JP5355928B2 - Manufacturing method of semiconductor substrate by bonding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor substrate that repairs a semiconductor layer missing region more efficiently by avoiding an increase in operation time, and reduces breaking and loss of a silicon film due to remaining foreign matter etc., during laser irradiation by accurately and effectively separating and removing the foreign matter remaining in the missing region of a single-crystal semiconductor layer. <P>SOLUTION: The single-crystal semiconductor layer is laminated on a support substrate, the missing region of the single-crystal semiconductor layer having been laminated is detected by a missing detection device, and the detected missing region is irradiated with a cluster ion beam to separate and remove dust; and a non-single-crystal semiconductor layer is formed on the missing region and single-crystal semiconductor layer, and the non-single-crystal semiconductor layer in the missing region is crystallized based upon detection information and subjected to flattening processing to remove the non-single-crystal semiconductor layer remaining after the crystallization. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a semiconductor substrate in which a single crystal semiconductor layer is provided on a supporting substrate by a bonding method, that is, a method for manufacturing an SOI substrate by a bonding method. More specifically, the present invention relates to a method for manufacturing a semiconductor substrate in which a single crystal semiconductor layer is bonded to a supporting substrate simply and efficiently by a bonding method. In particular, the present invention relates to a method for manufacturing a semiconductor substrate in which the rupture / disappearance of a non-single-crystal semiconductor film due to the remaining foreign matter is reduced.

2. Description of the Related Art Conventionally, a technique related to a semiconductor substrate, that is, an SOI substrate, in which a single crystal silicon layer is provided on an insulating support substrate such as heat resistant glass (see Patent Documents 1 and 2). For example, a manufacturing method in which the entire surface of a crystallized glass having a strain point of 750 ° C. or higher is protected with an insulating silicon film, and a single crystal silicon layer obtained by a hydrogen ion implantation separation method is fixed onto the insulating silicon film. (Patent Document 1).
When the single crystal semiconductor layer such as single crystal silicon is formed on the support substrate, the surface of the support substrate and the single crystal semiconductor layer on the wafer are brought into close contact with each other, and the single crystal semiconductor layer is transferred by heat treatment. That is, it has a bonding process.

If foreign matter is present on any surface during the transfer, a single crystal semiconductor layer is not formed on a supporting substrate such as a glass substrate around the foreign matter, and a semiconductor layer defect region occurs.
The semiconductor layer defect region generated at that time is considerably larger even when the foreign matter is small. For example, even when the foreign matter has a diameter of 1 μm, the defect region has a diameter of about 1000 μm. As a result, the device formed in the defective region becomes defective.

There is already a technique for repairing a defective portion generated in an SOI substrate manufactured by a bonding method (Patent Document 2).
In this repair technique, an amorphous silicon film is formed on the entire surface of a single crystal semiconductor layer, the front surface is crystallized by heat treatment or laser treatment, and then flattened by polishing treatment to repair a defective portion.
JP 11-163363 A JP-A-8-250421

  However, in this conventional repair technique, the entire amorphous silicon film formed on the entire surface of the single crystal semiconductor layer is crystallized, resulting in an increase in work time and a decrease in productivity. That is, the entire crystallization of the non-crystalline silicon film and the removal process of the crystallized silicon film require a longer time than the crystallization process of only the buried portion and the removal process in an uncrystallized state.

Accordingly, the present inventor avoids an increase in working time when repairing the above-described semiconductor layer defect region, and more efficiently repairs the semiconductor substrate provided with a single crystal semiconductor layer by a bonding method. We have succeeded in developing the manufacturing method and have already filed a patent application (Japanese Patent Application No. 2008-60554).
In the manufacturing method, a single crystal semiconductor layer is bonded to a supporting substrate, and after bonding, a defect region of the single crystal semiconductor layer is detected by a defect detection device, and after the detection, a single crystal semiconductor layer is formed on the single crystal semiconductor layer and the defect region. Forming a crystalline semiconductor layer, then crystallizing the non-single-crystal semiconductor layer in the defect region based on the detection information, and then performing a planarization process to remove the non-single-crystal semiconductor layer remaining after the crystallization. It is a feature.

The present invention is a further improvement of the semiconductor substrate manufacturing method described above.
That is, according to the present invention of the prior application, after detecting the defect region of the single crystal semiconductor layer, the detection region is irradiated with a special ion beam to accurately and effectively separate the remaining foreign matter. It has been found that the silicon film can be removed, and the ground can be smoothed. As a result, the rupture / disappearance of the silicon film due to the remaining foreign matter can be reduced, and the present invention has been successfully developed.

Therefore, the present invention avoids an increase in working time when repairing a semiconductor layer defect region, and can repair more efficiently, and a method for manufacturing a semiconductor substrate provided with a single crystal semiconductor layer by a bonding method In addition to this, non-single crystals such as silicon films accompanying the remaining of foreign matters during laser irradiation are obtained by accurately and effectively separating and removing foreign matters remaining in the defect region of the single crystal semiconductor layer. Another object of the present invention is to provide a method for manufacturing a semiconductor substrate in which the rupture / disappearance of the semiconductor film is reduced.

