JP4307915B2 - Processing method and equipment using cleaving of samples - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single crystal sample processing method and apparatus, and more particularly to a method and apparatus suitable for application to slicing or dicing.
[0002]
[Prior art]
As is well known, single crystal Si is produced by the Czochralski method (CZ method) or the like. According to this manufacturing method, a rod-shaped single crystal Si ingot having a cross-sectional diameter of 200 mmφ or more and a length of 1 m or more (a single crystal Si ingot is referred to as a “silicon ingot”) is produced. In this CZ method, as is well known, polycrystalline silicon melted in a quartz crucible is adjusted to a temperature suitable for single crystal growth, and a single crystal seed crystal is immersed in the melt. Dislocation occurs at this time, but it is made dislocation-free by necking for dislocation-free growth, gradually increasing the diameter while controlling the pulling rate of the seed crystal and the melt temperature, and a shoulder is formed, which is desired. When the diameter is formed, a straight body portion having a constant diameter is formed, and an inverse conical tail portion is formed while gradually reducing the diameter, thereby completing the lifting.
[0003]
In the slicing process, a hard and brittle silicon ingot is cut with a slicing machine to produce a thin wafer. Alternatively, as the rotating thin blade (for example, the blade has a thickness of 10 to several tens of μm), the inner peripheral blade is cut by the inner peripheral blade and the outer peripheral blade is cut by the outer peripheral blade. The wafer is then subjected to rough surface polishing (lapping) and mirror polishing (polishing). As an example, in the manufacture of solar cells and the like, a mask is provided on the surface of the wafer, an impurity diffusion layer is formed by impurity implantation, a PN junction is formed, a metal film is deposited, and a pattern is formed on the electrode wiring. That is a solar cell.
[0004]
In a substantially cylindrical silicon ingot that is a base material of a semiconductor wafer, when the height direction of the cylinder is the z axis and the two axes that define the plane perpendicular to the z axis are the x and y axes, the vertical direction is the z axis. A single crystal is produced so that the lattice plane (001) plane of the single crystal coincides with the flat surface, and the (100) plane is cut (cut) on the cylindrical side surface. The surface of a semiconductor wafer made of single crystal silicon is a (001) plane (usually used in the (001) plane in many cases). In this case, a number of silicon ingots 10 are cut in a direction perpendicular to the z-axis to produce a substantially disk-shaped wafer. The (100) plane is cut out, and the cut out plane is also called an orientation flat.
[0005]
When the silicon ingot is cut into a wafer, as shown in FIG. 8, it is cut with a wire saw 11 or the like, so that a cutting allowance and a thickness are required to some extent. For this reason, the blade of a wire saw is made thin (width 0.2 mm-1.0 mm), and the cutting margin is shortened. In order to cut at high speed, the thin plate needs to have a certain thickness (0.3 mm to 1.0 mm). The wire saw 11 is not a reciprocating motion but a one-way motion. In FIG. 8, for the sake of simplicity, the wire saw 11 has been described as an example. However, as a cutting machine for cutting a thin plate from a single crystal ingot, an inner peripheral blade type cutting machine, an outer peripheral blade type cutting machine, an ingot rotary type Various types of cutting machines such as a cutting machine, a horizontal type, and a vertical type are used.
[0006]
For example, from a silicon ingot having a length of 1 m, silicon wafers of 500 pieces (with cutting margin = 1.0 mm and thickness = 1.0 mm) to 2,000 pieces (with cutting margin = 0.2 mm and thickness = 0.3 mm) Is disconnected. It takes a long time to cut the wafer. For example, it takes about 8 hours to cut about 300 wafers.
[0007]
In the semiconductor technology, various techniques for preventing misalignment due to charge-up in a processing process using a charged particle beam are conventionally known (for example, Patent Documents 1 and 2).
[0008]
[Patent Document 1]
JP 2002-57151 A (first page)
[Patent Document 2]
Japanese Patent Laid-Open No. 11-154479 (FIG. 1)
[Non-Patent Document 1]
M. Neuberger and SJ Welles, Silicon Data Sheet DS-162. 17 (Oct. 1969)
[0009]
[Problems to be solved by the invention]
If, for example, about 2500 wafers can be cut from a 1 m long silicon ingot, a solar cell will be produced at the same cost as the current polycrystalline silicon, and a single crystal is used. The use of the solar cell for general purposes is also close. A solar cell needs to absorb light and needs a certain degree of strength for processing, and thus has a thickness limitation. Summing up these conditions, it is known that the thickness of the wafer should be 0.1 mm or more.
