JPS583372B2 - Denshibi Muohandoutaikitaiichiawasesuru Hohououoyobi Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention is disclosed in U.S. Pat.
This is an improved version of the electron beam type circuit pattern manufacturing apparatus and positioning apparatus described in each specification of No. 0101.

In prior art circuit pattern fabrication equipment, a planar photocathode source (also referred to as an "electromask") is placed on an electroresist layer (also referred to as an "electronic mask") on the major surface of the substrate at a distance from the photocathode source. A patterned electron beam is generated that is directed at the electroresist layer (also referred to as a "sensing layer"), causing differential solubility between irradiated and non-irradiated areas of the electroresist layer.

The solubility difference pattern is created by selectively etching or selectively doping the circuit component layer or substrate through the developed window pattern of the electroresist layer after removing the less soluble portion of the electroresist layer to form a window pattern. or transferred to the pattern of the circuit component layer or substrate by being deposited on the circuit component layer, for example by evaporation, sputtering, oxidation or epitaxial growth, through a window pattern in the electroresist layer.

The resolution of an electronic imaging device, e.g. less than 0.5 microns, may, however, make it difficult to place a circuit component pattern in the same location many times if the same resolution cannot be maintained during the alignment of successive photocathode sources. It is also lowered during formation.

To make an integrated circuit device, for example, it is necessary to superimpose and irradiate an electroresist layer with at least two to ten different circuit component patterns.

These circuit component patterns are then developed and transferred to the circuit component layer by etching, doping or deposition.

The electron beam for each pattern is 0.0.
Each time it must be aligned with a precisely located area of the major surface with an accuracy of less than 5 microns.

Otherwise, the accuracy and economy of electronic imaging devices will not be achieved in the final integrated circuit device.

An apparatus has been developed for accurately juxtaposing multiple circuit component patterns using electron beam induced conductivity marks (EBICs).

See US Pat. No. 3,710,101, issued January 9, 1973.

At least one and preferably two small indexing electron beam patterns (which are spaced apart from each other) and marks of predetermined cross-sectional shape are applied to the photocathode source to generate alignment beam sections and corresponding positions. A detection mark of a predetermined shape, preferably the same shape as the aligned beam portion, is formed in the oxide film on the substrate and a metal layer is placed thereon.

At each detection mark, a DC voltage is applied across the oxide film between the metal layer and the substrate.

The current flowing between the terminals varies depending on the portion or area of the detection mark illuminated by the corresponding alignment beam section.

Therefore, by reading the electron-induced current corresponding to the illuminated area of the detection mark, the alignment beam section can be precisely aligned with the detection mark.The flowing current is processed by an amplifier, thereby actuating the servomechanism. positioning and directing the patterned electron beam by moving the photocathode source or substrate or by varying the magnetic fields formed by focusing and deflecting electromagnetic coils surrounding the photocathode source and substrate; Perform automatic alignment of beam sections and corresponding detection marks.

A difficulty encountered with this alignment device is that the detection marks have to be made on the substrate itself.

Although this can be achieved without any hindrance in some instances,
A separate manufacturing process is required to create detection marks on the substrate for the alignment device.

Furthermore, the portion of the substrate where the detection mark is formed is not used in the integrated circuit, so a large portion of the substrate is wasted.

Additionally, the alignment device requires providing circuitry across the detection mark, which can be expensive and cumbersome, and renders the detection mark unreadable at large distances.

DISCLOSURE OF THE INVENTION A method and apparatus are provided for aligning an electron beam to a semiconductor substrate with a desired accuracy of, for example, 0.5 microns or less.

The present invention eliminates the manufacturing steps previously required to create alignment devices for electronic image projection devices.

Moreover, the areas of the major surface of the substrate in which the detection marks are located are made useful in some instances for use in fabricated integrated circuits.

The reading from the detection mark can then be taken at a point far away from the detection mark.

A semiconductor body such as silicon, silicon carbide, germanium and gallium arsenide is provided, which semiconductor body generates cathodoluminescence, the intensity of which corresponds to the thickness of the semiconductor body.

The substrate may be a single crystal wafer made using well known techniques.

Alternatively, the substrate may be an epitaxially grown layer on a suitable supporting substrate, such as sapphire.

In either case, the semiconductor substrate can be detected by forming at least one, preferably two widely spaced detection marks of a predetermined shape near the main surface (on which integrated circuits and other electronic circuit components are formed). is prepared for use in the alignment device.

Each detection mark having a predetermined shape can differentiate the cathodoluminescence generated on the semiconductor substrate depending on the area irradiated with the electron beam.

