JP2010086824A - Ion implantation method, and ion implantation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel ion implantation method in which a variety of patterns of implantation amount distribution can be made inexpensively and an uneven implantation such that implantation distributions between each implantation regions become continuous and smooth can be performed. <P>SOLUTION: In the ion implantation, at least one of scanning of an ion beam IB by electric field or magnetic field or translation movement of the substrate is carried out by simultaneously rotating the substrate W centered on a rotating axis RA crossing the surface on which the ion beam IB is irradiated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ion implantation method for performing non-uniform ion implantation on a substrate.

  In recent years, the price of wafers has risen, and it is required that more semiconductor elements can be produced from one wafer without waste as much as possible. In order to improve the yield by manufacturing a plurality of semiconductor elements having different characteristics from a single wafer or compensating the characteristics of the semiconductor elements, ions are intentionally and unevenly distributed over the entire surface of the wafer. An ion implantation method for implantation is used.

  Examples of an ion implantation method for manufacturing a plurality of semiconductor elements having different characteristics include the ion implantation methods described in Patent Document 1 and Patent Document 2. The ion implantation method described in Patent Document 1 scans a line-shaped ion beam from one end of a wafer to the other end. Scanning from one end to the center of the substrate is performed at a certain speed, and scanning from the center position of the substrate to the other end is performed at another speed. After the ion beam scanning is completed, the wafer is rotated 90 degrees. Then, the same ion beam scanning is repeated again to form a plurality of regions having different ion implantation amounts.

  The ion implantation method described in Patent Document 2 also scans a line-shaped ion beam a plurality of times from one end to the other end of the wafer, restricts the region irradiated with the ion beam by a shutter, The ion implantation amount can be changed.

  However, in the ion implantation method described in Patent Document 1, since the scanning speed of the ion beam is switched only at the center position of the wafer, the patterns of regions having different ion implantation amounts that can be formed are limited. It is difficult to fully respond to requests. In addition, in the ion implantation method described in Patent Document 2, it is necessary to prepare a shutter and a mechanism for controlling the shutter separately in a normal ion implantation apparatus in order to form regions having different ion implantation amounts. The cost will increase accordingly.

  On the other hand, as an ion implantation method for compensating the peripheral characteristics of the wafer for which it is difficult to obtain desired characteristics and improving the yield, there is a method described in Patent Document 3. In the ion implantation method of Patent Document 3, the ion beam scanning speed is switched from one end to the first intermediate point, from the first intermediate point to the second intermediate point, and from the second intermediate point to the other end. The method includes an implantation process for forming three regions with different ion implantation amounts by one ion beam scan, and a rotation process for rotating the wafer by a predetermined angle after the implantation process is completed. In this ion implantation method, an implantation process and a rotation process are alternately repeated to increase the number of divisions of the region and approximate the shape of the region at the center of the wafer to a circular shape, thereby obtaining an approximately donut-shaped ion implantation distribution.

However, in this ion implantation method, since the region at the center of the wafer is only approximately circular, the implantation distribution near the boundary of the region where the approximation error occurs varies more than the center and is continuous. Therefore, it is difficult to set a desired injection amount.
Japanese Patent No. 3692999 Japanese Patent Application Laid-Open No. 11-339711 JP 2005-235682 A

  The present invention has been made in view of the above-described problems, is inexpensive, can give diversity to the pattern of the injection amount distribution, and the injection distribution between the injection regions is continuous and smooth. It is an object of the present invention to provide a novel ion implantation method capable of performing simple implantation.

  That is, in the ion implantation method of the present invention, at least one of scanning of the ion beam or translational movement of the substrate by an electric field or a magnetic field is simultaneously performed while rotating the substrate about the rotation axis RA intersecting the surface irradiated with the ion beam. It is made to perform.

  The ion implantation apparatus according to the present invention includes a rotation mechanism that rotates a substrate around a rotation axis that intersects a surface irradiated with an ion beam, an ion beam scanning mechanism that scans the ion beam with an electric field or a magnetic field, or the substrate. It comprises at least one of a translation mechanism that translates and includes a control mechanism that simultaneously performs rotation of the substrate and at least one of scanning of the ion beam or translation of the substrate.