[0010]
Therefore, in principle, 10,000 wafers can be taken out from a 1 m long silicon ingot.
[0011]
Accordingly, it is an object of the present invention to provide a method and an apparatus that can particularly reduce the time required for wafer fabrication with high accuracy for a single crystal ingot.
[0012]
Another object of the present invention is to provide a method and an apparatus capable of obtaining a wafer having high purity and high surface accuracy.
[0013]
Still another object of the present invention is to provide a method and an apparatus capable of dividing a workpiece into a plurality of dies with high machining accuracy.
[0014]
[Means for Solving the Problems]
A method according to one aspect of the present invention for achieving the above object is as follows:
(A) cutting a single crystal sample side surface in a direction forming a predetermined angle with respect to the cleaved surface of the sample to create a plane;
(B) surface-treating the cut plane;
(C) irradiating the plane with a processing beam along a direction parallel to the cleaved surface of the sample, causing the sample to cleave along the irradiation position of the beam, and cutting the cleaved surface into a cut surface Cutting into a thin plate.
[0015]
The method according to another aspect of the present invention is as follows:
(A) cutting a side surface of the ingot in a direction perpendicular to the cleavage plane of the ingot to create a plane;
(B) surface treating the plane;
(C) Irradiating and driving a beam for processing along a direction parallel to the cutting direction with respect to the plane, causing the ingot to cleave along the irradiation position of the beam, Cutting into a wafer to be performed, and is suitable for application to a slicing process.
[0016]
In the present invention, preferably, in the step (b), the plane is mirror-finished. In the present invention, preferably, in the step (c), the irradiation position of the processing beam on the plane of the single crystal ingot reciprocates within a predetermined range of the cutting line of the ingot. The processing beam may be swung.
[0017]
A method according to another aspect (side surface) of the present invention for solving at least one of the above problems is to irradiate a processing beam onto a single crystal sample which is an object to be processed, and to give an impact to the sample. The sample is cleaved, and the sample is divided using the cleaved surface of the sample as a cut surface, and is suitable for application to a process of dividing a wafer into a plurality of dies. The
[0018]
In the present invention, the beam is preferably an electron beam, or an electron beam and an ion beam, or a laser beam.
[0019]
An apparatus according to still another aspect of the present invention includes a beam source that irradiates a processing beam on a surface of a single crystal sample, and the processing source from the beam source is applied to a cut portion of the sample. The beam is irradiated while being swept linearly within a predetermined range, and the supply of the processing beam is controlled in the beam source, thereby impacting the surface of the sample and causing cleavage. In the apparatus according to the present invention, preferably, the processing beam is controlled so as to rise rapidly.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The outline, principle, and embodiment of the configuration of the present invention will be described below.
[0021]
The method according to the present invention comprises the following steps.
[0022]
Step 1: A plane is created by cutting the surface of the straight body (side surface) of a single crystal ingot in a direction perpendicular to the cleavage plane of the ingot.
[0023]
Step 2: The surface is mirror-polished with a polishing apparatus.
[0024]
Step 3: A processing beam (electron beam) is driven along the cutting direction with respect to the mirror-finished plane, and the ingot is cleaved along the irradiation position of the beam. Cut into wafers.
[0025]
In step 3, the beam for processing is swung so that the irradiation position of the beam for processing on the plane reciprocates within a predetermined range along the cutting line of the ingot.
[0026]
As described above, the present invention applies an impact with a beam to cause cleavage, and cuts into a substantially disk-shaped thin wafer having a cleavage plane as a cutting plane.
[0027]
When the present invention is applied to a dicing process in which a wafer is divided into a plurality of dies, the wafer is cleaved by irradiating a single crystal wafer with a processing beam and giving an impact to the wafer. The sample is divided using the cleaved surface of. In addition, this invention is applicable to the arbitrary division processes of a single-crystal sample besides the dicing process in a semiconductor manufacturing process. The present invention is suitably applied to single crystal silicon (Si), gallium arsenide (GaAs), silicon carbide (SiC), diamond, sapphire dicing and the like.
