JP2571277Y2 - Beam profile interlock device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam profile interlock device for interlocking an ion implantation device based on a measurement value obtained from a beam profile monitor for measuring the shape and beam current density of an ion beam. In particular, the present invention relates to a beam profile interlock device provided in an ion implanter using an electron shower as needed.

[0002]

2. Description of the Related Art An ion implantation apparatus ionizes impurities to be diffused, selectively extracts these impurity ions by mass spectrometry using a magnetic field to form an ion beam, accelerates the ion by an electric field, and irradiates an ion irradiation target. This means that impurities are implanted into the ion irradiation target, and the impurities that determine the characteristics of the device in the semiconductor process can be implanted at an arbitrary amount and depth with good controllability. Device.

[0003] Generally, the above-described ion implantation apparatus includes:
The configuration and the current density distribution of the ion beam are measured. If the measurement result is not proper, an interlock is applied and the operation is not shifted to the implantation operation.

[0004] The start-up of the apparatus in this ion implantation apparatus is performed as follows. As shown in FIG. 3, a machine host computer (hereinafter, referred to as a machine host)
The recipe including the ion species, the beam current, and the energy is set in the machine controller 22 in accordance with the instruction from 21. Thereby, the machine controller 22 starts up the beam while controlling the ion implantation apparatus main body 23, and performs beam shaping so as to be optimal for the set recipe. The beam shape and beam current density distribution of this ion beam are measured by the beam profile monitor 24,
Information on the measurement result is transmitted to a beam profile interlock device (hereinafter, referred to as an interlock device) 25.

[0005] The memory 28 of the interlock device 25
Is the X of the ion beam, which is set in advance by the setting device 29.
The set values of the width in the direction (for example, the horizontal direction) and the Y direction (for example, the vertical direction) and the beam current density are stored, and the measurement result input via the I / O port 26 is calculated by the CPU 27. After that, it is compared with the set value in the memory 28 described above. Then, if each value of the measurement result is within the set value, the interlock device 25 sends the information to the machine controller 2 via the I / O port 26.
2 outputs a signal indicating "OK", while if it is out of the set value, outputs a signal indicating "NG".

[0006] The machine controller 22 includes:
When the signal of "OK" is received, the ion implantation is started, but when the signal of "NG" is received, the interlock is applied and the operation does not shift to the implantation operation.

[0007] If the current density of the ion beam is too high, an excessive charge is accumulated in an ion irradiation target, and charge-up easily occurs. Therefore, in order to reduce the charge-up, an ion beam having a large beam shape and a low density is desirable. Conventionally, the memory 28 of the interlock device 25 has a beam shape as large as possible and a low density ion beam. Setting value is registered.

In recent years, ion implanters have been used to neutralize the ion beam together with the ion beam in order to prevent charge-up due to positive charge generated on the irradiation surface of the ion irradiation object during the implantation of positive ions such as boron. An ion beam neutralizing device that irradiates a target for ion irradiation in the form of a shower with thermal electrons for use is mounted.

When an electron shower using this ion beam neutralizer is used, if the beam shape is too large, electrons do not reach the center of the ion beam. Also, it is necessary to slightly reduce the beam shape. Therefore, according to a command from the machine host 21,
When the condition "use electron shower" is set in the machine controller 22, the machine controller 2
2 controls the ion implantation apparatus main body 23 and shapes the ion beam so that the beam shape is slightly smaller than that in the normal mode in which the electron shower is not used.

[0010]

However, in the above-described conventional interlock device 25, the beam profile monitor 2 is used regardless of the use of the electron shower.
4 is compared with the set value in the normal mode in the memory 28, so that when the electron shower is used, the apparatus is started up normally, and the beam shape conforms to the recipe. However, there is a problem that the interlock may work.

The present invention has been made in view of the above, and an object of the present invention is to provide a beam profile interlock device in which an interlock does not operate unless there is an abnormality.