The predetermined shapes of the detection marks are preferably all the same, and are preferably regular geometric shapes such as circles, rectangles, and triangles.

The predetermined shape of the detection mark can be made in various suitable embodiments.

For example, each detection mark can be formed by simply making a recess of a predetermined shape in the semiconductor substrate.

Therefore, the electron beam can penetrate into the semiconductor body and provide a cathodoluminescence difference on the opposite major surface of the semiconductor body.

Alternatively, the metal layer or insulating layer that absorbs or reflects the electron beam is exposed on the main surface (this has a predetermined shape).
may be formed on the main surface so as to partition.

Additionally, the negatives of the embodiments described above may also provide the desired cathodoluminescence differences.

Specifically, instead of a depression, a mesa of a predetermined shape can be provided.

By doing so, stronger cathodoluminescence is emitted when the electron beam irradiates the area surrounding the detection mark than when it irradiates the area surrounding the detection mark.

Similarly, an opaque layer can be fabricated on the major surface in a predetermined shape rather than defining the exposed surface portion in the shape of a desired detection mark.

In order to align the electron beam with the semiconductor body, the electron beam to be aligned is arranged such that its alignment beam portion is projected onto the main surface of the semiconductor body in the vicinity of the corresponding detection mark. .

Each alignment beam section has a predetermined cross-sectional shape and is typically of the same geometric shape.

To make alignment simple and accurate in various embodiments, the cross-sectional shape of each alignment beam portion is substantially the same as the predetermined shape of the corresponding detection mark.

In any embodiment, a detection body, such as a photodetector, is placed adjacent the opposite major surface of the semiconductor body to detect cathodoluminescence generated by irradiation of the semiconductor body at least in the vicinity of the detection mark. It will be destroyed.

The electron beam is moved relative to the semiconductor substrate while detection continues until detected cathodoluminescence indicates optimal alignment of the alignment beam portion with the corresponding detection mark.

The alignment beam portion and the detection mark may be of any suitable relative size within practical limits, provided that the shapes of both are given.

However, each alignment beam portion has the same cross-sectional shape as the predetermined shape of the corresponding detection mark, so that alignment can be determined simply by reading the maximum or minimum value of the electrical signal from the detected object. desirable.

Otherwise, it will be necessary to process the electrical signals electrically.

The alignment beam section is then oscillated over the corresponding detection mark in order to determine the optimum alignment of the alignment beam section with the corresponding detection mark.

The invention is particularly useful for patterning circuit components with great precision in an electroresist layer or series of electroresist layers on a major surface of a semiconductor substrate.

Typically, alignment is accomplished by selectively illuminating the electroresist layer with either a scanning electron beam or a patterned electron beam generated by a photocathode source.

When using a scanning electron beam for selective irradiation, it is desirable that the main surface of the semiconductor substrate be divided into adjacent fields, and that detection marks of predetermined shapes be arranged symmetrically at the boundaries of the fields.

In this way, the electron beam is aligned with each field in turn and the fields can then be selectively illuminated.

After each field is selectively irradiated, the semiconductor body is moved to align the scanning electron beam with other fields and selectively irradiate the field.

In aligning a photocathode source with a precisely positioned region of a major surface of a semiconductor body in an electronic imaging device, 2
Preferably, the detection marks are spaced apart from one another along the periphery on the major surface of the integrated circuit, and the corresponding alignment beam portions are formed by a patterned electron beam generated by a photocathode source. provided as part of.

Preferably, the detection object is placed near the detection mark, preferably adjacent to the opposite major surface of the semiconductor substrate.

The light generated by the alignment beam portion impinging on or near a corresponding detection mark is detected by a corresponding detector, which emits an electrical signal corresponding to the intensity of the light.

The patterned electron beam is then manually or automatically moved relative to the semiconductor substrate until the detected cathodoluminescence indicates optimal alignment of the alignment beam portion with the corresponding detection mark. It will be done.

Alignment is accomplished automatically by electrical circuitry for moving the patterned electron beam relative to the semiconductor substrate in response to electrical signals from the detector.

For this purpose, the electrical circuitry is preferably synchronized with a modulation means for oscillating the movement of each alignment beam section over the detection mark, and the position of the alignment beam section and the detection mark is preferably synchronized with the modulation means. a phase detector for detecting errors from alignment along orthogonal axes and producing a corresponding electrical signal; and a patterned electron beam from a photocathode source responsive to the electrical signal from the phase detector. and actuating means for varying the electrical input to the electromagnetic means directed to the semiconductor body.