  In such a case, the ion beam is scanned on the substrate while the substrate is rotated or the substrate is mechanically translated, so that the ion implantation distribution of the substrate can be made continuous and smooth. it can.

  In addition, by adjusting the rotation speed of the substrate and the scanning speed of the ion beam or translational movement of the substrate, the pattern of the region into which ions are implanted and the implantation amount can be changed, and the substrate has various distributions. An ion implantation distribution can be formed.

  Furthermore, since it is not necessary to provide an extra device for shielding the ion beam in order to form a non-uniform ion implantation distribution, non-uniform ion implantation can be performed without increasing the cost.

  In order to form a donut-shaped ion implantation distribution in the vicinity of the center of rotation of the substrate without performing ion implantation at all, a band-shaped ion is formed by reciprocating an ion beam at a predetermined distance from the center of rotation of the substrate. What is necessary is just to form a beam.

  In order to form a donut-shaped ion implantation distribution on the entire surface of the substrate while performing ion implantation near the rotation center of the substrate, a band-shaped ion beam is formed by reciprocal scanning of the ion beam so as to pass through the rotation center of the substrate. That's fine.

  In order to keep the amount of ion implantation by the belt-like ion beam constant and to obtain an implantation distribution that depends only on the rotation speed of the substrate, the magnitude of the reciprocating scanning speed may be kept constant. In such a case, since the peripheral speed continuously increases as the position is away from the center of rotation, a more gentle donut-shaped injection distribution can be obtained.

  In order to form not only the donut-shaped distribution but also various point-targeted injection distributions, the speed of the reciprocating scanning may be changed. This is because when the reciprocating scanning speed is changed, the amount of ions injected from the belt-like ion beam into the substrate can be controlled in an approximately inverse proportion of the speed.

  As a specific method for obtaining another donut-shaped implantation distribution, the distance between the band-like ion beam and the center of rotation can be changed by translating the substrate.

  In addition to the point-symmetric ion implantation distribution, in order to further divide the region and form various implantation patterns, when the rotation angle of the substrate reaches a predetermined angle, What is necessary is just to change the magnitude | size of a reciprocating scanning speed. For example, in addition to point symmetry, line symmetry can be added to the implantation distribution.

  As a simpler method for performing ion implantation so that the ion implantation distribution has a smooth distribution, the ion beam is a spot-like beam, and the ion beam is moved by relatively moving the substrate and the ion beam. What is necessary is just to change the distance between and the center of rotation.

  As a specific method for easily forming a fine ion implantation distribution, the substrate and the ion beam are moved relative to each other only by translation while the substrate is rotated, and the beam intensity of the ion beam is adjusted. It is possible to change the position according to the position on the substrate.

  As a simple and efficient method for performing ion implantation so that the ion implantation distribution has a smooth distribution, the ion beam is a band-shaped beam, and the substrate and the ion beam are moved relative to each other, and the ion beam is ionized. The distance between the beam and the center of rotation may be changed.

  As a specific method for performing ion implantation simply by the band-shaped ion beam as described above, the substrate and the ion beam are relatively moved only by rotating the substrate while being rotated, and the ions are moved. For example, the beam intensity of the beam is changed according to the position on the substrate.

  Thus, in the present invention, while the substrate is rotated, the ion beam is simultaneously scanned or the substrate is translated, so that the ion implantation distribution to be formed can be made smooth and various patterns can be obtained. The ion implantation distribution can be formed. In addition, since it is not necessary to use another member such as a shutter for performing ion implantation of various patterns, an increase in cost can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a top view of the ion implantation apparatus 100, and FIG. 2 shows a side view in which the periphery of the substrate W in FIG. 1 is enlarged. In the following description, the coordinate axis is set to form a right-handed system with the Y axis as the vertical direction, the Z axis as the extending direction of the rotation axis RA of the substrate W, and the X axis as the axis orthogonal to the Y axis in the irradiation surface of the substrate W. The explanation will be made using

  The ion implantation apparatus 100 of the present embodiment is used, for example, to improve the yield by compensating the characteristics of the peripheral portion of the substrate W in the manufacture of a semiconductor element. In the present embodiment, the case where ion implantation is performed on a circular wafer W as the substrate W is described as an example. The shape of the substrate W is not particularly limited to a circular shape.

