JP5863153B2 - Ion implanter - Google Patents

Description

  The present invention relates to an ion implantation apparatus having a function of improving the uniformity of a beam current distribution in the long side direction of a ribbon-like ion beam.

  Conventionally, an ion implantation apparatus that uses a ribbon-like ion beam having a longer side longer than the substrate size to move the substrate in a direction transverse to the ion beam and performs ion implantation processing on the entire surface of the substrate has been used. Yes.

  Patent Document 1 describes this type of ion implantation apparatus. This ion implantation apparatus has a function of adjusting the uniformity of the beam current distribution in the long side direction of the ion beam so that the amount of ions implanted in the plane of the substrate is uniform.

  This function will be briefly described. First, in order to grasp the distribution of the beam current in the long side direction of the ion beam, this distribution is measured using a plurality of beam current measuring devices.

  Next, the current value control that calculates the average value of the beam current measured by all beam current measuring instruments and increases or decreases the amount of current that flows through multiple filaments so that the calculated average value approaches the set value. Perform the routine.

  Thereafter, the plurality of beam current measuring devices are grouped so as to correspond to the number of filaments, and the average value of the beam currents measured in each group is calculated.

  As a result of the calculation, one group having the largest difference between the average value of the calculated beam current and the set value is specified. A uniformity control routine for increasing / decreasing the amount of current flowing through the filaments corresponding to this group is executed so that the average value of the beam currents of the specified group approaches the set value.

  Eventually, the current value control routine and the uniformity control routine described above are executed at least once until the average value of the entire beam current falls within a stop range within a range of several percent from the set value. .

JP 2001-84950 A

  FIG. 15A shows the distribution of the beam current in the long side direction of the ribbon-like ion beam. Due to damage of members arranged in the beam transport path of the ion implantation apparatus, minute singular points T1 and T2 having different beam currents from other parts may be generated in the beam current distribution.

  When an ion beam having such a beam current distribution is measured using the beam current measuring device described in Patent Document 1, the following problems arise.

  As shown in FIG. 15B, the beam current measuring instrument 13 has a measuring part 51 (concave part) and a non-measuring part 52 (convex part). It is assumed that the ion beam having the beam current distribution shown in FIG. 15A is applied to the beam current measuring device 13 along the vertical direction of the paper. In that case, the singular points T1 and T2 are irradiated to the areas P1 and P2 of the beam current measuring device 13, respectively. Here, since the areas P1 and P2 correspond to the non-measurement unit 52 of the beam current measuring device 13, the beam currents at the singular points T1 and T2 cannot be measured. In other words, the existence of a singular point cannot be recognized from this measurement data.

  When the beam current cannot be measured at the singular points T1 and T2, when the substrate 8 moves at a constant speed along the vertical direction of the drawing with respect to the ion beam having the beam current distribution shown in FIG. As described in FIG. 15C, approximately three types of implantation regions A1 to A3 are formed in the substrate 8 according to the implantation amount.

  FIG. 15D shows an outline of the injection amount distribution corresponding to each injection region shown in FIG. In each implantation region, the implantation amount increases in the order of A3, A1, and A2. In recent years, since the structure of a semiconductor device has been miniaturized, the influence of a singular point appears greatly, and even if the difference in the injection amount between the singular point and other points is about 1%, the substrate 8 is considered to be defective. There is a case.

  Even if it becomes possible to measure the beam current at such singular points T1 and T2 by using some method, the singular point T1 and the beam having a small beam current as shown in FIG. When the singular point T2 having a large current appears close to the beam current distribution, the homogenization adjustment method described in Patent Document 1 has the following problems.

  In Patent Document 1, the beam current distribution is divided into groups, and the average value of the beam current in each group is calculated. When the relationship between the beam currents at the two singular points cancels each other and is within the same group, the average value within this group falls within the stop range without any problem. As a result, the substrate 8 is irradiated with the ion beam including the singular points T1 and T2 with insufficient uniformity control, which may cause an implantation failure of the substrate 8.

  Therefore, the main object of the present invention is to improve the uniformity of the beam current distribution having a singular point different from the others with the beam current value protruding.

One ion implantation equipment of the present invention, by using a ribbon ion beam generated by the ion source, by moving the substrate in a direction transverse to the ion beam, the ion implantation process on the entire surface of the substrate In a mass spectrometry type ion implantation apparatus having an analysis electromagnet and an analysis slit to be performed, a beam current measuring device for measuring a beam current distribution in a long side direction of the ion beam downstream of the analysis slit, the analysis electromagnet, and the analysis slit At least one deflection member is provided in the beam transport path between the substrate and the ion beam periodically scans the ion beam along its long side during the ion implantation process to the substrate .

With the above configuration, even if there is a singular point different from the others due to the beam current value protruding in the beam current distribution, the protruding amount of the beam current at this singular point can be reduced. Thereby, the uniformity of the beam current distribution used for the ion implantation process can be improved.