[0012]

Beam profile interlocking device of the present invention SUMMARY OF THE INVENTION To solve the above problems, the form of the ion beam generated by ion implantation apparatus body
Storage means for storing a set value which is set in advance as a normal value of the beam shape and beam current density before beam startup, and measurement values obtained from the beam measurement means for measuring the shape and beam current density of the ion beam and the above settings The following means are taken in a beam profile interlock apparatus having a determination means for determining whether or not to apply an interlock to the ion implantation apparatus main body based on the values.

That is, when the electron shower is not used, the setting value stored in the storage means is directly used as a comparison value in accordance with a recipe set when the beam of the ion implantation apparatus is started. When the electron shower is used, the stored set value is changed to obtain a comparison value, and the obtained comparison value is compared with the measured value to determine whether or not to perform interlock.

[0014]

According to the above arrangement, the storage means stores the set values set before the beam is started. Then, the determination means obtains a comparison value by directly changing or changing the set value stored in the storage means according to a recipe set when the beam of the ion implantation apparatus is started. That is, when the recipe including the condition of having the electron shower is set, the ion beam is formed so as to be smaller than that without the shower. And the normal values of the beam current density change. For this reason, the setting value set as a normal value when there is no shower as described above,
When there is no shower, the comparison value is used as it is, and when there is a shower, a value that is reduced by a predetermined numerical value is used as the comparison value. Therefore, the comparison value is a normal value indicating the shape of the ion beam and the beam current density obtained as a result of normal beam start-up for the set recipe.

In the ion implantation apparatus main body in which the beam is set up based on the set recipe, the beam shape and the beam current density at that time are measured by the beam measuring means, and the measured values are measured by the beam profile interlock device. Is transmitted to Then, the measured value is compared with the comparison value corresponding to the recipe by the determination means, and it is determined whether or not to apply an interlock to the ion implantation apparatus main body. Never.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

The beam profile interlock device according to this embodiment (hereinafter referred to as an interlock device)
Is equipped with an ion implantation apparatus which is equipped with an ion beam neutralizer and can use an electron shower as needed.

As shown in FIG. 1, the ion implanter includes a machine host computer (hereinafter referred to as a machine host) 1, a machine controller 2, an ion implanter main body 3, and a beam profile monitor as beam measuring means. 4 and the interlock device 5 described above.

The ion implantation apparatus main body 3 includes an ion source section for ionizing an implantation element and extracting it as an ion beam.
A mass separation unit that selects and extracts only predetermined implanted ions,
It comprises an end station section for setting an ion irradiation target such as a wafer and performing an implantation process, and various power supplies (ion source power supply and extraction power supply) for supplying power to the above-described sections. Further, the ion implantation device main body 3 includes the above-described ion beam neutralization device.

The machine host 1 communicates with the machine controller 2 and issues various commands to the machine controller 2 to automatically perform beam startup, wafer transfer, implantation processing, beam shutdown, and the like. It has a function to perform it.

The machine controller 2 controls the operation of the ion implantation apparatus main body 3 based on an instruction from the machine host 1 or an operator operating a keyboard (not shown). For example, when a recipe including an ion species, a beam current, energy, the use of an electron shower, and other conditions is set in the machine controller 2 by a command from the machine host 1, the machine controller 2 sets the recipe. The ion implantation apparatus main body 3 is operated with various parameters (gas flow rate, arc current, source magnet current, acceleration voltage, Q lens trim potentiometer value, Q lens balance potentiometer value, etc.) corresponding to the recipe.

When a recipe is set by a command from the machine host 1 or an operator, the machine controller 2 outputs a binary signal indicating whether or not an electron shower is used (for example, "1" when a shower is used, and "1" when no shower is used). “0”) is output to the interlock device 5.
Then, the machine controller 2 performs beam shaping so that the beam shape is slightly smaller when there is an electron shower than when there is no electron shower.