[0028]
[Principle of the Invention]
The cutting of the single crystal ingot according to the present invention uses cleavage as its principle. Cleaving of a single crystal refers to a phenomenon that instantaneously breaks in the crystal axis direction when an impact is applied in a certain crystal axis direction. The cleaved surface is a flat and low-impurity surface, and many semiconductor experiments are usually performed on this surface. For example, when the surface atoms are densely arranged on the cleavage plane of the single crystal, the unevenness of the surface roughness is set to a minute height such as one or two layers of the size of the atoms. Hereinafter, the cutting procedure will be described.
[0029]
When slicing a wafer using cracks in the crystal axis direction due to cleavage, it is necessary that the beam be uniformly implanted in the crystal axis direction (the flying of charged particles (electrons or ions) in the single crystal ingot). The distance is uniform). If the surface is rough, cleavage may not occur well. Therefore, a plane is cut out on the side surface of the ingot extending in a direction orthogonal to the cleavage plane, the plane is flattened with a polishing device (mirror finish), and, for example, an electron beam is shaken to give an impact. Causes defects and cleaves. Embodiments of the present invention will be described below with reference to the drawings.
[0030]
【Example】
FIG. 1 is a diagram schematically showing the configuration of an embodiment of the present invention. The apparatus according to an embodiment of the present invention includes an electron beam source 20 and is set so that the electron beam 21 is focused on the surface (flat surface) 12 of the silicon ingot 10. The surface (flat surface) 12 of the silicon ingot 10 is formed by cutting or grinding the cylindrical outer peripheral side surface of the silicon ingot 10 in a direction perpendicular to the cleavage surface ([110] or [111] surface) of the silicon ingot 10. By grinding, the cut and cut surfaces are subjected to primary polishing with a polishing apparatus, and after the primary polishing, finish polishing is performed to remove haze and finish to a complete mirror surface, and mirror processing is performed.
[0031]
The silicon ingot 10 may be covered with a mask (not shown) having an opening at a position where the electron beam 21 is irradiated.
[0032]
In the substantially cylindrical silicon ingot 10 that is a base material of a semiconductor wafer, the cleavage plane is a [110] or [111] plane.
[0033]
The silicon ingot 10 is fixed, and the electron beam source 20 reciprocates the electron beam 21 with respect to the flat surface 12 of the silicon ingot 10 on a straight line within a predetermined range sufficient to cause cleavage. An impact is applied to the ingot 10 by the electron beam 21 with a predetermined width (beam trace in FIG. 1) to create a lattice defect. At the same time, the temperature of that portion rises and thermal stress is generated by thermal expansion. It can be easily generated. Thereby, slicing of the wafer is performed.
[0034]
Due to the electron beam irradiation, electrons are reflected to the outside by elastic collision with the surface atoms of the ingot (solid), or inelastic collision with the solid constituent atoms repeatedly, and penetrate into the solid while losing energy. In this case, heat generation, solid atom excitation, ionization, secondary electrons, and X-ray generation occur. Irradiation with an electron beam partially raises the temperature of the ingot surface, resulting in lattice defects that can be caused by distortion of the crystal lattice due to dislocations. When an electron beam is used, a filament (cathode) that emits electrons is used, and an electron beam apparatus including a control electrode (grid), an anode, a focusing lens, and a deflection coil is used. In addition, in the silicon ingot 10, you may make it cover with the mask (not shown) which has an opening in the location irradiated with an electron beam. Alternatively, a neutral beam having good beam directivity may be used as a processing beam for creating lattice defects.
[0035]
In this embodiment, the irradiation spot of the high-current electron beam 21 from the electron beam source 20 is reciprocated along the cleavage plane of the silicon ingot 10 to cause cleavage, and the period of the reciprocating vibration (sweep period). For example, the moving speed of the beam irradiation position exceeds the speed of sound. The electron beam 21 is swept at the frequency. In the case of CRT, the electron beam is swept at a frequency of 50 MHz or more, and far exceeds the speed of sound (9 km / s) in silicon. However, when the focal shape is linear using a cylindrical lens or the like, the sweep may not be particularly necessary. This is because the sweep is performed along the crystal axis in the case of a beam having a focal point, but if the focal shape is a linear shape, the same action and effect may be obtained without sweeping the beam. Because.
