JP2009231819A - Method of manufacturing soi substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve lamination efficiency and suppress bonding defects even in laminating a plurality of semiconductor substrates on base substrates. <P>SOLUTION: A plurality of the semiconductor substrates are provided on a first substrate support stand, the base substrates are provided on a second substrate support stand, the second substrate support stand is disposed above the first substrate support stand so as to allow the surfaces of a plurality of the semiconductor substrates to face the base substrates with a predetermined distance, a plurality of the semiconductor substrates or the base substrates are charged, the distance between the surfaces of a plurality of the semiconductor substrates and those of the base substrates is narrowed to allow a plurality of the semiconductor substrates to contact the surfaces of the base substrates, thereby contacting and bonding the surfaces of the base substrates with those of a plurality of the semiconductor substrates. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for manufacturing an SOI (Silicon on Insulator) substrate and a method for manufacturing a semiconductor device.

In recent years, integrated circuits using an SOI (Silicon on Insulator) substrate in which a thin single crystal semiconductor film is present on an insulating surface instead of a bulk silicon wafer have been developed. Since the parasitic capacitance between the drain of the transistor and the substrate is reduced by using the SOI substrate, the SOI substrate is attracting attention as improving the performance of the semiconductor integrated circuit.

As one of methods for manufacturing an SOI substrate, a Smart Cut (registered trademark) method is known. An outline of a method for manufacturing an SOI substrate by the smart cut method will be described below. First, an embrittlement region is formed at a predetermined depth from the surface by implanting hydrogen ions into the first silicon wafer using an ion implantation method. Next, the first silicon wafer implanted with hydrogen ions is bonded to the second silicon wafer through the silicon oxide film. Thereafter, heat treatment is performed to separate a part of the first silicon wafer into a thin film using the embrittled region as a cleavage plane, and a single crystal silicon film is formed on the second silicon wafer to obtain an SOI substrate. . The smart cut method is sometimes called a hydrogen ion implantation separation method.

A method of forming a single crystal silicon film on a support substrate made of glass using such a smart cut method has been proposed (see, for example, Patent Document 1). Furthermore, recently, as an SOI substrate for an active matrix liquid crystal display, a technique for making a piece of single crystal silicon on a glass substrate in a tile shape has been disclosed (see Patent Document 2).

Since the glass substrate can have a larger area than a silicon wafer and is inexpensive, it is possible to manufacture a large-area and inexpensive SOI substrate by using the glass substrate as a base substrate. Usually, the size of a silicon ingot or a silicon wafer serving as a base material for forming a single crystal silicon layer is small with respect to a glass substrate. Therefore, when a large glass substrate is used as the base substrate, it is effective in terms of cost reduction to use a plurality of silicon wafers bonded to a large-area glass substrate.

Moreover, in the smart cut method, a method of repeatedly reusing the silicon wafer, which is a peeling substrate, by cleaving it after cleaving has been proposed (for example, Patent Document 3).

JP 2004-87606 A JP 2005-539259 A JP 2007-251129 A

When multiple semiconductor substrates are bonded to a large base substrate, the multiple semiconductor substrates are arranged on a support base in advance, and then the multiple semiconductor substrates are bonded to the base substrate at the same time for efficient bonding. Can do. However, when the thicknesses of the plurality of semiconductor substrates are different from each other, the thin semiconductor substrate may not contact the base substrate and may not be bonded or bonding may be insufficient. In addition, when the semiconductor substrate is reused, the thickness of the semiconductor substrate is often different, and such a problem may occur remarkably.

In view of the above problems, an object of one embodiment of the present invention is to improve bonding efficiency and suppress bonding defects even when a plurality of semiconductor substrates are bonded to a base substrate.

One embodiment of the present invention is characterized in that at least one of a semiconductor substrate and a base substrate is charged, and the semiconductor substrate and the base substrate are bonded to each other using static electricity.

According to one embodiment of the present invention, a plurality of semiconductor substrates are provided over a first substrate support base, a base substrate is provided over a second substrate support base, and the surfaces of the plurality of semiconductor substrates and the surface of the base substrate are predetermined. The second substrate support base is disposed above the first substrate support base so as to face each other with a distance of, and the plurality of semiconductor substrates or the base substrate are charged, and the surface of the plurality of semiconductor substrates and the surface of the base substrate are By narrowing the interval, the plurality of semiconductor substrates are brought into contact with the surface of the base substrate, and the surface of the base substrate and the surfaces of the plurality of semiconductor substrates are bonded.

With this method, since a plurality of semiconductor substrates can be brought into contact with the surface of the base substrate using static electricity, the thicknesses of the plurality of semiconductor substrates provided on the first substrate support base vary. Even in this case, the bonding efficiency can be improved and the bonding failure between the base substrate and the plurality of semiconductor substrates can be suppressed.

In addition, as a method for charging the semiconductor substrate or the base substrate, one of the first substrate support base and the second substrate support base is set to the ground potential, and the other is set to the positive potential or the negative potential. A method of applying a DC voltage between the substrate support and the substrate can be used.

As another method for charging the semiconductor substrate or the base substrate, a method of applying positive ions or negative ions to the surface of a plurality of semiconductor substrates or the surface of the base substrate can be used.

According to one embodiment of the present invention, a plurality of semiconductor substrates are provided over a first substrate support base, a base substrate is provided over a second substrate support base, and the surfaces of the plurality of semiconductor substrates and the surface of the base substrate are predetermined. The second substrate support base is disposed above the first substrate support base so as to face each other with a distance of, and both the plurality of semiconductor substrates and the base substrate are charged so as to have different polarities. By narrowing the distance between the surface of the base substrate and the surface of the base substrate, a plurality of semiconductor substrates are brought into contact with the surface of the base substrate, and the surfaces of the base substrate and the surfaces of the plurality of semiconductor substrates are joined.

As a charging method for both the plurality of semiconductor substrates and the base substrate, one of the first substrate support base and the second substrate support base is set to a positive potential, and the other is set to a negative potential. A method of applying a DC voltage to the substrate support can be used.

As another charging method for both the plurality of semiconductor substrates and the base substrate, either positive ions or negative ions are applied to the surfaces of the plurality of semiconductor substrates, and the surface of the base substrate is added so that the polarity is different from that of the semiconductor substrate. A method of imparting the other of ions or negative ions can be used.

In addition, it is preferable to apply pressure to each of the plurality of semiconductor substrates after bringing the plurality of semiconductor substrates into contact with the surface of the base substrate. In particular, it is preferable to use a rectangular substrate having corners as the semiconductor substrate and apply pressure to one corner of each of the plurality of semiconductor substrates.

As a method of applying pressure to the semiconductor substrate, a method is used in which lift pins provided below the first substrate support are raised through openings formed in the first substrate support and the lift pins are brought into contact with the semiconductor substrate. be able to.

Further, the bonding of the plurality of semiconductor substrates and the base substrate can be performed in a reduced pressure atmosphere.

In this specification, “single crystal” refers to a crystal in which crystal planes and crystal axes are aligned, and atoms or molecules constituting the crystal are spatially ordered. However, single crystals are composed of regularly arranged atoms, but some include lattice defects that have some disorder in this alignment, and some that have lattice strain intentionally or unintentionally. .

In this specification, a semiconductor device refers to all devices that can function by utilizing semiconductor characteristics, and an electro-optical device, a semiconductor circuit, and an electronic device are all included in the semiconductor device.

In this specification, a display device includes a light-emitting device and a liquid crystal display device. The light emitting device includes a light emitting element, and the liquid crystal display device includes a liquid crystal element. The light emitting element includes, in its category, an element whose luminance is controlled by current or voltage, and specifically includes an inorganic EL (Electro Luminescence) element, an organic EL element, and the like.

According to one embodiment of the present invention, even when a plurality of semiconductor substrates are bonded to a base substrate, bonding can be efficiently performed and bonding defects can be suppressed.

