JPS6332221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for annealing and heating a sample with a scanning charged particle beam, and more particularly to an apparatus for uniformly annealing a silicon wafer etc. by scanning the silicon wafer. .

Conventionally used annealing heating equipment includes the one shown in Figure 1.
The electron beam b emitted from is focused by a focusing lens c, and the focused electron beams b1, b2, b
3 is corrected by the astigmatism correction lens d, and then deflected by the sawtooth wave signals H and V supplied to the deflection coil f, and as shown in FIGS. is scanned over a length l. The scanning time is indicated by the time width t in FIG. 3a.

At this time, during the return of each scanning line sl, the electron beam b is blanked by blanking signals BH and BV supplied to the blanking coil g, so that it does not scan over the sample E. There is.

That is, during this blanking, since the electron beam b is irradiated onto the aperture i, it is blocked by the aperture i and is not supplied below the aperture i.

Note that symbols h1 and h2 in FIG. 1 indicate X-ray shields.

However, in such a conventional annealing heating device, the aperture i is irradiated with the electron beam b, and a large current (several mA to several tens of mA) is passed through the aperture i, and this current becomes high temperature. There is a problem that it melts, and furthermore, since X-rays are generated by the irradiated electron beam b, there is a problem that an X-ray shield h1 must be provided to cover the aperture i.

Furthermore, by irradiating the aperture i with the electron beam b, a problem arises in that dirt adheres to the passage path of the electron beam b.

Therefore, in order to solve these problems, it is possible to blank the electron beam b by applying a high negative voltage to the grid (Wehnelt) of the electron gun a, but this method has the problem of slow response speed. In addition, there is a further drawback that load fluctuations seen from the power source of the electron gun a become large, making it impossible to stably irradiate the electron beam b.

The present invention is an attempt to solve these problems.The present invention anneales and heats the sample by scanning the sample with a focused charged particle beam, and during blanking, focuses the focused charged particle beam. An object of the present invention is to provide an annealing heating device for a sample using a scanning charged particle beam, which is capable of performing stable and uniform annealing heating of a sample by controlling the deflection of the beam and irradiating the heat-resistant surface while detouring the beam. purpose.

For this reason, the annealing heating device of the present invention performs annealing heating scanning over a sample with a charged particle beam, and also deflects the charged particle beam to return the sample.
A charged particle source that generates a charged particle beam, a focusing lens that focuses the charged particle beam, a sawtooth signal generator for vertical scanning, and a vertical retrace signal that corresponds to a vertical coordinate outside the sample. a vertical scanning sawtooth wave signal from the vertical scanning sawtooth signal generator, and a vertical deflection control signal from the vertical blanking signal and the horizontal blanking signal. a vertical deflection signal generation circuit for generating a vertical deflection; a vertical deflection circuit to which the vertical deflection control signal is supplied; a vertical deflector for vertical deflection in response to a vertical deflection signal from the vertical deflection circuit; a sawtooth signal generator for horizontal scanning;
A horizontal deflection circuit to which a sawtooth wave signal for horizontal scanning is supplied from the sawtooth wave signal generator for horizontal scanning; and a horizontal deflection circuit that performs horizontal deflection in response to a horizontal deflection signal from the horizontal deflection circuit. a deflector is provided, a heat-resistant surface that is irradiated with the charged particle beam during return of the heating scan is provided away from the sample, and each output from the vertical deflection circuit and the horizontal deflection circuit is characterized in that the charged particle beam is controlled via the vertical deflector and the horizontal deflector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for annealing and heating a sample using a scanning charged particle beam as an embodiment of the present invention will be described below with reference to the drawings.

The attached drawings show a sample annealing heating apparatus according to the present invention, and FIG. 4 is an overall configuration diagram thereof, and FIG.
The figure is a schematic diagram for explaining the scanning procedure.
Figures a and b are waveform diagrams for explaining the action, Figure 7 is a schematic diagram showing the main parts, Figure 8 a
~f are waveform diagrams for explaining their effects, Figure 9 is a schematic diagram showing the main parts, and Figure 10 a.
-e are waveform diagrams for explaining their effects, and FIGS. 11a and 11b are schematic diagrams showing the arrangement of the heat-resistant surfaces.