[0036]
The cleavage of the silicon ingot 10 is performed instantaneously. For this reason, according to the present embodiment, the wafer cutting process is completed in a very short time.
[0037]
The cut wafer (as-cut wafer) is subjected to a series of processes such as chamfering, lapping, heat treatment, polishing, etc., and used for manufacturing a target device (for example, a solar cell, an integrated circuit, etc.). For example, a product device (for example, a solar cell, an integrated circuit, etc.) is manufactured on a wafer by a known manufacturing process. As a method for manufacturing a solar cell, for example, a p-type single crystal Si wafer may be formed by vapor phase diffusion, coating diffusion, or ion implantation. ⁺ The process includes forming an impurity layer to form a PN junction, forming a front electrode using a transparent conductive member, and further forming a back electrode. As a structure for preventing efficiency reduction due to light reflection on the surface of the solar cell, a structure in which minute (for example, 1 to 2 μm) pyramidal irregularities are formed on the surface of the solar cell and surface reflection is reduced by multiple reflection (CNR solar cell ( Of course, it is also possible to use Comsat Non Reflective Solar Cell)).
[0038]
In the above embodiment, the single crystal Si ingot has been described as an example. For example, a III-V group compound semiconductor material such as single crystal GaAs may be used.
[0039]
According to the above embodiment using cleavage for cutting an ingot into a thin plate, the following effects are obtained.
[0040]
In this embodiment, since no saw is used, a cutting allowance based on the thickness of the saw blade is not required. For this reason, more wafers can be obtained. Moreover, a thin wafer can be obtained. According to this embodiment, from a silicon ingot having a length of 1 m, in principle, several thousand wafers and several times as many wafers can be taken out.
[0041]
In this embodiment, since the saw material is not mixed into the cut surface of the wafer, the purity is high and the surface accuracy is high.
[0042]
Since cleavage occurs instantaneously, the cutting work time can be shortened. For this reason, the manufacturing cost can be reduced.
[0043]
The cleaved surface has surface atoms aligned, and according to this embodiment, processing into a solar cell is facilitated. In other words, a wafer cut from an ingot using cleavage has good characteristics such as surface roughness compared to the one cut by a blade or the like. The processing such as mirror finishing is facilitated, and the manufacturing cost can be further reduced.
[0044]
As described above, according to this embodiment, an important technical problem in making a device such as a solar cell with a silicon single crystal or a GaAs single crystal is solved. It goes without saying that the wafer cut in the above-described embodiment is used for manufacturing any semiconductor device other than the solar cell.
[0045]
FIG. 2 is a diagram for explaining a second embodiment of the present invention. The external force that causes the silicon ingot to cleave is preferably applied impactively and suddenly. That is, it is preferable to shorten the rise time of the electron beam 21 extremely. In the electron beam source 20, it may not always be easy to apply a high voltage suddenly. Therefore, in this embodiment, the electron beam 21 is applied to the collector plate 22 in advance, and an external force is applied to the silicon ingot 10 by switching the deflection (position toward the electron beam 21). In this case, the collector plate 22 may be provided in the same direction as the tracing direction by modulating the electron beam 21. In FIG. 2, the single crystal silicon ingot 10 is moved to the irradiation position of the electron beam 21 every time the wafer is cut. Alternatively, the electron beam source 20 is moved to move the irradiation position of the electron beam 21 to the next cutting position. In FIG. 2, when the electron beam source 20 is moved, the collector plate 22 is disposed along the longitudinal direction of the ingot 10. In FIG. 2, the cleavage plane is the [110] or [111] plane of the crystal plane.
[0046]
The workpiece to be cut by cleavage may be GaAs, SiC, or the like in addition to single crystal silicon.
[0047]
Electron beam irradiation causes lattice defects (transitions) in the single crystal, electron beam energy causes thermal expansion, and internal stress changes in temperature (thermal stress), which is thought to cause cleavage. The
[0048]
For this reason, if the silicon ingot is cooled in advance before cleaving by irradiation with an electron beam, thermal stress due to larger thermal expansion is generated than in the case of room temperature, and favorable cleavage is obtained. The silicon ingot is cooled by, for example, liquid nitrogen.