More specifically, it is desirable to have a processing chamber in which the substrate is disposed, and the deflection member is disposed in a beam transport path between the analysis electromagnet and the processing chamber.

  The deflecting member is preferably a member that deflects the ion beam by a magnetic field.

  When a member that deflects an ion beam with an electric field is used, electrons contained in the ion beam are attracted to the deflecting member. By attracting electrons by such a deflecting member, the influence of the space charge effect appears strongly on the ion beam, and the ion beam diverges greatly. In order to prevent such an adverse effect on the ion beam, it is desirable to use a member that performs magnetic deflection as the deflection member.

  Further, the deflecting member is composed of a first deflecting member that deflects the ion beam by an electric field and a second deflecting member that deflects the ion beam deflected by the first deflecting member by a magnetic field. During the ion implantation process to the substrate, the intensity of the electric field generated by the first deflection member is variable, and the direction and magnitude of the magnetic field generated by the second deflection member are substantially constant. It may be configured.

  When such a configuration is used, the output of the drive source for driving the second deflecting member can be kept substantially constant, so that the output control of the drive source corresponding to the second deflecting member is simplified. Thereby, the control during the ion implantation process to the substrate can be simplified.

  On the other hand, the deflection member is composed of a first deflection member and a second deflection member, and the deflection amount of the ion beam at each deflection member is substantially equal and the deflection directions are opposite to each other. But you can.

  By adopting such a configuration, the traveling direction of the ion beam deflected by the first deflecting member can be returned to the original by the second deflecting member. Therefore, it is possible to easily adjust the ion beam implantation angle to the substrate.

  Further, the deflection member is composed of a first deflection member and a second deflection member, and the first deflection member is disposed between the analysis electromagnet and the analysis slit, The second deflecting member may be arranged on the downstream side of the analysis slit.

  With such a configuration, the size of the ion beam to be deflected can be made equal. As a result, the capacity of the drive source for driving each deflecting member can be made substantially the same, which is advantageous in that the drive source for driving each deflecting member can be used.

  In addition, it is desirable to have a shaping mask for shaping an end portion in the long side direction of the ion beam that is not irradiated to the substrate among the ion beams that have passed through the deflecting member during the ion implantation process to the substrate. .

  When a member other than the substrate is irradiated with an ion beam, the member is sputtered by the ion beam, and dust (particles) is generated from the member, which may enter the substrate and cause poor implantation of the substrate. . By using the shaping mask as described above, the amount of the ion beam irradiated to a place other than the substrate can be reduced, so that the possibility of the substrate becoming defective in implantation can be reduced.

  Even if the beam current value protrudes in the beam current distribution and there is a singular point different from the others, the protruding amount of the beam current at this singular point can be reduced. Thereby, the uniformity of the beam current distribution in the long side direction of the ion beam can be improved.

It is a figure which shows an example of the ion implantation apparatus in this invention. (A) represents the state on the XZ plane, and (B) represents the state on the YZ plane. It is the figure which expanded the mode of the ion beam after passing the deflection | deviation member as described in FIG.1 (B). It is a figure showing an example of the deflection | deviation member described in FIG. (A) represents the state on the YZ plane, and (B) represents the state on the XZ plane. It is a figure showing another example of the deflection | deviation member described in FIG. (A) represents the state on the YZ plane, and (B) represents the state on the XZ plane. It is a figure showing the modification of the deflection | deviation member of FIG. It is a figure which shows another example of the ion implantation apparatus in this invention. (A) represents the state on the XZ plane, and (B) represents the state on the YZ plane. It is a figure showing the relationship between a ribbon-shaped ion beam and the beam current distribution in the long side direction. It is a figure showing the relationship between the beam current distribution of the ion beam scanned in the long side direction, and the implantation amount distribution formed on a board | substrate. (A) is a beam current distribution of the ion beam at each position when scanned in the long side direction. (B) is an implantation region formed on the substrate. (C) is an injection amount distribution in the substrate plane. It is a figure which shows another example of the ion implantation apparatus in this invention. (A) represents the state on the XZ plane, and (B) represents the state on the YZ plane. It is a figure showing an example of the deflection | deviation member of FIG. (A) represents the state on the YZ plane, and (B) represents the state on the XZ plane. It is the figure which expanded the mode of the ion beam irradiated to the board | substrate as described in FIG. It is a figure which shows the other example of the ion implantation apparatus in this invention. It is a figure which shows an example of the shaping mask which shapes the edge part of the long side direction of an ion beam. (A) Shows the state on the YZ plane. (B) represents a state on the XY plane. It is a figure showing an example of an analysis slit. (A) is an example of an analysis slit. (B) is an example of the analysis slit provided with the function of the shaping mask of FIG. It is a figure showing the problem in a prior art. (A) is the distribution of the beam current in the long side direction of the ion beam. (B) is a beam current measuring device. (C) represents an implantation region formed on the substrate. (D) is an injection amount distribution in the substrate surface.

