JP3314456B2 - Ion implanter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implanter for electrically implanting an ion beam into a target by electrically scanning an ion beam in parallel. More specifically, the present invention relates to a scan voltage waveform optimal for implantation conditions. The present invention relates to a means for stably performing ion implantation with good uniformity by using the method.

[0002]

2. Description of the Related Art FIG. 11 is a schematic plan view showing an example of a conventional ion implantation apparatus. FIG. 12 is a side view showing a portion from the scanning electrode to the back Faraday of the apparatus shown in FIG.

This ion implantation apparatus converts a spot-shaped ion beam 2 emitted from an ion source 4, subjected to mass analysis by a mass analysis electromagnet 6, accelerated by an acceleration tube 8, and narrowed down by a Q lens 10 into a scanning power supply. The two pairs of scan electrodes 14 and 16 to which scan voltages (voltages close to a triangular wave) V ₁ and V ₂ 180 degrees out of phase with each other from 18 are applied, ie, the ion beam 2 deflected on the one hand and the other on the other hand By deflecting in the opposite direction by the same angle, a wide ion beam (parallel beam) 2 is electrostatically scanned in the X direction (for example, in the horizontal direction; the same applies hereinafter) to perform parallel scanning.
I am trying to make. A voltage is supplied to the Q lens 10 from a Q lens power supply 12.

In this example, a pair of deflection electrodes 20 is provided between the scanning electrodes 14 and 16, so that the ion beam 2 is moved in a Y direction substantially perpendicular to the X direction (for example, in a vertical direction). (The same applies hereinafter) by a predetermined angle α (for example, about 7 degrees) to separate a neutral beam that travels straight.

A target (eg, a wafer) 22 to be implanted is disposed downstream of the scanning electrode 16 and is moved by the target driving device 24 in the Y direction (FIG. 11) in the irradiation area of the ion beam 2. In addition, mechanical scanning is performed in the direction of the front and back of FIG. 1 (to be described later with reference to FIG. 1), and the ion beam 2 is uniformly scanned over the entire surface of the target 22 by cooperation with the scanning of the ion beam 2 in the X direction (ie, by so-called hybrid scanning). Ion implantation is performed.

In such an ion implantation apparatus, if the scanning voltages V ₁ and V ₂ are simply triangular waves, the scanning speed of the ion beam 2 on the target 22 will not be constant and the implantation uniformity will deteriorate. In this example, the scanning voltage waveform is shaped in accordance with the method previously proposed by the same applicant (JP-A-4-22900).

The main point of the scanning voltage waveform shaping method is shown in FIG.
This will be described with reference to FIGS. FIG.
FIG. 2 is an enlarged plan view showing a portion from a scanning electrode to a back Faraday of the apparatus shown in FIG. 1 to be described later.

A front Faraday 26 and a back Faraday 28 are disposed on the upstream side and the downstream side in the beam traveling direction (Z direction) of the target 22, respectively. Each Faraday 26, 28 is a multi-point Faraday in this example, and is composed of a plurality of beam current measurement arrays whose positions are known in advance. When the measurement is performed by the front Faraday 26, the deflection angle of the ion beam 2 in the Y direction is reduced (for example, to α / 2), and when the measurement is performed by the back Faraday 28, the target 22 is moved to a position that does not hinder the measurement.

The temporal changes in the beam currents I _f and I _b measured by the Faradays 26 and 28 are measured by a waveform data logger 32.
And used as data for waveform shaping by the waveform shaper 34.

The waveform shaper 34 generates a scanning voltage waveform V (t) such that the ion implantation amount on the target 22 becomes uniform by the following logic.

First, the front Faraday 26
The sampling of the ion beam 2 being scanned is performed.
FIG. 14 shows an example of the waveform of the beam current _If obtained by this. The horizontal axis is a time axis, and T is one reciprocating scan. In the figure, the solid line is a signal of a certain channel of the front Faraday 26 (for example, a beam current measurement array of X = X _f1 ), and the broken line is a channel inside thereof (for example, X = X
_f2 ), and the peak time indicates that the ion beam 2 is incident on the front of a certain channel of the front Faraday 26 at that time. In this way, the positions {X _f1 , X _f2 ,.
, X _fn }, the time {T _f1 , T _f2 ,..., T _fn } at which the ion beam 2 is incident at that position is obtained for each channel of the front Faraday 26.

Similarly, in the back Faraday 28, the time of incidence {T _b1 , T _b2 ,..., Of the ion beam 2 at the position {X _b1 , X _{b2 ,.}
T _bn } data is obtained.

A scanning voltage waveform applied from the waveform shaper 34 to the scanning power supply 18 has a function V indicating a scanning voltage with respect to time t.
(T), the function V (t) and the previous data {T
_f1, ···, T _fn} and {T _b1, ···, from T _bn}, the front Faraday 26 and back Faraday 2
8 (i.e. Z = Z _f and Z = Z _b positions) in the scan voltage data point sequence showing the relationship between the scanning position X of the input and the ion beam 2 of the _{V {(V f1, X f1} ), (V f2 , X _f2 ),
..., ( _Vfn , _Xfn )} and {( _Vb1 , _Xb1 ),
(V _b2 , X _b2 ),..., (V _bn , X _bn )} are obtained. Simply speaking, if the time t is known, the scanning voltage V at that time can be known, and if the time t is known, the scanning position at that time can be known. If V is known, the scanning position X can be known.

By approximating, for example, a higher-order function using this data point sequence, the front Faraday 26 (Z =
Z _f) and back Faraday 28 Request (Z = Z _b) function represents a relationship between a scanning position X of the scanning voltage V and the ion beam 2 at X _f (V) and X _b (V). These two functions and the front Faraday 26 (Z = Z _f), back Faraday 28 (Z = Z _b) and target 22 (Z = Z _t)
From the positional relationship, a function X representing the relationship between the scanning voltage V and the scanning position X of the ion beam 2 on the target 22
_t (V) is expressed as follows.