[0049]
Next, the range of the electron beam in single crystal silicon is about 22 μm at an acceleration energy of 60 Kev and about 200 μm at an acceleration energy of 150 Kev. When the voltage is kept constant and the current value is increased, the energy of electrons injected into the single crystal silicon ingot increases. However, when the temperature rises above the melting point of single crystal silicon, the single crystal silicon melts and thermal stress is generated. do not do.
[0050]
In the electron beam source, it is preferable to irradiate the electron beam with a current that generates the maximum thermal stress in the single crystal silicon for a certain acceleration voltage.
[0051]
The processing beam may be configured to oscillate in a pulsed manner.
[0052]
The focusing of the charged particle beam is determined by the beam voltage and the Coulomb repulsive force of the charged particle charge. A high voltage is used to reduce the beam diameter (spot).
[0053]
In order to reduce the Coulomb repulsive force, a method of simultaneously irradiating an electron beam (negatively charged electrons) and an ion beam (positively charged ions) is used. The charge density in the beam is reduced, the beam focusing property is improved, and the spot diameter can be reduced as compared with the case of irradiation with only the electron beam.
[0054]
Hereinafter, embodiments of the electron beam source 20 will be described. First, a general electron beam source will be outlined. Electrons are accelerated from the cathode of the electrode (201 in FIG. 5) by the voltage applied to the electrode, jump out into the vacuum, and are focused by the focusing coil (204 in FIG. 5) so that the beam has a focus, and the deflection coil (FIG. 5). 205), the electron beam is controlled to be guided to a required position. The main specifications of the welding machine are: acceleration voltage: 60 Kv, beam flow: 0.1 A, beam diameter: 0.1-0.3 mm, deflection coil frequency: 5 kHz or less, and other than welding, quenching and vacuum sealing It is used for such as.
[0055]
As is well known, a CRT (cathode ray tube) such as a television receiver has almost the same configuration of a welder and a filament, an electrode, a grid, and an electrode, and the electron lens system is the same. The focal spot is smaller (about 50 μm) and the acceleration voltage is lower (about 20 KV). CRT is more precise than electron lens system. The degree of vacuum is higher for CRT. This is because the voltage is low and the beam spot is reduced. The horizontal deflection yoke and the vertical deflection yoke are swept by sawtooth waves synchronized with the horizontal frequency and the vertical frequency from the horizontal deflection circuit and the vertical deflection circuit, respectively. The current value of CRT is on the order of 0.1 mA.
[0056]
In addition, the electron microscope has a small spot diameter, the electron beam acceleration voltage is about 400 kV, a high vacuum is applied, the object is not destroyed, and the current value is extremely low in order to reduce the beam spot diameter. An electron microscope does not require a large amount of power to accelerate the electron beam. On the other hand, since the welding machine needs to melt metal or the like, it requires more power than an electron microscope or a CRT, and the current increases accordingly. In other words, the power consumption of these is
Electron microscope <CRT <Welding machine
It becomes.
[0057]
Next, the structure of the electron gun and electrode of the cleavage electron beam in this embodiment will be described below. An electron beam apparatus for cleaving a single crystal silicon ingot is different from the above-described welding, CRT, and electron microscope. That is, it is necessary to raise the electron beam rapidly so as to cope with the occurrence of cleavage by applying a blade to the semiconductor crystal to give an impact. On the other hand, in welding machines, CRTs, and electron microscopes, the electrodes are only used to accelerate the electron beam to the required voltage. A power supply that instantly starts up high power at a high voltage is expensive or difficult to manufacture. Therefore, in this embodiment, as shown in FIG. 3, the anode is divided into two electrodes 104 and 105. The second acceleration power source 107 is a DC voltage power source, and controls the voltage of the first acceleration power source 106 to control the rise time of the electron beam 105.
[0058]
FIG. 4 is a diagram showing an example of a voltage waveform of the cleavage electron beam acceleration power source of FIG. As shown in FIG. 4, the second acceleration power source (acceleration power source 2) is a DC power source. The first acceleration power source (acceleration power source 1) that controls the on / off of the electron beam has a reverse voltage with respect to the second acceleration power source in order to make the electric field near the filament zero when the electron beam is off. Apply it. When the electron beam is extracted, the output voltage of the first acceleration power supply is set to a positive voltage with a short rise time, and the electric field of the filament portion is set in a direction in which the electron beam can be extracted.
