, the flag Faraday 4 blocks the ion beam 5 and measures the beam current with a built-in Faraday cup sensor.
[0015]
Thereafter, as shown in FIG. 1B, when the implant process is started, the flag Faraday 4 moves to a predetermined position, passes through the slit 6a of the decomposition aperture 6, passes the ion beam 5, and reaches the wafer. .
[0016]
Conventionally, as this operation is repeated, the surface 4B adjacent to the ion beam of the flag Faraday 4 is sputtered with a constituent base material (stainless steel) by the ion beam, and in the worst case, it is implanted or adhered as an impurity onto the wafer. It was.
[0017]
Therefore, in this embodiment, in order to suppress this sputtering phenomenon and prevent contamination on the wafer, the surface 4B adjacent to the ion beam 5 of the flag Faraday 4 is formed into an R surface shape.
[0018]
Thus, by changing the shape of the flag Faraday 4, the surface 4 </ b> B adjacent to the ion beam 5 has a shape having R from the plane, and the area in contact with the ion beam 5 can be significantly reduced. That is, the side of the flag Faraday 4 that is in surface contact with the ion beam can be brought into line contact, the amount of spatter can be reduced by reducing the contact area, and as a result, the amount of impurity contamination can be suppressed. It becomes possible.
[0019]
Next, a second embodiment of the present invention will be described.
[0020]
FIG. 2 is a perspective view showing the configuration of the flag Faraday in the large current ion implantation apparatus showing the second embodiment of the present invention. The same parts as those in the conventional example are denoted by the same reference numerals, and the description thereof is omitted.
[0021]
Even when the surface to be sputtered of the flag Faraday 4 is shielded with a carbon plate or the like, the sputtering proceeds as long as the surface adjacent to the ion beam 5 has a planar shape, and contamination by the shielding material or the underlying base material is exposed. As the sputtering proceeds until the metal contamination, metal contamination constituting the base material occurs.
[0022]
In view of this, the shape of the shield plate is reduced to a sputter area by using a shape having R as shown in FIG.
[0023]
That is, the shield plate 4 </ b> C having the R surface 4 </ b> D is provided on the side surface of the flag Faraday 4.
[0024]
As described above, according to the second embodiment, the contamination by the material (carbon or the like) constituting the shield plate 4C can be reduced by reducing the sputter area.
[0025]
In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.
[0026]
【The invention's effect】
As described above in detail, according to the present invention, the following effects can be obtained.
(A) By making the shape of the side surface of the flag Faraday into the R surface, the surface adjacent to the ion beam has a shape having R from the plane, and the area in contact with the beam can be significantly reduced. As a result, the amount of impurity contamination can be suppressed.
(B) By reducing the sputter area, contamination by the material (carbon or the like) constituting the shield plate is reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a flag Faraday in a high current ion implantation apparatus according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a configuration of a flag Faraday in a large current ion implantation apparatus showing a second embodiment of the present invention.
FIG. 3 is a perspective view showing a configuration of a flag Faraday in a conventional high current ion implantation apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixing part 2 Guide plate 3 Drive shaft 4 Flag Faraday 4B A surface close to the ion beam (R surface shape)
4C Shield plate 4D R surface 5 Ion beam

Claims (2)

The shape of the surface to be close to the b Onbimu configured to R-shaped, high-current ion implanter comprising an ion beam current measuring device with a structure to reduce the area of contact with the ion beam. And Lee Onbimu current measuring device, a surface close to the ion beam of the ion beam current measuring apparatus protects, the shape of the surface close to the ion beam structure to reduce the area of contact with the construction vertebral Onbimu the R-type A high current ion implanter having a shield .

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