  FIG. 1 shows an example of an ion implantation apparatus IM according to the present invention. FIG. 1A shows a state on the XZ plane, and FIG. 1B shows a state on the YZ plane. The X-, Y-, and Z-axis directions (X direction, Y direction, and Z direction) described in this figure and other figures described later are respectively the short side direction and long side direction of the ion beam 3 irradiated on the substrate 8. The direction of travel. The ion beam handled in the present invention is a positively charged ion beam unless otherwise specified.

  An example of an ion implantation apparatus IM used in the present invention will be described with reference to FIGS. 1 (A) and 1 (B). On the downstream side of the ion source 1 (on the traveling direction side of the ion beam 3), an extraction electrode system 2 is arranged, and thereby the ribbon-shaped ion beam 3 is extracted from the ion source 1.

  The extracted ion beam 3 passes through the analysis electromagnet 4 and the analysis slit 5. Thereby, unnecessary ions contained in the ion beam 3 are removed. In addition, the structure which does not provide such an analysis electromagnet 4 and the analysis slit 5 may be sufficient.

  A deflection member 6 is provided on the downstream side of the analysis slit 5. While the ion implantation process to the substrate 8 is performed by the deflecting member 6, the ion beam 3 is continuously deflected along the long side direction (Y direction in the drawing). In other words, this deflection is performed as a periodic scan having a specific width. This is illustrated in FIG. The broken line in the figure indicates the trajectory of the ion beam 3 when the deflection in the Y direction is maximized, and the solid line indicates the trajectory of the ion beam 3 when the deflection is not performed (the deflection amount is zero). . Also, the alternate long and short dash line in the figure shows the trajectory of the ion beam 3 when the deflection in the direction opposite to the Y direction is maximized.

  The above-mentioned three trajectories are representative ion beam 3 trajectories when periodic scanning is performed. Actually, the trajectory of the ion beam 3 indicated by a broken line and the ion beam indicated by a one-dot chain line. Between the three orbits, the orbit of the ion beam 3 changes every moment.

  The ion beam 3 that has passed through the deflection member 6 proceeds to the processing chamber 7. A substrate 8 (for example, a semiconductor substrate such as silicon or gallium arsenide) is disposed in the processing chamber 7. The back surface of the substrate 8 is supported by a support member 9, and the support member 9 is configured to move along the direction in which the linear drive mechanism 10 is extended by the linear drive mechanism 10. The linear drive mechanism 10 is connected to the rotation mechanism 12 via a connecting member 11.

  The rotation mechanism 12 has a function of rotating the linear drive mechanism 10 around the Y axis, and thereby the tilt angle of the substrate 8 is adjusted. After the tilt angle is adjusted, the linear drive mechanism 10 moves the substrate 8 supported by the support member 9 along the extending direction (X direction in FIG. 1A).

  As shown in FIG. 1B, the dimension of the ion beam 3 in the Y direction is larger than the dimension of the substrate 8 in the same direction. Therefore, the entire surface of the substrate 8 is irradiated with the ion beam 3 by moving the substrate 8 in the X direction so as to cross the ion beam 3 by the linear drive mechanism 10. In the examples shown in FIGS. 1A and 1B, since the tilt angle is zero degrees, the substrate 8 moves along the X direction, but the tilt angle is zero degrees. If not, the substrate 8 moves along a direction inclined by a tilt angle with respect to the X direction. In addition, the number of times the substrate 8 crosses the ion beam 3 may be one or more.

  A beam current measuring instrument 13 is provided in the processing chamber 7. For example, the beam current measuring device 13 is configured by a multi-point Faraday cup composed of a plurality of Faraday cups as disclosed in Patent Document 1. While the ion implantation process to the substrate 8 is not performed, the substrate 8 is retracted to a position where the ion beam 3 is not irradiated by the linear drive mechanism 10. For example, the retracted position is an end portion on the X direction side of the linear drive mechanism 10 illustrated in FIG. By moving the substrate 8 to such a retracted position, the ion beam 3 can be measured by the beam current measuring device 13 while the ion implantation into the substrate 8 is not performed.

  FIG. 2 shows a state in which the ion beam 3 after passing through the deflection member 6 shown in FIG. 1 (B) is partially enlarged. Here, with respect to the trajectories of the three ion beams 3 representing the state when scanned by the deflecting member 6 (the trajectories of the ion beams depicted by the solid line, the broken line, and the alternate long and short dash line), the direction of the long side thereof The center trajectories at are shown as C1-C3, respectively.

  When the angle formed by the center track C1 and the center track C2 is θ1, and the angle formed by the center track C1 and the center track C3 is θ2, θ1 and θ2 may be the same or different. In other words, the scanning width when scanning the ion beam 3 along the Y direction (maximum deflection width of the ion beam 3) is the same as when scanning the ion beam 3 in the Y direction side and the ion beam 3 on the opposite side in the Y direction. At the time of scanning, it may be the same or different.