[0059]
In order to cleave the sample, it is necessary to apply stress instantly. The instant may be, for example, a time during which a sound wave is transmitted. This is performed by crushing the sample mechanically by a method such as hitting a knife edge or the like along the cleavage axis of the sample. As a condition for an impact, a shock wave is required. Since shock waves travel beyond the speed of sound, the speed of sound gives a standard. In addition, it is necessary to apply a force in the direction of breaking the sample. This corresponds to the use of a knife edge or the like in normal mechanical cleavage. In the present invention, energy is injected by beam irradiation, the temperature of the sample rises, and thermal expansion uses a mechanism in which force acts in the direction of breaking the sample. For this reason, it is possible to perform cleavage with higher accuracy than mechanical cleavage.
[0060]
This rise time (rise) depends on the size of the sample causing the cleavage.
(time) is calculated to be about μs (microseconds) as an order.
[0061]
Setting the rise time of the output voltage of the first acceleration power source 106 in FIG. 3 to μ seconds can be easily realized with a known circuit as long as it is about 2 kV.
[0062]
Next, still another embodiment of the present invention will be described. In the above embodiment, cleavage is used to cut the wafer from the ingot. However, in this embodiment, the single crystal material by the electron beam is cleaved to divide the wafer into a plurality of dies.
[0063]
FIG. 5 is a diagram for explaining the present embodiment. That is, a single crystal such as silicon, gallium arsenide, silicon carbide (SiC), diamond, or sapphire is used as the sample 206 and is divided by irradiation with an electron beam. Scan (sweep) the electron beam at high speed.
[0064]
Since the sample 206 is a single crystal and extremely pure material is an insulator, the sample 206 is charged by the electron beam irradiation, and the position of the electron beam is shifted. In the experiment, it deviates by about 1 mm (depending on conditions) from the position at which the aim was first placed on the metal plate. Also, as a result of charging, the beam may not run on a straight line.
[0065]
Therefore, as shown in FIG. 6, a conductive member 304 is thinly applied or pasted on the surface of the single crystal sample 301 such as silicon, gallium arsenide, silicon carbide (SiC), sapphire, etc., on the side where the electron beam 303 hits. Alternatively, plating is performed, and the surface of the conductive member 304 is grounded by taking an electrical contact 305 with a grounded sample stage 302 and wire connection or the like. The charge on the surface of the sample 301 is discharged.
[0066]
Alternatively, as shown in FIG. 7, a conductive mask 306 is placed near the surface of the sample 301, and the mask 306 is brought into electrical contact 305 with the sample table 302. The electron beam 303 passes through the mask window 307 and strikes the surface of the sample 301. In this embodiment, the conductive member applied to the surface does not enter the sample.
[0067]
A laser may be used as the processing beam.
[0068]
In the embodiment of FIG. 1, the electron beam 21 is scanned (swept) linearly on the processing surface. By using, for example, a cylindrical lens for the focusing control lens system, the shape of the focal point can be made linear. In this case, no beam sweep is required. The line (the focal point of the beam) is along the crystal axis direction. For example, in a silicon single crystal having a thickness of 2 mm, the absorption of light having a wavelength of 1.1 to 6.5 μm is 55% at room temperature, so that it penetrates deeper into the silicon single crystal. For this reason, there is an effect equivalent to increasing the voltage by which the electron beam is extracted (equivalent to 500 keV). In addition, since various pulse lasers can be applied to this wavelength region, the degree of freedom in designing the apparatus is expanded (Non-Patent Document 1).
[0069]
Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the configuration of the above embodiment, and can be made by those skilled in the art within the scope of the principle of the present invention. It goes without saying that various modifications and corrections of the wax are included.
[0070]
【The invention's effect】
As described above, according to the present invention, since slicing is performed using cleavage by electron beam irradiation, there is an effect that a cutting allowance is unnecessary or small, and more thin plates can be obtained.
[0071]
Further, according to the present invention, there is an effect that a thin wafer can be obtained.
[0072]
Furthermore, according to the present invention, since the saw material is not mixed into the cut surface of the wafer, it is possible to provide a wafer with extremely high purity and high surface accuracy.
