Abstract:
To select a relative velocity profile to be used in scanning an actual work piece with an ion implant beam of an ion implantation tool, the implantation of a virtual work piece is simulated. A dose distribution is calculated across the virtual work piece based on an implant beam profile and a relative velocity profile. A new relative velocity profile is then determined based on the calculated dose distribution and the relative velocity profile used in calculating the dose distribution. A new dose distribution is then calculated using the new relative velocity profile. A new relative velocity profile is determined and a corresponding new dose distribution is calculated iteratively until the new dose distribution meets one or more predetermined criteria. The new relative velocity profile is stored as the selected relative velocity profile when the new dose distribution meets the one or more predetermined criteria.
Abstract:
An ion implanter and a method for implanting a wafer are provided, wherein the method includes the following steps. First, a wafer has at least a first portion requiring a first doping density and a second portion requiring a second doping density is provided. The first doping density is larger than the second doping density. Thereafter, the first portion is scanned by an ion beam with a first scanning parameter value, and the second portion is scanned by the ion beam with a second scanning parameter value. The first scanning parameter value can be a first scan velocity, and the second scanning parameter value can be a second scan velocity different than the first scan velocity. Alternatively, the first scanning parameter value can be a first beam current, and the second scanning parameter value can be a second beam current different than the first beam current.
Abstract:
Techniques for measuring ion beam current, especially for measuring low energy ion beam current, are disclosed. The technique may be realized as an ion beam current measurement apparatus having at least a planar Faraday cup and a voltage assembly. The planar Faraday cup is located close to an inner surface of a chamber wall, and intersects an ion beam path. The voltage assembly is located outside a chamber having the chamber wall. Therefore, by properly adjusting the electric voltage applied on the planar Faraday cup by the voltage assembly, some undesired charged particles may be adequately suppressed. Further, the planar Faraday cup may surround an opening of a non-planar Faraday cup which may be any conventional Faraday cup. Therefore, the whole ion beam may be received and measured well by the larger cross-section area of the planar Faraday cup on the ion beam path.
Abstract:
This invention discloses an ion implantation apparatus that has an ion source and an ion extraction device for extracting an ion beam therefrom. The ion implantation apparatus includes an ion beam sweeping-and-deflecting device disposed immediately next to the ion extraction device. The ion implantation apparatus further includes a magnetic analyzer for guiding the ion beam passed through the deflecting-and-sweeping device. The mass analyzer is also used for selecting ions with specific mass-to-charge ratio to pass through a mass slit to project onto a substrate. The sweeping-and-deflecting device is applied to deflect the ion beam to project through the magnetic mass analyzer and the mass slit for sweeping the ion beam over a surface of the substrate to carry out an ion implantation.
Abstract:
A variable aperture within an aperture device is used to shape the ion beam before the substrate is implanted by shaped ion beam, especially to finally shape the ion beam in a position right in front of the substrate. Hence, different portions of a substrate, or different substrates, can be implanted respectively by different shaped ion beams without going through using multiple fixed apertures or retuning the ion beam each time. In other words, different implantations may be achieved respectively by customized ion beams without high cost (use multiple fixed aperture devices) and complex operation (retuning the ion beam each time). Moreover, the beam tune process for acquiring a specific ion beam to be implanted may be accelerated, to be faster than using multiple fixed aperture(s) and/or retuning the ion beam each time, because the adjustment of the variable aperture may be achieved simply by mechanical operation.
Abstract:
Techniques for low temperature ion implantation are provided to improve the throughput. During a low temperature ion implantation, an implant process may be started before the substrate temperature is decreased to be about to a prescribed implant temperature by a cooling process, and a heating process may be started to increase the substrate temperature before the implant process is finished. Moreover, one or more temperature adjust process may be performed during one or more portion of the implant process, such that the substrate temperature may be controllably higher than the prescribe implant temperature during the implant process.
Abstract:
A system and a method for moving a wafer during scanning the wafer by an ion beam. The proposed system includes an extendable/retractable arm, a holding apparatus and a driving apparatus. At least a length of the extendable/retractable arm is adjustable. The holding apparatus is capable of holding a wafer and is fixed on a specific portion of the extendable/retractable arm. Furthermore, the driving apparatus is capable of extending and/or retracting the extendable/retractable arm, such that the holding apparatus is moved together with the specific portion. In addition, the proposed method includes the following steps. First, hold the wafer by a holding apparatus fixed on a specific portion of an extendable/retractable arm. After that, adjust a length of the extendable/retractable. Therefore, the holding apparatus, i.e. the wafer, can be moved by the extension/retraction of the extendable/retractable arm.
Abstract:
Techniques for low temperature ion implantation are provided to improve throughput. Specifically, the pressure of the backside gas may temporarily, continually or continuously increase before the starting of the implant process, such that the wafer may be quickly cooled down from room temperature to be essentially equal to the prescribed implant temperature. Further, after the vacuum venting process, the wafer may wait an extra time in the load lock chamber before the wafer is moved out the ion implanter, in order to allow the wafer temperature to reach a higher temperature quickly for minimizing water condensation on the wafer surface. Furthermore, to accurately monitor the wafer temperature during a period of changing wafer temperature, a non-contact type temperature measuring device may be used to monitor wafer temperature in a real time manner with minimized condensation.
Abstract:
An ion implantation method for achieving angular uniformity throughout a workpiece and application thereof are provided. The ion beam has at least one beamlet striking the workpiece surface with corresponding incident angles. The workpiece is mapped to an imaginary planar coordinate system. The incident angle of a center beamlet of the ion beam has a projection on the coordinate system forming a projection angle with an axis thereof. A workpiece orientation of the workpiece is adjusted based on the projection angle such that the contribution of each beamlet to the overall ion beam intensity upon striking the workpiece surface is rendered substantially the same from respective directions of each of the coordinate axes.
Abstract:
A method to rotate individual pad of a batch disk to an implant angle and lock them in place, with the pad surface having conical or near conical surface to minimize the implant angle variation across a wafer on the pad for both tilt angle and twist angle, at large tilt angle implant. The implanter includes a disk with multiple attached pads that can hold substrates securely when the hub is at rest or rotates. The disk rotates around its spin axis, which moves laterally at a programmed speed profile so that all substrates on the hub can get evenly touched by the fixed ion beam. The pad rotation axis is at an angle with the disk spin axis, and the angle is preferable 90 degrees. The nominal of the pad surface is at an angle, i.e., a tilt angle, relative to the incident ion beam. A rotation mechanism is applied to each individual pad to rotate the pad to the desired tilt angle. A locking mechanism is applied to each individual pad assembly to lock the pad at the desired tilt angle with minimum angle variation under high centrifugal force during fast disk spin. The locking mechanism includes: a) add brake to the rotation mechanism in the pad assembly so that the pad cannot rotate due to mechanical friction force or lock-key. B) use motor to hold the pad assembly. The sum of the friction torque and the motor holding torque should be larger than the centrifugal torque. A torque balancing mechanism is applied to pad mechanical design to minimize the total pad rotation torque under centrifugal force during fast disk spin by adding mass to counter balance the original wafer pad mass.