[0015]

[Number 1] _{X t (V) = {(} Z b -Z t) X f (V) + (Z t -
_{Z f) X b (V)} } / (Z b -Z f)

The waveform shaper 34 uses the equation 1 to calculate the scanning speed dX of the ion beam 2 on the target 22.
A scanning voltage waveform is generated such that _t (V) / dt becomes constant. More specifically,

## EQU2 ## dX _t (V) / dt = {dX _t (V) / dV}.
Since {dV (t) / dt}, the scan voltage waveform data is generated such that the scan voltage waveform data becomes constant regardless of the scan position of the ion beam 2.

Here, when the scanning voltage V is a triangular wave,
The function X _t (V) representing the scanning position of the ion beam is usually not straight, but slightly S-shaped as shown in FIG. This is because when the trajectory of the ion beam 2 has a large amplitude as shown in FIG. 13, the ion beam 2 passes near the electrode having a high potential (positive potential) while passing through the scanning electrode 16 on the downstream side. The ion beam 2 is decelerated and the effect of the bending back is increased, and the ion beam 2 tends to converge slightly toward the center. Therefore, in the case of scanning with dV / dt = constant triangular wave, the scanning speed is small in the small amplitude portion. Is faster, and the scanning speed is slower in the large amplitude part.

The derivative dX _t (V) / of this function X _t (V)
dV is shown in FIG. This represents the scanning speed with the scanning voltage V as a variable. Therefore, in this state, the amount of ions implanted into the target 22 increases as going to the periphery.

In order to correct such unevenness of the scanning speed, the derivative dV (t) / dt of the scanning voltage V (t) is used.
As shown in FIG. 17, the derivative dX _t (V) of FIG.
By changing the scan voltage waveform in the opposite relationship to / dV, the scan voltage waveform may be shaped so that the derivative of Equation 2, that is, the scan speed dX _t (V) / dt is kept constant.

The scanning voltage V (t) thus shaped
Is shown by a solid line F in FIG. The dashed line E in the figure is the original triangular wave, and the solid line F is slightly raised near its peak. Such a waveform is generated in the waveform shaper 34 in this example, and is supplied to the scanning power supply 18.

The scanning power supply 18 is, as shown in FIG.
Pressure amplifier 18a in this example output the waveform shaper 34 different scanning voltages V ₁ of 180 degrees out of phase from each other by boosting the given scanning voltage waveform V (t) and from V ₂
And 18b, such scanning voltages V ₁ ,
If the ion beam 2 is scanned by V ₂ , the scanning speed of the ion beam 2 on the target 22 becomes constant even if the bending back action of the ion beam 2 is non-uniform. Can improve the injection uniformity.

Referring again to FIGS. 11 and 12, the target 22 is located below the end of the front Faraday 26.
Is provided with a dose monitor Faraday 30 for measuring the beam current of the ion beam 2 at the time of ion implantation with respect to. The ion beam 2 is scanned (ie, overscanned) so as to pass through the dose monitor Faraday 30. A beam current measuring device 31 such as a current integrator is connected to the dose monitor Faraday 30, and the injection amount (dose amount) to the target 22 is controlled by the beam current I measured by these devices.

The control of the injection processing operation including the calculation of the injection amount, the control of the injection time, and the control of the target driving device 24 is performed by the injection control device 40.

The above-described control of the Q lens power supply 12 and the scanning power supply 18 is performed by a Q scanner controller 36 in this example. The control parameters of the Q lens power supply 12 include a Q trim (a parameter that determines an absolute value of a voltage applied to an electrode forming the Q lens 10) and a Q balance (which configures the Q lens 10) that governs the focusing of the ion beam 2. (A parameter that determines how to apply a voltage to the upper, lower, left, and right electrodes). The scanning parameters of the scanning power supply 18 include an X offset (a parameter that determines the scanning center position in the X direction) and an X scan (a parameter that determines the amplitude of the scanning voltage).

[0025]

However, in the above ion implantation apparatus, the target 22
The scanning voltage waveform data for keeping the scanning speed of the ion beam 2 constant is shown in Table 1 for each ion type used for ion implantation.
Are stored in the waveform data logger 32 as table-like data as shown in FIG. That is, the scanning voltage waveform data includes the ion beam 2 for each ion species of the ion beam 2.
Is registered as a section of the energy region and the beam current region. Symbols B1 to B33 in each section indicate scanning voltage waveforms, respectively.

[0026]

[Table 1]

For example, when the ion species is B ⁺ , the energy of the ion beam 2 and the beam current are 80 KeV,
When the current is 200 μA, the waveform of B21 is used.
For V, 150 μA, use the waveform of B21,
At 20 KeV and 50 μA, the waveform of B3 is used. That is, conventionally, such scanning voltage waveforms from B1 to B40 are created and registered in advance, and a scanning voltage waveform that meets the implantation conditions is called out of the waveforms at the time of ion implantation, and the scanning voltage waveform is used by using it. I am trying to make.

However, if the table-like data as described above is used, the scan voltage waveform is called out ignoring the difference between the injection conditions in each section, so that the optimum scan voltage for the injection condition at that time is used. There is a problem that a waveform cannot be used, and there is a limit in improving the injection uniformity.

The spot size of the ion beam 2 changes depending on how the control parameters of the Q lens power supply 12 are set, which affects the uniformity of the implantation. Therefore, even if ion implantation is performed using the same scanning voltage waveform, there is a problem that the implantation uniformity changes, that is, the reproducibility of the implantation uniformity is poor.

Further, there is no means for simply evaluating the ion implantation uniformity and the parallelism of the ion beam 2 before the ion implantation using the scanning voltage waveform selected as described above before implantation. As the ion implantation must be performed without being convinced whether the scanning voltage waveform selected as described above is really appropriate or not,
There is a problem that it is uneasy, and even if an abnormality has occurred in the scanning voltage waveform or the like for some reason, it cannot be known, so that abnormal injection cannot be prevented.