4A and 4B illustrate an example of a method for manufacturing an SOI substrate. FIG. 5 shows an example of a substrate support used in a method for manufacturing an SOI substrate. 4A and 4B illustrate an example of a method for manufacturing an SOI substrate. FIG. 5 shows an example of a substrate support used in a method for manufacturing an SOI substrate. FIG. 9 illustrates an example of a method for creating an SOI substrate. 10A and 10B illustrate an example of a method for manufacturing a semiconductor device using an SOI substrate. 10A and 10B illustrate an example of a method for manufacturing a semiconductor device using an SOI substrate. FIG. 11 illustrates an example of a display device using an SOI substrate. FIG. 11 illustrates an example of a display device using an SOI substrate. FIG. 11 illustrates an example of a semiconductor device using an SOI substrate. FIG. 11 illustrates an example of a semiconductor device using an SOI substrate. It is a figure which shows the electronic device using an SOI substrate.

Embodiments of the present invention will be described below with reference to the drawings. However, it will be readily understood by those skilled in the art that the present invention can be implemented in many different modes, and that forms and details can be changed without departing from the spirit and scope of the present invention. . Therefore, the present invention is not construed as being limited to the description of this embodiment mode. Note that in all the drawings for describing the embodiments, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

(Embodiment 1)
In this embodiment, a method for manufacturing an SOI substrate by bonding a plurality of semiconductor substrates and a base substrate will be described with reference to drawings.

First, a plurality of semiconductor substrates (here, the semiconductor substrates 100a to 100c) are provided on the first substrate support base 151, and the base substrate 120 is provided on the second substrate support base 161. Then, the second substrate support base 161 is arranged above the first substrate support base 151 so that the surfaces of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 face each other with a predetermined interval (FIG. 1A )reference). That is, the base substrate 120 is disposed above the semiconductor substrates 100a to 100c.

In addition, an insulating film is provided in advance on the surfaces of the semiconductor substrates 100a to 100c when bonding to the base substrate 120 is performed.

The first substrate support 151 is preferably provided with a substrate placement portion for fixing the plurality of semiconductor substrates in the horizontal direction. For example, as shown in FIG. 2, a plurality of substrate placement portions 152 having recesses may be provided on the first substrate support base 151. By providing a semiconductor substrate on the substrate placement portion 152 of the first substrate support base 151, even when a plurality of semiconductor substrates are provided on the first substrate support base 151, misalignment of the semiconductor substrate is prevented. In addition, a plurality of semiconductor substrates can be bonded to desired positions on the base substrate 120. In FIG. 2, FIG. 2A shows a top view of the first substrate support base 151, and FIG. 2B shows a cross section taken along a line AB in FIG. 2A.

Next, after charging one of the plurality of semiconductor substrates (here, the semiconductor substrates 100a to 100c) or the base substrate 120, the distance between the surfaces of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 is narrowed (FIG. 1). (See (B)).

In FIG. 1B, a DC voltage is applied between the first substrate support base 151 and the second substrate support base 161 (here, as an example, the ground potential, the first potential is applied to the second substrate support base 161). In this case, the semiconductor substrates 100a to 100c are charged by applying a negative potential (or a positive potential) to the substrate support stand 151 of the above. In this case, the first substrate support base 151 and the second substrate support base 161 function as electrodes. Of course, the present invention is not limited to this, and the base substrate 120 may be charged (in this case, if a ground potential is applied to the first substrate support base 151 and a negative potential (or positive potential) is applied to the second substrate support base 161). Good).

When the distance between the surface of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 becomes narrow to some extent, the semiconductor substrates 100a to 100c and the base substrate 120 attract each other due to static electricity, and the semiconductor substrates 100a to 100c support the first substrate. The base 151 is separated from the base 151 and contacts the surface of the base substrate 120 (see FIG. 1C).

The distance between the surface of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 when the semiconductor substrates 100a to 100c are brought into contact with the base substrate 120 using static electricity takes into consideration the weight and size of the semiconductor substrates 100a to 100c. Thus, it can be controlled by adjusting the value of the DC voltage applied between the first substrate support base 151 and the second substrate support base 161.

From the viewpoint of suppressing the positional deviation of the semiconductor substrates 100a to 100c in the base substrate 120, when the semiconductor substrates 100a to 100c come into contact with the base substrate 120 due to static electricity, the surfaces of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 are It is preferable to make the interval as short as possible. As an example, when the distance between the surface of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 is 1 mm or less (preferably 0.3 mm or less), the semiconductor substrates 100a to 100c are moved upward due to static electricity. The value of the DC voltage applied between the first substrate support base 151 and the second substrate support base 161 can be adjusted so as to contact the substrate 120.

As described above, by using the static electricity to bring the semiconductor substrates 100a to 100c into contact with the base substrate 120, even when the thicknesses of the semiconductor substrates 100a to 100c are different, bonding is performed efficiently and bonding is poor. Can be suppressed.

Subsequently, the semiconductor substrates 100a to 100c are bonded to the surface of the base substrate 120 by applying pressure to the semiconductor substrates 100a to 100c in contact with the base substrate 120 (see FIG. 1D).

For example, when a rectangular substrate is used as the semiconductor substrates 100a to 100c, the base substrate 120 and the semiconductor substrates 100a to 100c are joined by applying pressure to one corner of each of the rectangular semiconductor substrates 100a to 100c. Can be made. In this case, the oxide film formed on the semiconductor substrate and the base substrate 120 start to be bonded from the portion to which pressure is applied, and the bond is spontaneously formed and extends over the entire surface. This joining process can be performed at normal temperature without van der Waals force or hydrogen bonding and without heat treatment. Note that in the process of FIG. 1C, when the semiconductor substrate and the base substrate are bonded, the bonding strength can be improved by the process of FIG.

As a means for applying pressure to the semiconductor substrate, the present embodiment shows a case where lift pins 154 provided below the substrate placement portion 152 are pressed against the corners of the semiconductor substrates 100a to 100c (FIG. 2). (See (A) and (B)). By providing lift pins 154 on the support table 157 and moving the support table 157 up and down, the lift pins 154 can be moved up and down through the openings 153 formed in the substrate placement portion 152.

The support table 157 can be lifted and lowered by operating a lifting mechanism 155 configured by a motor or the like. Alternatively, a plurality of pressure sensors 158 may be provided on the upper surface of the support base 157. In this case, the load applied to the lift pin 154 by the pressure sensor 158 is detected and output to the control unit 156, and the control unit 156 controls the operation of the lifting mechanism 155 based on the output result from the pressure sensor 158. be able to.

For example, when the lift pin 154 is raised and pressure is applied to the semiconductor substrate attached to the base substrate 120, the control unit 156 controls the operation of the elevating mechanism 155 according to the output from the pressure sensor 158, so that the contact interface is Bonding is performed by gradually increasing the pressure. By gradually increasing the pressure applied to the contact interface, it is possible to reduce bonding failure due to sudden application of pressure. Further, by providing the tip of the lift pin 154 that comes into contact with the semiconductor substrate with an elastic body such as silicon rubber, it is possible to reduce poor bonding due to sudden pressure application.

The opening 153 is preferably provided in a region corresponding to at least one of end portions (preferably corner portions) of the semiconductor substrates 100a to 100c. This is because bonding failure can be reduced by starting bonding from the end portion of the semiconductor substrate to which pressure is applied in bonding to the base substrate 120. In the case where the semiconductor substrate has a circular shape such as a circular shape, an opening 153 may be provided in a region corresponding to the peripheral portion of the semiconductor substrate. That is, “one corner” can be read as “peripheral”. In addition, the part which applies a pressure is not restricted to the corner | angular part and peripheral part of a semiconductor substrate.

2 shows a case where the shape of the lift pins 154 (the shape of the surface in contact with the semiconductor substrate) is a circle, the invention is not limited to this. It may be rectangular or elliptical. Further, the cross-sectional shape of the opening 153 is not limited to a circle as long as the lift pin 154 can pass therethrough.