  The ion implantation apparatus 100 performs at least one of scanning of the ion beam IB by an electric field or a magnetic field or translational movement of the substrate W while rotating the substrate W around a rotation axis RA intersecting a surface irradiated with the ion beam IB. Can be performed simultaneously.

  More specifically, the ion implantation apparatus 100 includes a scanner 1 that deflects the ion beam IB emitted from the ion source IS by an electric field or a magnetic field and scans the substrate W, and the substrate W attached thereto. A rotation mechanism 2 for rotating the table T, a translation mechanism 3 for moving the table T up and down in the vertical Y-axis direction, the scanner 1, the rotation mechanism 2 and the translation mechanism 3 simultaneously. And a control mechanism C that can be operated. As shown in FIGS. 1 and 2, the wafer W is mounted such that its irradiation surface faces in the horizontal direction, the ion beam IB is scanned in the X-axis direction by the scanner 1, and the wafer W is translated and moved. 3 is scanned in the Y-axis direction and rotated by the rotation mechanism 2 around the Z-axis.

  The scanner 1 forms a band-like ion beam IB by reciprocally scanning the spot-like ion beam IB in the X-axis direction by an electric field or a magnetic field. Here, the band-like ion beam IB means that the speed at which the scanner 1 scans the spot-like ion beam IB is sufficiently higher than the rotation speed and translational movement speed of the wafer W to be described later. It can be handled as a strip. In particular, in this specification, a band-like ion beam whose width in the short side direction is substantially equal to the diameter of the spot-like ion beam is referred to as a line-like ion beam. In the present embodiment, since the scanner 1 scans the ion beam IB only in the X-axis direction, a linear ion beam IB is formed.

  The scanner 1 can scan the ion beam IB and change the ion implantation amount implanted into the wafer W by changing the scanning speed. More specifically, the ion implantation amount increases in proportion to the irradiation time of the ion beam IB. Microscopically, when the scanning speed of the ion beam IB is increased, the ion beam IB quickly passes over the wafer W, so that the amount of ion particles irradiated on a unit area on the wafer W is reduced and the speed is increased. This is because the amount of ions irradiated to a unit area on the wafer W increases because the passage is slow when the value is reduced. That is, it can be seen that there is an inversely proportional relationship between the magnitude of the relative velocity between the ion beam IB and the wafer W and the amount of ion implantation. Therefore, the ion implantation amount on the line can be arbitrarily set by changing the scanning speed in the X-axis direction. In the following explanation, the distribution of the ion implantation amount on the line is mainly shown for easy understanding, but this distribution is formed by changing the scanning speed in the X-axis direction. How to change the scanning speed in the X-axis direction from the distribution can be easily calculated from the inverse relationship as described above. When the ion implantation intensity is zero, the ion beam scanning speed is made very large so that the implantation amount can be ignored, or the ion beam irradiation is temporarily stopped. .

  The rotation mechanism 2 rotates the table T to which the wafer W is attached, and is composed of, for example, a rotation motor and an angle detector that detects the rotation angle. The angle detector detects the rotation angle and uses the difference to calculate the rotation speed. The rotation speed can be maintained at a constant speed or can be changed.

  The translation mechanism 3 moves the table T in the Y-axis direction by, for example, a motor, and is used to change the radial position where the irradiation surface is irradiated with the linear ion beam IB.

  The control mechanism C is composed of, for example, a general-purpose computer or a dedicated control board equipped with an output device such as a CPU, a memory, and a display, and an input device such as a keyboard and a mouse. The devices are controlled according to the program stored in the memory. The control mechanism C can operate not only the devices at the same time but also synchronize the movements of the devices by associating the scanning speed, rotation speed, movement speed, and rotation angle with a program. It is also configured.

  Here, to synchronize means to give a predetermined relationship between the moving speed of the wafer W in the radial direction by the translation mechanism 3 and the rotating speed of the wafer W, for example. More specifically, the number of rotations of the wafer W while the linear ion beam IB is moved once in the radial direction of the wafer W and scanned once, and the like can be mentioned. That is, by synchronizing at least one of the rotational speed of the wafer W and the scanning speed of the ion beam IB or the translational movement speed of the wafer W by the translational movement mechanism 3, the number of times the ion beam is scanned onto the wafer W as described above. The relationship between the number of rotations of the wafer is defined, and a desired ion implantation distribution can be obtained.

