JP4273533B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a substrate having a single crystal silicon-insulator structure and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, as a manufacturing method of a single crystal silicon-insulator substrate (Silicon-On-Insulator, hereinafter abbreviated as SOI), a method of bonding a single crystal silicon thin film and a quartz substrate, or oxygen ions in a single crystal silicon substrate are used. There has been known a method of forming a quartz region in a single crystal silicon substrate by annealing after ion implantation.
[0003]
FIG. 9A to FIG. 9C are cross-sectional views illustrating an example of a method for manufacturing a semiconductor device according to a conventional technique. In this example, a method of forming a quartz region in a single crystal silicon substrate by annealing after oxygen ions are implanted into the single crystal silicon substrate is shown.
[0004]
FIG. 9A shows a step of implanting oxygen ions 902 into the single crystal silicon substrate 901 using an ion implantation apparatus.
[0005]
FIG. 9B is a diagram showing a silicon region 903 implanted with oxygen ions, formed by the above-described process.
[0006]
Through the above-described ion implantation process, a silicon region 903 having a peak at a predetermined depth in the single crystal silicon substrate 901 and oxygen ions having a distribution in the depth region before and after the peak is formed. The distribution in the depth direction of the concentration of oxygen ions in the silicon region 903 implanted with oxygen ions is shown in the figure as a graph.
[0007]
In FIG. 9C, a thermal process is performed on the semiconductor device obtained in the above-described process, and oxygen ions in the silicon region 903 implanted with oxygen ions are reacted with silicon which is a raw material of the substrate to form silicon dioxide. This is a step of forming the silicon dioxide thin film 904. Further, in this thermal process, the silicon on the surface side of the silicon dioxide thin film 904 is single-crystallized from an amorphous state, and the single-crystal silicon in that portion has an insulating silicon dioxide thin film 904 immediately below, so that the SOI device It becomes a region where the formation of can be performed.
[0008]
[Problems to be solved by the invention]
In these methods, the single crystal silicon thin film obtained is formed on a quartz substrate. Quartz has a thermal conductivity that is two orders of magnitude lower than that of single crystal silicon. As a result, the temperature rise due to the power consumed inside is extremely large compared to devices formed on ordinary single-crystal silicon substrates. MOS devices for high-speed operation and power devices for high-current switching However, it is extremely limited in practice.
[0009]
In order to avoid this problem, a method of epitaxially growing single crystal silicon on sapphire having higher thermal conductivity than quartz is also known. However, sapphire substrates themselves are very expensive, and large-diameter substrates are difficult to obtain.
[0010]
In order to solve this problem, a method of epitaxially growing sapphire on a single crystal silicon substrate and further epitaxially growing single crystal silicon thereon is introduced in IEICE Technical Report SDM92-117. Since the constants differ by 4% or more, it is very difficult to obtain a good single crystal.
[0011]
SUMMARY OF THE INVENTION Accordingly, the present invention aims to solve such conventional problems and provide means for manufacturing an SOI substrate suitable for a MOS device for high-speed operation and a power device for large-current switching. It is said.
[0012]
[Means for Solving the Problems]
The present invention relates to a method of manufacturing a semiconductor device in which a gap communicating with the outside of a substrate is formed in a specific section having a specific depth in a single crystal silicon substrate, wherein the silicon of the single crystal silicon substrate is formed on the single crystal silicon substrate. A step of introducing a raw material that reacts with gas using an ion implantation method, and applying heat to the single crystal silicon substrate and the raw material, thereby reacting the silicon of the single crystal silicon substrate and the raw material. And a step of forming a void by promoting, and a step of single-crystallizing silicon of the single crystal silicon substrate immediately above the void.
[0013]
Alternatively, in a method of manufacturing a semiconductor device in which a gap communicating with the outside of a single crystal silicon substrate is formed in a specific section having a specific depth, the single crystal silicon substrate reacts with silicon of the single crystal silicon substrate. And introducing a raw material to be gasified using an ion implantation method, and applying heat to the single crystal silicon substrate and the raw material to promote the reaction of the silicon of the single crystal silicon substrate and the raw material. A step of forming a void, and a step of performing epitaxial growth on silicon of the single crystal silicon substrate in the void.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing an embodiment of a semiconductor device according to the present invention.
[0015]
A void 102 having helium gas is formed in a specific section in a specific depth range of the single crystal silicon substrate 101.
[0016]
FIG. 2 is a perspective view showing an embodiment of a semiconductor device according to the present invention.
[0017]
A void region 202 is formed in a specific section in a specific depth range of the single crystal silicon substrate 201. The void region 202 is opened on a side surface of the single crystal silicon substrate 201, and the opening is formed so as to open to both side surfaces of the substrate after being cut out at least for each chip.
[0018]
3A to 3C are perspective views showing an example of a method for manufacturing the semiconductor device according to the present invention shown in FIG.
[0019]
FIG. 3A shows a process of injecting helium ions into the single crystal silicon substrate 301 partially masked with the resist 302 using an ion implantation apparatus.