As shown in FIG. 4, an electron gun 1 as a charged particle source is installed above the mirror body of a scanning electron microscope as an annealing heating device, and an electron beam as a charged particle beam is emitted from the electron gun 1. 2 is about to be fired.

This electron beam 2 is supplied to a DC power source 3 for a focusing lens.
The light is focused by the focusing lens 4, and the astigmatism is corrected by the astigmatism correction coil 6 by the astigmatism correction power source 5.

Focused and astigmatism-corrected electron beam 2
In the vertical direction, the vertical deflection circuit 7a
The deflection is controlled in the horizontal direction by a vertical deflector 8a which receives a vertical deflection signal from the horizontal deflection circuit 7b and deflects it vertically, and in the horizontal direction, a horizontal deflector which receives a horizontal deflection signal from the horizontal deflection circuit 7b and deflects it horizontally. The deflection is controlled by 8b.

The vertical deflection circuit 7a receives a vertical deflection control signal Vs from a waveform generator 9a serving as a vertical deflection signal generation circuit, and the horizontal deflection circuit 7b receives a sawtooth waveform for horizontal scanning. It is adapted to receive a horizontal deflection control signal Hs from a waveform generator 9b serving as a signal generator.

Further, a sample insertion section is formed below these deflection circuits 8a, 8b, and a sample 10 is placed in this sample insertion section.

An X-ray shield 11 made of lead or the like is provided to surround the sample 10, and as shown in FIGS. It is provided. Therefore, the heat energy per unit area that the heat-resistant surface 12 receives becomes small, and the temperature of a portion of the heat-resistant surface 12 does not particularly rise and melt.

Further, a cooling device (not shown) is provided below the heat-resistant surface 12, so that the heat-resistant surface 12 is constantly cooled. In particular, the cooling device has a high cooling efficiency at point P' shown in FIG. 11b, which corresponds to point P in FIG. 5. The material of this heat-resistant surface 12 is
Metals such as tungsten, molybdenum, nickel, and copper.

As shown in FIG. 7, the waveform generator 9a as the vertical deflection signal generating circuit described above includes a sawtooth wave signal generator 13 for vertical scanning and a vertical retrace signal generator 14. A blanking signal BH and a vertical blanking signal BV are input.

The waveform generator 9a includes each of these signal generators 13,
14, a vertical deflection control signal Vs (see FIGS. 6b, 8f, and 10b) is generated by a changeover switch SW1.

That is, as shown in FIG. 7, the sawtooth wave signal V for vertical scanning (see FIG. 8b) and the vertical retrace signal S1 corresponding to the vertical coordinates (see FIG. 8c)
] is supplied to each input terminal of the changeover switch SW1, and furthermore, in order to control the switching of these signals V and S1, a horizontal blanking signal BH [see Fig. 8d] and a vertical blanking signal are supplied to the OR circuit 15. A ranking signal BV (see Fig. 8e) is input.

The output G from the OR circuit 15 is supplied to the changeover switch SW1 as a high-level OR of the blanking signals BH and BV, and when this signal G is high level, the vertical retrace signal S1 is output. When the signal is at low level, the sawtooth wave signal V for vertical scanning is output, and the vertical deflection control signal Vs (see FIG. 8f) is generated.
This signal Vs is supplied to the vertical deflection circuit 7a.

Note that FIG. 8a shows the waveform of the signal H generated from the sawtooth wave signal generator 17 for horizontal scanning.

The vertical retrace signal S1 is applied to the retrace lines 2a and 2b outside the sample placement area 16 (within the level width A2 in the signal) shown in FIG. 5 in order to scan the outside of the sample during retrace.
Vertical levels V1 and V2 corresponding to [see Figure 5]
The absolute values are set to predetermined levels each having a larger absolute value.

As shown in FIG. 9, the waveform generator 9b as the horizontal deflection signal generating circuit described above operates in conjunction with the horizontal scanning sawtooth signal generator 17 and the vertical retrace signal generator 14 to output the signal. It is equipped with a horizontal retrace signal generator 18 that outputs a signal, and is adapted to input a vertical blanking signal BV.