The beam profile monitor 4 measures the beam shape and beam current density distribution of the ion beam generated by the ion implanter body 3 under the control of the machine controller 2 before the ion implantation is started. This measurement result is displayed on an oscilloscope. The measurement of the beam shape is specifically performed by measuring the width of the beam cross section in the X direction (for example, the horizontal direction) and the Y direction (for example, the vertical direction). The beam profile monitor 4 is connected to the interlock device 5 and transmits the measurement result to the interlock device 5.

The interlock device 5 has an I / O port 6 for inputting a measurement result from the beam profile monitor 4 and for inputting and outputting signals to and from the machine controller 2. Further, the interlock device 5 includes a CPU 7 as a determination unit, a memory 8 as a storage unit, and a setting unit 9.

The memory 8 includes a ROM in which a processing program is stored, and a RAM in which an area for temporarily storing processing data and an area for storing set values set by the setting unit 9 are formed. Have been.

The set value set by the setting unit 9 is set in advance by an operator. When the electron shower is not used, the beam shape (beam cross section of the ion beam) generated in the ion implanter body 3 is not used. X
Direction and the width in the Y direction) and the beam current density.

The CPU 7 performs the following processing according to the processing program stored in the ROM while temporarily storing the processing data in the RAM of the memory 8. That is, when the signal “0” indicating “no use of the electron shower” is input from the machine controller 2, the CPU 7 inputs the setting value stored in the RAM of the memory 8 as a comparison value from the beam profile monitor 4 as it is. The measured value is compared with the measured value. On the other hand, the CPU 7 sends “use electron shower” from the machine controller 2.
When the presence signal “1” is input, a predetermined numerical value is subtracted from the set value (set value is changed), and the obtained value is compared with the measured value from the beam profile monitor 4 as a comparative value. . If the measured value from the beam profile monitor 4 is within the comparison value, the CPU 7 sends a binary signal (“OK”) to the machine controller 2 through the I / O port 6. For example, while outputting “1”), if it is out of the comparison value, a signal (for example, “0”) indicating “NG” for interlocking the ion implantation apparatus main body 3 is output.

When the machine controller 2 receives the "OK" signal "1" from the interlock device 5, the machine controller 2 controls the ion implantation device main body 3 according to the various parameters set at this time. The ion implantation operation is started.

On the other hand, if the machine controller 2 receives the "NG" signal "0" from the interlock device 5, it does not shift to the injection operation but performs the following operation. That is, when the recipe is set by an instruction from the operator (that is, when the apparatus is started up manually), the machine controller 2 stops the operation of the ion implantation apparatus main body 3. Further, when a recipe is set by a command from the machine host 1 (that is, when the apparatus startup is automatically performed), the machine controller 2 transmits a signal indicating startup failure to the machine host 1. in this case,
The machine host 1 issues a command to change the setting parameters to the machine controller 2 so that the parameters become optimal for the recipe. And machine controller 2
Starts the beam of the ion implantation apparatus main body 3 again with parameters different from the previous time. The operation of adjusting the above parameters is repeated a predetermined number of times until a signal “OK” is obtained from the interlock device 5. However, if the signal “OK” is not obtained from the interlock device 5 even if the above operation is repeated a predetermined number of times, the operation of the ion implantation device main body 3 is stopped.

In the above configuration, the operation of the interlock device 5 when the recipe including the condition with the electron shower is set in the machine controller 2 by the instruction from the operator will be described below with reference to the flowchart of FIG. I do.

In this case, the I / O of the interlock device 5
A signal "1" indicating the presence of an electron shower is input from the machine controller 2 to the port 6 (S1). At this time, the CPU 7 performs an operation of subtracting a predetermined numerical value from the set value of the width in the X and Y directions of the beam cross section stored in the RAM of the memory 8 (S
2) The numerical value obtained by this operation is used as a comparison value in the memory 8
(S3). The set value of the beam current density is stored as it is in the RAM of the memory 8 as a comparison value.

