JP4867113B2 - Ion implantation method and ion implantation apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ion implantation method and an ion implantation apparatus used for forming a plurality of regions having different ion implantation amounts in a semiconductor wafer.
[0002]
[Prior art]
In the ion implantation method, impurities are ionized, electrically accelerated as an ion beam, and implanted into a wafer such as silicon (Si). Since impurities can be introduced into a fine region with high accuracy, Widely used in manufacturing processes.
[0003]
In this ion implantation method, (1) an ion beam is deflected by applying an electric field, and an electrostatic scan is performed to scan the wafer surface. (2) an ion beam is deflected by applying a magnetic field, so that Magnetic field scanning to be performed, (3) Mechanical scanning to perform scanning of the ion beam by moving the wafer side mounted on the support table by a motor is performed, and any one of (1) to (3) The scanning method is applied to scanning in the X and Y directions orthogonal to each other within the wafer surface.
[0004]
Specifically, the hybrid scan method in which the electrostatic scan of (1) or the magnetic field scan of (2) is applied in the X direction and the mechanical scan of (3) is applied in the Y direction, both in the X and Y directions. (3) Mechanical scan method using mechanical scan, electrostatic scan method applying electrostatic scan (1) in both XY directions, and XY magnetic field scan method applying magnetic field scan (2) in both X and Y directions is there.
[0005]
If the ion implantation method as described above is used, ions can be uniformly implanted over the entire surface of the wafer. In addition, when a wafer on which a mask is formed in advance using a photoresist is used, desired impurities can be selectively and accurately injected into a desired region.
[0006]
[Problems to be solved by the invention]
By the way, at the stage of development and trial manufacture of semiconductor devices, tests for implanting ions into a wafer under various conditions are performed to determine final ion implantation conditions. However, since the ion implantation method as described above can perform implantation only under one condition per wafer, there is a problem that a large amount of wafers are required and the cost is increased. This is especially true since the diameter of the wafer has increased in recent years.
[0007]
Thus, in order to reduce the number of wafers used, a mask is formed on the wafer and a plurality of ion implantation regions are provided. In this method, each time ions are implanted into one region, a mask is formed. Therefore, it takes time to work and the cost increases.
[0008]
The present invention has been made in view of such problems, and an object of the present invention is to form a plurality of regions having different implantation amounts on a single semiconductor wafer by a simple method and to reduce manufacturing costs. It is an object of the present invention to provide an ion implantation method and an ion implantation apparatus that can be used.
[0010]
[Means for Solving the Problems]
Louis on injection method by the present invention, by scanning the ion beam, a first step of implanting ions into a predetermined region of the semiconductor wafer, after the first stage, overlapping the region injected with ions And a second step of forming a plurality of regions having different ion implantation amounts by scanning the ion beam at least once.
[0013]
Louis on injection device by the present invention is to generate an ion beam, an ion beam injection means for injecting into the semiconductor wafer, so that a plurality of regions with different injection amounts semiconductor wafer is formed, by scanning the ion beam ions were implanted into a predetermined region of the semiconductor wafer Te, then superimposed on the injection region is obtained by a scanning area control means for scanning at least once an ion beam.
[0016]
Or in Louis on injection method by the present invention is ion-implantation apparatus, by being scanned superimposed a plurality of times by changing the area, ion implantation dose into the semiconductor wafer is different regions.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0019]
[First Embodiment]
FIG. 1 is a schematic configuration of an ion implantation apparatus 10 according to a first embodiment of the present invention, and FIGS. 2 to 6 are diagrams for explaining an ion implantation method using the ion implantation apparatus 10. . The ion implantation apparatus 10 is separated by an ion source unit 11 that ionizes impurities, a mass analysis unit 12 that selects and separates desired ions from impurities ionized by the ion source unit 11, and the mass analysis unit 12. An accelerating unit 13 for accelerating the desired ions as an ion beam; a beam deflecting unit 14 for deflecting the ion beam by applying an electric field to inject the accelerated ion beam over the entire surface of the wafer 16; And a sample chamber 15 for installing a wafer 16 on which a deflected ion beam is irradiated.
[0020]
The beam deflection unit 14 includes an electrostatic scan electrode 14A that applies an electric field to the ion beam, and an electrostatic scan control unit 14B that controls an applied voltage to the electrostatic scan electrode 14A.
[0021]
The sample chamber 15 includes a support base 17 for mounting the wafer 16, a motor 19 for driving the support base 17, and a mechanical scan control unit that controls the driving of the motor 19 to scan the ion beam. 18 and a beam detector 20 that measures the amount of ions implanted by detecting the current generated by the ion beam applied to the wafer 16. This ion implantation apparatus 10 is driven by a hybrid scan system, and performs electrostatic scanning by the electrostatic scan control unit 14B in the X direction of the wafer 16, and by the mechanical scan control unit 18 in the Y direction of the wafer 16. A mechanical scan is performed. This scanning method employs a single wafer method in which the wafers 16 are placed one by one on the support base 17 and irradiated with an ion beam.