The waveform generator 9b includes each of these signal generators 17,
In response to electric signals H and Vc from 18, a horizontal deflection control signal Hs (see FIGS. 6a and 10e) is generated by a changeover switch SW2.

That is, as shown in FIG. 9, a switch is used to select the horizontal scanning sawtooth signal H (see FIG. 10a) and the horizontal retrace signal Vc (see FIG. 10c).
A vertical blanking signal BV (see FIG. 10d) is supplied to each input terminal of SW2, and furthermore, in order to switch and control these signals H and Vc.

This changeover switch SW2 is configured to output a horizontal retrace signal Vc corresponding to the coordinate in the horizontal direction from the horizontal retrace signal generator 18 when the vertical blanking signal BV is at a high level, that is, during vertical blanking. Vertical blanking signal
When BV is at a low level, a sawtooth wave signal H for horizontal scanning is output from the sawtooth wave signal generator 17 for horizontal scanning.

The output signal Hs (see FIG. 10e) from the changeover switch SW2 is supplied to the horizontal deflection circuit 7b.

Note that FIG. 10b shows the waveform of the signal Vs output from the waveform generator 9a.

The horizontal deflection control signal Hs causes the electron beam 2 to scan horizontally, and in combination with the vertical deflection control signal Vs during vertical blanking,
The electron beam 2 is designed to irradiate only a fixed point P (see FIG. 5) on the outside of the sample.

In addition, the horizontal deflection control signal Hs is applied to retrace lines 2c and 2d outside the sample placement area 16 (within the level width A1 in the signal) in order to scan the outside of the sample during retrace.
Horizontal levels H1 and H2 corresponding to [see Figure 5]
When the absolute values are large, together with the vertical deflection control signal Vs, the lengths L ₁ and L ₃ in FIG.
The area corresponding to the image is scanned.

With the above configuration, the electron beam 2 emitted from the electron gun 1 is focused by the focusing lens 4 by the focusing lens DC power source 3, and is also focused by the astigmatism correction coil by the astigmatism correction power source 5. 6, astigmatism is corrected.

On the other hand, in the waveform generator 9a, the sawtooth wave signal V for vertical scanning from the sawtooth wave signal generator 13 for vertical scanning and the vertical retrace signal S1 from the vertical retrace signal generator 14 are switched to the respective switching switches. SW
At the same time, the output signal G from the OR circuit 15 is input to the changeover switch SW1. As a result, a vertical deflection control signal Vs is generated and supplied to the vertical deflection circuit 7a.

In the waveform generator 9b, the horizontal scanning sawtooth signal H from the horizontal scanning sawtooth signal generator 17 and the horizontal retrace signal Vc from the horizontal retrace signal generator 18 are switched to the respective switching switches. SW2
When the vertical blanking signal BV is simultaneously input to the changeover switch SW2,
A horizontal deflection control signal Hs is generated and supplied to the horizontal deflection circuit 7b.

The focused and astigmatically corrected electron beam 2 is deflected in the vertical direction by a vertical deflector 8a which receives a vertical deflection signal from a vertical deflection circuit 7a and vertically deflects it. In the horizontal direction deflection circuit 7b
The deflection is controlled by a horizontal deflector 8b which receives a horizontal deflection signal from the horizontal deflector 8b and deflects it horizontally.

Therefore, when scanning the sample 10, as shown in FIGS. 5 and 6 a and b, the electron beam emitted from point P first scans the sample placement area 16 as scanning line SL ₁ . scan. At this time, the scanning length is L, of which length L ₂ is within the sample placement area 16, and the electron beam scanning over the sample 10 within this length L ₂ This is the effective amount of annealing heating. Note that each scanning line SL ₁ ,
The electron beam forming SL ₂ , . . . is schematically shown in FIG. 5, and actually passes through point P.

The electrical signals generating the scanning line SL ₁ are as shown in FIG. 6a,
It is for the interval of time width T ₁ shown in b, and the time width t ₁
corresponds to length L ₁ , time width t ₂ corresponds to length L ₂ ,
The time width t ₃ corresponds to the length L ₃ .