Preferably, the electrical circuit also includes termination means for terminating the vibrations by the actuating means upon optimal alignment of the alignment beam portion and the corresponding detection mark.

The invention will become more easily apparent from the following illustrative description with reference to the accompanying drawings.

Embodiment (Example applied to an electronic image projection device) An electronic image projection device suitable for implementing the present invention (excluding alignment technology and alignment device).

) are described in U.S. Pat. Nos. 3,679,497 and 3,710,101.

In order to simplify and clarify the explanation in this specification, a portion of the explanation regarding the electronic image projection device will be given here as well.)

FIG. 1 shows an electronic image projection device.

Chamber 10 made of non-magnetic material and hermetically sealed
is provided with removable end caps 11 and 12 for accessing parts.

A suction port 1 is provided in the side wall of the chamber 10 to create a partial vacuum in the chamber 10 after the chamber 10 is hermetically sealed.
3 is also provided.

Cylindrical photocathode source or electromask 14
A semiconductor body 15 alignable with the semiconductor body 15 is placed substantially parallel and spaced apart within the chamber 10 .

The semiconductor body 15 is an epitaxial layer on a single-crystal semiconductor wafer such as silicon or a support substrate such as sapphire, and is capable of generating cathodoluminescence with an intensity corresponding to its thickness.

The semiconductor substrate 15 is supported by a substrate holder 16, which will be explained in more detail later.

The photocathode source 14, substrate receiver 16 are placed in a parallel arrangement by annular plate-like supports 17, 18, respectively.

The photocathode source 14 and the substrate receiver 16 are connected to the tubular spacer 1
Exactly released by 9.

The spacer 19 is connected to the grooved flange 20 via gaskets 22, 23 near the periphery of the supports 17, 18, respectively.
, 21.

All these assemblies are connected to a photocathode source 1 in a chamber 10.
4 and the semiconductor body 15 are supported from the end cap 11 of the chamber 10 by a support 17.

The photocathode source 14 is made as a negative electrode and the semiconductor body 15 is made as an anode to direct and accelerate the electrons emitted from the photocathode source 14 towards the semiconductor body 15.

To do this, the substrate receiver 16 and the supports 17 and 18 are made of highly conductive material and the spacers 19
is made of highly insulating material.

For example, the voltage of -10 kilovolts power supply 19A is
It is applied between 7 and 18.

That is, the voltage is applied to the supports 17 and 18 and the base receiver 1.
6 to a photocathode source 14 and a semiconductor body 15.

Three sets of electromagnetic coils are placed perpendicular to each other around the chamber 10 to control the electron beam impinging on the semiconductor substrate 15.

That is, cylindrical electromagnetic coils 241, 242 and 2
43 is placed axially along the electron beam path from the photocathode layer 14 to the semiconductor body 15, causing the electrons to swirl and move radially as they travel the distance from the photocathode source to the semiconductor body.

These electromagnetic coils are used to focus the electron beam.
The rotation θ and size M of the patterned electron beam emitted from the photocathode source are controlled.

The rectangular electromagnetic coils 251 and 252 and 261 and 262 are arranged symmetrically perpendicularly to each other and also perpendicularly to the electromagnetic coils 241 to 243 in a Helm-Horso pair, so that when the electrons travel the distance from the photocathode source to the semiconductor substrate, the electrons are deflect to the side.

These electromagnetic coils control the direction (in the direction of the X and Y coordinates) of the patterned electron beam emitted from the photocathode source.

In operation, a light source 2 such as a mercury lamp with a reflector 27A behind it
7 irradiates the photocathode layer 28 (eg gold or palladium) in the photocathode source 14.

This photocathode layer 28 is illuminated through a substantially transparent substrate 29, such as quartz, on which is a layer 30 containing the negative of the desired circuitry pattern.

Layer 30 is made of a material that is opaque to light (eg titanium dioxide).

Accordingly, the photocathode layer is made of a material that emits a patterned electron beam corresponding to the desired circuit component pattern.

A portion of the patterned electron beam emitted from the photocathode source 14 is divided into at least one and preferably two relatively small aligned beam portions 41 and 42 (eg, 300 microns by 300 microns) having a predetermined cross-sectional shape (e.g. Figure 3).

These alignment beam portions 41 and 42 are preferably widely spaced and located at respective ends along the periphery of the patterned electron beam from the photocathode source.

As shown in FIG.
The photocathode source 14 is precisely mounted within physically permissible limits and therefore precisely mounted to the photocathode source 14.