  In the present invention, the single crystal semiconductor layer is bonded to the supporting substrate simply and efficiently by the bonding method, and in addition, the non-single crystal semiconductor layer is ruptured / disappeared due to residual foreign matter (dust) during laser irradiation. A method for manufacturing a reduced semiconductor substrate is provided, in which the single crystal semiconductor layer is bonded to a support substrate, and after bonding, a defect region of the single crystal semiconductor layer is detected by a defect detection device, After the detection, the defect region is irradiated with a cluster ion beam to separate and remove foreign matter, and then a non-single crystal semiconductor layer is formed on the defect region and the single crystal semiconductor layer, and the defect is formed based on the detection information after the formation. The non-single-crystal semiconductor layer in the region is crystallized and then planarized to remove the non-single-crystal semiconductor layer remaining after the crystallization.

In the present invention, it is preferable to do the following.
(1) The bonding of the semiconductor layer is performed by tightly bonding the semiconductor wafer on the support substrate, and then separating at a layered damaged region previously formed on the wafer, so that a part of the wafer remains in a thin layer shape. It is due to letting.
(2) The tight bonding of the semiconductor wafer onto the support substrate is performed after the insulating layer is formed on the support substrate.
(3) The layered damaged region is formed by forming an insulating layer on the surface of the semiconductor wafer, and irradiating the ion beam accelerated by an electric field after the formation through the insulating layer to a predetermined depth of the semiconductor wafer. It must be formed in layers.

Moreover, the following is also preferable in the present invention.
(4) The thickness of the single crystal semiconductor layer is 20 to 500 nm.
(5) The semiconductor wafer is tightly coupled to the support substrate by pressing the one end of the semiconductor wafer after the semiconductor wafer is brought into close contact with the support substrate.
(6) The tight bonding of the semiconductor wafer onto the support substrate means that the semiconductor wafer is brought into intimate contact with the support substrate and one end thereof is pressurized, followed by further heat treatment.
(7) The tight bonding of the semiconductor wafer on the support substrate is to interpose an insulating film between them.

Furthermore, the present invention also preferably has the following.
(8) Separation in the layered damaged area shall be performed by heat treatment and causing the separation.
(9) The defect detection apparatus includes an image analysis unit having a CCD and an image analysis program for outputting position coordinates of a defect region necessary for image analysis, and a computer for functioning the program.
(10) The planarization process is CMP, DRY etching, or a combination thereof.

  As described above, the present invention simply and efficiently bonds the single crystal semiconductor layer to the support substrate by the bonding method, and in addition, the non-single crystal semiconductor layer is ruptured / disappeared due to the remaining foreign matter during laser irradiation. A method for manufacturing a reduced semiconductor substrate is provided, in which the single crystal semiconductor layer is bonded to a support substrate, and after bonding, a defect region of the single crystal semiconductor layer is detected by a defect detection device, After the detection, the defect region is irradiated with a cluster ion beam to separate and remove dust, and then a non-single crystal semiconductor layer is formed on the defect region and the single crystal semiconductor layer, and the defect is formed based on the detection information after the formation. The non-single-crystal semiconductor layer in the region is crystallized and then planarized to remove the non-single-crystal semiconductor layer remaining after the crystallization.

As a result, the crystallization of the non-single-crystal semiconductor layer targets only the defect region of the semiconductor layer, so that the irradiation region can be extremely reduced, for example, when crystallization is performed by laser irradiation.
In addition, the removal of the semiconductor layer that exists after the crystallization treatment such as laser irradiation other than the defect region at the time of the planarization treatment is performed by crystallization as in the case of the prior art because the semiconductor layer to be removed is in an amorphous state. Since it is not, it can be done easily without any hassle.

In the present invention, the foreign matter (dust) remaining in the defect region of the single crystal semiconductor layer is separated and removed by irradiating the cluster ion beam, so that the foreign matter can be more accurately and effectively separated and removed. As a result, rupture / disappearance of the non-single-crystal semiconductor layer due to remaining foreign matter or the like during laser irradiation can be reduced.
In addition, since the cluster ion beam is irradiated to remove the foreign matter, the surface of the support on which the non-single crystal semiconductor layer is formed can be smoothed. From this point as well, the non-single unit at the time of laser irradiation during crystallization can be obtained. The rupture / disappearance of the crystalline semiconductor layer can be reduced.

As described above, according to the present invention, a semiconductor substrate in which a single crystal semiconductor layer is bonded to a supporting substrate can be manufactured simply and efficiently, and at the same time, a non-single crystal at the time of laser irradiation during crystallization Rupture / disappearance of the semiconductor layer can be reduced.

The best mode for carrying out the present invention and various aspects of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the best mode and various aspects for carrying out the invention described above, and various changes can be made in the form and details without departing from the spirit and scope of the present invention. This is because those skilled in the art can easily understand this.
In the description of the present invention, the same reference numerals in the drawings are used in common in different drawings.