Next, when a measured value (width of the beam cross section in the X and Y directions, beam current density) is input from the beam profile monitor 4 via the I / O port 6 (S4), Measurement values and RAM of the memory 8
Is compared with the comparison value stored in (S5).

Thereafter, if the measured value is within the comparison value, the CPU 7 outputs a signal "1" indicating "OK" to the machine controller 2 via the I / O port 6 (S).
6). On the other hand, if the measured value is out of the comparison value, the CPU 7 outputs a signal “0” indicating “NG” for interlocking the machine controller 2 via the I / O port 6 ( S7).

As described above, when the electron shower is used, the beam is shaped so that the beam shape becomes smaller than that in the normal mode. In the interlock device 5, the set value is correspondingly small. Therefore, it is possible to avoid a situation in which the interlock works even if the beam shape matches the recipe as in the related art.

When a recipe including the condition of no electron shower is set in the machine controller 2, a signal “0” indicating no electron shower is sent from the machine controller 2 to the I / O port 6 of the interlock device 5. It will be input (S1). In this case, C
The PU 7 sets the set value stored in the RAM of the memory 8 as a comparison value as it is (S8), and thereafter performs the same processing (S4 to S7) as described above to determine whether or not to interlock. I do.

As described above, in the present interlock device 5, even if the shape of the ion beam changes depending on the use of the electron shower (depending on the recipe), the interlock does not work unless there is an abnormality.

[0037] The present invention has only to be configured to compare values depending on the presence or absence of the electron shower use in at least a recipe is changed, in yet other additional conditions, the ion beam according to the setting If the conditions that require a change in the shape or beam current density (depending on the ion implanter used, for example, orientation flat angle, implantation angle, device registration number) are included in the recipe, the conditions should be adjusted with or without the use of the electron shower. In addition, a configuration in which the comparison value can be changed according to the condition is also included in the gist of the present invention.

[0038]

As described above, in the beam profile interlock device of the present invention, the judgment means is determined in accordance with the recipe set at the time of starting the beam of the ion implantation apparatus main body.
When the electron shower is not used, the set value stored in the storage unit is used as a comparison value as it is, and when the electron shower is used, the stored value is changed to obtain a comparison value. The comparison value and the measured value are compared to determine whether to apply an interlock to the ion implantation apparatus main body.

[0039] Therefore, even when the normal value of the shape and <br/> beam current density of the ion beam generated by ion implantation apparatus main body is changed according to the recipe set, the actual measurement value measured by the beam measuring means The comparison value compared with is a normal value indicating the shape and beam current density of the ion beam obtained as a result of normal beam startup for the set recipe. There is no effect.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a block diagram showing a main part of an ion implantation apparatus provided with a beam profile interlock device.

FIG. 2 is a flowchart showing an operation of the beam profile interlock device.

FIG. 3 is a block diagram showing a main part of an ion implantation apparatus provided with a conventional beam profile interlock device.

[Explanation of symbols]

 Reference Signs List 3 ion implanter main body 4 beam profile monitor (beam measuring means) 5 beam profile interlock device 7 CPU (judgment means) 8 memory (storage means) 9 setting device

Claims (1)

(57) [Scope of request for utility model registration] 1. A storage means for storing, as normal values of a shape and a beam current density of an ion beam generated by an ion implantation apparatus main body, a set value which is set in advance before starting a beam, and a shape and a beam of the ion beam. A beam profile interlock including: a determination unit configured to determine whether to apply an interlock to the ion implantation apparatus body based on a measurement value obtained from a beam measurement unit that measures a current density and the set value. In the apparatus, when the electron shower is not used, the determination unit determines the set value stored in the storage unit as a comparison value as it is, according to a recipe set at the time of starting the beam of the ion implantation apparatus main body. When using the shower, change the set value stored above to obtain a comparison value, and then A beam profile interlock device, which determines whether to apply an interlock by comparing a value with the measured value.