The semiconductor body 15 has a flat periphery 31 and the body receiver 1
6 has a recess 32 into which the semiconductor body 15 fits.

Base receiver 16 has pins 33 , 34 , 35 and 36 located in each quadrant near the periphery of recess 32 .

The semiconductor body 15 is fixed by supporting its flat periphery 31 with pins 33 and 34 and its curved periphery 37 with pins 35.

Thus, the semiconductor body is positioned with an accuracy of less than about 25 microns.

A movable pin 36 attached to a compression spring 38 is pressed against the curved periphery of the semiconductor body 15 to hold the semiconductor body 15 firmly and thus position the semiconductor body 15 accurately.

First example of detection marks (FIG. 3) As shown in FIG. 3, detection marks 39 and 40 having a predetermined shape are attached to the semiconductor substrate 15, and the detection marks 39 and 40 are attached to the semiconductor substrate 15, and the detection marks 39 and 40 are placed on the semiconductor substrate 15 in a manner corresponding to the area of the detection marks irradiated by the electron beam. Differentiate the cathodoluminescence generated by the substrate.

The predetermined shaped detection marks 39 and 40 are applied by forming recesses in the predetermined planar semiconductor body 15, preferably with a flat bottom.

Etch or ion mill the semiconductor substrate through the desired planar window pattern in a photoresist or electroresist layer (not shown).
lling), the detection marks 39 and 4 are
0 can be formed accurately.

As shown, detection marks 39 and 40 preferably have substantially the same shape as alignment beam portions 41 and 42 of predetermined cross-sectional shape.

The cross-sectional shape of the alignment beam portion and mark may therefore be any suitable geometric shape, such as square, rectangular or circular, for example a square with side a of about 0.25 mm (10 mils). desirable.

The thickness of the semiconductor body 15 is determined in particular by the detection marks 39 and 4.
Where zero is present, it is important for the operation of the alignment device.

The thickness of the semiconductor body 15 at the location of the detection mark must be sufficiently thin so that the electron beam penetrates into the semiconductor body 15 and the cathodoluminescence emanates from the opposite major surface of the body 15.

The acceptable thickness depends on the energy level of the electron beam.

For example, a 10 kilovolt electron beam requires a thickness of about 1 micron or less, whereas a 30 kilovolt electron beam requires a thickness of about 5 microns or less.

On the main surface 15A of the semiconductor substrate 15, a layer of electroresist (not shown) (on which an accurate circuit component pattern is formed) is placed.

Detection bodies 43 and 44, such as photodetectors, are placed behind the detection marks 39 and 40 in the substrate receiver 16.

Lead wires 45 and 4 are connected to each detection body 43 and 44, respectively.
6, 45A and 46A are connected, and these lead wires exit through the vacuum seal 47 of the chamber 10 to the outside.

Detectors 43 and 44 are adapted to detect cathodoluminescence (which is infrared when the semiconductor substrate is silicon) generated by the semiconductor substrate;
In addition, the detection object has a size similar to the detection mark 3 so that the cathodoluminescence from the semiconductor substrate 15 can be detected even if it is dispersed or scattered in or near the detection mark.
9 and 40 and partition them.

Therefore, the detection bodies 43 and 44 are placed very close to the detection marks 39 and 40, and their shape is such that the resolution of the optical signal and therefore the accuracy of alignment between the detection marks and the detection bodies is not degraded.

Note in this regard that in some embodiments, detectors 43 and 44 are placed on the same side of semiconductor body 15 as the photocathode source so that reflected cathodoluminescence is detected. It is better.

However, the detection bodies 43 and 44 are
The photocathode source 14 is preferably placed on the opposite side of the photocathode source 14 .

During operation, the alignment beam portion 4 has a predetermined cross-sectional shape.
1 and 42 are respectively corresponding detection marks 3 having a predetermined shape.
9 and 40 and overlap.

The electron beam penetrates into the semiconductor substrate 15 and produces infrared cathodoluminescence with an intensity corresponding to the depth of penetration of the electron beam.

Therefore, alignment can be accurately recorded simply by observing the intensity of light with the detectors 43 and 44.

What should be noted in connection with this is that the filtering bodies 48 and 49
It is more desirable to insert the sensor between the semiconductor substrate 15 and the detection bodies 43 and 44.

Therefore, only the intense light provided by the alignment beam portions 41 and 42 that impinge on the detection marks 39 and 40 is recorded on the detection object.