Therefore, according to the present invention, it is possible to perform ion implantation using a scanning voltage waveform that is optimal for implantation conditions, and furthermore, to achieve ion implantation uniformity and parallelism of an ion beam when using the scanning voltage waveform. It is a main object of the present invention to provide an ion implantation apparatus which can easily evaluate the ion implantation before implantation, and thereby perform ion implantation with good uniformity reliably and stably.

[0032]

In order to achieve the above object, an ion implantation apparatus according to the present invention comprises: a scan voltage waveform data which is a source of the scan voltage; a Q lens power parameter which is a control parameter of the Q lens power; A scanning power supply parameter that is a control parameter of the scanning power supply, a beam current measurement range that is a measurement range for measuring a beam current in the beam current measuring device, front Faraday data that is an ion beam scanning position data measured by the front Faraday, and A plurality of pieces of scanning voltage waveform information composed of back Faraday data, which is the scanning position data of the ion beam measured by the back Faraday, is stored in advance in the implantation control device in association with a waveform identification code one by one. In the case of the injection control device,
Using the waveform identification code, scan voltage waveform information corresponding to the implantation condition is read, and using the read scan voltage waveform information, the expected implantation uniformity and ion implantation on the target when ion implantation is performed under that condition. The present invention is characterized in that an expected parallelism of a beam is calculated and displayed on a display, and ion implantation can be performed using the read scanning voltage waveform information.

[0033]

According to this ion implantation apparatus, a plurality of pieces of scanning voltage waveform information including scanning voltage waveform data and the like are registered in association with a waveform identification code one by one, not as table-like data as in the related art. Therefore, the scanning voltage waveform information corresponding to the injection condition can be finely read using the waveform identification code. Therefore, it is possible to use an optimal scanning voltage waveform for the injection condition at that time,
The best injection uniformity can be obtained.

In addition, the scanning voltage waveform information includes a Q lens power supply parameter and a scanning power supply parameter which affect the injection uniformity, and these are included in association with the scanning voltage waveform data. It is possible to control the Q lens power supply and the scanning power supply using these parameters, so that almost the same implantation uniformity can be obtained by performing ion implantation using the same scanning voltage waveform. Also has excellent reproducibility.

Moreover, the expected implantation uniformity and the expected parallelism when the ion implantation is performed using the read scanning voltage waveform information are calculated and displayed on the display device. It can be easily evaluated before injection. Therefore, the ion implantation apparatus can be started up in a short time in a state that matches the implantation conditions. Further, by evaluating the expected injection uniformity and the expected parallelism, abnormal injection can be prevented, so that it is safe.

[0036]

FIG. 1 is a schematic plan view showing an ion implantation apparatus according to one embodiment of the present invention. Parts that are the same as or correspond to those in the conventional example of FIG. 11 are denoted by the same reference numerals, and differences from the conventional example will be mainly described below.

The side view and the enlarged plan view of the portion from the scanning electrode to the back Faraday of the apparatus of this embodiment are the same as those shown in FIGS.

In the conventional example, a Q-scanner controller 3 for controlling the offset, scanning width, etc. of the ion beam 2
6. A waveform shaper 34 for executing a scanning waveform process to create an appropriate scanning voltage waveform, and a waveform data logger 3 for storing the created scanning voltage waveform group and outputting a waveform according to a request.
2 are separate units, but in this embodiment they are combined into one waveform shaping controller 38 both physically and functionally. And this waveform shaping control device 3
A signal is exchanged between the injection control device 8 and the injection control device 42.

The implantation control device 42 corresponds to the conventional implantation control device 40, and will be described later in this ion implantation device (that is, as shown in FIGS. 5 to 10).
The injection processing operation is controlled. This injection control device 42
CR with touch panel for man-machine interface
T44, which also serves as a display and an input device.

In this embodiment, the scanning voltage waveform data is not a table-like data (see Table 1) as in the prior art, but a plurality of scanning voltage waveforms each comprising data as shown in Table 2. The scanning voltage waveform information is treated as a part of the information, and such a plurality of pieces of scanning voltage waveform information are associated with the waveform identification (ID) code one by one and stored in advance in the injection control device 42, more specifically, the hard disk or the like. It is stored (registered) in the storage device. That is, a waveform identification code is used as an identification code for registering and reading out the scanning voltage waveform information, and a certain injection condition (recipe) is used.
Is determined, scanning voltage waveform information to be used for injection under that condition is handled using a waveform identification code.

[0041]

[Table 2]

Here, the scan voltage waveform data is a digital data string representing a basic triangular wave or a scan voltage waveform corrected by waveform shaping (for example, a waveform as shown by a solid line F in FIG. 18). 1024 per cycle
It is represented by a data string of points (one point of data is 12 bits).

The Q lens power supply parameter is a control parameter of the Q lens power supply 12 described above, and specifically, a Q trim (Q lens 10
And Q balance (a parameter that determines how to apply a voltage to the upper, lower, left, and right electrodes forming the Q lens 10), and these parameters are used in this embodiment. In the example, each is 0-1
It is represented by a dial value of 00%. These are the values when the scan voltage waveform data was created. This is because if these parameters change, the state of the ion beam 2 changes, which affects the uniformity of implantation and the parallelism. Therefore, it is necessary to use the data at the time of generating the scanning voltage waveform data.

The scanning power supply parameters are the control parameters of the scanning power supply 18 described above. Specifically, the X offset (the parameter for determining the scanning center position in the X direction) and the X scanning (the parameter for determining the scanning voltage amplitude) are included. Which are referred to in this example as 0-10
It is represented by a dial value of 0%. These are the values when the scan voltage waveform data was created. This is because if these parameters change, the state of the ion beam 2 changes, which affects the uniformity of implantation and the parallelism. Therefore, it is necessary to use the data at the time of generating the scanning voltage waveform data.