  The values of θ1 and θ2 may be determined in consideration of the device structure. This is because the degree of implantation angle allowed is determined by the device structure formed on the substrate 8. For example, if the implantation angle (the angle between the normal line and the traveling direction of the ion beam applied to the substrate with respect to the normal line to the substrate surface) is large, the device structure has a deep trench structure. Then, ion implantation cannot be performed on the side surface near the bottom of the trench structure. Therefore, in consideration of the allowable angle determined by such a device structure, the maximum deflection width of the ion beam 3 so as to be θ1 and θ2 (a practical value is about several degrees) smaller than the allowable angle. Can be determined.

  If the ion beam 3 is periodically scanned along the long side direction by the deflecting member 6 while the ion implantation process to the substrate 8 is performed, the ion beam 3 can be expressed by another expression. It can be said that the position (center position) of the central trajectory of the ion beam 3 irradiated to the substrate 8 changes in the long side direction.

  3 to 5 show specific examples of the deflecting member 6 shown in FIG. Specific examples of these will be described below.

  FIGS. 3A and 3B show a deflection member 6 having a pair of deflection electrodes each composed of a first electrode 21 and a second electrode 22. 3A shows a state when the deflecting member 6 is viewed from the YZ plane, and FIG. 3B shows a state when the deflecting member 6 is viewed from the XZ plane.

  One end of the AC power supply 23 is connected to the first electrode 21, and the other end is connected to the second electrode 22. By periodically changing the voltage applied to each electrode by the AC power source 23, the illustrated electric fields E1 and E2 appear alternately between the electrodes every predetermined time. Note that the electric field strengths of the electric field E1 and the electric field E2 are not always constant, and increase and decrease with time. Periodic scanning of the ion beam 3 is performed by such an electric field.

  In this example, the AC power supply 23 is used to periodically change the voltage applied to each electrode, but a DC power supply may be used instead of the AC power supply 23. In the case of using a DC power supply, it is conceivable to use a bipolar power supply that can continuously change the output value according to time and change the polarity. The use of such a DC power supply in place of the AC power supply 23 is the same in other embodiments described later.

  Although the example in which the ion beam 3 is scanned by the action of an electric field has been described in FIG. 3, the ion beam 3 may be scanned by the action of a magnetic field. An example of this is shown in FIG. FIGS. 4A and 4B show a deflection member 6 having a pair of deflection coils each composed of a first coil 24 and a second coil 25. 4A shows a state when the deflecting member 6 is viewed from the YZ plane, and FIG. 4B illustrates a state when the deflecting member 6 is viewed from the XZ plane.

  Each coil described in this example is an air-core coil, and is supported and fixed to the beam transport path by a support member (not shown). One end of an AC power source 23 as a drive source is connected to the first coil 24, and the other end is connected to the second coil 25. Moreover, the crossover part 30 is provided between each coil, and, thereby, each coil is electrically connected.

  By changing the amount of current supplied to each coil by the AC power source 23, the illustrated magnetic field B1 and magnetic field B2 appear alternately between the coils. As in the case of the electric field, the magnetic flux densities of the magnetic field B1 and the magnetic field B2 are not always constant and increase / decrease with time. Periodic scanning of the ion beam 3 is performed by such a magnetic field.

  FIG. 5 shows another example in which the ion beam 3 is scanned by the action of a magnetic field. In this example, a first coil 24 and a second coil 25 are wound around a pair of magnetic poles 27 formed on an H-shaped yoke 26. The supply of current to each coil may be performed using the AC power source 23 described in the example of FIG. Instead of the example of FIG. 4, such a deflecting member 6 may be used to periodically scan the ion beam 3.

  Although there are various configurations as the deflecting member 6, from the viewpoint of reducing the spread of the ion beam 3 due to the space charge effect, it has been described with reference to FIGS. 4 and 5 by scanning the ion beam 3 with the electric field described with reference to FIG. A configuration in which the ion beam 3 is scanned by a magnetic field is desirable.

  When an electric field is used, electrons contained in the ion beam 3 are attracted to an electrode having a positive potential, so that the amount of electrons in the ion beam 3 is reduced. As a result, the influence of the space charge effect appears strongly, and the ion beam 3 is greatly diverged. Considering such an adverse effect on the ion beam 3, it can be said that the configuration in which the deflecting member 6 scans the ion beam 3 with a magnetic field is preferable to the configuration using an electric field.

  Further, in the configuration of FIG. 5, a yoke 26 surrounding the periphery of the ion beam 3 is required. Although depending on the size of the ion beam, the weight of the yoke of an electromagnet used in a general ion implantation apparatus ranges from several hundred kilograms to several tons. It can be said that the configuration using the air-core coil of FIG. 4 is more desirable than the configuration including the yoke.