When the alignment beam portion and the corresponding detection mark have the same predetermined shape, it is detected where the detected cathodoluminescence shows the maximum intensity of the cathodoluminescence from the semiconductor substrate 15. Optimum positioning is possible with just

4 to 8 show various modifications of the detection marks 39 and 40 having a predetermined shape.

Second example of detection marks (Fig. 4) In Fig. 4, detection marks 39' and 4 of a predetermined shape are shown.
0' is applied by forming a mesa or protrusion on a semiconductor substrate 15' of a predetermined shape.

Each mesa can also be formed with a high degree of accuracy by etching or ion milling the negative of the mesa in the semiconductor body 15' through a suitable photomask or electromask window pattern.

This first variant operates virtually the same as the embodiment shown in FIG.

However, here the thickness of the semiconductor body is more important in the area surrounding the detection marks than in the areas where the detection marks 39' and 40' are applied.

The reason is that what is detected is the absence rather than the presence of cathodoluminescence.

Then, if the alignment beam portion and the corresponding detection mark have the same predetermined shape, optimal alignment is obtained where the minimum intensity of cathodoluminescence is detected.

Third example of detection marks (FIG. 5) Detection marks 39'' and 40'' having a predetermined shape are formed by forming a non-transparent layer 5 on the main surface 15A'' of the semiconductor substrate 15'' in a region surrounding them. It can be attached by.

The detection marks 39'' and 40'' having a predetermined shape are therefore formed by the exposed surface portion (which has a predetermined shape) of the main surface 15A''.

The non-permeable layer 5 can be easily produced using common techniques.

That is, a non-transparent layer is formed over the entire surface area of the main surface 15A'', and then this non-transparent layer is etched or ion milled to form a desired detection mark on the surface portion of the main surface 15''. It is exposed in the form of

The remainder of the alignment system is as described above with respect to FIGS. 1-3.

Non-transparent layer 5 may be made of any suitable material, such as a metal or oxide, that absorbs or reflects the electron beam as desired.

In this regard, it should be noted that "non-transparent layer" does not mean a layer that completely absorbs or reflects the electron beam.

The "opaque layer" need only absorb or reflect enough electronic energy to make an appreciable difference in the generated cathodoluminescence.

The non-transparent layer may itself be cathodoluminescent if it generates light appreciably different from the cathodoluminescence from the semiconductor body 15''.

In operation, as described with reference to FIG. 3, positioning is performed by reading the maximum intensity cathodoluminescence with detectors 43'' and 44''.

Fourth example of detection marks (FIG. 6) As shown in FIG. 15A''' by forming a non-permeable layer 5 on top.

The non-transparent layer 5 has the same predetermined shape as the desired detection mark and is formed of the same material and in the same manner as the non-transparent layer of FIG.

This modified example is a negative version of the modified example shown in FIG. The only difference is in the operation at which the least intense cathodoluminescence is detected in order to achieve optimal alignment.

Fifth Example of Detection Marks (FIG. 7) As shown in FIG. 7, detection marks 39"" and 40"" having a predetermined shape are attached in approximately the same manner as 1 described in connection with FIG.

Materials and operation are identical except for the semiconductor substrate.

That is, the semiconductor body 15'' is an epitaxially grown layer supported on a suitable substrate 6, such as sapphire, which is transparent to cathodoluminescence.

Sixth Example of Detection Marks (FIG. 8) In FIG. 8, detection marks 39'''' and 40'''' of predetermined shapes are provided in substantially the same manner as described in connection with FIG.

The materials and operation are also identical, except for the semiconductor substrate.

In FIG. 8, a semiconductor body 15'''' is epitaxially grown on a suitable support substrate 6, such as sapphire, which is transparent to cathodoluminescence.

Irrespective of the embodiments and variations of the method for aligning an electron beam with a semiconductor substrate, the present invention provides a method for aligning an electron beam with a semiconductor substrate.
The present invention provides a method for aligning a patterned electron beam generated by a patterned electron beam to a precisely positioned region of a major surface of a semiconductor substrate 15.

Additionally, identical detection marks and similar alignment beam sections of successive photocathode sources are used to ensure that all patterned electron beams selectively impinge on the semiconductor substrate with the desired accuracy, e.g. within a fraction of a micron. By using , the semiconductor body can be aligned similarly to a continuous photocathode source.

The error is reduced to such an accuracy that the detection mark and the photocathode layer emitting the corresponding alignment beam portion can be shaped and spatially positioned.

This can be done without any difficulty using a scanning electron microscope and an electronic image projection device.

If the predetermined cross-sectional shape of the alignment beam portion differs from the predetermined shape of the corresponding detection mark, the readings of the detectors 43 and 44 for determining the optimal alignment will differ slightly from the readings described above.