[0073]
According to the present invention, since cleavage occurs instantaneously, slicing or dicing time can be shortened, and the manufacturing cost can be reduced.
[0074]
According to the present invention, the cleaved surface has aligned surface atoms, facilitating the device processing process. And according to this invention, the reduction of the manufacturing cost of a semiconductor device can be aimed at.
[0075]
Furthermore, according to the present invention, the rise time of the electron beam is shortened, and cleavage by the electron beam is facilitated.
[0076]
Furthermore, according to the present invention, the processing accuracy by the charged particle beam is improved by preventing the sample from being charged.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an embodiment of the present invention.
FIG. 2 is a diagram for explaining an embodiment of the present invention.
FIG. 3 is a diagram for explaining the configuration of an electron beam source according to an embodiment of the present invention.
4 is a diagram for explaining an example of a voltage waveform of an acceleration power supply of the electron beam source of FIG. 3;
FIG. 5 is a diagram for explaining another embodiment of the present invention.
FIG. 6 is a diagram for explaining another embodiment of the present invention.
FIG. 7 is a diagram for explaining another embodiment of the present invention.
FIG. 8 is a view for explaining cutting of a conventional wafer.
[Explanation of symbols]
10 Silicon ingot
12 Flat surface (cut-out surface)
20 Ion source
21 Electron beam
22 Collector plate
101 Filament power supply
102 Filament
103 electron beam
104 First anode (anode 1)
105 Second anode (anode 2)
106 First acceleration power source (acceleration power source 1)
107 Second acceleration power source (acceleration power source 2)
201 cathode
202 anode
203 electron beam
204 Focusing coil
205 Deflection coil
206 samples
301 samples (insulating samples)
302 Sample stand
303 Electron beam
304 Conductive member
305 Electrical contact
306 mask
307 Mask window

Claims (16)

(A) cutting a sample side surface of a single crystal, which is an object to be processed, in a direction perpendicular to the cleavage plane of the sample to create a plane;
A step of mirror polishing the (b) the cut plane,
(C) irradiating the plane with a processing beam along a direction parallel to the cleaved surface of the sample, causing the sample to cleave along the irradiation position of the beam, and cutting the cleaved surface into a cut surface Cutting into a thin plate, and
A processing method comprising :
The beam comprises an electron beam;
The anode for extracting the electron beam from the electron emission device is divided into a first anode and a second anode, and a second acceleration power supply voltage applied to the second anode is applied as a positive DC power as an acceleration power source for the electron beam. And a first acceleration power supply voltage applied to the first anode is controlled from a reverse voltage when the beam is turned off to a positive voltage, thereby controlling the rise time of the electron beam. . When cutting a single crystal ingot, which is a workpiece, into wafers using cleavage,
(A) cutting the body side surface of the ingot in a direction perpendicular to the cleavage plane of the ingot to create a plane;
(B) mirror-finishing the plane;
(C) At least a part of the planned cutting line is irradiated with a processing beam and driven into the plane, and the ingot is cleaved along the irradiation position of the beam, and the cleavage plane is used as a cutting plane. Cutting into wafers;
A processing method comprising :
The beam comprises an electron beam;
The anode for extracting the electron beam from the electron emission device is divided into a first anode and a second anode, and a second acceleration power supply voltage applied to the second anode is applied as a positive DC power as an acceleration power source for the electron beam. And a first acceleration power supply voltage applied to the first anode is controlled from a reverse voltage when the beam is turned off to a positive voltage, thereby controlling the rise time of the electron beam. . (A ) cutting a sample side surface of a single crystal, which is an object to be processed, in a direction perpendicular to the cleavage plane of the sample to create a plane;
(B) mirroring the cut plane;
(C) irradiating the plane with a processing electron beam along a direction parallel to the cleaved surface of the sample, causing the sample to cleave along the irradiation position of the electron beam, Cutting into a thin plate as a cutting surface;
A processing method comprising:
Prepare a collector plate to which a positive voltage is applied to the electron beam,