  In the embodiment described with reference to FIGS. 1 to 5, the ion beam 3 is scanned along both sides along the long side direction based on the ion beam 3 when not scanned. . Apart from this, it may be configured to scan only one side of the ion beam 3 when not scanned. An example of this is shown in FIG.

  FIG. 6A shows the state of the ion implantation apparatus IM having such a configuration on the XZ plane. FIG. 6B shows a state of the same ion implanter IM on the YZ plane. The configuration of the ion implantation apparatus IM illustrated in FIG. 6 is the same as the configuration described in FIG. 1 except for the configuration of the deflecting member 6, and thus detailed description of each part is omitted.

  In the example of FIG. 6, the ion beam 3 is scanned only in the Y direction by the deflecting member 6. The trajectory of the ion beam 3 drawn by a broken line in FIG. 6B is the trajectory of the ion beam 3 when the deflection in the Y direction is maximized. The trajectory of the ion beam 3 drawn by a solid line is the trajectory of the ion beam 3 when the swing width (deflection amount) is zero.

  Further, θ3 shown in the figure forms, in the long side direction of the ion beam 3, a central trajectory of the ion beam 3 when the amplitude is zero and a central trajectory of the ion beam 3 when the amplitude is maximum. Is an angle. The angle of θ3 may be determined in consideration of the device structure as described in the case of θ1 and θ2.

  The deflecting member 6 may be configured such that the configuration described with reference to FIGS. 3 to 5 is slightly changed so that the ion beam 3 is periodically scanned in the Y direction. For example, in the example of FIG. 3, the first electrode 21 is fixed to the ground potential, and the voltage applied to the second electrode 22 is continuously changed in the range of 0 V to −several V over time. Just keep it. As a result, only the electric field E2 is generated between the electrodes, whereby the ion beam 3 can be scanned in the Y direction. Similarly, in the example of FIGS. 4 and 5, a configuration of a driving source that generates only the magnetic field B <b> 2 between the first coil 24 and the second coil 25 may be used.

  Even in the example of FIG. 6 described above, the center position of the ion beam 3 in the long side direction can be moved on the substrate 8 during the ion implantation process to the substrate 8.

  Although the configuration of the deflecting member 6 used in the present invention has been described, the operation and effect when such a deflecting member 6 is used will be described with reference to FIGS. 7 and 8.

  The beam current distribution in the long side direction of the ribbon-like ion beam 3 is shown in FIG. In general, the beam current sharply decreases at the end in the long side direction of the ion beam. For this reason, in order to make the implantation amount distribution in the plane of the substrate 8 uniform, the ion implantation process to the substrate 8 is performed using the central portion of the long side direction of the ion beam. This central portion is a portion W1 shown in the figure, and is a portion excluding about a dozen or so percent from the end of the beam, depending on the characteristics of the ion beam and how much margin is left from the end of the ion beam. In the present invention, this W1 is called a first injection effective width.

  8A to 8C show the relationship between the beam current distribution of the ion beam 3 scanned in the long side direction and the implantation amount distribution formed on the substrate. The three beam current distributions shown in FIG. 8 (A) are the examples of FIGS. 1 to 5, and the ion beam when the ion beam 3 is swung to the opposite side in the Y direction and the Y direction (maximum broken line and dashed line). This corresponds to the beam current distribution of the ion beam (drawn ion beam) and the beam current distribution of the ion beam (ion beam drawn by a solid line) when the ion beam 3 is not shaken.

  In FIG. 8A, the respective beam current distributions are shown separated in the vertical direction on the paper surface. This is intentionally shifted in order to make it easy to see the state of each beam current distribution. The left-right direction on the paper surface corresponds to the direction along the Y direction described in FIGS.

  Each beam current distribution has the first implantation effective width W1 described in FIG. Specifically, in the beam current distribution drawn by a broken line, the width between D1 and D2 corresponds to the first implantation effective width W1. Further, in the beam current distribution drawn by the solid line, the width between E1 and E2 corresponds to the first injection effective width W1. In the beam current distribution drawn by the one-dot chain line, the width between F1 and F2 corresponds to the first injection effective width W1. In addition, 2d shown is the scanning width of the ion beam 3.

  As described with reference to FIG. 7, it has been described that it is desirable to perform ion implantation processing on the substrate 8 using the first implantation effective width W1 in order to make the distribution of implantation amount into the substrate 8 uniform. However, when the ion beam 3 is scanned during the ion implantation process as in the present invention, the region corresponding to the second implantation effective width W2 that is narrower than the first implantation effective width W1 is used to the substrate 8. It is desirable to perform the ion implantation process. In this way, the injection uniformity within the surface of the substrate 8 can be made higher.

  However, since the required degree of implantation uniformity in the plane of the substrate 8 varies depending on the characteristics of the device, the region of the second implantation effective width W2 described here is not necessarily used, and ions to the substrate 8 are necessarily used. There is no need to perform the injection process. In some cases, the ion implantation process to the substrate 8 may be performed using a region that protrudes from the second effective implantation width W2 or the first effective implantation width W1.