In addition, the atmosphere at the time of bonding the semiconductor substrates 100a to 100c and the base substrate 120 is preferably a reduced pressure atmosphere (including a vacuum). For example, 5 Pa to 5 × 10 ⁻³ Pa, preferably 5 × 10 ⁻² Pa to 5 × 10 ⁻³ Pa. By performing in a reduced pressure atmosphere, contamination can be prevented from entering the bonding surface, and impurities can be effectively prevented from adhering to the charged semiconductor substrates 100a to 100c.

After the step shown in FIG. 1D, after the semiconductor substrates 100a to 100c are bonded to the surface of the base substrate 120, an SOI substrate is manufactured by separating or polishing a part of the semiconductor substrates 100a to 100c. be able to.

In addition, when the semiconductor substrates 100a to 100c are brought into contact with the base substrate 120 by using static electricity to bond the semiconductor substrates 100a to 100c and the base substrate 120 and sufficient bonding strength is obtained, The step in FIG. 1D may be omitted. In this case, a lift pin or the like for applying pressure is not necessary, so that the apparatus used for bonding can be simplified.

By using the above-described method, even when a plurality of semiconductor substrates having different thicknesses are bonded to the base substrate, bonding can be performed efficiently and bonding defects can be suppressed.

In the above-described method, the method for charging the semiconductor substrates 100a to 100c or the base substrate 120 is not limited to the structure illustrated in FIG. For example, the semiconductor substrates 100a to 100c may be charged by selectively applying ions (positive ions or negative ions) having a desired polarity to the surfaces of the semiconductor substrates 100a to 100c using a charger. As the charger, a commercially available static eliminator (ionizer) can be used.

Further, both the semiconductor substrates 100a to 100c and the base substrate 120 may be charged. In this case, the semiconductor substrates 100a to 100c and the base substrate 120 are charged so as to have different polarities. For example, a DC voltage is applied between the substrate support base 151 and the substrate support base 161 (a positive potential (or negative potential) is applied to the substrate support base 151 and a negative potential (or positive potential) is applied to the substrate support base 161). Alternatively, one of positive ions and negative ions is applied to the surfaces of the semiconductor substrates 100a to 100c using a charger, and the other of the positive ions and negative ions is applied to the surface of the base substrate 120 so that the polarity is different from that of the semiconductor substrates 100a to 100c. May be given.

In the above step, it is preferable that the semiconductor substrates 100a to 100c and the base substrate 120 be subjected to a charge removal process after the semiconductor substrates 100a to 100c and the base substrate 120 are bonded. By performing the static elimination treatment, occurrence of electrostatic breakdown or the like can be suppressed when an element is manufactured using the SOI substrate obtained later. For the static elimination treatment, a commercially available static eliminator (ionizer) can be used.

Next, a method for manufacturing an SOI substrate using the above-described method will be described more specifically with reference to the drawings.

First, a plurality of semiconductor substrates are prepared. Here, the case where the semiconductor substrate 100a, the semiconductor substrate 100b, and the semiconductor substrate 100c are used is described (see FIG. 3A-1).

As the semiconductor substrates 100a to 100c, commercially available polycrystalline semiconductor substrates or single crystal semiconductor substrates can be used. For example, a polycrystalline or single crystal silicon substrate, a germanium substrate, or a compound semiconductor substrate such as gallium arsenide or indium phosphide is used. be able to. As a commercially available silicon substrate, a circular substrate having a diameter of 5 inches (125 mm), a diameter of 6 inches (150 mm), a diameter of 8 inches (200 mm), and a diameter of 12 inches (300 mm) is typical. The shape is not limited to a circular shape, and a silicon substrate processed into a rectangular shape or the like can also be used. In the following description, a case where a single crystal silicon substrate processed into a rectangular shape is used as the semiconductor substrates 100a to 100c will be described.

Next, the insulating film 102a is provided over the surface of the semiconductor substrate 100a, and the embrittlement region 104a is provided at a predetermined depth from the surface of the semiconductor substrate 100a (see FIG. 3A-2). Similarly, for the semiconductor substrates 100b and 100c, insulating films 102b and 102c are provided on the surface, respectively, and embrittled regions 104b and 104c are provided at predetermined depths from the surface.

As the insulating films 102a to 102c, for example, a single layer such as a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a silicon nitride oxide film, or a film in which these layers are stacked can be used. These films can be formed using a CVD method, a sputtering method, or the like. In the case where the insulating films 102a to 102c are formed using a CVD method, a silicon oxide film formed using an organic silane such as tetraethoxysilane (abbreviation: TEOS: chemical formula Si (OC ₂ H ₅ ) ₄ ) or the like. Can be used for the insulating films 102a to 102c.

For example, after a silicon oxynitride film and a silicon nitride oxide film are sequentially stacked over the semiconductor substrates 100a to 100c, ions are introduced into a region having a predetermined depth from the surface of the semiconductor substrates 100a to 100c, and then CVD is performed. A silicon oxide film formed using tetraethoxysilane by a method may be formed over the silicon nitride oxide film.

Note that a silicon oxynitride film has a composition that contains more oxygen than nitrogen, and includes Rutherford Backscattering (RBS) and Hydrogen Forward Scattering (HFS). ) In the range of 50 to 70 atomic% oxygen, 0.5 to 15 atomic% nitrogen, 25 to 35 atomic% Si, and 0.1 to 10 atomic% hydrogen. It means what is included. In addition, the silicon nitride oxide film has a composition containing more nitrogen than oxygen. When measured using RBS and HFS, the concentration range of oxygen is 5 to 30 atomic%, nitrogen. Is contained in the range of 20-50 atomic%, Si is 25-35 atomic%, and hydrogen is 15-25 atomic%. However, when the total number of atoms constituting silicon oxynitride or silicon nitride oxide is 100 atomic%, the content ratio of nitrogen, oxygen, Si, and hydrogen is included in the above range.

The insulating films 102a to 102c may be formed by performing thermal oxidation treatment on the semiconductor substrates 100a to 100c. In this case, the thermal oxidation treatment is preferably performed in an oxidizing atmosphere to which halogen is added. As an example of such thermal oxidation treatment, a temperature of 900 ° C. to 1150 ° C. in an atmosphere containing hydrogen chloride (HCl) in a ratio of 0.5 to 10% by volume (preferably 3% by volume) with respect to oxygen ( Thermal oxidation is typically performed at 1000 ° C. The treatment time may be 0.1 to 6 hours, preferably 0.5 to 1 hour. The thickness of the oxide film to be formed is 10 nm to 1000 nm (preferably 50 nm to 200 nm), for example, 100 nm.

The embrittled regions 104a to 104c can be formed by irradiating the semiconductor substrates 100a to 100c with ions having kinetic energy. Here, the semiconductor substrates 100a to 100c are irradiated with ions through the insulating films 102a to 102c, and the embrittled regions 104a to 104c are formed by damaging the crystal structure of a predetermined depth of the semiconductor substrates 100a to 100c. The ions are ions that are excited by generating a plasma of the source gas by exciting the source gas and extracting ions contained in the plasma from the plasma by the action of an electric field.

The depth of the region where the embrittled regions 104a to 104c are formed can be adjusted by the kinetic energy, mass and charge, and incident angle of ions. Kinetic energy can be adjusted by acceleration voltage, dose, etc. Embrittlement regions 104a to 104c are formed in regions having a depth substantially equal to the average ion penetration depth. Therefore, the thickness of the semiconductor layer separated from the semiconductor substrates 100a to 100c is determined by the depth to which ions are added. The depth at which the embrittled regions 104a to 104c are formed is adjusted so that the thickness of the semiconductor layer is 10 nm to 500 nm, preferably 50 nm to 200 nm.

The embrittlement regions 104a to 104c can be formed by ion doping treatment. The ion doping process can be performed using an ion doping apparatus. A typical ion doping apparatus is a non-mass separation type apparatus that irradiates an object to be processed disposed in a chamber with all ion species generated by plasma excitation of a process gas. The non-mass separation type apparatus is because the object to be processed is irradiated with all ion species without mass separation of ion species in the plasma. On the other hand, the ion implantation apparatus is a mass separation type apparatus. An ion implantation apparatus is an apparatus that mass-separates ion species in plasma and irradiates a target object with ion species having a specific mass.