Optimal alignment is no longer indicated by the maximum or minimum value of the signal reading from the detector.

Rather, by selecting a point during the peak condition, taking into account any differences in the geometry of the alignment beam section and the detection mark, or by moving the alignment beam section into and out of the area of the corresponding detection mark. By selecting a point on the rise of the signal from the detector when the signal reading reaches its peak condition and optimal alignment is achieved.

The latter alignment sequence aligns the edge of the detection mark.

Any of the embodiments and variations can be readily used in manual or automatic alignment devices having electrical signal processing circuitry as described below.

The above-described embodiments and variations for alignment devices are, however, more useful for aligning with a scanning electron beam device as described below, rather than in aligning with an electron image projection device as described above. It is.

The current flowing from the detector bodies 43 and 44 is processed by suitable electronic amplifiers and servomechanisms to automatically transfer the entire patterned electron beam relative to the semiconductor substrate and to align the alignment beam portions 41, 42. They are accurately positioned in line with the detection marks 39 and 40, respectively.

For this purpose, suitable means, such as modulation means, are used to oscillate the electrical input to the electromagnetic coil, thereby causing the alignment beam sections 41 and 42 to oscillate over the detection marks 39 and 40; In a typical example, a circle is drawn.

Therefore, the electrical output from detectors 43 and 44 will be modulated.

ELECTRICAL CIRCUIT (FIG. 9) The electrical circuit shown in block diagram form in FIG.
This is for accurately aligning the semiconductor substrate 15 with respect to the entire patterned electron beam from.

The modulated electrical signal from the infrared detector 43 is sent via lead 46 to a preamplifier 50 and then the amplified signal is sent via lead 51 to a tuned amplifier 52.

The output of the tuned amplifier 52 is sent through a lead 53 to a phase adjuster 54 and then through a lead 55 to a phase detector 56.
sent to.

Gated oscillator 57 supplies reference signals 90° out of phase with each other to phase detector 56 through lead wires 58 and 5960 and 61, respectively.

The output of phase detector 56 therefore consists of an X error signal sent through lead 62 and a Y error signal sent through lead 63, which error signals are integrated by leads 65 and 66 after passing through gate 64. Vessel 6
7,68.

Integrators 67 and 68 have DC outputs to adders 69 and 70, respectively, where the DC output is connected to gated oscillator 57.
The AC outputs are modulated by the AC outputs sent through lead wires 71 and 72, respectively.

The summed modulated signal is transmitted to the electromagnetic coils 251 and 252 of the Helmholtz pair in this example and 2
61 and 262 to a controller in a power device (not shown) of the type commonly used.

Similarly, the modulated signal from the detection object 44 is transmitted to the lead wire 46A.
to preamplifier 73 and then to lead 74.
It is sent to a tuned amplifier 75 through a lead wire 76 to a phase adjuster 77 through a lead wire 78, and to a phase detector 79 through a lead wire 78.

The gated oscillator 57 or the two reference signals mentioned above (with a phase difference of 90 degrees) are connected to lead wires 80 and 8, respectively.
1, the signal is supplied to the phase detector 79.

Therefore, two outputs are generated from the phase detector 79.

One output is a theta error signal sent through lead 82 which is sent through gate 83 and lead 84 to a motor-driven precision potentiometer 86 that increases or decreases the current to electromagnetic coil 24 to increase or decrease the pattern. The rotation of the converted electron beam is controlled.

The other output is the M error signal.

This M error signal is used to control the size of the patterned electron beam with a motor driven interlock potentiometer 89 that adjusts the main focusing magnetic field.
3 and lead wire 88.

The error signals sent through leads 62, 63, 82.87 are also electronically cross-fed to a four-input delayed zero detector 94 through leads 90, 9192, 93, respectively.

The output of this zero detector 94 is sent via lead 95 to a set-reset flip-flop 96.

Operation of flip-flop 96 is initiated by actuating a start sequence switch.

When flip-flop 96 begins to operate, current begins to flow through leads 97 and 98, causing light source 27 (first
), causing the photocathode source 14 to emit an electron beam (comprising two alignment beam sections 41 and 42).

Similarly, current flows through lead wires 97 and 99 to gated oscillator 57, and gated oscillator 57 generates sine waves whose phases are 90° different from each other to adders 69 and 70 through lead wires 58 and 71, 60 and 72, respectively. Provides AC output.

The entire patterned electron beam, including alignment beam portions 41 and 42, is oscillated in a 6 micron diameter circle at a frequency of, for example, 45 hertz.