  From the viewpoint of the utilization efficiency of the ion beam 3, if the scanning width of the ion beam 3 is too large, the region that is not irradiated on the substrate 8 increases, so it cannot be said that the implantation process is very efficient. Therefore, at least during the ion implantation process to the substrate 8, the ion beam 3 has a relationship such that the periodically scanned ion beam 3 includes the substrate 8 when viewed from the direction in which the substrate 8 is moved. It is conceivable to set a scanning width. In other words, the ion beam 3 is scanned such that the end of the ion beam 3 does not cover the surface of the substrate 8.

  Each beam current distribution shown in FIG. 8 has two singular points T1 and T2 having different beam currents compared to other portions as shown in FIG. 15 described as a conventional example. FIG. 8B shows the state of the implantation region formed in the substrate 8 when the ion beam 3 is periodically scanned during the ion implantation process.

  Compared with the conventional example shown in FIG. 15C, in FIG. 8B, the width of the injection region due to the singular point (the width shown in the left and right direction on the paper in the regions indicated by A2 and A3) is wider. Yes. This is because the influence of a singular point spreads in the scanning direction when the ion beam 3 is periodically scanned.

  On the other hand, as can be understood by comparing the implantation amount distribution in the plane of the substrate 8 with FIG. 15D of the conventional example and FIG. 8C of the present invention, the present invention is more in the plane of the substrate 8. It can be seen that the uniformity of the injection amount is high. This is because in the present invention, the ion beam 3 is periodically scanned, so that the protruding portion of the beam current at the singular point spreads in the scanning direction of the ion beam 3 and is averaged according to the scanning width. is there. Thereby, the uniformity of the beam current distribution of the ion beam 3 is improved, and the uniformity of the implantation distribution in the plane of the substrate 8 can be enhanced.

  In the embodiments described so far, the ion beam 3 applied to the substrate 8 is periodically scanned by the deflecting member 6, so that the direction of travel of the ion beam 3 varies with time. Due to the presence of such variations, it has been difficult to adjust the implantation angle to the substrate 8 to a predetermined angle.

  As a technique for solving such a problem, it is conceivable to use the ion implantation apparatus IM shown in FIG. FIG. 9A shows a state when the ion implantation apparatus IM is viewed from the XZ plane, and FIG. 9B illustrates a state when the ion implantation apparatus IM is viewed from the YZ plane.

  Since most of the configuration of the ion implantation apparatus IM illustrated in FIG. 9 is the same as the configuration illustrated in FIG. 1, a description will be given here of portions having different configurations.

  As shown in FIGS. 9A and 9B, the ion implantation apparatus IM includes a first deflection member 61 and a second deflection member 62. The ion beam 3 is bent back by such two deflecting members. Specifically, this is performed using the configuration shown in FIG.

  10A and 10B, at a certain time, the first deflection member 61, the third coil 28, and the fourth coil 29 having the first coil 24 and the second coil 25 are shown. The state of the ion beam 3 passing through the second deflecting member 62 provided with is depicted.

  Individual configurations of the first deflection member 61 and the second deflection member 62 are the same as those described with reference to FIG. In each deflecting member, a current flows through each coil so that magnetic fields having opposite directions and the same magnitude are generated. With such a configuration, when the ion beam 3 passes through each deflecting member, a Lorentz force having the same magnitude of force and the opposite direction acts on the ion beam 3. Thereby, the traveling direction of the ion beam 3 can be restored.

  In this example, the method of restoring the trajectory of the ion beam 3 at a specific time has been described. However, the correction of the traveling direction of the ion beam 3 is performed by controlling the amount of current flowing in each coil and the direction of the current. Then, it is performed in accordance with the trajectory of the ion beam 3 that changes with time by periodic scanning.

  FIG. 11 illustrates a state in which the positions of the central trajectories C1 to C3 in the long side direction of the ion beam 3 periodically scanned are changed by the first deflecting member 61 and the second deflecting member 62. . Since the directions of the central trajectories C1 to C3 are parallel to each other, the substrate 8 need only be inclined at a desired angle thereafter. Therefore, it is possible to easily adjust the injection angle to the substrate 8 to a predetermined angle.

  In the example of FIG. 9, the first deflecting member 61 and the second deflecting member 62 are configured to use a member that deflects the ion beam 3 by a magnetic field. However, both members are members that deflect the ion beam 3 by an electric field. It may be configured with. Alternatively, a member that deflects the ion beam 3 with an electric field may be used for one deflecting member, and a member that deflects the ion beam 3 with a magnetic field may be used for the other deflecting member.