Next, a specific ion implantation method will be described.
As shown in FIG. 3, the center of the linear ion beam IB is formed by reciprocal scanning in the X-axis direction at a position separated from the center of the wafer W by a predetermined distance, and is not moved in the Y-axis direction. Will be described below at a constant rotational speed ω.

  Specifically, the scanner 1 scans the spot-like ion beam IB in the X-axis direction, and at the same time, the rotation mechanism 2 rotates the wafer W around the rotation axis RA to perform ion implantation.

The magnitude of the scanning speed of the ion beam IB in the X-axis direction is kept constant during the ion beam IB irradiation, and the ion beam IB is implanted on the line during the ion beam irradiation as shown in FIG. FIG. 5 shows the ion implantation amount distribution on the wafer W when the amount is constant. In the following description, for simplicity, the ion implantation amount of the ion beam IB on the line is referred to as ion implantation intensity. Further, regarding the ion implantation distribution on the wafer W, a perspective view and a cross-sectional view in the X-axis direction are shown together. In the perspective view, contour lines of the ion implantation amount are shown by thin lines. As can be seen from FIG. 5, a point-symmetric ion implantation distribution centered on the rotation axis RA is formed, and the ion implantation distribution continuously changes. Further, since the ion beam IB is not irradiated to the inner circle region smaller than the radius √2r0 from the inner end of the linear ion beam IB to the center of rotation, the ion implantation amount is substantially zero. In addition, it can be seen that in the peripheral region, the amount of ion implantation in the portion where the line-shaped ion beam IB is large protrudes, and the amount of ion implantation decreases as it goes outward. This is because the scanning speed is kept constant and the amount of ions irradiated by the line-shaped ion beam IB is constant on the line, but the circumferential speed increases with the rotation of the wafer W toward the outside. This is because the amount of ions irradiated to the outside per unit area decreases.

  The result of ion implantation distribution on the wafer W when the magnitude of the scanning speed of the ion beam IB in the X-axis direction is changed so that the ion implantation intensity increases toward the outer periphery as shown in FIG. Is shown in FIG. At this time, the rate of change of the ion implantation intensity is increased toward the outer periphery. More specifically, the ion implantation amount from the intermediate point to the outer periphery of the line beam is expressed by an exponential function with the radius as a variable, and the distribution of the ion implantation amount on the wafer W when the exponent is larger than 1. is there. For example, the expression is as follows.

However, r0 ≦ | x | ≦ R0 Formula (1)
It should be noted that I _(x) = 0 when 0 ≦ | x | ≦ r0

Here, I _(x) is the ion implantation amount of the line beam in the X-axis direction, I0 is a conversion coefficient of the ion implantation amount, x is the coordinate in the X-axis direction on the line beam, R0 is the radius of the wafer W, r0 Is the radius from the center of rotation to the center of the line beam.

  As in the ion implantation distribution on the wafer W shown in FIG. 7, by appropriately selecting the exponent a of the exponential function with respect to the rotation speed ω of the wafer W, the rate of change in the radial direction of the wafer W can be made substantially constant. Can be. Also, if the speed of reciprocating scanning of the ion beam IB in the X-axis direction with respect to the rotational speed ω is made very large and the number of rotations of the wafer W is made very large, a smooth and gentle change can be made due to the averaging effect. The ion implantation distribution possessed can be obtained.

  FIG. 8 shows the ion implantation intensity on the line when the index a is smaller than 1 in the above-described equation (1). Further, the ion implantation distribution on the wafer W in this case is shown in FIG. Here too, by appropriately selecting a, the amount of ion implantation in the region where the ion implantation has been performed can be made substantially equal, and a hollow cylindrical ion implantation distribution as shown in FIG. 9 can be formed.