(Embodiment 1)
The first embodiment will be described with reference to FIGS. As the single crystal semiconductor wafer, for example, a single crystal semiconductor made of a Group 4 element such as single crystal silicon, single crystal germanium, or single crystal silicon germanium can be used. Furthermore, compound semiconductors such as gallium arsenide and indium phosphide can also be used.
Note that here, a single crystal silicon wafer is used as a semiconductor wafer, and a glass substrate 51 is used as a supporting substrate. FIG. 1 shows a case where the single crystal semiconductor layer is a single crystal silicon layer 54.

First, H is doped on a single crystal silicon wafer. The damaged layer is formed in the vicinity of a depth of about 100 to 300 nm from the Si surface by acceleration of H doping. Further, a bonding layer 52 is formed on the single crystal silicon wafer. As the bonding layer, a SiON film (silicon oxynitride film) is formed with a thickness of 50 nm, and a SiNO film (silicon nitride oxide film) is formed with a thickness of 50 nm. These can be formed by CVD. The bonding layer may have a single layer structure or a laminated structure, but the surface average roughness is Ra = 4 nm or less by means such as CMP (Chemical Mechanical Polishing) treatment of the surface.
On the other hand, the bonding layer 53 having a surface average roughness of Ra = 4 nm or less is also formed on the glass substrate. As the bonding layer, a film using silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, or the like can be used, and a single-layer structure or a stacked structure may be used.
These bonding layers naturally also have a function as a buffer layer or a blocking layer.

  Note that in the above, the silicon oxynitride film refers to a film having a higher oxygen content than nitrogen, and the silicon nitride oxide film refers to a film having a higher nitrogen content than oxygen. Specifically, the silicon oxynitride film has oxygen of 50 to 70 atomic%, nitrogen of 0.5 to 15 atomic%, and silicon of 25 to 35 when measured using Rutherford backscattering method or hydrogen forward scattering method. It means what is contained in the range of atomic%, hydrogen 0.1-10 atomic%. On the other hand, when measured using the same method for a silicon nitride oxide film, oxygen is 5 to 30 atomic%, nitrogen is 20 to 55 atomic%, silicon is 25 to 35 atomic%, and hydrogen is 10 to 25 atomic%. The one included in the range.

Then, when the wafer and the glass substrate are brought into close contact with each other and subjected to heat treatment at 400 to 600 ° C., when the wafer is separated, the layer having the Si layer peeled off from the wafer on the glass surface is H-doped. It is formed with a target film thickness by acceleration. At that time, if there is a foreign substance on the surface of either the wafer or the glass substrate, a defect region of the single crystal semiconductor layer (hereinafter sometimes simply referred to as “semiconductor layer defect region”) is formed. FIG. 1A shows a cross-sectional view of the glass substrate 51 at this time. A single crystal semiconductor layer (a bonding layer formed on a single crystal silicon wafer when a single crystal silicon layer 54 in FIG. 1 corresponds) is shown. 52 is missing.
Note that FIG. 1 illustrates the case where the single crystal semiconductor layer is the single crystal silicon layer 54 as described above.

In the present invention, as described above, the defect region of the semiconductor layer is detected by the defect detection device, and the defect region is irradiated with the cluster ion beam based on the detection information to separate and remove the foreign matter 55, and additionally embedded in the defect region. The non-crystalline semiconductor layer 57 is selectively crystallized, and the position information of the semiconductor layer defect region is acquired by using, for example, an optical inspection device as the detection device.
More specifically, for example, by using a CCD camera to capture the luminance at each position of an image captured by the CCD camera, the region different from the luminance of the single crystal semiconductor layer is a semiconductor except for a marker portion formed in advance in the image. It is recognized by a later data processing unit as a layer defect region.

Then, based on the recognized position information of the semiconductor layer defect region, the cluster ion beam is irradiated to separate and remove the foreign matter 55, and FIG. 1 (B) shows a cross-sectional view at this time. is there. In this case, since the irradiated beam is a cluster ion beam, not only foreign substances can be separated and removed, but also the support surface on which the amorphous semiconductor layer 57 is formed is smoothed.
Therefore, this smoothing can reduce rupture / disappearance of the non-single-crystal semiconductor layer during laser irradiation during crystallization.

  Next, a non-single-crystal semiconductor layer 57 is formed over these, that is, over the single-crystal semiconductor layer and the defect region (FIG. 1C). The non-single-crystal semiconductor layer is formed using an amorphous semiconductor formed by vapor deposition or sputtering using a semiconductor material gas typified by silane or germane, and the amorphous semiconductor is irradiated with light energy or thermal energy. A polycrystalline semiconductor or the like crystallized by use can be used.

  When the CVD method is used for the film formation, the coverage is good, so that the formed non-single crystal semiconductor film preferably fills the single crystal semiconductor layer defect region. However, when a silicon film is formed by CVD film formation, if the hydrogen concentration in the film is high, the silicon film may disappear by a later laser treatment. Need to be released. In this embodiment, since silicon is used for the single crystal semiconductor layer, an example in which a silicon film is formed by a CVD method is described.

Then, the silicon film formed so as to fill the semiconductor layer defect region is selectively crystallized by the laser 58 based on the detection information (FIG. 1D). Note that in the present invention, the non-single-crystal semiconductor layer remaining other than the defective portion is removed by performing the planarization process after the crystallization process (FIG. 1E).
The diameter of the defect part is several mm, but the laser irradiation part is set at least in a range wider than the defect part, preferably in a range wider than 1 mm so that the surrounding normally formed single crystal semiconductor layer is included. To do. As a result, the silicon film at the defective portion is crystal-grown using the surrounding single crystal semiconductor layer as a base.