In this embodiment, hydrogen is added to the semiconductor substrates 100a to 100c with an ion doping apparatus. A gas containing hydrogen is supplied as a plasma source gas. For example, H ₂ is supplied. Hydrogen gas is excited to generate plasma, and ions included in the plasma are accelerated without mass separation, and the semiconductor substrates 100a to 100c are irradiated with the accelerated ions.

In the ion doping apparatus, the ratio of H ₃ ^{+ to} the total amount of ion species (H ⁺ , H ₂ ⁺ , H ₃ ⁺ ) generated from hydrogen gas is 50% or more. More preferably, the ratio of H ₃ ⁺ is 80% or more. Since the ion doping apparatus does not perform mass separation, one of the plurality of ion species generated in the plasma is preferably 50% or more, and more preferably 80% or more. By irradiating ions of the same mass, ions can be added while being concentrated at the same depth of the semiconductor substrates 100a to 100c.

In order to form the embrittled regions 104a to 104c in shallow regions, it is necessary to lower the ion acceleration voltage. However, by increasing the proportion of H ₃ ⁺ ions in the plasma, atomic hydrogen (H) is reduced. It can be efficiently added to the semiconductor substrates 100a to 100c. Since H ₃ ⁺ ions have a mass three times that of H ⁺ ions, when one hydrogen atom is added at the same depth, the acceleration voltage of H ₃ ⁺ ions is three times the acceleration voltage of H ⁺ ions. It becomes possible to do. If the acceleration voltage of ions can be increased, the tact time of the ion irradiation process can be shortened, and productivity and throughput can be improved.

The step of irradiating the semiconductor substrates 100a to 100c with the accelerated ions can also be performed with an ion implantation apparatus. The ion implantation apparatus is a mass separation type apparatus that mass-separates a plurality of ion species generated by plasma-exciting a source gas from a target object disposed in a chamber and irradiates specific ion species. Therefore, when an ion implantation apparatus is used, H ⁺ ions and H ₂ ⁺ ions generated by exciting hydrogen gas are mass-separated and one of H ⁺ ions or H ₂ ⁺ ions is accelerated, The semiconductor substrates 100a to 100c are irradiated.

Next, the base substrate 120 is prepared (see FIG. 3B).

As the base substrate 120, a substrate made of an insulator is used. Specifically, a glass substrate used for the electronic industry such as aluminosilicate glass, aluminoborosilicate glass, and barium borosilicate glass is used as the base substrate 120. By using an inexpensive glass substrate that can be increased in area as the base substrate 120, cost can be reduced as compared with the case of using a silicon wafer. In addition, a plastic substrate having heat resistance that can withstand the processing temperature in the manufacturing process may be used.

Next, using the method shown in FIG. 1, the surfaces of the plurality of semiconductor substrates 100a to 100c and the surface of the base substrate 120 are opposed to each other, and the insulating films 102a to 102c and the base substrate 120 are brought into contact with each other. (See FIG. 3C), a pressure of about 0.1 to 50 N / cm ² , preferably about 0.1 to 20 N / cm ² is applied to one corner of each of the semiconductor substrates 100a to 100c. The insulating films 102a to 102c and the base substrate 120 start to be bonded from the portion where the pressure is applied, and the bonding is spontaneously formed and covers the entire surface. This bonding process is performed at room temperature without van der Waals force or hydrogen bond, and is not accompanied by heat treatment. Therefore, a substrate having a low heat resistance temperature such as a glass substrate should be used for the base substrate 120. Can do.

After bonding the semiconductor substrates 100a to 100c to the base substrate 120, it is preferable to perform heat treatment for increasing the bonding strength between the base substrate 120 and the insulating films 102a to 102c. The temperature of this heat treatment is a temperature at which cracks are not generated in the embrittled regions 104a to 104c, and the heat treatment can be performed in a temperature range from room temperature to less than 400 ° C. Further, by bonding the semiconductor substrates 100a to 100c to the base substrate 120 while heating in this temperature range, the bonding strength at the bonding interface between the base substrate 120 and the insulating films 102a to 102c can be strengthened. For the heat treatment, a heating furnace such as a diffusion furnace or a resistance heating furnace, an RTA (Rapid Thermal Annealing) apparatus, a microwave heating apparatus, or the like can be used.

Note that the insulating films 102 a to 102 c and the base substrate 120 are preferably subjected to surface treatment before the insulating films 102 a to 102 c formed over the semiconductor substrates 100 a to 100 c are bonded to the base substrate 120. As the surface treatment, ozone treatment (for example, ozone water cleaning), megasonic cleaning, and ozone water cleaning can be performed. Further, ozone water cleaning and cleaning with hydrofluoric acid may be repeated a plurality of times. By performing such surface treatment, dust such as organic substances on the surfaces of the insulating films 102a to 102c and the base substrate 120 can be removed and the surface can be made hydrophilic.

In addition, surface treatment by plasma treatment may be performed as the surface treatment. For example, an inert gas (for example, Ar gas) and / or a reactive gas (for example, O ₂ gas or N ₂ gas) is introduced into a vacuum chamber, and a surface to be processed (here, the base substrate 120 or the insulating film) 102a to 102c) is applied with a bias voltage to form a plasma state. Electrons and Ar cations are present in the plasma, and Ar cations are accelerated in the cathode direction (surface to be processed). The surface to be processed can be sputter-etched by the accelerated Ar cation colliding with the surface to be processed. At this time, sputter etching is preferentially performed from the convex portion of the surface to be processed, and the flatness of the surface to be processed can be improved.

Next, heat treatment is performed to separate the embrittled regions 104a to 104c, whereby single crystal semiconductor films 124a to 124c are provided over the base substrate 120 with the insulating films 102a to 102c interposed therebetween (see FIG. 3D). .

By performing the heat treatment, the element added by ion doping is deposited in the minute holes formed in the embrittled regions 104a to 104c due to the temperature rise, and the internal pressure rises. As the pressure rises, volume changes occur in minute holes in the embrittled regions 104a to 104c and cracks occur in the embrittled regions 104a to 104c, so that the semiconductor substrates 100a to 100c are cleaved along the embrittled regions 104a to 104c. . Since the insulating films 102 a to 102 c are bonded to the base substrate 120, single crystal semiconductor films 124 a to 124 c separated from the semiconductor substrates 100 a to 100 c are formed over the base substrate 120. In addition, the temperature of the heat treatment here is a temperature that does not exceed the strain point of the base substrate 120.

For this heat treatment, a heating furnace such as a diffusion furnace or a resistance heating furnace, a rapid thermal annealing (RTA) apparatus, a microwave heating apparatus, or the like can be used. For example, the heating can be performed using an RTA apparatus at a heating temperature of 550 ° C. to 700 ° C. and a processing time of 0.5 minutes to 60 minutes.

As described above, after the insulating films 102a to 102c on the semiconductor substrate 100 and the base substrate 120 are bonded together, the bonding strength can be increased by performing heat treatment a plurality of times. Note that without performing the heat treatment for increasing the bonding strength between the base substrate 120 and the insulating films 102a to 102c described above, the heat treatment in FIG. 3D is performed, whereby the base substrate 120 and the insulating films 102a to 102c are formed. The heat treatment step for increasing the bonding strength and the heat treatment step for separation in the embrittled regions 104a to 104c may be performed simultaneously.

Through the above steps, an SOI substrate in which the single crystal semiconductor films 124a to 124c are provided over the base substrate 120 with the insulating films 102a to 102c interposed therebetween can be manufactured.

Note that in the above steps, planarization treatment may be performed on the surface of the obtained SOI substrate. By performing the planarization treatment, the surface of the SOI substrate can be planarized even when unevenness is generated on the surfaces of the single crystal semiconductor films 124a to 124c provided over the base substrate 120 after peeling.