  In order to make the ion implantation distribution smoother while making a region where no ion implantation is performed in the center of the wafer W easier, the ion implantation is performed even when 0 ≦ | x | ≦ r0. You can do that. In this way, since the ion beam is not irradiated to the inner circle region of the distance r 0 where the line-shaped ion beam IB is away from the center of the wafer W, the ion implantation distribution becomes zero and the ion beam implantation intensity on the line Therefore, the setting of scanning of the ion beam IB becomes very simple. In other words, an arbitrary ion implantation distribution is provided only on the outer side of the wafer W where the ion beam IB is formed, by simply forming the implantation intensity distribution of the ion beam IB applied to the wafer W over the entire area. Can be formed by a simple calculation or control method.

  Next, an ion implantation method will be described in which a linear ion beam IB is formed so as to pass through the center of rotation as shown in FIG. Even in this case, the ion beam IB and the wafer W are not moved in the Y-axis direction.

  As shown in FIG. 11, the ion implantation intensity on the line increases from the rotation center to the radius r 0 and decreases from the radius r 0 to the radius R 0 of the wafer W. The ion implantation distribution is shown in FIG.

  As shown in FIG. 12, it is possible to obtain a symmetric ion implantation distribution with respect to the center of rotation while performing ion implantation into a circle having a radius r0. In other words, if the linear ion beam IB is formed or irradiated so as to pass through the center of the wafer W, ion implantation can be performed over the entire area of the wafer W.

  Similarly to the case where the linear ion beam IB is separated from the rotation center, the equation (1) is expanded and used, and the index a is adjusted to adjust the radial direction of the slope as shown in FIG. The rate of change can be made constant, or a cylindrical ion implantation distribution as shown in FIG. 9 can be used. In other words, by adjusting the scanning speed of the ion beam IB and adjusting the ion implantation intensity according to the rotation speed of the wafer W, a linear ion implantation distribution can be obtained.

  Another ion implantation method when the line-shaped ion beam IB is formed at the center of the wafer W will be described.

  The scanning speed of the ion beam IB is decreased at the outer peripheral portion and is increased at the inner peripheral portion, that is, as shown in FIG. 13, many ions are implanted into the outer peripheral portion of the wafer W and implanted into the inner peripheral portion. The ion implantation intensity is set so as to reduce the amount of ions to be generated. At this time, the rotational speed ω of the wafer W is constant.

The distribution of ion implantation intensity is expressed as follows using an equation.
In the embodiment of FIG. 13, the case where a = 1 is shown.

  The ion implantation distribution in this case is as shown in FIG. 14, and a certain amount of ions can be implanted over the entire area on the wafer W. Intuitively explaining this result, the rotational speed of each point on the wafer W increases as it goes outward, and the amount of ions to be implanted decreases, so that it is shown in FIG. 13 and equation (2). If an appropriate ion implantation intensity is given, they cancel each other, and a certain amount of ions can be implanted over the entire region. Here, the ion implantation intensities I1 and S at 0 ≦ | x | ≦ S / 2 indicate that when the ion implantation is completed, the ion implantation amount in the region near the rotation center of the wafer W is different from the ion implantation amount in the other region. They are set to be approximately equal.

Next, an ion implantation method when the ion implantation intensity is changed in two stages will be described. As shown in FIG. 15, on the inner side, the ion implantation intensity is changed so that the ion implantation amount is reduced linearly in the central portion as in the above-described embodiment and the ion implantation amount is increased toward the outer side. In the portion, the ion implantation intensity is changed at a larger change rate than in the inner peripheral portion. Specifically, it is described by an expression:
It becomes. In this embodiment, a = 1 is set as a linear distribution, and S << R0. In this case, the inner peripheral portion of the wafer W as shown in FIG. 16 performs a certain amount of ion implantation, and the outer peripheral portion forms a distribution in which the rate of change is constant and the ion implantation amount increases toward the outer peripheral portion. can do.

  Next, as shown in FIG. 17, a line-shaped ion beam IB is formed on the outer periphery of the wafer W, and the wafer W is moved in the negative Y-axis direction to scan the line-shaped beam from the outer periphery to a certain radius. An ion implantation method for simultaneously rotating the wafer W will be described.