The beam current measurement range is a measurement range in which the beam current I is measured by the beam current measuring device 31, and in this embodiment, 1 μA, 2 μA, 4 μA, 8
μA, 16 μA, 32 μA, 64 μA, 128 μA, 2
56 μA, 512 μA, 1.024 mA, 2.048 m
A. These values are values corresponding to the input current of 100%. This beam current measurement range is the range used when creating the scanning voltage waveform data. This is because the state of the ion beam 2 changes depending on the beam current, which affects the uniformity of implantation and the parallelism. Therefore, it is necessary to use different scanning voltage waveforms depending on the beam current value. However, the difference of beam current in each range is
The effects are small and are ignored here.

The front Faraday data and the back Faraday data are X-direction scanning position data of the ion beam 2 measured by the front Faraday 26 and the back Faraday 28, respectively, that is, the data point sequence _{デ ー タ} (V _f1 , X _f1 ), ( _Vf2 , _Xf2 ), ..., ( _Vfn ,
_Xfn )} and {( _Vb1 , _Xb1 ), ( _Vb2 , _Xb2 ) _,.
.., (V _bn , X _bn )}. These data can be updated to data collected by using the final scan voltage waveform after the scan voltage waveform shaping process is completed.

Of the data in Table 2, the actual components of the waveform are the former three, namely, the scanning voltage waveform data, the Q lens power source parameter and the scanning power source parameter, and the others are the supplementary situation data. It is included in the voltage waveform information for the reason described above. Referring to FIG. 19, the scanning voltage waveform is obtained by multiplying the scanning voltage waveform data by the above-described dial value representing the Q lens power supply parameter and the scanning power supply parameter, and determining the scan width and offset of the ion beam 2 by the energy of the ion beam 2. Is multiplied by an auto-tracking signal to be corrected according to the following formula, and D / A-converted. The resultant signal is supplied from the waveform shaping control device 38 to the scanning power supply 18 as the above-described scanning voltage waveform V (t), and is amplified there and scanned.
₁ and V ₂ are supplied to the scan electrodes 14 and 16.

According to this method, the scanning power supply parameters X offset and X scanning described above (more specifically, by the dial value representing them)
It is possible to adjust by changing the scan width and scan offset of the ion beam 2 in the X direction. On the other hand, in the conventional ion implantation apparatus shown in FIG. 11, although the scanning width and the scanning offset of the ion beam 2 in the X direction can be temporarily controlled by the Q. scanner controller 36, the Q.
This is only for adjusting the beam by giving a scanning voltage waveform of a triangular wave to the scanning power supply 18, but not for reading and using the registered waveform that has been shaped from the waveform shaper 34 during actual ion implantation. It is possible. This is because, in the conventional ion implantation apparatus, the Q-scanner controller 36 and the waveform shaper 34 for outputting a correction waveform are different devices from each other.
4 cannot be adjusted. In the apparatus of this embodiment, the functions corresponding to the conventional waveform shaper 34 and the Q / scanner controller 36 are integrated into one waveform shaping controller 38, so that the correction waveform as described above can be adjusted. is there.

FIG. 2 shows an example of a waveform shaping screen on the CRT 44 with a touch panel of the injection control device 42, and FIG. 3 shows an example of a waveform registration screen. The CRT 44 with a touch panel also displays a main screen and the like for a setup (start-up) operation of the ion implantation apparatus (refer to FIGS. 5 to 11 described later). Omitted.

Details of the contents (processing operations and the like) shown on this screen will be described later with reference to the flowcharts of FIGS. 5 to 10. However, if briefly described here, the following will be described. is there.

The scanner adjustment switch section 50 is a section for selecting a “scanner adjustment” mode for automatically adjusting the scanning width and scanning offset of the ion beam 2 by controlling the scanning power supply 18.

The Q lens adjustment switch section 53 is a section for selecting a “Q lens adjustment” mode for automatically adjusting the degree of stop of the ion beam 2 by controlling the Q lens power supply 12.

The basic triangular wave switch section 51 is a part for selecting a “basic triangular wave” mode for returning a scanning voltage waveform to a basic triangular wave (an unprocessed triangular wave).

The beam profile switch unit 49 measures the X-direction scanning position of the ion beam 2 in front of and behind the target 22 using the front Faraday 26 and the back Faraday 28, and based on the data, the ion beam 2 is scanned. This is a part for selecting a “beam profile” mode for calculating an expected injection uniformity and an expected parallelism.

The waveform shaping switch section 48 is based on the data in the "beam profile" mode so as to improve the injection uniformity (that is, to make the beam scanning speed on the target 22 constant). This is a portion for selecting the “waveform shaping” mode for shaping the scanning voltage waveform by the method described above and creating a new scanning voltage waveform.

The check beam switch section 52 is a section for selecting a “check beam” mode for calculating a dose correction coefficient k described later.

The execution switch unit 54 is a part for selecting an “execution” mode in which execution of the processing of each mode is started after each mode is selected.

The waveform registration switch unit 55 registers (stores) the scanning voltage waveform information as shown in Table 2 in a storage means (for example, a hard disk) in the injection control device 42 using the waveform identification code. This is the part for selecting the mode. When this is selected, the waveform registration screen of FIG. 3 opens as a sub screen. Here, the waveform identification code setting switch unit 71 is a switch unit for starting the setting of the waveform identification code, and when the switch is pressed to input the waveform identification code from input means such as a keyboard, it is displayed on the display unit 74, When the registration switch 72 is pressed, the scanning voltage waveform information at that time is registered in the storage means in association with the waveform identification code.

The waveform readout switch section 56 is a section for selecting a "waveform readout" mode in which the scan voltage waveform information registered in the storage means is read out therefrom using a waveform identification code. When this is selected, a waveform reading screen substantially similar to that of FIG. 3 opens.

The waveform deletion switch unit 57 is a part for selecting a “waveform deletion” mode in which the scanning voltage waveform information registered in the storage means is deleted therefrom using a waveform identification code. When this is selected, a waveform deletion screen almost similar to FIG. 3 is opened.