  At this time, it is preferable to irradiate the laser beam while the processing substrate is heated by means such as irradiation with heated nitrogen or microwave so that the melting time of the silicon film becomes longer. Thus, in order to melt a silicon film and grow a crystal with a single crystal semiconductor layer as a base, it is necessary to heat the non-single crystal silicon film to a temperature higher than the heat resistant temperature of the glass substrate. In heat treatment using lamp annealing or the like, Have difficulty.

The present invention selectively separates and removes foreign substances by selectively irradiating a cluster ion beam based on positional information of a semiconductor layer defect region detected by a defect detection device, and selectively irradiating a non-single crystal semiconductor film with a laser. In this method, a defect detection device, a cluster ion beam irradiation device, and a laser direct drawing device are used.
The present invention is characterized by irradiating a cluster ion beam in order to separate and remove the foreign matters remaining in the detected defect region, which will be described in detail below with reference to FIG.

  In the present invention, the defect detection device first detects the defect region of the semiconductor layer, which will be first described with reference to FIG. The image analysis unit (21) forming a part of the defect detection apparatus (1) shown in FIG. 2 is provided separately from the cluster ion beam irradiation apparatus, and data processing is performed on the position information (22) of the semiconductor layer defect area. Part (23). In this case, the position information of the semiconductor layer defect region is acquired by the CCD (33), and the image analysis unit 21 performs image analysis. The detected data, that is, the defect region position information (22) is the data processing unit (23). ) Is output.

Although not shown, the image analysis unit 21 includes an image analysis program for outputting position coordinates of a defective area necessary for image analysis, and a computer that functions the program, and is a substrate obtained from a CCD. By comparing the relative difference in luminance within the substrate surface from the surface image, the defective area is determined.
In order to determine a defective area using this image analysis program, the following two methods are preferable.

  First, the structure information (film quality, film thickness) of the desired laminated structure formed on the support substrate is first input to the image analysis program, so that the structure information of the defective region and the structure information (film quality, film thickness, Film thickness) is stored in advance in an image analysis program, and then a semiconductor layer formation region in which a stacked structure is actually formed on a support substrate and a semiconductor layer defect region in which the stacked structure is not formed are simulated. Calculating each image brightness, calculating a threshold value of the image brightness for determining the defective area from the calculated image brightness, and outputting the position coordinates of the defective area based on the threshold value It is.

Second, a semiconductor layer forming region having a desired laminated structure and a semiconductor layer defect region where the laminated structure is not formed are formed in advance on a support substrate, and the CCD is formed using both regions as reference materials. The image brightness is measured by using the measured image brightness, a threshold value of the image brightness for determining the defective area is calculated from the measured image brightness, and the position coordinates of the defective area are output based on the threshold value.
In the apparatus used for manufacturing the semiconductor substrate of FIG. 2, a CCD (33) is separately installed for the defect detection apparatus (1), but the CCD for the laser direct drawing apparatus (2) is not installed. (31) may be shared by both.

The present invention is characterized by irradiating a cluster ion beam in order to separate and remove foreign matters remaining in the defect area detected as described above. After the cluster ion beam irradiation, the defect area and A non-single crystal semiconductor layer is formed on the single crystal semiconductor layer, and after the formation, the non-single crystal in the defect region is crystallized based on the detection information.
Since it is as mentioned above, based on FIG. 2, cluster ion beam irradiation is demonstrated first. For the cluster ion beam irradiation, a cluster ion beam irradiation apparatus 3 including a high pressure gas supply unit 41, a nozzle 42, a shutter 43, an ion source 44, an extraction electrode and acceleration electrode 45, a lens electrode 46, and the like is used.

The high-pressure gas supply unit 41 uses a gas regardless of the magnitude of reactivity, such as argon, carbon, boron, nitrogen, and silicon, and injects it at a high pressure. In addition to the gas, a reactive gas such as SF ₆ gas may be used.
The high-pressure material gas injected from there is ejected into the vacuum through a trumpet-shaped thin tube called the nozzle 42, whereby the gas is cooled to below the condensing temperature by adiabatic expansion and combined by van der Waals force. A cluster is created.

  A shutter 43 is provided between the nozzle and the substrate, and receives a signal from the data processing unit 23 and adjusts the generation time of cluster ions and the like. In the adjustment, cluster ions can be generated intermittently at high speed. In the present embodiment, a data processing unit 23 is provided in the cluster ion beam irradiation apparatus, receives a luminance and position information from the optical inspection apparatus, determines a semiconductor layer defect area, and stores information on the defect area (RAM, ROM, etc.), a microprocessor including a CPU, etc., and a substrate to which the cluster ion beam is irradiated by irradiation position control means (in FIG. 2, the shutter and position drive control unit 30 correspond) The position of the surface of 27 is controlled.