  In this ion implantation method, the locus of the center of the line-shaped ion beam IB on the wafer W draws a spiral as shown in FIG. Here, the magnitude of the scanning speed of the ion beam IB in the X-axis direction is controlled to be always constant, that is, the implantation amount distribution on the line is set to a constant value. Further, the rotational speed of the wafer W is set to be very large with respect to the translational movement speed of the wafer W in the Y-axis direction. That is, the number of rotations of the wafer W is very large for one scanning of the ion beam IB, and a sufficiently rotationally symmetric ion implantation distribution is obtained.

As shown in FIG. 18, the translational movement in the Y-axis direction and the rotation of the wafer W are synchronized so that the spirals are equally spaced. Specifically, it is expressed as follows.

  Here, θ is the rotation angle of the wafer W, y is the y coordinate of the linear ion beam IB, t is the time, and T is the ion implantation end time.

  When ion implantation is performed based on such equations (4) and (5), as shown in FIG. 19, the most ion implantation is performed on the outer periphery, and the amount of ion implantation gently decreases inward. Go. This is because the line-like ion beam IB moves relative to the wafer W from the outside to the inside, so that the outer portion has a relatively high relative speed, so the amount of ion implantation per time is small, but from the inside. This is because the number of times of ion implantation increases, and as a result, more ions are implanted.

Similarly to FIG. 18, FIG. 20 shows a state in which the locus of the center of the linear ion beam IB on the wafer W draws a spiral. FIG. 20 differs from FIG. 18 in that the interval between the spirals becomes shorter toward the inside. In this way, a hollow cylindrical ion implantation distribution can be formed as shown in FIG. The specific amount of movement in the Y-axis direction in this case is as follows. The rotation angle is the same as in equation (5), and the case where the linear ion beam IB moves from the inside to the outside of the wafer W will be described.

  Next, as shown in FIG. 10, while the line-shaped ion beam IB is formed so as to pass through the rotation center of the wafer W, the wafer W is simultaneously rotated at a constant speed, and the rotation angle of the wafer W is predetermined. An ion implantation method for changing the scanning speed of the ion beam IB in the X-axis direction when the angle is reached will be described.

  As shown in FIG. 22, every time the wafer W rotates 90 degrees, the scanning speed of the ion beam IB in the X-axis direction is switched from high speed to low speed and from low speed to high speed. Then, as shown in FIG. 23, it is possible to obtain an ion implantation distribution having four regions that are point-symmetric with respect to the rotation center and line-symmetric. Further, if the angle at which the rotation speed or scanning speed is switched is reduced, more regions can be formed.

  In the above-described embodiment, ion implantation is performed with the same ion implantation intensity over the entire area of a certain angle region, and a plurality of regions having different ion implantation amounts are formed in the circumferential direction of the wafer W. The ion beam intensity may be changed based on the radial position of the wafer W by giving a distribution to the scanning speed in the radial direction of the IB. In this case, not only can a certain amount of ions be implanted within a certain angle region, but also the ion implantation distribution can be changed in the radial direction as described above. In other words, by changing the ion implantation amount according to the angle, the ion implantation distribution in the circumferential direction of the wafer W is changed, and the ion implantation distribution is also changed in the radial direction by changing the ion beam implantation intensity. An accurate injection distribution can be obtained.

  More specifically, as shown in FIG. 24, for example, in a certain angle region where the wafer W is rotated from θ1 to θ2, the ion beam implantation intensity is reduced to a low intensity in the inner circle region up to the radius r1. The ring region from r1 to r2 may be set to a high intensity, and the ring region having a radius from r2 to radius R0 may be set to have the same ion implantation distribution as the inner circle region. In the region where the wafer W is rotated by θ2 or more, the ion implantation distribution in the radial direction of the wafer W can be obtained by reducing or increasing the overall ion implantation intensity at a certain magnification as shown in FIG. In addition to being divided into four types, the ion implantation distribution in the circumferential direction of the wafer W can also be changed to make the ion implantation distribution point-symmetric with respect to the center of the wafer W. Further, in addition to the ion implantation distribution that is point-symmetric with respect to the center, the angle at which the ion implantation intensity in the circumferential direction is switched is changed variously, or the values of the radii r1 and r2 are changed for each angular region. The ion implantation intensity may be changed so that the number of regions with different ion implantation intensity in the radial direction is changed.