The displays 60, 61 and 62 show the expected injection uniformity calculated in the "beam profile" mode,
This is a part for displaying the maximum value and the minimum value of the expected parallelism, respectively. The display section 63 is a section for displaying the dose correction coefficient k calculated in the “check beam” mode.

Here, a method of calculating the above-described expected injection uniformity, expected parallelism, and dose correction coefficient k when one piece of scanning voltage waveform information is selected by the waveform identification code will be described.

First, the expected injection uniformity will be described.
By using the front Faraday data and the back Faraday data included in the selected scanning voltage waveform information, a function X _t (V) representing the scanning position of the ion beam on the target 22 shown in Equation 1 above, Further, the scanning speed dX _t (V) / dt of the ion beam on the target 22 shown in Expression 2 can be obtained. The injection amount for the target 22 is determined by the scanning speed dX _t (V)
/ Dt, and its inverse ｛dX _t (V) / d
The expected injection uniformity is determined by determining t｝ ⁻¹ for the entire area of the target 22 and further determining its standard deviation. The result is displayed on the display unit 60 in FIG.

Next, the expected parallelism will be described. The parallelism is, as shown in FIG. 4, the scanning direction X of the ion beam 2.
Is defined as an angle θ of the ion beam 2 with respect to this Z direction. By using the front Faraday data and the back Faraday data included in the selected scanning voltage waveform information,
As described in the conventional example, the front Faraday 2 of the ion beam 2 at the scanning voltage V corresponding to each other.
6 above (Z = Z _f) scanning position in the X _f (V) and the back Faraday 28 above (Z = Z _b) at a scanning position X _b (V)
Therefore, the parallelism θ (V) at the scanning voltage V can be quantitatively obtained by the calculation of the following equation.

[0065]

Equation 3] θ (V) = {(X f (V) -X b (V)} / (Z b -Z f) (rad)

For example, when the ion beam 2 is completely parallel to the Z direction at a certain scanning voltage V, θ = 0.
The above calculation is performed for the entire area of the target 22, thereby obtaining the parallelism for the entire area of the target 22. The maximum and minimum values are displayed on the display units 61 and 62 in FIG. 2, respectively.

Next, the dose correction coefficient k will be described. The dose D to the target 22 is generally expressed as follows.

[0068]

D = I · t / n · e · S where I is beam current, t is implantation time, n is ion valence, e is elementary charge, and S is implantation area.

Since the beam actually injected into the target 22 corresponds to the beam current received by the entire back Faraday 28 in this ion implantation apparatus, when n = 1, the dose amount D is expressed as follows. You.

[0070]

Equation 5] _{D = I B · t / e} · S B where I _B is the beam current flowing through the entire back Faraday 28, S _B is the opening area of the entire back Faraday 38.

The beam current measured by the above-described dose monitor Faraday 30 is not the same as the beam current actually irradiated on the target 22 (this corresponds to the beam current measured by the back Faraday 28). It is necessary to perform the correction, and the dose correction coefficient k for the correction is defined as follows.

[0072]

K = (S _B / S _D ) × (I _D / I _B ) where I _D is a beam current flowing through the dose monitor Faraday 30, and S _D is an opening area of the dose monitor Faraday 30. Since S _B and S _D are known in advance, the dose correction coefficient k can be obtained by obtaining I _D and I _B immediately before the start of injection. The result is displayed on the display unit 63 in FIG.

[0073] By the way, the number of the I _B which is determined from the number 6 5
And rearranging yields the following equation:

[0074]

D = _ID · t / k · e · _SD That is, using the beam current _ID measured by the dose monitor Faraday 30 and the dose correction coefficient k,
The dose D actually injected into the target 22 can be obtained.

Next, a set-up (start-up) operation up to the start of the implantation process of the ion implantation apparatus will be described with reference to FIGS. The setup mode is roughly divided into a full auto setup (FIG. 5) and a manual setup (FIG. 8). And
Fixed waveform mode (Figure 6) for full auto setup
And the arbitrary waveform mode (FIG. 7). Similarly, in the manual setup, the fixed waveform mode (Fig. 9)
And an arbitrary waveform mode (FIG. 10).

First, the fully automatic setup shown in FIG. 5 will be described. This is to start up the device automatically. First, a CRT with a touch panel of the injection control device 42
On the main screen 44 (not shown), implantation conditions such as the mass number, energy, dose amount, beam current, and waveform identification code of ions to be used are set (step 100).
By pressing the setting end switch unit (Step 101), selecting the start-up switch unit (Step 102), and pressing the execution switch unit (Step 103), Step 1 is performed.
Enter the full auto setup operation of 04. This fully automatic setup includes a fixed waveform mode shown in FIG.
There is an arbitrary waveform mode shown in FIG. In this embodiment, the switching between the two modes is such that when the waveform identification code is all 0, the arbitrary waveform mode is entered, and when not, the fixed waveform mode is entered. However, the present invention is not limited to this.

The fixed waveform mode shown in FIG. 6 uses scanning voltage waveform information registered in advance, and uses the above-described waveform identification code to read out the scanning voltage waveform information. First, in step 110, basic operating parameters are selected and determined according to the injection conditions, which are internally set for the device together with the injection conditions. The basic operation parameters are initial setting data used at the time of full automatic setup, and are determined by, for example, a matrix of the energy of the ion beam 2 and the beam current for each ion type. That is, “arc voltage”, “arc current”, “source magnet current”, and “Q · scanner dial value” with respect to the mass number, energy and beam current in the injection conditions.
Say. The former three are parameters for extracting the ion beam in the ion source 4. “Q · scanner dial value” is a dial value representing the above-described Q lens power supply parameter and scanning power supply parameter. The basic operation parameters are registered and set in the injection control device 42 in advance, and are selected and determined according to the injection conditions at that time during the fully automatic setup. If there is no basic operation parameter corresponding to the injection condition, the calculation is performed by interpolation of two neighboring conditions.