The generated cluster is further ionized by an electron impact method with an ion source 44 composed of a filament and an anode to form cluster ions. The cluster ions are accelerated by an electric field of several kV to several tens of kV by the extraction electrode and the acceleration electrode 45, and the irradiation shape is adjusted as a cluster ion beam by the lens electrode 46, and collides with the target surface.
The cluster ion beam can be focused on a minute region (about several tens of μm) by using a lens electrode 46, that is, an electrostatic lens. Moreover, directivity is good and it is suitable as a method of processing a desired fine part.

The cluster ion beam is said to be the lateral sputtering effect, and ions generated by the decomposition of cluster ions at the irradiated location are scattered in the horizontal direction and flattened in the vicinity of the irradiated location by colliding with uneven portions on the substrate surface. effective.
Since the lateral sputtering effect is more effective as the acceleration energy is larger, a process with a high selection ratio for reducing the acceleration energy and a base planarization process for increasing the acceleration energy are combined. For the treatment, cluster ion beam treatment using different gases may be performed.

As described above, the non-reactive gas can be used as the source gas of the cluster ion beam. However, a reactive gas such as SF ₆ gas can also be used, but when SF ₆ gas is used, The effect of selecting the garbage to be separated and removed can be expected. That is, the SF ₆ gas becomes SF ₆ cluster ions, and Si and W are easily etched by irradiating them. At this time, the smaller the acceleration energy is, the more dominant the etching by chemical reaction is, so that the selection ratio between Si and SiO ₂ increases. For example, the selection ratio at an acceleration voltage of 10 keV is about 30. When a glass substrate is used as the support substrate or when SiO ₂ is used as the base film of the semiconductor layer, if the main component of dust is Si or W, damage to the base due to cluster ion irradiation is reduced by the above selection ratio. be able to.

In the present invention, as described above, after the cluster ion beam irradiation, a non-single crystal semiconductor layer is formed on the defect region and the single crystal semiconductor layer, and after the formation, the non-single crystal of the defect region is formed based on the detection information. Crystallization is performed using a laser direct drawing apparatus.
The laser direct drawing apparatus can use the technology of the conventional laser direct drawing apparatus. A specific example of an apparatus used for manufacturing a semiconductor substrate including this direct drawing apparatus is shown in FIG. FIG. 3 shows that at least a laser light source, a shutter, a mirror driver, a movable mirror, and a lens for irradiating a laser on the substrate on the stage from the laser light source are provided.

The apparatus illustrated in FIG. 3 includes a defect detection device 21, a defect region position information 22, a data processing unit 23, and the like, similar to the apparatus illustrated in FIG. In the apparatus shown in FIG. 1, the two are provided in duplicate, and of course, they may be provided separately in both of them. However, the defect detecting device 21 and the like are provided in only one, and the other is provided in the other. Needless to say, the defect detection device 21 or the like may also be used.
For example, it is needless to say that the defect detection device 21 and the like may be attached to the cluster ion beam irradiation device 3 shown in FIG. 2 and may be used without being attached in the direct drawing device.

Further, when the CCDs 33 are individually installed, a maximum of four CCDs are required as is apparent from FIGS. 2 and 3. However, as described above, since the CCDs 31 can be used together, it is possible to make one by using the CCDs 33 as well. Nor.
Further, the data processing unit (23) used for detecting the semiconductor layer defect region described above also processes information for driving the laser direct drawing apparatus. In the laser direct drawing apparatus, laser irradiation is performed in order to crystallize a silicon film formed on a glass as a support substrate, and the laser light source (24) crystallizes the formed silicon film. It should have a constant output with sufficient energy.

As the light source of the laser light, gas laser such as Ar laser, Kr laser, excimer laser, single crystal YAG, YVO ₄ , forsterite (Mg ₂ SiO ₄ ), YAlO ₃ , GdVO ₄ , polycrystalline (ceramic) Laser using YAG, Y ₂ O ₃ , YVO ₄ , YAlO ₃ , GdVO ₄ as a medium with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta added as dopants A laser oscillated from one or plural kinds of glass laser, ruby laser, alexandrite laser, Ti: sapphire laser, copper vapor laser, or gold vapor laser can be used. Furthermore, when a solid-state laser whose laser medium is a solid is used, there are advantages that a maintenance-free state can be maintained for a long time and output is relatively stable.

  Similarly, a data processing unit that forms part of the defect detection device receives brightness and position information from the optical inspection device, determines a semiconductor layer defect region, and stores information on the defect region (RAM, ROM, etc.). ), A microprocessor including a CPU, etc., and a substrate to be irradiated (irradiated with laser light passing through a light control means (the shutter (25) and the movable mirror (26) in FIG. 3 correspond)) 27) The surface position and the like are controlled.

  As shown in FIG. 3, on the optical path of the laser light emitted from the laser light source, a movable mirror (26) which is a light control means that receives a signal from the data processing unit and is controlled by the mirror driver (28). ) Is provided. The movable mirror can scan light (electromagnetic waves) in the X and Y axis directions and irradiate a desired portion with laser light. In this case, it is preferable to use a polygon mirror or a galvanometer mirror. Similarly, a shutter (25) controlled by the signal constituting the light control means is provided so that the emission timing of the laser light source can be controlled by the data processing unit.