As the planarization treatment, CMP (Chemical Mechanical Polishing), etching treatment, laser light irradiation, or the like can be performed. Here, the single crystal semiconductor films 124a to 124c are recrystallized and the surface is flattened by irradiating a laser beam after performing an etching process (etchback process) combining one or both of dry etching and wet etching. To do.

By irradiation with laser light from the upper surface side of the single crystal semiconductor film, the upper surface of the single crystal semiconductor film can be melted. After melting, the single crystal semiconductor film is cooled and solidified, whereby a single crystal semiconductor film with improved flatness on the upper surface is obtained. By using laser light, the base substrate 120 is not directly heated, so that the temperature rise of the base substrate 120 can be suppressed. Therefore, a substrate with low heat resistance such as a glass substrate can be used for the base substrate 120.

Note that melting of the single crystal semiconductor film by laser light irradiation is preferably partial melting. This is because, when completely melted, there is a high possibility that the crystallinity is lowered due to disordered nucleation after the liquid phase is formed and the crystallinity is lowered. On the other hand, by partial melting, crystal growth proceeds from a solid phase portion that is not melted. Thereby, defects in the semiconductor film can be reduced. Here, complete melting means that the single crystal semiconductor film is melted to the vicinity of the lower interface to be in a liquid state. On the other hand, partial melting means that in this case, the upper part of the single crystal semiconductor film is melted into a liquid phase, but the lower part is not melted and remains in a solid phase.

A pulsed laser is preferably used for the laser light irradiation. This is because high-energy pulsed laser light can be instantaneously oscillated, and it becomes easy to create a molten state. The oscillation frequency can be about 1 Hz to 10 MHz.

After the laser light irradiation as described above, a thinning process for reducing the thickness of the single crystal semiconductor film may be performed. In order to reduce the thickness of the single crystal semiconductor film, an etching process (etchback process) in which one of dry etching or wet etching or a combination of both is applied may be applied. For example, when a single crystal semiconductor film is a layer made of a silicon material, capable of using SF ₆ and 0 ₂ in the process gas as a dry etching to thin the single crystal semiconductor film.

Note that the planarization process is not limited to the SOI substrate, and may be performed on the separated semiconductor substrates 100a to 100c. By flattening the surfaces of the separated semiconductor substrates 100a to 100c, the semiconductor substrates 100a to 100c can be reused in the manufacturing process of the SOI substrate.

The heat treatment apparatus described in this embodiment can be implemented in appropriate combination with a method for manufacturing an SOI substrate and a method for manufacturing a semiconductor device which are described in other embodiments in this specification.

(Embodiment 2)
In this embodiment, a method for manufacturing an SOI substrate, which is different from the above embodiment, will be described with reference to FIGS. 4A is a top view of the first substrate support base 151, FIG. 4B is a cross-sectional view taken along line A-B in FIG. 4A, and FIG. 4C is FIG. The cross section between CD of (A) is shown.

The first substrate support base 151 has a plurality of substrate placement portions 152 having recesses for fixing the semiconductor substrate, and the plurality of semiconductor substrates can be fixed to the substrate placement portion 152, respectively. Each of the substrate placement portions 152 is provided with a plurality of openings 153, and a plurality of lift pins 154 that can be moved up and down via the openings 153 are provided below the substrate placement portion 152. The lift pins 154 are provided on the support base 157, and the lift pins 154 can be moved up and down by moving the support base 157 up and down (see FIG. 4).

The support table 157 can be lifted and lowered by operating a lifting mechanism 155 configured by a motor or the like. Further, the pressure sensor 158 may be provided on the upper surface of the support base 157. The load applied to the lift pin 154 by the pressure sensor 158 is detected and output to the control unit 156, and the control unit 156 can control the operation of the lifting mechanism 155 based on the output result from the pressure sensor 158. Here, a configuration is shown in which a support base 157 is provided for each lift pin, and the support base 157 is operated independently using the lifting mechanism 155.

Hereinafter, a method for bonding a plurality of semiconductor substrates and a base substrate will be described with reference to FIG.

First, the base substrate 120 is provided above the first substrate support 151 on which the semiconductor substrates 100a to 100c are provided so that the surfaces of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 face each other with a predetermined interval. A second substrate support base 161 is disposed. Then, one of the semiconductor substrate (here, the semiconductor substrates 100a to 100c) and the base substrate 120 is charged (see FIG. 5A).

Here, the semiconductor substrates 100a to 100c are charged by selectively applying ions (positive ions or negative ions) having a desired polarity using the charger 160. As the charger, a commercially available static eliminator (ionizer) can be used. Further, one of the semiconductor substrates 100a to 100c and the base substrate 120 may be charged, or both may be charged so that the semiconductor substrates 100a to 100c and the base substrate 120 have different polarities. Note that the charging method is not limited to the method using the charger 160, and as shown in the first embodiment, the semiconductor substrate 100a is applied by applying a DC voltage between the substrate support base 151 and the substrate support base 161. One or both of ˜100c and the base substrate 120 may be charged.

Next, the plurality of lift pins 154 provided below the first substrate support base 151 are raised through the openings 153. The lift pins 154 are brought into contact with the lower surfaces of the semiconductor substrates 100a to 100c to raise the semiconductor substrates 100a to 100c, thereby narrowing the distance between the surfaces of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 (FIG. 5 (B)).

When the distance between the surface of the semiconductor substrates 100a to 100c and the surface of the base substrate 120 is reduced to some extent, the semiconductor substrates 100a to 100c and the base substrate 120 are attracted by static electricity, and the semiconductor substrates 100a to 100c are separated from the lift pins 154. , Contact the surface of the base substrate 120. Subsequently, one of the plurality of lift pins 154 supporting the semiconductor substrate is raised to apply pressure to the semiconductor substrate, thereby bonding the semiconductor substrates 100a to 100c to the surface of the base substrate 120 (FIG. 5C )reference).

Whether or not the semiconductor substrates 100a to 100c are in contact with the surface of the base substrate 120 (away from the lift pins 154) can be detected based on a load applied to the pressure sensor 158 provided on the support base 157. For example, after the pressure sensor 158 detects that the semiconductor substrates 100a to 100c are in contact with the surface of the base substrate 120, the control unit 156 operates the lifting mechanism 155 to raise the specific lift pin 154. Can do.

As described above, by using the static electricity to bring the semiconductor substrates 100a to 100c into contact with the base substrate 120, even when the thicknesses of the semiconductor substrates 100a to 100c are different, bonding is performed efficiently and bonding is poor. Can be suppressed.

In the present embodiment, the case where the openings 153 are provided in the regions corresponding to the four corners of the semiconductor substrates 100a to 100c is shown, but the present invention is not limited thereto.

The heat treatment apparatus described in this embodiment can be implemented in appropriate combination with a method for manufacturing an SOI substrate and a method for manufacturing a semiconductor device which are described in other embodiments in this specification.

(Embodiment 3)
In this embodiment, a method for manufacturing a semiconductor device using the SOI substrate manufactured in the above embodiment will be described.

First, a method for manufacturing an n-channel thin film transistor and a p-channel thin film transistor is described with reference to FIGS. Various semiconductor devices can be formed by combining a plurality of thin film transistors (TFTs).

The case where an SOI substrate manufactured by the method of Embodiment Mode 1 is used as an SOI substrate will be described.

FIG. 6A is a cross-sectional view of an SOI substrate manufactured by the method described with reference to FIGS.

First, the single crystal semiconductor film 124a is patterned by etching to form semiconductor films 251 and 252 as shown in FIG. The semiconductor film 251 constitutes an n-channel TFT, and the semiconductor film 252 constitutes a p-channel TFT.

As shown in FIG. 6C, an insulating film 254 is formed over the semiconductor films 251 and 252. Next, the gate electrode 255 is formed over the semiconductor film 251 with the insulating film 254 interposed therebetween, and the gate electrode 256 is formed over the semiconductor film 252.