[0022]
In this ion beam device 10, impurities are ionized by the ion source unit 11, desired ions are selected and separated from the ionized impurities by the mass analyzer 12, and desired ions are accelerated by the acceleration unit 13 to be ionized. Become a beam. The accelerated ion beam is deflected in the X direction by the electric field applied between the electrostatic scan electrodes 14A under the control of the electrostatic scan control unit 14B of the beam deflecting unit 14, and is thereby placed on the support base 17. Scanning (electrostatic scanning) in the X direction is performed on the wafer 16 that has been processed. On the other hand, in the Y direction, the support base 17 is reciprocated under the control of the mechanical scan control unit 18, whereby the Y direction scan (mechanical scan) is performed on the wafer 16. As described above, as shown in FIG. 2, the entire surface of the wafer 16 is irradiated with the ion beam.
[0023]
By the way, when the scanning of the wafer 16 with the ion beam is performed without performing any correction for the reason that the scanning speed of the ion beam and the wafer 16 is not constant in the surface of the wafer 16 (see FIG. 4A), Ions are not uniformly implanted over the entire surface of the wafer 16. Therefore, conventionally, as shown in FIG. 4B, the amount of ions injected into the wafer 16 by the beam detection unit 20 is measured, and the electrostatic scan control unit is based on the measured amount of ions. In 14B and the mechanical scan control unit 18, correction is performed so that the scanning speed is constant.
[0024]
In this embodiment, a plurality of regions having different ion implantation amounts are formed in one wafer 16, and the ion beam scanning speed is made constant so that ions are uniformly implanted in each region. At the same time, the scanning speed of the ion beam is changed for each different region.
[0025]
That is, in the present embodiment, as shown in FIG. 3, the wafer 16 is irradiated with an ion beam scanned by an electrostatic scan in the X direction. At this time, the ion detection amount to the wafer 16 is measured by the beam detection unit 20, and the electrostatic scan control unit 14B is based on the measured ion injection amount as shown in FIG. , in each of the regions inside the region a ₁ to d ₁ while controlling so that the scanning speed of the ion beam is constant, between the different regions a ₁ to d ₁ is controlled so as scan speed changes. Thereby, a plurality of regions a _{1 to} d ₁ having different ion implantation amounts are formed in the X direction of the wafer 16.
[0026]
On the other hand, when a plurality of regions having different ion implantation amounts are formed in the Y direction of the wafer 16, the ion beam is scanned by mechanical scanning as shown in FIG. At this time, the ion implantation amount into the wafer 16 is measured by the beam detection unit 20, and the mechanical scan control unit 18 uses the measured ion implantation amount as shown in FIG. 6B. while in each of the area inside a ₂ to d ₂ for controlling so that the scanning speed of the ion beam is constant, changing the moving speed of the wafer 16 so that the scanning speed is changed between different regions a ₂ to d ₂ . As a result, a plurality of regions a _{2 to} d ₂ having different ion implantation amounts are formed in the Y direction of the wafer 16.
[0027]
Note that regions having different ion implantation amounts in the X direction and the Y direction may be simultaneously formed on one wafer 16, or both regions may overlap.
[0028]
Further, in such an ion implantation apparatus 10, when a wafer 16 on which various patterns are formed by using a photoresist, for example, by applying a mask having different line widths of openings, a larger number of ion implantation regions can be obtained. Can do.
[0029]
As described above, in the present embodiment, the scanning speed of the ion beam in the X direction or the Y direction of the wafer 16 or the moving speed of the wafer 16 is changed. Can be formed. Therefore, various ion implantation regions can be obtained for one wafer, the number of wafers to be used can be reduced, and costs at the development and trial production stages can be reduced.
[0030]
[Modification]
In the first embodiment, a hybrid scan method using an electrostatic scan that scans an ion beam by applying an electric field in the X direction and a mechanical scan that moves a wafer by a motor in the Y direction is used. For example, as shown in FIG. 7, mechanical scanning may be applied in both the X direction and the Y direction. In this scanning method, a plurality of wafers 16 are set on the support base 17, and the plurality of wafers 16 can be irradiated with an ion beam, enabling batch processing.
[0031]
[Second Embodiment]
8 and 9 are diagrams for explaining an ion implantation method according to the second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different portions are described.