Once alignment beam portions 41, 42 are focused or aligned with detection marks 39, 40, respectively, by the operation of integrators 67, 68 and potentiometers 86, 89, the error signals flowing through leads 90, 9192, and 93 are A value of zero is reached and this is detected by the zero detector 94.

Zero detector 94 generates an electrical signal that is sent to flip-flop 96 through lead 95 when a zero is detected.

This terminates operation of gated oscillator 57 and closes gates 64 and 83 by signals sent through leads 100 and 101, respectively.

A selective electron beam exposure time sequence of the electroresist layer over all areas of the semiconductor body 15 is then initiated and continued until the electroresist layer is fully exposed.

A suitable period of time for sufficient electron beam treatment of the electroresist layer to appropriately vary its solubility in the selected solvent is typically 3 seconds to 10 seconds.

Although the photocathode source 14 generates a patterned electron beam from the entire emissive area during the alignment period, the electroresist layer over the entire area of the semiconductor body 15 is not appreciably exposed due to the short alignment period. .

Embodiment (Example applied to a scanning electron microscope) As is clear from FIGS. 10 to 12, the scanning electron beam 102
The present invention can similarly be used to align a semiconductor body 103 to a semiconductor body 103.

A scanning electron microscope applied to this invention is shown in US Pat. No. 3,679,497.

The detection marks 105 each have the same predetermined shape and are arranged on the main surface 10 in a pattern with constant intervals as shown in FIG.
It is preferable that they be spaced apart over 4.

It is then desirable to divide the main surface 104 into adjacent symmetrical fields.

The reason for dividing the main surface into several fields in this way is that it is suitable for selectively irradiating the electroresist layer 112 on the semiconductor substrate 103 with minimum distortion.

It is desirable that each detection mark 105 has a predetermined shape that is the same as or larger than the scanning electron beam.

This operates exactly the same as the alignment beam section in the alignment device.

An electroresist layer is then created on the main surface 104 in which the circuit component pattern is to be accurately formed.

A series of detectors 106 are disposed within substrate receiver 107, preferably adjacent an opposite major surface 108 of semiconductor body 103.

Each detection object 106 is connected to the detection mark 106 in order to detect cathodoluminescence generated at and near the detection mark 105 when the semiconductor substrate 103 is irradiated.
placed near 5.

As shown in FIGS. 11 and 12, this configuration uses a scanning electron beam from field to field to selectively illuminate a major surface 104 of a semiconductor body 103 in order to selectively illuminate precisely selected areas of the major surface of the semiconductor body. It can be used to align with.

The semiconductor body 103 is divided into adjacent fields.

Preferably, the fields are bounded by detection marks 105, e.g., a detection mark is at the intersection of each field, or centered along each side of each field, and a detection object 106 is located at each detection mark 105. placed near.

In order to align the scanning electron beam 102 with, for example, the field 109, the scanning electron beam 102 is modulated so as to sequentially overlap two diagonal detection marks, for example 1051 and 1052.

The output signal from the detector is supplied to a cathode ray tube (CRT) 110.

This also applies to the computer 1 that controls the scanning electron beam 102.
11 with the intended position of the detection mark for precise alignment.

The signals from the two detection objects 106 corresponding to the detection marks 1051 and 1052, respectively, are detected by the detection marks 1051 and 10.
The scanning electron beam 102 is directed toward the semiconductor substrate 103 until it is focused on the intended position of the semiconductor substrate 52 and thus the overlapping input of the alignment.
be moved against.

Thereafter, the scanning electron beam 102 is modulated so as to sequentially overlap two other detection marks 1053 and 1054 on the diagonal line, which means that the output from the detection object corresponding to the detection mark is the detection mark 1053 from the computer 111 and 1054
CRT11 within the range of the superimposed and intended input for
The scanning electron beam 102, continuing until it coincides with 0, is then aligned and ready for selective irradiation of the field on command from the computer 111.

At the end of the irradiation of the field 109, the semiconductor body 103 is exposed to the scanning field of the scanning electron beam.
It is physically moved to coincide with the field 109' above which is to be selectively illuminated next.

The alignment sequence is then repeated as described above.

The positioning device shown in FIG.
It represents a manual device for those skilled in the art, since alignment adjustments can be made according to the readings on the T.

This is not a desirable arrangement as it requires a relatively long time to complete the alignment sequence.