Next, an arc discharge for extracting the ion beam 2 is established in the ion source 4 based on the basic operation parameters (step 111), and the acceleration energy of the ion beam 2 is set (step 11).
2) An ion species to be subjected to mass analysis (that is, selectively derived therefrom) in the mass analysis electromagnet 6 is selected (step 113), and the ion beam 2 to be irradiated on the target 22 by controlling an arc discharge current in the ion source 4 or the like.
Is adjusted (step 114).

Next, when the waveform identification code has been set (step 115), the operation proceeds to the beam profile check operation of step 116. Here, the scan voltage waveform information registered in advance as described above is read out by the set waveform identification code, and the above-described predicted injection is performed using the front Faraday data and the back Faraday data included therein. Uniformity and expected parallelism are calculated. Since these calculation methods are as described above, duplicate description is omitted here. Then, these are compared with the permissible values in the case of the injection condition at that time, and if both are within a certain permissible range with respect to the permissible value, the process proceeds to the next step 117; To stop the operation and wait for the judgment of the operator (step 120). However, the process proceeds to step 120 instead of proceeding immediately in one trial. If the injection uniformity and parallelism still do not fall within the allowable range after several attempts, the process may proceed to step 120. , It is more practical. In addition, when the injection conditions (recipe) are given online from the host computer to the injection control device 42, the allowable values of the injection uniformity and the parallelism are included in the injection conditions. In the case of offline, the injection control device 4
2 may have a fixed allowable value.

The check beam in step 117 is a process for calculating the above-described dose correction coefficient k and determining whether or not the result is normal. Since the method of this calculation is as described above, a duplicate description is omitted here. However, in this embodiment, data sampling and calculation processing for obtaining the dose correction coefficient k in one check beam processing are performed. Is repeated for five cycles, and the dose correction coefficient k obtained in each cycle is averaged to obtain the actually used dose correction coefficient k. At this time, the dose correction coefficient k of each cycle is within a certain range (for example, 0.
If 8 ≦ k ≦ 1.2) and the variance value of the 5 data is within a certain range (for example, 0.002 or less), the process proceeds to step 118 as normal, and if not satisfied, step 1
Proceed to step 20 and wait for an operator's decision.

When the process proceeds to step 118, the transfer of the target 22 to be ion-implanted to be mounted on the target driving device 24 is started, and then in step 119, the implant is processed. This implant process is a process of calculating the number of ion beam scans from the set dose amount (implantation amount), the actual beam current, and the implantation amount per scan of the ion beam 2 based on the actual dose.
If this is obtained, the process proceeds to step 105 in FIG. 5, and the ion implantation process is performed based on the number of scans.

In the arbitrary waveform mode of FIG. 7, an arbitrary new scanning voltage waveform is created from scratch without using the previously registered scanning voltage waveform information.

In FIG. 7, steps 110 to 11
4 and the processing operations of steps 117 to 119 are the same as those of FIG. The difference from FIG. 7 is steps 121 to 124.

That is, when the beam current adjustment is completed in step 114, the beam current is adjusted to meet the injection conditions at that time.
The control parameters for the Q lens power supply 12 are adjusted (step 121), and the control parameters for the scanning power supply 18 are adjusted (step 122). These parameters are included in the scanning voltage waveform information as shown in Table 2 in the case of the fixed waveform mode, but the arbitrary waveform mode described here uses such scanning voltage waveform information. Because there is no, it is adjusted each time.

Next, at step 123, a beam profile check operation is performed. Here, unlike step 116 in FIG. 6, the ion beam 2 is actually scanned and the front Faraday 26 and the back Faraday 2 are scanned.
After collecting the scanning position data of the ion beam 2 at 8,
The expected injection uniformity and expected parallelism as described above are calculated. For that purpose, first, the ion beam 2 is scanned with the basic triangular wave. If the expected injection uniformity and the expected parallelism at the time of scanning are within the predetermined allowable range as described above, the process proceeds to step 117. However, since the basic triangular wave is not usually within this allowable range, the process proceeds to step 117. The operation proceeds to the scanning voltage waveform shaping operation.

At step 124, the scanning voltage waveform is shaped so that the scanning speed of the ion beam 2 on the target 22 is constant according to the waveform shaping method described with reference to FIGS. Is done.
After the waveform shaping, the process returns to step 123, and such an operation is performed so that the expected injection uniformity and the expected parallelism fall within a certain allowable range (step 123), and the dose correction coefficient k falls within a certain allowable range (step 123). This is repeated until step 117). Step 118 and subsequent steps are as described above.

In the manual setup shown in FIG. 8, the apparatus is started up manually. Steps 130 and 1
Reference numeral 31 denotes steps 100 and 1 at the time of full auto in FIG.
01, and the setup operation in step 132 is the same as that in steps 110 to 114 in FIG. 6 or FIG. The operations of steps 133 to 137 are performed on the screen as illustrated in FIGS. 2 and 3 of the CRT 44 with a touch panel of the injection control device 42.

At step 133, a waveform mode is selected. In the case of the fixed waveform mode, the operation proceeds to the waveform generation operation of step 134 (the contents are shown in FIG. 9), and in the case of the arbitrary waveform mode, the operation proceeds to the waveform generation operation of step 135 (the contents are shown in FIG. 10).

In the case of the fixed waveform mode, as shown in FIG. 9, a waveform identification code is set (step 150), and the waveform readout switch 56 (see FIG. 2, the same applies to the switch) is pressed (step 151). The registered scan voltage waveform information is read. Next, when the beam profile switch unit 49 is pressed, the expected injection uniformity and the expected parallelism are calculated using the front Faraday data and the back Faraday data in the read scanning voltage waveform information (step 152). The method of this operation is
Since this is the same as in step 116 of FIG. 6,
A duplicate description is omitted. However, here, even if the calculation is completed, the automatic comparison with the allowable value is not performed, and the calculation result is displayed on the display unit 60 to the waveform shaping screen (FIG. 2) of the CRT 44 with the touch panel (FIG. 2).
62 are displayed.