Furthermore, the stage (29) to which the support substrate is fixed may be moved to selectively irradiate the laser by a method of synchronizing the laser light source emission timing and the stage movement. At this time, on / off control of the laser light source is performed with a shutter, which is a light control means, and the laser beam is selectively irradiated while moving the stage.
When performing this laser irradiation, a marker is formed at a desired position on the substrate, and the substrate on the stage is positioned by the position drive control unit (30) using the marker as a reference point.

For the positioning, it is preferable to use a method of recognizing an image captured by the CCD (31) by image processing. In general, the precision positioning method using a marker as described above is not limited to a laser processing step in semiconductor device fabrication, for example, a photolithographic exposure step, a laser semiconductor device formation, cutting, and the like. It is used in the laser direct drawing process used for openings and the like. However, since no element is formed at the time of the crystallization, a positioning error of about several hundred μm is allowed. The marker may be formed on the insulating film below the semiconductor layer.
When the laser direct drawing apparatus is employed when crystallizing the non-single crystal semiconductor layer in the single crystal semiconductor layer deficient region as described above, the process of irradiating the laser as described above is monitored through the CCD (31) ( It is preferable to provide means that can be confirmed in step 32).

In the present invention, after crystallizing the silicon layer in the semiconductor layer defect region on the substrate in this way, the single crystal semiconductor layer is flattened and thinned by CMP, DRY etching, or a combination thereof, and the desired film thickness is obtained. To do.
Here, the single crystal semiconductor layer has a thickness of 50 nm. Since the amorphous semiconductor layer formed by CVD other than the semiconductor defect region disappears by the thinning, it is not necessary to crystallize the portion which is not the semiconductor layer defect region with the laser as described above.
Note that when the single crystal semiconductor layer is thinned and the Si film is thinned, an effect of improving the S value is expected. However, in this case, an optimum condition is adopted because of a trade-off with a decrease in I _on. It will be.

Thereafter, an Si layer is formed in an island shape, a gate insulating film is further formed to a thickness of 10 to 100 nm, a gate metal made of Ta, W, or the like is formed thereon, an interlayer film, a wiring is formed, A desired element is formed.
Note that since the thickness of the single crystal semiconductor layer is as described above, the thickness of the channel portion is 50 nm.

FIG. 4 is a flowchart showing all the steps of the manufacturing method of the present invention described above with reference to FIGS.
The process shown in FIG. 1 includes a step of forming a single crystal semiconductor layer on a support substrate (11), a step of obtaining information on a semiconductor layer defect region with an optical inspector (12), a step of removing foreign matter (13), silicon This is achieved by performing a film forming step (14), a step of crystallizing silicon in a semiconductor layer defect region with a laser (15), and a step of planarizing the semiconductor layer (16). Thereafter, a step (17) of forming a thin film transistor layer having a structure suitable for the desired semiconductor device is performed.

  The cluster ion beam irradiation in the present invention can effectively separate and remove foreign matters such as dust, and as a result, can reduce the rupture / disappearance of the non-single-crystal semiconductor layer due to the remaining foreign matters during laser irradiation. Further, since the cluster ion beam is irradiated to remove the foreign matter, the surface of the support on which the non-single crystal semiconductor layer is formed can be smoothed. This smoothing also causes non-single laser irradiation during crystallization. The rupture / disappearance of the crystalline semiconductor layer can be reduced.

  Further, the selective laser irradiation according to the present invention is more effective for shortening the processing time as the substrate has a larger area and the smaller the semiconductor layer defect region. For example, if a single point laser with a width of 500 μm and a processing speed of 350 mm / sec is used and the entire surface of a rectangular support substrate having a size of 600 × 720 mm is irradiated with laser to perform crystallization, then one support substrate Although the processing time is 1 hr to 1.5 hrs, the processing time can be shortened by limiting and selectively performing this laser irradiation region according to the present invention. For example, the semiconductor layer defect region is usually 1% or less according to the experience of the present applicant, and accordingly, the laser energy applied to the substrate can be greatly reduced.

(Embodiment 2)
This embodiment mode shows details of a manufacturing process until a single crystal semiconductor layer is transferred onto a supporting substrate, according to the method for manufacturing a semiconductor substrate of the present invention. In this embodiment mode, a semiconductor substrate in which a single crystal semiconductor layer is fixed to a supporting substrate through a buffer layer serving as an insulating layer will be described. However, the interposition of this buffer layer is preferable but necessary. is not. Note that in this embodiment mode, the buffer layer is formed over a single crystal semiconductor wafer, but may of course be formed over a supporting substrate as in Embodiment Mode 1. An example of a semiconductor film substrate manufactured by the manufacturing method of the present invention is shown in a perspective view in FIG.

  In the semiconductor substrate 10, a single crystal semiconductor layer 116 is attached to a support substrate 100, and the single crystal semiconductor layer 116 is provided over the support substrate 100 with a buffer layer 101 interposed therebetween. The semiconductor substrate 10 is a so-called SOI structure substrate in which a single crystal semiconductor layer is formed over an insulating layer. Note that, as described above, a single crystal semiconductor made of a Group 4 element such as single crystal silicon, single crystal germanium, single crystal silicon germanium, or the like can be used for the single crystal semiconductor layer. Furthermore, compound semiconductors such as gallium arsenide and indium phosphide can also be used.