[0032]
In this ion implantation method, as shown in FIG. 8, an electrostatic scan that scans an ion beam by applying an electric field in both the X direction in the plane of the wafer 16 and the Y direction orthogonal thereto is applied. Electrostatic scanning method. An ion implantation apparatus using this ion implantation method uses an electrostatic scan control unit in the Y direction in place of the mechanical scan control unit 18 in the Y direction in the ion implantation apparatus 10 of the above embodiment.
[0033]
In the present embodiment, the ion beam is scanned using the electrostatic scan control unit 14B in both the X direction and the Y direction. First, ions are implanted into a predetermined region of the semiconductor wafer 16, and the ions are implanted. The ions are implanted by scanning the ion beam at least once so as to overlap with the region. Specifically, first, as shown in FIG. 9A, an ion beam is scanned in the X and Y directions using the electrostatic scan control unit 14B, and ion implantation is performed on the entire surface (region a ₃ ) of the wafer 16. Do.
[0034]
Next, as shown in FIG. 9B, the ion beam is implanted into the region b ₃ by overlapping the region a _{3 of the} wafer 16 and reducing the area scanned with the ion beam.
[0035]
Subsequently, as shown in FIGS. 9C and 9D, the area to be scanned with the ion beam is further reduced, and the regions c ₃ and d ₃ of the wafer 16 are irradiated one after another. As a result, four regions having different ion implantation amounts are formed in the wafer 16. In addition, since an effect is the same as that of the said embodiment, the description is abbreviate | omitted.
[0036]
The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above-described embodiment, the ion beam is scanned by applying an electric field in the beam deflecting unit 14, but instead of applying an electric field, a magnetic field may be applied to scan the ion beam.
[0038]
【The invention's effect】
As described above, according to the ion implantation apparatus of an ion implantation method or claim 6, wherein according to claim 1, so that the ion implantation amount is different regions are formed, the semiconductor wafer by scanning the ion beam Since ions are implanted into a predetermined region of the substrate and the ion beam is scanned at least once over the implanted region, various ion implantation conditions can be easily obtained for one wafer. In addition, the number of wafers to be used can be reduced, and the cost can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an ion implantation apparatus according to a first embodiment of the present invention.
FIG. 2 is a view for explaining an ion implantation method using the ion implantation apparatus shown in FIG. 1;
FIG. 3 is a view for explaining an ion implantation method using the ion implantation apparatus shown in FIG. 1;
4 is a diagram for explaining an ion implantation method using the ion implantation apparatus shown in FIG. 1; FIG.
FIG. 5 is a diagram for explaining an ion implantation method using the ion implantation apparatus shown in FIG. 1;
6 is a diagram for explaining an ion implantation method using the ion implantation apparatus shown in FIG. 1; FIG.
FIG. 7 is a diagram for explaining an ion implantation method according to a modification of the first embodiment.
FIG. 8 is a diagram for explaining an ion implantation method according to a second embodiment of the present invention.
FIG. 9 is a diagram for specifically explaining an ion implantation method according to a second embodiment;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Ion implantation apparatus, 11 ... Ion source part, 12 ... Mass analysis part, 13 ... Acceleration part, 14 ... Beam deflection part, 14A ... Electrostatic scan electrode, 14B .. Electrostatic scan control unit, 15 ... Sample chamber, 16 ... Wafer, 17 ... Support base, 18 ... Mechanical scan control unit, 19 ... Motor, 20 ... Beam detection unit

Claims (6)

An ion implantation method for forming a plurality of regions having different ion implantation amounts on a semiconductor wafer by scanning an ion beam,
A first stage of scanning the ion beam to implant ions into a predetermined region of the semiconductor wafer;
After said first step, superimposed on the injection of the ion region, the second phase and the free Mui on injection method of forming a plurality of regions with different amount of ion implantation by scanning at least one time the ion beam . The area for scanning the ion beam is changed between the first stage and the second stage.
The ion implantation method according to claim 1. Compared with the scanning area of the ion beam in the first stage, the scanning area of the ion beam in the second stage is reduced.
The ion implantation method according to claim 2. In the second stage, the ion beam is scanned twice or more, and the scanning area of the ion beam is reduced each time.
The ion implantation method according to claim 3. In the first step, ion implantation is performed on the entire surface of the semiconductor wafer.
The ion implantation method according to any one of claims 1 to 4. An ion implantation apparatus that scans an ion beam to form a plurality of regions having different ion implantation amounts on a semiconductor wafer,
An ion beam injection means for generating an ion beam and injecting it into the semiconductor wafer;
The ion beam is scanned to inject a predetermined region of the semiconductor wafer so that a plurality of regions having different implantation amounts are formed in the semiconductor wafer, and then the ions are superimposed at least once on the implantation region. ion-implantation apparatus and a scanning area control means for scanning the beam.

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