The displayed contents are judged by the operator (step 153). If the contents are satisfactory, the operator presses the execution switch 55 (step 154), and the process proceeds to step 136 in FIG. If it is not satisfied, the process returns to step 150 and the operation after setting another waveform identification code may be repeated.

In the case of the arbitrary waveform mode, as shown in FIG. 10, the control parameters for the Q lens power supply 12 are adjusted (step 155), and the control parameters for the scanning power supply 18 are further adjusted (step 156).
Since these are the same as steps 121 and 122 in FIG. 7, the duplicate description is omitted here.

Next, the beam profile switch unit 4
When 9 is pressed, the expected injection uniformity and the expected parallelism are calculated in the same manner as in step 123 in FIG. 7 (step 157). However, here, even if the calculation is completed, the automatic comparison with the allowable value is not performed, and the calculation result is displayed on the display units 60 to 62 of the waveform shaping screen of the CRT 44 with the touch panel.

The displayed contents are judged by the operator (step 158). If the contents are satisfactory, the operator presses the execution switch 55 (step 161).
Proceeds to step 136.

If not satisfied, the waveform shaping switch section 48 is pressed (step 159), and the execution switch section 55 is pressed (step 160). As in step 124 of FIG. 7, the scanning voltage waveform is shaped. Done. After completion of this, the process returns to step 157, and when the beam profile switch unit 49 is pressed, the expected injection uniformity and the expected parallelism in the new shaped scanning voltage waveform are calculated and displayed. Subsequent steps are the same as above.

When the processing has proceeded to step 136 in FIG. 8, when the check beam switch section 52 is pressed, the same as in step 117 in FIG. 6 or FIG.
The calculation of the dose correction coefficient k is performed. However, here, even if the calculation is completed, the automatic comparison with the allowable value is not performed, and the calculation result is displayed on the above-described display unit 63 of the CRT 44 with a touch panel.

Next, when the execution switch section 55 is pressed (step 137), the touch panel C
The RT 44 switches to the main screen, and when the implant switch is pressed (step 138), the number of scans of the ion beam 2 is calculated in the same manner as in step 119 of FIG. 6 or FIG. When pressed (step 139), the transfer of the target 22 is started in the same manner as in step 118 of FIG. 6 or FIG. 7, and the process proceeds to step 141 to perform ion implantation.

[0097]

According to the first aspect of the present invention, a plurality of scanning voltage waveform information including the scanning voltage waveform data and the like are not handled as table-like data as in the prior art, but correspond to a waveform identification code one by one. Since the scan voltage waveform information is registered together, the scan voltage waveform information corresponding to the injection condition can be finely read using the waveform identification code. Therefore, the most suitable scanning voltage waveform can be used for the injection condition at that time, so that the best injection uniformity can be obtained.

Moreover, the scanning voltage waveform information includes the Q lens power supply parameter and the scanning power supply parameter which affect the injection uniformity, and these are included in association with the scanning voltage waveform data. It is possible to control the Q lens power supply and the scanning power supply using these parameters, so that almost the same implantation uniformity can be obtained by performing ion implantation using the same scanning voltage waveform. Also has excellent reproducibility.

Further, the expected implantation uniformity and the expected parallelism when the ion implantation is performed using the read scanning voltage waveform information are calculated and displayed on the display device. It can be easily evaluated before injection. Therefore, the ion implantation apparatus can be started up in a short time in a state that matches the implantation conditions. Further, by evaluating the expected injection uniformity and the expected parallelism, abnormal injection can be prevented, so that it is safe. According to the invention of claim 2, scanning
Multiple scan voltage waveform information including voltage waveform data
Instead of using tabular data as in
Since it is registered by associating it with another code one by one,
Scan voltage waveform according to injection condition using waveform identification code
Information can be read out in detail. Therefore,
It is possible to use the optimal scanning voltage waveform for the injection conditions at the time.
Therefore, the best injection uniformity can be obtained.
Moreover, this scanning voltage waveform information has an effect on the injection uniformity.
Lens power supply parameters and scanning power supply parameters
And at least one of the beam current measurement ranges
These are associated with the scan voltage waveform data.
Are included, so use these parameters to implement
Position, so that the same scanning
Approximately uniform implantation by ion implantation using voltage waveform
And therefore excellent reproducibility of injection uniformity.
Have been. Moreover, using the read scan voltage waveform information,
Implantation uniformity and prediction when ion implantation is performed
Since the parallelism is calculated and displayed on the display,
Easily evaluate injection uniformity and parallelism before injection
be able to. Therefore, the ion implanter can be operated in a short time.
It is possible to start up in a state that matches the injection conditions.
You. In addition, these expected injection uniformity and expected parallelism are
Evaluation can prevent abnormal injection
So it is safe.

According to the third aspect of the present invention , the expected injection uniformity and the expected parallelism are each compared with a predetermined allowable value of the injection condition at that time, and both of them are within a certain allowable range with respect to the allowable value. since to be able to enter the injection process on condition that it is in, Ki de is possible to reliably prevent abnormal infusion, stability further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an ion implantation apparatus according to one embodiment of the present invention.

FIG. 2 is a CRT with a touch panel of the injection control device in FIG.
FIG. 6 is a diagram showing an example of a waveform shaping screen in FIG.

FIG. 3 is a CRT with a touch panel of the injection control device in FIG. 1;
FIG. 6 is a diagram showing an example of a waveform registration screen in FIG.

FIG. 4 is a diagram for explaining the definition of the parallelism of an ion beam.

FIG. 5 is a flowchart illustrating an example of a basic operation at the time of full auto setup.

FIG. 6 is a flowchart showing an example of the contents of a fully automatic setup step in FIG. 5 in a fixed waveform mode.

FIG. 7 is a flowchart showing an example of the contents of a fully automatic setup step in FIG. 5 in an arbitrary waveform mode.

FIG. 8 is a flowchart illustrating an example of a basic operation during manual setup.

FIG. 9 is a flowchart showing an example of the contents of the waveform generation step in FIG. 8 in the fixed waveform mode.