Therefore, the detection mark is of the same predetermined shape as the scanning electron beam, and instead of a CRT (manual adjustment) an automatic device similar to that described with respect to FIG. It is desirable to align the

Although the presently preferred embodiments of the invention have been described in detail, it is to be understood that the invention can be made and used in various ways within the scope of the claims.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an electronic image projection device embodying the present invention, Fig. 2 is a front view taken along the line ■-■ in Fig. 1, and Fig. 3 is a front view taken along the line -■ in Fig. 2. FIG. 4 is a cross-sectional perspective view of the first modified example, FIG. 5 is a cross-sectional perspective view of the second modified example, and FIG. 6 is a cross-sectional perspective view of the third modified example. 7 is a cross-sectional perspective view of the fourth modification, FIG. 8 is a cross-sectional perspective view of the fifth modification, and FIG. 9 is a cross-sectional perspective view of the fourth modification. FIG. 10 is a block diagram of an electrical circuit for an electronic image projection apparatus shown in FIG. FIG. 11 is a top view of a portion of the semiconductor body of FIG. 11 without the electroresist layer applied, and FIG. 12 is a top view of a portion of the semiconductor body of FIG. 2 is a flowchart showing the interrelationships of functional components when using . 14 is a photocathode layer, 15, 103 is a semiconductor substrate, 1
9 is a spacer, 19A is a power supply, 241, 242, 24
3,251,252,261,262 are electromagnetic coils, 3
9, 40, and 105 are detection marks, 41 and 42 are alignment beam portions, 43 and 44106 are detection objects, and 102 is a scanning electron beam.

Claims (1)

[Scope of Claims] 1. A method of precisely aligning an electron beam with a selected region of a major surface of a semiconductor substrate in order to fabricate a circuit pattern on the semiconductor substrate, which method comprises: A. thickness of the semiconductor substrate; At least two detection marks consisting of depressions or protrusions of a predetermined shape provided by changing the thickness of the semiconductor substrate are provided on the main surface of the semiconductor substrate capable of generating cathodoluminescence with an intensity corresponding to the intensity of the semiconductor substrate. a step of forming the detection mark or each detection mark and making a difference in the cathodoluminescence generated on the semiconductor substrate in accordance with the area of the detection mark irradiated with an electron beam; B. being aligned; projecting the electron beam to the main surface of the semiconductor substrate, the electron beam having at least two alignment beam portions corresponding to the at least two detection marks, and the alignment beam portion or each alignment beam a step in which the portion has a predetermined cross-sectional shape; C. cathodoluminescence generated in the semiconductor substrate at and near a location where the or each alignment beam portion overlaps and irradiates a corresponding detection mark; D. detecting by an external detector and transmitting the electron beam through the semiconductor substrate; E. positioning the electron beam relative to the semiconductor substrate where detected cathodoluminescence indicates optimal alignment of the alignment beam portion with a corresponding detection mark. , a method of aligning an electron beam with a semiconductor substrate. 2. An apparatus for selectively irradiating precisely positioned areas on the principal surface of a semiconductor substrate in order to produce a circuit pattern, comprising: A. a patterned electron beam including at least one alignment beam portion with a predetermined cross-sectional shape; B a semiconductor body having at least one detection mark adjacent to its major surface corresponding to each alignment beam portion; C a photocathode source for positioning the semiconductor body away from said photocathode source; D means for applying a voltage between the semiconductor substrate and the photocathode source, thereby directing electrons from the photocathode source to a certain portion of the main surface of the semiconductor substrate to selectively irradiate this portion; E directing a patterned electron beam from the photocathode source to illuminate a selected portion of the major surface of the semiconductor body proximate to a precisely positioned area and proximate to a detection mark of the major surface of the semiconductor body; electromagnetic means for directing each alignment beam portion to illuminate a selected portion of the surface portion; G. detection means for detecting cathodoluminescence generated at or near a location and generating an electrical signal corresponding to the detection mark area illuminated by the alignment beam portion; G. the semiconductor substrate; substantially aligning the alignment beam portion with a respective detection mark in response to the electrical signal from the detection means for moving the patterned electron beam relative to the semiconductor body; an electrical circuit for positioning and directing a patterned electron beam from the photocathode source relative to the semiconductor substrate such that precisely positioned areas of a major surface can be selectively irradiated with the patterned electron beam; The semiconductor substrate is capable of generating cathodoluminescence with an intensity corresponding to its thickness, each detection mark has a predetermined shape, and the semiconductor substrate has a shape corresponding to an area of the detection mark irradiated with the electron beam. A device for aligning an electron beam with a semiconductor substrate, which is characterized by being able to differentiate the generated cathodoluminescence.