The retrace lines 2d and 2a from the end of the scanning line SL ₁ are the scanning portion of the first half of the sample 10 (point P in FIG. 5, the retrace line 2
Since it is close to the half plane including a), it passes through the retrace line 2a, passes through point P, and heads to the starting end of the next scanning line SL ₂ .

The electrical signals that generate the retrace lines 2d and 2a at this time are those in a period of time width T ₁₂ , the t _A part corresponds to the retrace line 2 d, the t _B part corresponds to the retrace line 2 a, and the t _C The part corresponds to the retrace line 2c.

In the scanning lines SL ₂ , SL ₃ , ... SL _i , SL _j ..., scanning and retrace in the same direction are performed sequentially in almost the same way as in the case of the scanning line SL ₁ , and the corresponding time width is are T ₂ , T ₃ . . . T _i , T _{j .} . . and are the same as in the time width T ₁ .

However, when the scanning line enters the latter scanning portion of the sample 10 (the half including the retrace line 2b in FIG. 5), the retrace line passes through symbols 2d', 2b, and 2c'.

Note that each scanning line that scans the second half of this sample 10 is also schematically shown in FIG. 5 in the same way as each scanning line that scans the first half of the sample 10 described above. , and finally the electron beam passes through each return line 2d', 2b, 2c' and returns to point P.

The deflection control signals Vs and Hs at this time are shown in Figure 6a and b, and the vertical deflection control signals at the time of retrace
Vs is shown in the _tD section.

As shown in Figures 10b and 10e, the horizontal deflection control signal Hs, which has the same time width as the vertical blanking signal, is at the same level as the horizontal retrace signal Vc, but the time width is several times this time width. The horizontal deflection control signal Hs may be the same as the horizontal blanking signal Vc.

Furthermore, even if the path that detours around the sample 10 is configured so that only the retrace line 2a passes through the retrace line 2b without taking the retrace path shown in FIG. The wire 2a may be configured not to pass through.

In these cases, the vertical retrace signal S1 may be set to either a predetermined level that is greater than or equal to the maximum value of the vertical scanning sawtooth wave signal V or a predetermined level that is less than or equal to the minimum value.

Further, the retrace path may be an arcuate retrace path that detours around the sample 10, and in this case, the retrace path includes the vertical retrace signal generator 14 and the horizontal retrace signal generator 18.
During each horizontal blanking, put a sine wave (sine wave) on one side and a cosine wave (cosine wave) on the other side, adjust the peak value, angular frequency and phase,
This can be achieved by adding them to the respective deflection control signals Vs and Hs.

Note that although the heat-resistant surface 12 is provided below the sample 10, it may be provided above.

As described in detail above, according to the sample annealing heating device using a scanning charged particle beam of the present invention, the sample is annealed and heated by scanning the sample with a focused charged particle beam, and the sample is blanked. In some cases, by controlling the deflection of a focused charged particle beam to irradiate it onto a heat-resistant surface while making a detour, it is possible to perform stable and uniform annealing heating of the sample. It has the advantage of achieving high temperature and uniform temperature distribution during heating.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional annealing heating means; Figure 1 is its overall configuration, Figure 2 is a schematic diagram for explaining its scanning procedure, and Figures 3 a to d are its FIGS. 4 to 11 are waveform diagrams for explaining the action, and FIGS. 4 to 11 show a sample annealing heating apparatus using a scanning charged particle beam as an embodiment of the present invention. FIG. Figure 5 is a schematic diagram for explaining the scanning procedure, Figure 6a,
b is a waveform diagram for explaining the action,
Fig. 7 is a schematic diagram showing the main parts, Figs. 8 a to f are waveform diagrams for explaining its operation, and Fig. 9
The figure is a schematic diagram showing the main parts, Figures 10a to 10e are waveform diagrams for explaining the action, and Figure 11 is a schematic diagram showing the main parts.
Figures a and b are both schematic diagrams showing the arrangement of the heat-resistant surfaces. 1... Electron gun as a charged particle source, 2... Electron beam as a charged particle beam, 2a, 2b, 2c,
2c', 2d, 2d'...Scanning line during retrace, 3...DC power supply for focusing lens, 4...Focusing lens, 5...
Astigmatism correction power supply, 6... Astigmatism correction coil, 7a... Vertical deflection circuit, 7b... Horizontal deflection circuit, 8a... Vertical polarizer, 8b...
Horizontal polarizer, 9a, 9b... waveform generator, 1
0...Sample, 11...X-ray shield, 12...Heat-resistant surface, 13...Sawtooth wave signal generator for vertical scanning, 14...Vertical retrace signal generator, 15...OR circuit, 16... ...Sample placement area, 17...Sawtooth wave signal generator for horizontal scanning, 18...Horizontal retrace signal generator, SW1, SW2...Selector switch, V
... Sawtooth wave signal for vertical scanning, H... Sawtooth wave signal for horizontal scanning, S1... Vertical retrace signal,
Vc...Horizontal blanking signal, Vs...Vertical deflection control signal, Hs...Horizontal deflection control signal, BV...Vertical blanking signal, BH...Horizontal blanking signal.