FIG. 10 is a flowchart showing an example of contents of a waveform generation step in FIG. 8 in an arbitrary waveform mode.

FIG. 11 is a schematic plan view showing an example of a conventional ion implantation apparatus.

FIG. 12 is a side view showing a portion from the scanning electrode to the back Faraday of the apparatus of FIGS. 1 and 11;

FIG. 13 is an enlarged plan view showing a portion from the scanning electrode to the back Faraday of the apparatus shown in FIGS. 1 and 11;

FIG. 14 is a schematic diagram partially showing an example of a signal from front Faraday or back Faraday.

FIG. 15 is a diagram illustrating an example of a function representing a scanning position of an ion beam on a target.

FIG. 16 is a diagram showing an example of a derivative of a function representing a scanning position of an ion beam on a target.

FIG. 17 is a diagram illustrating an example of a derivative representing a scanning voltage.

FIG. 18 is a diagram showing an example of a shaped scanning voltage waveform.

19 is a diagram showing the concept of a method of generating a scanning voltage waveform in the waveform shaping control device in FIG.

[Explanation of symbols]

 2 Ion beam 4 Ion source 10 Q lens 12 Q lens power supply 14,16 Scan electrode 18 Scan power supply 22 Target 24 Target drive 26 Front Faraday 28 Back Faraday 30 Dose mode Faraday 31 Beam current measuring device 32 Waveform data logger 34 Waveform shaper 36 Q scanner controller 38 Waveform shaping controller 42 Injection controller 44 CRT with touch panel

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 37/317 H01J 37/147 H01L 21/265

Claims (3)

(57) [Claims] 1. A Q lens for extracting an ion beam extracted from an ion source and subjected to mass analysis and acceleration, a Q lens power supply for supplying a voltage to the Q lens, and an ion beam from the Q lens in an X direction. Two sets of scan electrodes that scan in parallel to each other, a scan power supply that supplies a scan voltage to the scan electrodes, and a target that is an injection target provided further downstream of the downstream ones of the scan electrodes. A target driving device for mechanically scanning the target in a Y direction substantially orthogonal to the X direction; and a measuring device for measuring a scanning position of the ion beam at a plurality of points, respectively, which is disposed on an upstream side of the target. A front Faraday and a back Faraday disposed downstream, and a beam of ion beam provided on the side of the target when ion implantation is performed on the target. A dose monitor Faraday for measuring the system current, a beam current measuring device connected to the dose monitor Faraday, and a scan speed of the ion beam on the target based on signals from the front Faraday and the back Faraday. A waveform shaping means for shaping the scanning voltage waveform of the ion beam so that the scanning speed is constant, and applying the waveform data to the scanning power supply; and an implantation control device for controlling an implantation processing operation in the ion implantation apparatus. In an ion implantation apparatus comprising:
The scan voltage waveform data that is the source of the scan voltage, the Q lens power supply parameter that is a control parameter of the Q lens power supply, the scan power supply parameter that is a control parameter of the scan power supply, and measurement for measuring a beam current with the beam current measurement device A plurality of scanning voltage waveforms including a beam current measurement range as a range, front Faraday data as an ion beam scanning position data measured at the front Faraday, and back Faraday data as an ion beam scanning position data measured at the back Faraday. The information is stored in advance in the injection control device in association with the waveform identification code one by one, and at the time of ion implantation, the scan control device uses the waveform identification code to perform scanning voltage waveforms corresponding to the implantation conditions. The information is read, and the read scan voltage waveform information When the ion implantation is performed under these conditions, the expected implantation uniformity on the target and the expected parallelism of the ion beam are calculated and displayed on a display, and the read scan voltage waveform information is used. An ion implantation apparatus characterized in that the ion implantation can be performed by performing ion implantation. 2. The method of claim 1, wherein the ion source is extracted from the ion source,
And a Q lens that focuses the ion beam
A Q lens power supply for supplying a voltage to the Q lens;
Scans that scan the ion beam from the laser beam in parallel in the X direction
Scanning electrode and a scanning power supply for supplying a scanning voltage to the scanning electrode
And a further downstream side of the scanning electrodes among the scanning electrodes.
The target to be injected is
Mechanically in a Y direction substantially orthogonal to the X direction.
Target drive and ion beam scanning position
Are measured at a plurality of points, respectively,
Faraday and lower part located upstream of the
Back Faraday located on the flow side and the target side
Is provided at the time of ion implantation for the target.
Dose monitor for measuring beam current of ion beam
Tafarada and connected to this dose monitor Faraday
Beam current measuring instrument, and the front Faraday and
And target based on signals from backfaraday
Find the scanning speed of the ion beam above, and this scanning speed
Shaping the ion beam scanning voltage waveform so that it is constant
Waveform shaping means for applying the waveform data to the scanning power supply
Stage and control the implantation process in the ion implanter
An ion implantation apparatus comprising:
Q lens power supply which is a control parameter of the Q lens power supply
Scanning, which is a control parameter of the scanning power supply.
Power parameters and beam current meter
Beam current measurement lens
And at least one of the scans
Measurement using the Faraday voltage waveform data
Front beam, which is the scanning position data of the ion beam
Data and the ions measured by the back Faraday
Back Faraday data which is beam scanning position data
The multiple scan voltage waveform information consisting of
One by one and stored in advance in the injection control device
At the time of ion implantation, the waveform
Using the identification code, scan voltage waveform information according to the injection conditions
Information, and using the read scanning voltage waveform information,
On the target when ion implantation is performed
Injection uniformity and expected ion beam parallelism
Performs calculations, displays them on the display unit, and
Ion implantation can be performed using probe voltage waveform information
An ion implantation apparatus characterized in that: 3. comparing the expected injection uniformity and the expected parallelism with predetermined tolerances for the injection conditions, respectively;
Claim both are to be able to enter the injection process on condition that within a certain tolerance range with respect to the allowable value 1 or
Or the ion implanter according to 2 .