Note that before the single crystal semiconductor film 124a is etched, an impurity element such as boron, aluminum, or gallium or an impurity element such as phosphorus or arsenic is added to the single crystal semiconductor film 124a in order to control the threshold voltage of the TFT. It is preferable to add to. For example, an impurity element is added to a region where an n-channel TFT is formed, and an impurity element is added to a region where a p-channel TFT is formed.

Next, as illustrated in FIG. 6D, an n-type low concentration impurity region 257 is formed in the semiconductor film 251, and a p-type high concentration impurity region 259 is formed in the semiconductor film 252. Specifically, first, an n-type low concentration impurity region 257 is formed in the semiconductor film 251. Therefore, the semiconductor film 252 to be a p-channel TFT is masked with a resist, and an impurity element is added to the semiconductor film 251. Phosphorus or arsenic may be added as the impurity element. By adding an impurity element by an ion doping method or an ion implantation method, the gate electrode 255 serves as a mask, and an n-type low-concentration impurity region 257 is formed in the semiconductor film 251 in a self-aligning manner. A region overlapping with the gate electrode 255 of the semiconductor film 251 becomes a channel formation region 258.

Next, after removing the mask covering the semiconductor film 252, the semiconductor film 251 to be an n-channel TFT is covered with a resist mask. Next, an impurity element is added to the semiconductor film 252 by an ion doping method or an ion implantation method. Boron can be added as the impurity element. In the impurity element addition step, the gate electrode 256 functions as a mask, and a p-type high concentration impurity region 259 is formed in the semiconductor film 252 in a self-aligning manner. The high concentration impurity region 259 functions as a source region or a drain region. A region overlapping with the gate electrode 256 of the semiconductor film 252 becomes a channel formation region 260. Although the method of forming the p-type high concentration impurity region 259 after forming the n-type low concentration impurity region 257 has been described here, the p-type high concentration impurity region 259 can be formed first.

Next, after removing the resist covering the semiconductor film 251, an insulating film having a single-layer structure or a stacked structure made of a nitrogen compound such as silicon nitride or an oxide such as silicon oxide is formed by a plasma CVD method or the like. By performing anisotropic etching on this insulating film in the vertical direction, sidewall insulating films 261 and 262 in contact with the side surfaces of the gate electrodes 255 and 256 are formed as shown in FIG. By this anisotropic etching, the insulating film 254 is also etched.

Next, as illustrated in FIG. 7B, the semiconductor film 252 is covered with a resist 265. In order to form a high concentration impurity region functioning as a source region or a drain region in the semiconductor film 251, an impurity element is added to the semiconductor film 251 with a high dose by an ion implantation method or an ion doping method. Using the gate electrode 255 and the sidewall insulating film 261 as a mask, an n-type high concentration impurity region 267 is formed. Next, heat treatment for activating the impurity element is performed.

After the heat treatment for activation, an insulating film 268 containing hydrogen is formed as shown in FIG. After the insulating film 268 is formed, heat treatment is performed at a temperature of 350 ° C. to 450 ° C. to diffuse hydrogen contained in the insulating film 268 into the semiconductor films 251 and 252. The insulating film 268 can be formed by depositing silicon nitride or silicon nitride oxide by a plasma CVD method with a process temperature of 350 ° C. or lower. By supplying hydrogen to the semiconductor films 251 and 252, defects that become trapping centers in the semiconductor films 251 and 252 and the interface with the insulating film 254 can be effectively compensated.

Thereafter, an interlayer insulating film 269 is formed. The interlayer insulating film 269 is an insulating film made of an inorganic material such as a silicon oxide film or a BPSG (Boron Phosphorus Silicon Glass) film, or a single-layer film or a laminated structure selected from organic resin films such as polyimide and acrylic. It can be formed of a film. After forming a contact hole in the interlayer insulating film 269, a wiring 270 is formed as shown in FIG. For example, the wiring 270 can be formed of a conductive film having a three-layer structure in which a low-resistance metal film such as an aluminum film or an aluminum alloy film is sandwiched between barrier metal films. The barrier metal film can be formed of a metal film such as molybdenum, chromium, or titanium.

Through the above steps, a semiconductor device having an n-channel TFT and a p-channel TFT can be manufactured. In the process of manufacturing the SOI substrate, the concentration of the metal element in the semiconductor film forming the channel formation region is reduced, so that a TFT with a small off-state current and a suppressed threshold voltage can be manufactured.

Although the manufacturing method of the TFT has been described with reference to FIGS. 6 and 7, a semiconductor device with high added value can be manufactured by forming various semiconductor elements such as a capacitor and a resistor in addition to the TFT. . Hereinafter, specific embodiments of the semiconductor device will be described with reference to the drawings.

First, a microprocessor will be described as an example of a semiconductor device. FIG. 10 is a block diagram illustrating a configuration example of the microprocessor 500.

The microprocessor 500 includes an arithmetic circuit 501 (also referred to as Arithmetic logic unit. ALU), an arithmetic circuit controller 502 (ALU Controller), an instruction analyzer 503 (Instruction Decoder), an interrupt controller 504 (Interrupt Controller), and a timing controller. 505 (Timing Controller), a register 506 (Register), a register controller 507 (Register Controller), a bus interface 508 (Bus I / F), a read-only memory 509, and a memory interface 510.

An instruction input to the microprocessor 500 via the bus interface 508 is input to the instruction analysis unit 503 and decoded, and then to the arithmetic circuit control unit 502, the interrupt control unit 504, the register control unit 507, and the timing control unit 505. Entered. The arithmetic circuit control unit 502, the interrupt control unit 504, the register control unit 507, and the timing control unit 505 perform various controls based on the decoded instruction.

The arithmetic circuit control unit 502 generates a signal for controlling the operation of the arithmetic circuit 501. The interrupt control unit 504 is a circuit that processes an interrupt request from an external input / output device or a peripheral circuit while the microprocessor 500 is executing a program. And processing an interrupt request. The register control unit 507 generates an address of the register 506 and reads and writes the register 506 in accordance with the state of the microprocessor 500. The timing control unit 505 generates a signal that controls the operation timing of the arithmetic circuit 501, the arithmetic circuit control unit 502, the instruction analysis unit 503, the interrupt control unit 504, and the register control unit 507. For example, the timing control unit 505 includes an internal clock generation unit that generates an internal clock signal CLK2 based on the reference clock signal CLK1. As shown in FIG. 10, the internal clock signal CLK2 is input to another circuit.

Next, an example of a semiconductor device having a function of performing transmission / reception of data without contact and an arithmetic function will be described. FIG. 11 is a block diagram illustrating a configuration example of such a semiconductor device. The semiconductor device illustrated in FIG. 11 can be referred to as a computer that operates by transmitting and receiving signals to and from an external device by wireless communication (hereinafter referred to as “RFCPU”).

As illustrated in FIG. 11, the RFCPU 511 includes an analog circuit unit 512 and a digital circuit unit 513. The analog circuit portion 512 includes a resonance circuit 514 having a resonance capacity, a rectifier circuit 515, a constant voltage circuit 516, a reset circuit 517, an oscillation circuit 518, a demodulation circuit 519, and a modulation circuit 520. The digital circuit unit 513 includes an RF interface 521, a control register 522, a clock controller 523, a CPU interface 524, a central processing unit 525, a random access memory 526, and a read only memory 527.

The outline of the operation of the RFCPU 511 is as follows. A signal received by the antenna 528 generates an induced electromotive force by the resonance circuit 514. The induced electromotive force is charged in the capacitor unit 529 through the rectifier circuit 515. Capacitance portion 529 is preferably formed of a capacitor such as a ceramic capacitor or an electric double layer capacitor. The capacitor portion 529 does not need to be integrated on the substrate constituting the RFCPU 511, and can be incorporated into the RFCPU 511 as another component.

The reset circuit 517 generates a signal that resets and initializes the digital circuit portion 513. For example, a signal that rises after a rise in the power supply voltage is generated as a reset signal. The oscillation circuit 518 changes the frequency and duty ratio of the clock signal in accordance with the control signal generated by the constant voltage circuit 516. The demodulation circuit 519 is a circuit that demodulates the received signal, and the modulation circuit 520 is a circuit that modulates data to be transmitted.