  As described above, according to the ion implantation apparatus 100 and the ion implantation method of the present embodiment, while the wafer W is rotated by the rotation mechanism 2, the ion beam IB is simultaneously scanned in the X-axis direction by the scanner 1, thereby Since the beam IB is formed or the wafer W is moved in the Y-axis direction by the translation mechanism 3, the ion implantation distribution formed on the wafer W can be made continuous and smooth.

  In addition, by adjusting the magnitude of the speed at which the ion beam IB is scanned in the X-axis direction, the switching timing, or changing the moving speed of the wafer W in the Y-axis direction, non-uniform symmetry about various rotation centers. An accurate ion implantation distribution can be obtained.

  In addition, since various non-uniform ion implantation distributions can be obtained only by the relative movement of the ion beam IB and the wafer W, there is no need to newly provide a member for shielding the ion beam IB. Can be prevented.

  The present invention is not limited to the above embodiment.

  For example, in the above-described embodiment, the wafer W is moved to move the linear ion beam in the Y-axis direction, but the ion beam may be scanned in the Y-axis direction by a scanner.

  The ion beam is not limited to a spot-like one, and the ion source itself emits a band-like ion beam. The ion beam may be relatively moved in the radial direction while rotating the wafer W. At this time, the intensity of the ion beam may be changed according to the position of irradiation on the wafer.

  Instead of a line-shaped ion beam, a band-shaped ion beam having a certain width in the short side direction may be used.

  When scanning the wafer W or the ion beam so that the locus of the ion beam on the wafer W is spiral, the ion beam may be in a spot shape.

  The adjustment of the ion implantation intensity is not limited only to the scanning speed of the ion beam. For example, the ion beam intensity may be controlled, or the spot diameter may be changed.

  The rotation of the wafer and at least one of the scanning of the ion beam or the translation of the wafer are synchronized, for example, so that the ion beam scans once on the wafer while the wafer rotates once, or the wafer For example, the ion beam scans on the wafer twice while the lens rotates once.

  The ion beam implantation intensity may be changed by factors other than the scanning speed while synchronizing any one of the scanning speed of the ion beam, the translational movement speed of the wafer, and the rotational movement speed. With such a configuration, not only the ion implantation distribution targeted for the point but also the ion implantation distribution can be changed in the circumferential direction, and ion implantation with various shapes can be performed.

  Even when a band-shaped or line-shaped ion beam is formed by scanning, the ion beam implantation intensity may be controlled by using the adjustment of the extraction voltage.

  A detector such as a Faraday cup for detecting the ion beam implantation amount may be provided, and the implantation distribution may be controlled based on the detected ion implantation amount. If a sequential injection amount is detected by the detector and feedback control is performed, a more accurate injection distribution can be formed.

  As a method of changing the ion beam implantation intensity, an opening member is provided on the beam line, the opening amount of which is controlled based on the position where the ion beam is irradiated onto the wafer, which changes the voltage of the extraction electrode of the ion source. Various methods are conceivable, such as adjusting the ion implantation amount by adjusting the spot diameter of the irradiated ion beam and the width of the belt-like beam, and controlling the intensity of the ion beam itself.

  The direction in which the ion beam and the substrate relatively move may be either from the bottom to the top or from the top to the bottom as viewed in the drawing. Similar ion implantation distribution can be obtained.

  The length in the longitudinal direction of the band-shaped or line-shaped ion beam irradiated on the wafer does not need to be greater than the diameter of the wafer. What is necessary is just to apply to a part on the wafer. That is, an ion beam having a length less than the radius may be used.

  In addition, various modifications are possible without departing from the spirit of the present invention, and the ion implantation methods may be appropriately combined.