  An example of a deflecting member that periodically scans the ion beam 3 by a combination of an electric field and a magnetic field is shown in FIG. In the ion implantation apparatus IM of FIG. 12, a ribbon-like ion beam 3 is extracted from the ion source 1 by the extraction electrode system 2, and unnecessary component ions are removed from the ion beam 3 by the analysis electromagnet 4 and the analysis slit 5.

  Thereafter, the ion beam 3 is scanned by the electric field along the long side direction by the first deflecting member 61 (for example, electrostatic scanner). The scanned ion beam 3 enters a second deflecting member 62 (for example, a collimator). Although the ion beam 3 is deflected by the magnetic field by the second deflecting member 62, the amount of deflection at this time is constant.

  The second deflection member 62 is an electromagnet provided with a pair of magnetic poles 40 facing in the X direction. By scanning the ion beam 3 with the first deflecting member 61, the trajectory of the ion beam 3 gradually changes over time from a solid line to a broken line. Therefore, after taking into account the outer shape of the ion beam 3 to be scanned (the trajectory of the ion beam 3 consisting of the solid line on the lower side of the paper and the broken line on the upper side of the paper), when this passes through the second deflection member 62 The shape of the magnetic pole 40 of the second deflection member 62 and the magnitude of the magnetic field are set in advance so as to be shaped into a parallel ion beam 3.

  By using such a configuration, the output of the second deflection member 62 can be fixed to a constant value. Thus, the scanning control of the ion beam 3 during the ion implantation process only needs to control the output of the first deflection member 61.

  The parallel ion beam 3 that has passed through the second deflecting member 62 is irradiated onto the substrate 8 disposed in the processing chamber 7. As in the previous embodiments, the substrate 8 is supported by a support member (not shown) and moved back and forth in the X direction so as to cross the ion beam 3. Thereby, the entire surface of the substrate 8 is irradiated with the ion beam 3.

  In the example of FIG. 12, a Faraday cup having a single measuring unit is described as the beam current measuring device 33. The beam current measuring device 33 is configured to move along the extending direction of the measuring device driving mechanism 14 by the measuring device driving mechanism 14. As a result, the beam current distribution in the long side direction of the ion beam 3 can be measured. Of course, during the measurement by the beam current measuring device 33, the substrate 8 is moved to a retracted position (not shown) provided on or below the paper surface. Instead of the beam current measuring device 13 of the multi-point Faraday cup described in the above embodiments, a beam current measuring device 33 configured by a Faraday cup having a single measuring unit described here may be used.

  The substrate 8 is not irradiated with all the ion beams 3 in the long side direction of the ion beam 3. For example, the end of the ion beam 3 is not irradiated on the substrate 8 but is irradiated on the wall surface in the processing chamber 7 and other members (the beam current measuring device 13, the support member 9, the linear drive mechanism 10, etc.). By irradiating the other member with the ion beam 3, the other member is sputtered to generate dust (particles).

  If this is mixed into the substrate 8, it will cause injection failure, and it is conceivable to reduce the generation of such extra particles. As a specific method, a shaping mask 31 shown in FIG. 13 is provided.

  FIG. 13 shows a configuration in which a shaping mask 31 is added to the ion implantation apparatus IM shown in FIG. 13A shows a state on the YZ plane, and FIG. 13B shows a state where the ion beam 3 is shaped by the shaping mask 31 on the XY plane.

  The shaping mask 31 is provided at a position that shields the end in the long side direction of the ion beam 3 that is not irradiated onto the substrate 8. Specifically, as shown in FIG. 13B, two shaping masks 31 are provided at positions where the upper and lower ends of the ion beam 3 are shielded. Since the shaping mask 31 can shield the end of the extra ion beam 3 that is not irradiated on the substrate 8, the generation of particles in the processing chamber 7 can be reduced. In addition, although the structure which provides two shaping masks 31 as an individual member is described here, this shaping mask 31 may be integrally formed.

  The function of the shaping mask 31 can be given to the analysis slit 5. An example of this is shown in FIG. FIG. 14A shows the analysis slit 5 used in the previous embodiments. FIG. 14B shows the analysis slit 5 having the function of the shaping mask 31. As can be understood with reference to FIG. 14B, for example, the shape of the analysis slit 5 is formed in a square shape when viewed from the Z direction. By doing so, it is possible to shape the end of the ion beam 3 in the long side direction using the upper and lower ends of the analysis slit 5 in the Y direction.

  When the analysis slit 5 is provided with the function of the shaping mask 31, the deflection member 6 is disposed upstream of the analysis slit 5. This is because when the ion beam 3 is scanned on the downstream side after passing through the analysis slit 5, the region of the ion beam 3 that is not irradiated on the substrate 8 becomes large.

  In the embodiments so far, the power source is used in common with the members constituting the deflecting member 6, but the power source corresponding to each member (individual electrodes and coils constituting a pair of electrodes and coils). May be prepared separately, and the outputs of these power supplies may be individually controlled. However, from the viewpoint of synchronizing the output of the power supply and cost, it is better to make the power supply as a drive source as common as possible.