As the support substrate 100, for example, various glass substrates used in the electronic industry such as aluminosilicate glass, aluminoborosilicate glass, and barium borosilicate glass are used. In addition to the above example, a substrate using a material having a softening point temperature higher than that of the glass substrate may be used. For example, a quartz substrate, a ceramic substrate, a sapphire substrate, a conductive substrate made of a conductor such as metal or stainless steel, or a substrate made of a semiconductor such as silicon or gallium arsenide may be used. However, when the surface has conductivity, an insulating layer is formed on the substrate surface.
Note that by using a light-transmitting substrate for the supporting substrate 100, the semiconductor substrate 10 suitable for manufacturing a transmissive or transflective display device can be manufactured.

Hereinafter, a method for manufacturing the semiconductor substrate 10 illustrated in FIG. 5 will be described with reference to FIGS.
First, as illustrated in FIG. 6A, the insulating layer 112 is formed over the single crystal semiconductor wafer 110. The insulating layer 112 can have a single-layer structure or a multilayer structure including two or more layers. The thickness can be 5 nm or more and 400 nm or less. In this embodiment, the buffer layer has a two-layer structure in which the insulating layer 112 includes the insulating film 112a and the insulating film 112b.
In the case where the insulating layer 112 has a two-layer structure and functions as a blocking layer, a combination of the insulating film 112a and the insulating film 112b includes, for example, a silicon oxide film and a silicon nitride film, and a silicon oxynitride film and a silicon nitride film. A silicon oxide film and a silicon nitride oxide film, a silicon oxynitride film and a silicon nitride oxide film, and the like.

The buffer layer is a general term for layers formed between the support substrate and the semiconductor layer for various purposes, and particularly focusing on the function of blocking the movement of elements that affect the electrical characteristics such as mobile ions. The layer is called a blocking layer.
The insulating layer means a layer formed using a non-conductive material, and the buffer layer and the blocking layer are usually formed using this.
Accordingly, in the present specification, these terms are used in this sense and are used properly.

For example, as the lower insulating film 112a for forming the buffer layer, the single crystal semiconductor wafer 110 can be oxidized to form an oxide film. The thermal oxidation treatment for forming this oxide film may be dry oxidation, but it is preferable to add a gas containing halogen to the oxidizing atmosphere. An oxide film containing halogen can be formed as the insulating film 112a. As the gas containing halogen, one or more kinds of gases selected from HCl, HF, NF ₃ , HBr, Cl ₂ , ClF, BCl ₃ , F, Br _{2 and the} like can be used.

  Next, as illustrated in FIG. 6B, the single crystal semiconductor wafer 110 is irradiated with an ion beam 121 including ions accelerated by an electric field through the insulating layer 112, so that the surface of the single crystal semiconductor wafer 110 is irradiated. A damaged region 113 is formed in a region having a predetermined depth. The ion beam 121 excites a source gas such as hydrogen gas or a gas containing hydrogen as a main component to generate source gas plasma, that is, hydrogen plasma, and ions contained in the plasma by the action of an electric field from the plasma. Generated by pulling out The thickness of the single crystal semiconductor layer separated from the single crystal semiconductor wafer 110 is determined by the depth to which ions are added. The depth at which the damaged region 113 is formed is adjusted so that the thickness of the single crystal semiconductor layer is 20 nm to 500 nm, preferably 20 nm to 200 nm.

  After the damaged region 113 is formed, a smooth and hydrophilic bonding surface 114 is formed on the surface of the insulating layer 112 as shown in FIG. In the step of forming the insulating layer 112 having the bonding surface 114, the heating temperature of the single crystal semiconductor wafer 110 is set to a temperature at which elements or molecules added to the damaged region 113 are not precipitated, and the heating temperature is preferably 350 ° C. or lower. In other words, this heating temperature is a temperature at which gas does not escape from the damaged region 113. Note that the insulating layer 112 can also be formed before the ion addition step. In this case, the process temperature when forming the insulating layer 112 can be 350 ° C. or higher.

  The bonding surface 114 is a smooth and hydrophilic surface formed on the surface of the insulating layer 112 formed on the surface of the single crystal semiconductor wafer 110. Therefore, the bonding surface 114 has an average surface roughness Ra of 0.7 nm or less, and more preferably 0.4 nm or less. Further, the thickness of the insulating layer 112 including the bonding surface can be greater than or equal to 10 nm and less than or equal to 200 nm. The preferred thickness is 5 nm or more and 500 nm or less, and more preferably 10 nm or more and 200 nm or less.

  Next, the single crystal semiconductor wafer 110 on which the insulating layer 112, the damaged region 113, and the bonding layer 114 are formed and the supporting substrate 100 are cleaned. This cleaning step can be performed by ultrasonic cleaning with pure water. In addition, the surface of the bonding layer 114 and the support substrate 100 can be activated by cleaning with ozone water, irradiation with an atomic beam or an ion beam, plasma treatment, or radical treatment. When an atomic beam or an ion beam is used, a rare gas neutral atom beam or a rare gas ion beam such as argon can be used.