1 is a schematic top view of an ion implantation apparatus according to an embodiment of the present invention. The enlarged side view of the wafer periphery of the ion implantation apparatus which concerns on the same embodiment. The schematic diagram explaining one Embodiment which concerns on the ion implantation method of this invention. The typical graph which shows an example of the ion implantation intensity | strength of an ion beam. The schematic diagram which shows the ion implantation distribution on the wafer at the time of using the ion implantation intensity | strength of FIG. The typical graph which shows another example of the ion implantation intensity | strength of an ion beam. The schematic diagram which shows the ion implantation distribution on the wafer at the time of using the ion implantation intensity | strength of FIG. The typical graph which shows another example of the ion implantation intensity | strength of an ion beam. The schematic diagram which shows the ion implantation distribution on the wafer at the time of using the ion implantation intensity | strength of FIG. The schematic diagram explaining another embodiment which concerns on the ion implantation method of this invention. The typical graph which shows the example from which the ion implantation intensity | strength of an ion beam differs. The schematic diagram which shows the ion implantation distribution on the wafer at the time of using the ion implantation intensity | strength of FIG. The typical graph which shows the example from which the ion implantation intensity | strength of an ion beam differs further. The schematic diagram which shows the ion implantation distribution on the wafer at the time of using the ion implantation intensity | strength of FIG. The typical graph which shows another different example of the ion implantation intensity | strength of an ion beam. The schematic diagram which shows the ion implantation distribution on the wafer at the time of using the ion implantation intensity | strength of FIG. The schematic diagram explaining further another embodiment which concerns on the ion implantation method of this invention. The schematic diagram which shows an example of the locus | trajectory on the wafer of an ion beam. FIG. 19 is a schematic diagram showing an ion implantation distribution on a wafer when an ion beam draws the locus of FIG. 18. The schematic diagram which shows another example of the locus | trajectory on the wafer of an ion beam. The schematic diagram which shows the ion implantation distribution on a wafer when an ion beam draws the locus | trajectory of FIG. The graph which shows an example in the case of changing ion intensity according to the rotation angle of a wafer. The schematic diagram which shows the ion implantation distribution at the time of using the ion intensity | strength of FIG. The schematic diagram which shows an example at the time of changing ion beam intensity according to the position of an ion beam with the rotation angle of a wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Ion implantation apparatus 1 ... Scanner 2 ... Rotation mechanism 3 ... Translation mechanism C ... Control mechanism

Claims (12)

  An ion implantation method characterized in that at least one of scanning of an ion beam by an electric field or a magnetic field or translational movement of the substrate is simultaneously performed while rotating the substrate around a rotation axis intersecting a surface irradiated with the ion beam. .   2. The ion implantation method according to claim 1, wherein a band-like ion beam is formed by reciprocal scanning of the ion beam at a position spaced apart from the rotation center of the substrate by a predetermined distance.   The ion implantation method according to claim 1, wherein a band-like ion beam is formed by reciprocating the ion beam so as to pass through the center of rotation of the substrate.   4. The ion implantation method according to claim 2, wherein the magnitude of the reciprocating scanning speed is kept constant.   4. The ion implantation method according to claim 2, wherein a magnitude of the reciprocating scanning speed is changed.   The ion implantation method according to claim 2, 3, 4, or 5, wherein the distance between the belt-like ion beam and the center of rotation is changed by moving the substrate in translation.   The ion implantation method according to claim 1, 2, 3, 4, 5 or 6, wherein the magnitude of the reciprocal scanning speed of the ion beam is changed when the rotation angle of the substrate reaches a predetermined angle.   The ion implantation method according to claim 1, wherein the ion beam is a spot-like beam, and the distance between the ion beam and the rotation center is changed by relatively moving the substrate and the ion beam.   9. The ion implantation method according to claim 8, wherein the substrate and the ion beam are moved relative to each other only by translation while the substrate is rotated, and the beam intensity of the ion beam is changed according to the position on the substrate.   The ion implantation method according to claim 1, wherein the ion beam is a belt-like beam, and the distance between the ion beam and the rotation center is changed by relatively moving the substrate and the ion beam.   The ion implantation method according to claim 10, wherein the substrate and the ion beam are moved relative to each other only by translation while the substrate is rotated, and the beam intensity of the ion beam is changed according to the position on the substrate. A rotation mechanism that rotates the substrate about a rotation axis that intersects the surface irradiated with the ion beam;
Comprising at least one of an ion beam scanning mechanism that scans the ion beam with an electric field or a magnetic field, or a translation mechanism that translates the substrate;
An ion implantation apparatus comprising: a control mechanism that simultaneously performs rotation of the substrate and at least one of scanning of the ion beam and translational movement of the substrate.