Claims (1)

[Scope of Claims] 1. A charged particle source 1 that generates a charged particle beam 2, in order to annealing and heating scan a sample 10 with the charged particle beam 2 and deflecting the charged particle beam 2 to return the charged particle beam 2. A focusing lens 4 that focuses the charged particle beam 2
and a vertical scanning sawtooth signal generator 13;
Vertical retrace signal generator 1 that generates a vertical retrace signal S ₁ corresponding to the vertical coordinates outside the sample 10
4, and the vertical scanning sawtooth signal generator 1
a vertical deflection signal generation circuit 9a that generates a vertical deflection control signal Vs from the vertical scanning sawtooth wave signal V from 3, the vertical retrace signal _S1 , and the horizontal blanking signal BH; Control signal
A vertical deflection circuit 7a to which Vs is supplied, a vertical deflector 8a that receives a vertical deflection signal from the vertical deflection circuit 7a and performs vertical deflection, and a sawtooth wave signal generator 17 for horizontal scanning; A horizontal deflection circuit 7b is supplied with a sawtooth wave signal H for horizontal scanning from the sawtooth wave signal generator 17 for horizontal scanning, and a horizontal deflection circuit 7b receives a horizontal deflection signal from the horizontal deflection circuit 7b and A horizontal deflector 8b for deflection is provided, and a heat-resistant surface 12 that is irradiated with the charged particle beam 2 during return of the heating scan is provided apart from the sample 10, and a An apparatus for annealing and heating a sample using a scanning charged particle beam, characterized in that each output from the horizontal deflection circuit 7b controls the charged particle beam 2 via the vertical deflector 8a and the horizontal deflector 8b. . 2 The vertical retrace signal generator 14 generates a predetermined level of the sawtooth wave signal V for vertical scanning outputted from the sawtooth wave signal generator 13 for vertical scanning at a predetermined level above the maximum value and below the minimum value. An apparatus for annealing and heating a sample using a scanning charged particle beam according to claim 1, which is configured to generate a vertical retrace signal _S1 comprising: 3 The horizontal deflection circuit 7b outputs the horizontal scanning sawtooth signal H and the vertical blanking signal.
Annealing heating of a sample with a scanning charged particle beam according to claim 1 or 2, configured to heat a fixed point during vertical blanking by generating a horizontal deflection signal from BV. Device. 4 The horizontal deflection circuit 7b is connected to the sample 10.
horizontal retrace signal corresponding to the outer horizontal coordinate of
A horizontal retrace signal generator 18 is provided which outputs Vc in conjunction with the vertical retrace signal generator 14, and the horizontal retrace signal generator 17 outputs the horizontal retrace wave H from the horizontal retrace signal generator 17. A sample using a scanning charged particle beam according to claim 1 or 2, which is configured to generate a horizontal deflection signal from a horizontal retrace signal Vc, a horizontal blanking signal BH, and a vertical blanking signal BV. annealing heating equipment. 5. A sample annealing heating device using a scanning charged particle beam according to any one of claims 1 to 4, wherein a cooling device is attached to the heat-resistant surface 12.