For example, the demodulation circuit 519 is formed of a low-pass filter, and binarizes an amplitude modulation (ASK) reception signal based on the amplitude fluctuation. In addition, in order to transmit transmission data by changing the amplitude of an amplitude modulation (ASK) transmission signal, the modulation circuit 520 changes the amplitude of the communication signal by changing the resonance point of the resonance circuit 514.

The clock controller 523 generates a control signal for changing the frequency and duty ratio of the clock signal in accordance with the power supply voltage or the current consumption in the central processing unit 525. The power supply management circuit 530 monitors the power supply voltage.

A signal input from the antenna 528 to the RFCPU 511 is demodulated by the demodulation circuit 519 and then decomposed into a control command and data by the RF interface 521. The control command is stored in the control register 522. The control command includes reading of data stored in the read-only memory 527, writing of data to the random access memory 526, an arithmetic instruction to the central processing unit 525, and the like.

The central processing unit 525 accesses the read only memory 527, the random access memory 526, and the control register 522 via the CPU interface 524. The CPU interface 524 has a function of generating an access signal for any of the read-only memory 527, the random access memory 526, and the control register 522 from the address requested by the central processing unit 525.

As a calculation method of the central processing unit 525, a method in which an OS (operating system) is stored in the read-only memory 527 and a program is read and executed together with activation can be employed. Further, it is also possible to adopt a method in which an arithmetic circuit is configured by a dedicated circuit and arithmetic processing is processed in hardware. In the system using both hardware and software, a system in which a part of arithmetic processing is performed by a dedicated arithmetic circuit and the remaining arithmetic operations are processed by the central processing unit 525 using a program can be applied.

Next, the display device will be described with reference to FIGS.

FIG. 8 is a diagram for explaining a liquid crystal display device. 8A is a plan view of a pixel of the liquid crystal display device, and FIG. 8B is a cross-sectional view of FIG. 8A taken along the line JK.

As shown in FIG. 8A, the pixel includes a single crystal semiconductor film 320, a scan line 322 intersecting with the single crystal semiconductor film 320, a signal line 323 intersecting with the scan line 322, a pixel electrode 324, and a pixel. An electrode 328 that electrically connects the electrode 324 and the single crystal semiconductor film 320 is provided. The single crystal semiconductor film 320 is a layer formed from a single crystal semiconductor film provided over the base substrate 120 and constitutes a TFT 325 of the pixel.

As the SOI substrate, the SOI substrate described in the above embodiment is used. As shown in FIG. 8B, a single crystal semiconductor film 320 is stacked over the base substrate 120 with the oxide film 102 interposed therebetween. As the base substrate 120, a glass substrate can be used. A single crystal semiconductor film 320 of the TFT 325 is a film formed by element isolation of a single crystal semiconductor film of an SOI substrate by etching. In the single crystal semiconductor film 320, a channel formation region 340 and an n-type high concentration impurity region 341 to which an impurity element is added are formed. The gate electrode of the TFT 325 is included in the scanning line 322, and one of the source electrode and the drain electrode is included in the signal line 323.

A signal line 323, a pixel electrode 324, and an electrode 328 are provided over the interlayer insulating film 327. A columnar spacer 329 is formed on the interlayer insulating film 327. An alignment film 330 is formed to cover the signal line 323, the pixel electrode 324, the electrode 328, and the columnar spacer 329. The counter substrate 332 is provided with a counter electrode 333 and an alignment film 334 that covers the counter electrode. The columnar spacer 329 is formed to maintain a gap between the base substrate 120 and the counter substrate 332. A liquid crystal layer 335 is formed in a gap formed by the columnar spacers 329. A connection portion between the signal line 323 and the electrode 328 and the high-concentration impurity region 341 has a step in the interlayer insulating film 327 due to the formation of the contact hole. Therefore, the alignment of the liquid crystal in the liquid crystal layer 335 is easily disturbed in the connection portion. For this reason, columnar spacers 329 are formed at the step portions to prevent disorder of the alignment of the liquid crystal.

Next, an electroluminescent display device (hereinafter referred to as an EL display device) will be described with reference to FIG. FIG. 9A is a plan view of a pixel of the EL display device, and FIG. 9B is a cross-sectional view of FIG. 9A taken along the line JK.

As shown in FIG. 9A, the pixel includes a selection transistor 401 made of TFT, a display control transistor 402, a scanning line 405, a signal line 406, a current supply line 407, and a pixel electrode 408. Each pixel is provided with a light-emitting element having a structure in which a layer (EL layer) formed including an electroluminescent material is sandwiched between a pair of electrodes. One electrode of the light emitting element is a pixel electrode 408. In the semiconductor film 403, a channel formation region, a source region, and a drain region of the selection transistor 401 are formed. In the semiconductor film 404, a channel formation region, a source region, and a drain region of the display control transistor 402 are formed. The semiconductor films 403 and 404 are layers formed from the single crystal semiconductor film 302 provided over the base substrate.

In the selection transistor 401, the gate electrode is included in the scanning line 405, one of the source electrode and the drain electrode is included in the signal line 406, and the other is formed as the electrode 410. In the display control transistor 402, the gate electrode 412 is electrically connected to the electrode 411, one of the source electrode and the drain electrode is formed as an electrode 413 electrically connected to the pixel electrode 408, and the other is supplied with current. Included in line 407.

The display control transistor 402 is a p-channel TFT. As shown in FIG. 9B, a channel formation region 451 and a p-type high concentration impurity region 452 are formed in the semiconductor film 404. Note that the SOI substrate manufactured in the above embodiment is used as the SOI substrate.

An interlayer insulating film 427 is formed to cover the gate electrode 412 of the display control transistor 402. Over the interlayer insulating film 427, a signal line 406, a current supply line 407, electrodes 411, 413, and the like are formed. Further, a pixel electrode 408 that is electrically connected to the electrode 413 is formed over the interlayer insulating film 427. The peripheral portion of the pixel electrode 408 is surrounded by an insulating partition layer 428. An EL layer 429 is formed over the pixel electrode 408, and a counter electrode 430 is formed over the EL layer 429. A counter substrate 431 is provided as a reinforcing plate, and the counter substrate 431 is fixed to the base substrate 120 by a resin layer 432.

There are two methods for controlling the gradation of an EL display device: a current driving method in which the luminance of a light-emitting element is controlled by current, and a voltage driving method in which the luminance is controlled by voltage. When the difference in values is large, it is difficult to adopt, and for this purpose, a correction circuit for correcting variation in characteristics is required. Since an EL display is manufactured by a manufacturing method including an SOI substrate manufacturing process and a gettering process, characteristics of the selection transistor 401 and the display control transistor 402 are eliminated from pixel to pixel, so that a current driving method is employed. be able to.

That is, various electrical devices can be manufactured by using an SOI substrate. Electrical equipment includes video cameras, digital cameras, navigation systems, sound playback devices (car audio, audio components, etc.), computers, game machines, personal digital assistants (mobile computers, mobile phones, portable game machines, electronic books, etc.) An image reproduction apparatus provided with a recording medium (specifically, an apparatus provided with a display device capable of reproducing audio data stored in a recording medium such as a DVD (digital versatile disc) and displaying the stored image data) An example of these is shown in FIG.

12A and 12B illustrate an example of a mobile phone to which the display device described above is applied. FIG. 12A is a front view, FIG. 12B is a rear view, and FIG. It is a front view at the time. The cellular phone 700 is composed of two housings 701 and 702. The cellular phone 700 is a so-called smartphone that has both functions of a cellular phone and a portable information terminal, has a built-in computer, and can perform various data processing in addition to voice calls.

A cellular phone 700 is composed of a housing 701 and a housing 702. A housing 701 includes a display portion 703, a speaker 704, a microphone 705, operation keys 706, a pointing device 707, a front camera lens 708, an external connection terminal jack 709, an earphone terminal 710, and the like. A housing 702 includes a keyboard. 711, an external memory slot 712, a rear camera 713, a light 714, and the like. The antenna is built in the housing 701.