  Moreover, although the example which scans the ion beam 3 periodically was described, the structure which scans aperiodically may be sufficient. That is, in the case of the present invention, the ion beam 3 is scanned from the Y direction to the opposite side in the Y direction, and this is repeated. However, the scanning speed is changed or the scanning width is changed for each scanning. Or may be changed. However, it is simple from the viewpoint of control to deflect the ion beam 3 periodically with a specific scanning width.

  Even if the scanning speed at the time of scanning is slower than the moving speed of the substrate 8 at the time of ion implantation, the effect of the present invention can be obtained, but in order to obtain a more remarkable effect, the scanning speed at the time of scanning is It is desirable to set it faster than the moving speed of the substrate.

  Further, when the first deflecting member 61 and the second deflecting member 62 are used, it is desirable to use the same power source capacity for each deflecting member. In this way, since it is not necessary to provide a power source corresponding to each deflecting member, the power source can be reused. In order to realize this, for example, it is conceivable to arrange two deflecting members so as to sandwich the analysis slit 5 as in the example of FIG. In this case, since the cross-sectional dimensions of the ion beams that pass through the deflecting members are substantially equal, if the power source can deflect this by the same amount, the power source capacity will naturally have the same capacity. .

  Further, the beam current measuring device 13 may be moved in the length direction so that the beam current at the singular points T1 and T2 can be measured.

  In this case, the scanning width of the ion beam 3 may be determined based on the measurement result. The wider the scan width, the more the beam current protrusion at the singular point can be averaged. Therefore, the scanning width of the ion beam 3 may be determined in consideration of the uniformity of the beam current distribution required in the implantation process and the measurement result.

  Furthermore, if the beam current distribution is not uniform even after averaging the beam currents protruding at the singular points based on the measurement results, an alarm is issued to stop the implantation process from the operator of the ion implantation system. You may make it provide the function to notify.

  Further, in the embodiments described so far, the number of the substrates 8 to be ion-implanted is one, but the present invention can also be used when processing two or more substrates.

  When ion implantation is performed on two or more substrates, and when a plurality of substrates are arranged along the X direction, the distance to which the substrates are moved is set so that the entire surface of each substrate is irradiated with an ion beam. Just change it.

  In addition, when a plurality of substrates are arranged along the Y direction, the dimension of the ion beam has a length that straddles the plurality of substrates in the long side direction of the ion beam. As described above, the ion beam may be periodically scanned during the ion implantation process to the substrate.

  Further, when a plurality of substrates are arranged in a matrix in the X direction and the Y direction, the plurality of substrates are regarded as one large substrate, and the ions described above are used for the large substrate using the embodiments described above. An injection process may be performed.

  In addition to the above, it goes without saying that various improvements and modifications may be made without departing from the scope of the present invention.

1. 2. ion source Ion beam4. 4. Analysis electromagnet Analysis slit6. Deflection member 8. Substrate 61. First deflecting member 62. Second deflection member W1. First injection effective width W2. Second effective injection width IM. Ion implanter

Claims (7)

Using a ribbon-like ion beam generated by an ion source and moving the substrate in a direction transverse to the ion beam, mass spectrometry having an analysis electromagnet that performs ion implantation processing on the entire surface of the substrate and an analysis slit Type ion implanter,
A beam current measuring device for measuring a beam current distribution in the long side direction of the ion beam downstream of the analysis slit;
At least one deflection member in a beam transport path between the analysis electromagnet and the substrate;
During the ion implantation process on the substrate, the deflection member periodically scans the ion beam along the long side direction. The ion implantation apparatus according to claim 1, further comprising a processing chamber in which the substrate is disposed, wherein the deflection member is disposed in a beam transport path between the analysis electromagnet and the processing chamber.   The ion implantation apparatus according to claim 1, wherein the deflection member is a member that deflects the ion beam by a magnetic field. The deflection member includes a first deflection member that deflects the ion beam by an electric field, and a second deflection member that deflects the ion beam deflected by the first deflection member by a magnetic field,
During the ion implantation process on the substrate, the electric field generated by the first deflection member is variable, and the magnitude of the magnetic field generated by the second deflection member is substantially constant. The ion implantation apparatus according to claim 1.   The deflection member includes a first deflection member and a second deflection member, and the deflection amount of the ion beam at each deflection member is substantially equal and the deflection directions are opposite to each other. The ion implantation apparatus according to claim 1.   The deflection member includes a first deflection member and a second deflection member, and the deflection amount of the ion beam at each deflection member is substantially equal and the deflection directions are opposite to each other. The ion implantation apparatus according to claim 1.   It has a shaping mask for shaping an end portion in the long side direction of the ion beam that is not irradiated to the substrate among the ion beams that have passed through the deflecting member during the ion implantation process to the substrate. The ion implantation apparatus according to any one of claims 1 to 6.

Images