FIG. 6D is a cross-sectional view illustrating the bonding process. The supporting substrate 100 and the single crystal semiconductor wafer 110 are brought into close contact with each other through the bonding layer 114. A pressure of about 300 to 15000 N / cm ² is applied to one end of the single crystal semiconductor wafer 110. This pressure is preferably 1000 to 5000 N / cm. The bonding layer 114 and the support substrate 100 start to be bonded from the portion where the pressure is applied, and the bonding portion reaches the entire surface of the bonding layer 114. As a result, the single crystal semiconductor wafer 110 is in close contact with the support substrate 100. Since this bonding step can be performed at normal temperature without heat treatment, a low heat resistant substrate having a heat resistant temperature of 700 ° C. or lower such as a glass substrate can be used as the supporting substrate 100.

  After the single crystal semiconductor wafer 110 is attached to the supporting substrate 100, heat treatment for increasing the bonding force at the bonding interface between the supporting substrate 100 and the bonding layer 114 is preferably performed. This processing temperature is a temperature at which cracks are not generated in the damaged region 113, and the processing can be performed in a temperature range of 200 ° C. or higher and 450 ° C. or lower. In addition, by bonding the single crystal semiconductor wafer 110 to the supporting substrate 100 while heating in this temperature range, the bonding force at the bonding interface between the supporting substrate 100 and the bonding layer 114 can be strengthened.

  Next, heat treatment is performed to cause separation in the damaged region 113, so that the single crystal semiconductor layer 115 is separated from the single crystal semiconductor wafer 110. FIG. 6E illustrates a separation step for separating the single crystal semiconductor layer 115 from the single crystal semiconductor wafer 110. The element denoted by the symbol 116 indicates the single crystal semiconductor wafer 110 from which the single crystal semiconductor layer 115 is separated.

  For this heat treatment, an RTA (Rapid Thermal Anneal) device, a resistance heating furnace, or a microwave heating device can be used. As the RTA apparatus, a GRTA (Gas Rapid Thermal Anneal) apparatus or an LRTA (Lamp Rapid Thermal Anneal) apparatus can be used. By this heat treatment, the temperature of the supporting substrate 100 to which the single crystal semiconductor layer 115 is attached is preferably increased to a range of 550 ° C. to 650 ° C.

Note that a plurality of single crystal semiconductor layers can be attached to one supporting substrate by using the method of this embodiment. A plurality of single crystal semiconductor wafers having the structure of FIG. 6C are attached to the supporting substrate. 6D to 6E, a semiconductor substrate including a supporting substrate to which a plurality of single crystal semiconductor layers is attached can be manufactured.

A step of separating and removing foreign substances from a semiconductor layer defect region of a single crystal semiconductor layer formed on a glass substrate which is a supporting substrate, and embedding a crystalline semiconductor layer. The apparatus used when performing cluster ion beam irradiation in the manufacturing method of the semiconductor substrate of Embodiment 1. FIG. An apparatus used for crystallization of a non-single crystal in a semiconductor layer defect region of a single crystal semiconductor layer in the method for manufacturing a semiconductor substrate of Embodiment 1. The flow which showed all the processes of the manufacturing method of this invention. A semiconductor film substrate manufactured by the manufacturing method of the present invention. Forming a single crystal semiconductor layer over the supporting substrate;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Defect detection apparatus 2 Laser direct drawing apparatus 3 Cluster ion beam irradiation apparatus 11 The process of forming a single crystal semiconductor layer in a support substrate 12 The process of removing a foreign material 13 The process of acquiring the information of a semiconductor layer defect area | region with an optical tester 14 Silicon Step of forming film 15 Step of crystallizing silicon in semiconductor layer defect region with laser 16 Step of planarizing semiconductor layer 17 Step of forming thin film transistor layer 21 Image analysis unit 22 Position information of semiconductor layer defect region 23 Data processing unit 24 Laser light source 25 Shutter 26 Movable mirror 27 Substrate irradiated 28 Mirror driver 29 Stage 30 Position drive control unit 31, 33 CCD camera 32 Monitor 41 High pressure gas supply unit 42 Nozzle 43 Shutter 44 Ion source,
45 Extraction electrode and acceleration electrode 46 Lens electrode

Claims (2)

  A single crystal semiconductor layer is bonded to a support substrate, and after bonding, a defect region of the single crystal semiconductor layer is detected by a defect detection device, and after the detection, the defect region is irradiated with a cluster ion beam to separate and remove foreign matters, A non-single-crystal semiconductor layer is formed on the defect region and the single-crystal semiconductor layer, and after the formation, the non-single-crystal semiconductor layer in the defect region is crystallized based on the detection information, and then planarized. A method for manufacturing a semiconductor substrate, comprising: removing a non-single-crystal semiconductor layer remaining after formation.   The bonding of the semiconductor layer is performed by tightly bonding the semiconductor wafer onto the support substrate and then separating it in a layered damaged region previously formed on the wafer, thereby leaving a part of the wafer in a thin layer shape. The method for manufacturing a semiconductor substrate according to claim 1, wherein the method is a semiconductor substrate.

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