In addition to the above structure, the cellular phone 700 may incorporate a non-contact IC chip, a small recording device, and the like.

The housings 701 and 702 that overlap each other (shown in FIG. 12A) can be slid, and are expanded as illustrated in FIG. 12C. The display portion 703 can incorporate a display panel or a display device to which the above-described method for manufacturing a display device is applied. Since the display portion 703 and the front camera lens 708 are provided on the same surface, they can be used as a videophone. Further, by using the display portion 703 as a viewfinder, still images and moving images can be taken with the rear camera 713 and the light 714.

By using the speaker 704 and the microphone 705, the mobile phone 700 can be used as an audio recording device (recording device) or an audio reproducing device. In addition, operation keys 706 can be used to perform incoming / outgoing calls, simple information input operations such as e-mail, scroll operation of a screen displayed on the display unit, cursor movement operation for selecting information displayed on the display unit, and the like. Is possible.

In addition, it is convenient to use the keyboard 711 when there is a lot of information to be handled, such as creation of a document or use as a portable information terminal. Further, by sliding the housings 701 and 702 (FIG. 12A) which overlap with each other, they can be developed as shown in FIG. When used as a portable information terminal, the mouse can be operated smoothly by using the keyboard 711 and the pointing device 707. The external connection terminal jack 709 can be connected to an AC adapter and various cables such as a USB cable, and charging and data communication with a personal computer or the like are possible. In addition, a large amount of data can be stored and moved by inserting a recording medium into the external memory slot 712.

The rear surface of the housing 702 (FIG. 12B) is provided with a rear camera 713 and a light 714, and a still image and a moving image can be taken using the display portion 703 as a viewfinder.

Further, in addition to the above functional configuration, an infrared communication function, a USB port, a TV one-segment reception function, a non-contact IC chip, an earphone jack, or the like may be provided.

Various electronic devices described with reference to FIGS. 12A and 12B can be manufactured by applying the above-described manufacturing method of the transistor and the display device.

100 Semiconductor substrate 102 Oxide film 120 Base substrate 151 Substrate support table 152 Substrate placement unit 153 Opening 154 Lift pin 155 Lifting mechanism 156 Control unit 157 Support table 158 Pressure sensor 160 Charger 161 Substrate support table 251 Semiconductor film 252 Semiconductor film 254 Insulating film 255 Gate electrode 256 Gate electrode 257 Low concentration impurity region 258 Channel formation region 259 High concentration impurity region 260 Channel formation region 261 Side wall insulating film 265 Resist 267 High concentration impurity region 268 Insulating film 269 Interlayer insulating film 270 Wiring 302 Single crystal semiconductor film 320 Single crystal semiconductor film 322 Scan line 323 Signal line 324 Pixel electrode 325 TFT
327 Interlayer insulating film 328 Electrode 329 Columnar spacer 330 Alignment film 332 Counter substrate 333 Counter electrode 334 Alignment film 335 Liquid crystal layer 340 Channel formation region 341 High concentration impurity region 401 Selection transistor 402 Display control transistor 403 Semiconductor film 404 Semiconductor film 405 Scanning Line 406 Signal line 407 Current supply line 408 Pixel electrode 410 Electrode 411 Electrode 412 Gate electrode 413 Electrode 427 Interlayer insulating film 428 Partition layer 429 EL layer 430 Counter electrode 431 Counter substrate 432 Resin layer 451 Channel formation region 452 High concentration impurity region 500 Micro Processor 501 Arithmetic circuit 502 Arithmetic circuit control unit 503 Instruction analysis unit 504 Control unit 505 Timing control unit 506 Register 507 Register control unit 508 Bus interface 509 Dedicated memory 510 Memory Interface 511 RFCPU
512 Analog circuit unit 513 Digital circuit unit 514 Resonant circuit 515 Rectifier circuit 516 Constant voltage circuit 517 Reset circuit 518 Oscillator circuit 519 Demodulator circuit 520 Modulator circuit 521 RF interface 522 Control register 523 Clock controller 524 CPU interface 525 Central processing unit 526 Random access memory 527 Dedicated memory 528 Antenna 529 Capacitance unit 530 Power management circuit 550 Heating temperature 700 Mobile phone 701 Case 702 Case 703 Display unit 704 Speaker 705 Microphone 706 Operation key 707 Pointing device 708 Surface camera lens 709 External connection terminal jack 710 Earphone terminal 711 Keyboard 712 External memory slot 713 Rear camera 714 Light 100a Semiconductor substrate 00b the semiconductor substrate 100c semiconductor substrate 102a insulating film 102b insulating film 104a embrittlement region 104b embrittled region 124a single crystal semiconductor film

Claims (10)

Providing a plurality of semiconductor substrates on a first substrate support;
Providing a base substrate on the second substrate support;
Disposing the second substrate support above the first substrate support so that the surfaces of the plurality of semiconductor substrates and the surface of the base substrate face each other with a predetermined interval;
Charging the plurality of semiconductor substrates or the base substrate;
By narrowing the distance between the surfaces of the plurality of semiconductor substrates and the surface of the base substrate, the plurality of semiconductor substrates are brought into contact with the surface of the base substrate, and the surfaces of the base substrate and the surfaces of the plurality of semiconductor substrates are bonded. And a method for manufacturing an SOI substrate. In claim 1,
The plurality of semiconductor substrates or the base substrate is charged with one of the first substrate support base and the second substrate support base being a ground potential and the other being a positive potential or a negative potential. A method for manufacturing an SOI substrate, which is performed by applying a DC voltage between a table and the second substrate support table. In claim 1,
A method for manufacturing an SOI substrate, wherein the plurality of semiconductor substrates or the base substrate is charged by applying positive ions or negative ions to the surfaces of the plurality of semiconductor substrates or the surface of the base substrate. Providing a plurality of semiconductor substrates on a first substrate support;
Providing a base substrate on the second substrate support;
Disposing the second substrate support above the first substrate support so that the surfaces of the plurality of semiconductor substrates and the surface of the base substrate face each other with a predetermined interval;
Charging both the plurality of semiconductor substrates and the base substrate to have different polarities,
By narrowing the distance between the surfaces of the plurality of semiconductor substrates and the surface of the base substrate, the plurality of semiconductor substrates are brought into contact with the surface of the base substrate, and the surfaces of the base substrate and the surfaces of the plurality of semiconductor substrates are bonded. And a method for manufacturing an SOI substrate. In claim 4,
The charging of the plurality of semiconductor substrates and the base substrate is performed by setting one of the first substrate support base and the second substrate support base to a positive potential and the other to a negative potential. A method for manufacturing an SOI substrate, which is performed by applying a DC voltage to a second substrate support. In claim 4,
The plurality of semiconductor substrates and the base substrate are charged by applying either positive ions or negative ions to the surfaces of the plurality of semiconductor substrates, and positive ions or negative ions on the surface of the base substrate so as to have a polarity different from that of the semiconductor substrate. A method for manufacturing an SOI substrate, which is performed by applying the other of negative ions. In any one of Claims 1 thru | or 6,
After bringing the plurality of semiconductor substrates into contact with the surface of the base substrate, pressure is applied to each of the plurality of semiconductor substrates to bond the surface of the base substrate and the surfaces of the plurality of semiconductor substrates. A method for manufacturing an SOI substrate. In any one of Claims 1 thru | or 7,
The first substrate support has a substrate arrangement region having a recess,
A method for manufacturing an SOI substrate, wherein the plurality of semiconductor substrates are respectively disposed in recesses of the substrate placement portion. In any one of Claims 1 thru | or 8,
A method for manufacturing an SOI substrate, wherein the bonding of the plurality of semiconductor substrates and the base substrate is performed in a reduced pressure atmosphere. In any one of Claims 1 thru | or 9,
A method for manufacturing an SOI substrate, wherein a glass substrate is used as the base substrate.

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