A processing method comprising: switching a deflection destination of the electron beam to a position to be cut on the plane from a state in which the collector plate is irradiated with the electron beam. The beam processing method according to claim 1, 2, any one of 3 to reciprocate on said plane at a predetermined speed, it is characterized. According to claim 1, the processing method according to any one of 3, wherein said beam is focused to become illuminated position is controlled such that the linear, characterized in that. The beam for processing prior to irradiating, the processing method according to claim 1, 2, any one of 3 including the step of cooling the object to be processed, it is characterized. The processing method according to any one of claims 1 , 2, and 3 , wherein a scratch is made in advance at a predetermined depth at a cutting position of the workpiece by diamond. The object to be processed is a silicon single crystal (Si), gallium arsenide (GaAs), silicon carbide (SiC), diamond, is at least one of sapphire, of claims 1 to 7, characterized in that The processing method as described in any one. A conductive member is provided on the surface of the sample,
The conductive member is grounded;
The discharge charge of the sample surface is irradiated with an electron beam, according to claim 1 or 3 processing method wherein a. Place a conductive mask on the surface of the sample,
The mask is grounded;
Discharging the sample surface charge,
Irradiating an electron beam from the mask window, the processing method according to claim 1 or 3, wherein the. Provided with a beam generation source that irradiates a processing beam on the surface of a single crystal sample,
The processing beam from the beam source is swept over a predetermined range of a cutting line with respect to the cutting position of the sample,
In the beam source, by controlling the rise of the working beam, wherein the surface of the sample by applying an impact causing cleavage, a processing apparatus for cutting or splitting of the sample along the cleavage plane ,
The beam comprises an electron beam;
The anode for extracting the electron beam from the electron emission device is divided into a first anode and a second anode, and a second acceleration power supply voltage applied to the second anode is applied as a positive DC power as an acceleration power source for the electron beam. And a first acceleration power supply voltage applied to the first anode is controlled from a reverse voltage when the beam is turned off to a positive voltage, thereby controlling the rise time of the electron beam. . A beam generation source for irradiating the surface of a single crystal sample with a processing beam;
Means for making the focal point of the processing beam linear;
And irradiating the cutting beam on the sample surface with the processing beam,
The processing beam is irradiated linearly on the surface of the sample, impacts the surface of the sample, causes cleavage, and cuts or divides the sample along the cleavage surface ,
The beam comprises an electron beam;
The anode for extracting the electron beam from the electron emission device is divided into a first anode and a second anode, and a second acceleration power supply voltage applied to the second anode is applied as a positive DC power as an acceleration power source for the electron beam. And a first acceleration power supply voltage applied to the first anode is controlled from a reverse voltage when the beam is turned off to a positive voltage, thereby controlling the rise time of the electron beam. . The processing apparatus according to claim 11 or 12 , wherein the processing beam is irradiated along the crystal axis direction of the sample on the surface of the sample. With a cylindrical lens,
The processing apparatus according to claim 11 , wherein the cylindrical lens is used so that a focal point of the processing beam is linear. A processing device that cuts a substantially cylindrical ingot as a base material of a wafer into a circular shape,
A means for irradiating the surface of a single crystal sample with a processing beam,
With respect to the plane cut in advance on the side surface of the ingot, the processing beam is swept and irradiated in a predetermined range corresponding to the position to be cut in a circle, and at a position corresponding to the irradiation position of the beam A processing apparatus that cleaves the ingot and cuts into a wafer having a cleavage plane as a cleavage plane,
The beam comprises an electron beam;
The anode for extracting the electron beam from the electron emission device is divided into a first anode and a second anode, and a second acceleration power supply voltage applied to the second anode is applied as a positive DC power as an acceleration power source for the electron beam. And a first acceleration power supply voltage applied to the first anode is controlled from a reverse voltage when the beam is turned off to a positive voltage, thereby controlling the rise time of the electron beam. . A processing device that cuts a substantially cylindrical ingot as a base material of a wafer into a circular shape,
A means for irradiating the surface of a single crystal sample with a processing beam,
With respect to the plane cut in advance on the side surface of the ingot, the processing beam is swept and irradiated in a predetermined range corresponding to the position to be cut in a circle, and at a position corresponding to the irradiation position of the beam Cleaving the ingot, cutting into a wafer whose cleavage plane is the cleavage plane,
A processing apparatus comprising: a collector plate that collects an electron beam along a longitudinal direction of the ingot; and controlling the rising of the electron beam by switching the deflection of the electron beam from the collector plate to the plane. apparatus.

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