[0020]
FIG. 3B is a diagram showing the silicon region 303 implanted with helium ions formed by the above-described process.
[0021]
By the above-described ion implantation process, a silicon region 303 having a peak at a predetermined depth in the single crystal silicon substrate 301 and implanted with helium ions having a distribution in the depth region before and after that is formed. The distribution in the depth direction of the concentration of helium ions in the silicon region 301 into which helium ions have been implanted is shown in the drawing as a graph.
[0022]
FIG. 3C shows a gap having a helium gas by gasifying the helium ions in the silicon region 303 into which helium ions have been implanted by performing a thermal process after removing the resist 302 of the semiconductor device obtained in the foregoing process. This is a step of forming 304. Further, in this thermal process, silicon on the surface side of the gap 304 having helium gas is single-crystallized from an amorphous state, and the single crystal silicon in that portion has a gap 304 having an insulating helium gas immediately below. Thus, an area where an SOI device can be formed is obtained.
[0023]
4A to 4C are perspective views showing an example of a method for manufacturing the semiconductor device according to the present invention shown in FIG.
[0024]
FIG. 4A shows a process in which helium ions are implanted into the single crystal silicon substrate 401 partially masked with the resist 402 by using an ion implantation apparatus.
[0025]
FIG. 4B is a diagram showing the silicon region 403 implanted with helium ions formed by the above-described process.
[0026]
By the above-described ion implantation process, a silicon region 403 having a peak at a predetermined depth in the single crystal silicon substrate 401 and implanted with helium ions having a distribution in the depth region before and after that is formed. The distribution in the depth direction of the concentration of helium ions in the silicon region 403 implanted with helium ions is shown in the figure as a graph.
[0027]
In FIG. 4C, a thermal process is performed after removing the resist 402 of the semiconductor device obtained in the above-described process, and the helium ions in the silicon region 403 implanted with helium ions are gasified to form the void 404. It is a process. Further, in this thermal process, silicon on the surface side from the gap 404 is single-crystallized from an amorphous state, and the single crystal silicon in that portion has an insulating gap 404 immediately below, so that an SOI device can be formed. Become an area.
[0028]
5A to 5C are perspective views showing an example of a method for manufacturing the semiconductor device according to the present invention shown in FIG.
[0029]
FIG. 5A shows a process in which fluorine ions are implanted into a single crystal silicon substrate 501 partially masked with a resist 502 by using an ion implantation apparatus.
[0030]
FIG. 5B is a diagram showing the silicon region 503 implanted with fluorine ions formed by the above-described process.
[0031]
By the above-described ion implantation step, a silicon region 503 having a peak at a predetermined depth in the single crystal silicon substrate 501 and implanted with fluorine ions having a distribution in the depth region before and after that is formed. The distribution in the depth direction of the concentration of fluorine ions in the silicon region 503 into which fluorine ions have been implanted is shown in the drawing as a graph.
[0032]
FIG. 5 (c) shows a process of removing the resist 502 of the semiconductor device obtained in the previous step and then performing a thermal process to react fluorine ions in the silicon region 503 into which fluorine ions are implanted with single crystal silicon. This is a step of forming a void 504 by forming a gap. Further, in this thermal process, silicon on the surface side from the gap 504 is single-crystallized from an amorphous state, and the single crystal silicon in that portion has an insulating gap 504 immediately below, so that an SOI device can be formed. Become an area.
[0033]
The voids thus obtained are characterized in that very efficient heat dissipation is possible by filling and circulating a cooling medium such as helium gas, ammonia gas, and freon gas.
[0034]
6A to 6C are perspective views showing an example of a method for manufacturing the semiconductor device according to the present invention shown in FIG.
[0035]
FIG. 6A shows a process in which helium ions are implanted into a single crystal silicon substrate 601 partially masked with a resist 602 using an ion implantation apparatus.
[0036]
FIG. 6B is a diagram showing a silicon region 603 implanted with helium ions formed by the above-described process.
[0037]
By the above-described ion implantation process, a silicon region 603 having a peak at a predetermined depth in the single crystal silicon substrate 601 and implanted with helium ions having a distribution in the depth region before and after that is formed. The distribution in the depth direction of the concentration of helium ions in the silicon region 601 implanted with helium ions is shown in the figure as a graph.
[0038]
FIG. 6C shows a void having helium gas by removing the resist 602 of the semiconductor device obtained in the previous step and then performing a thermal process to gasify the helium ions in the silicon region 603 implanted with helium ions. This is a step of forming 604. Further, in the thermal process when forming the epitaxial silicon layer 605, the silicon on the surface side of the gap 604 having helium gas is single-crystallized from an amorphous state, and the single-crystal silicon in that portion has an insulating helium gas immediately below it. Since the void 604 is included, it is a region where an SOI device can be formed.
[0039]
7A to 7C are perspective views showing an example of a method for manufacturing the semiconductor device according to the present invention shown in FIG.
[0040]
FIG. 7A shows a process in which helium ions are implanted into a single crystal silicon substrate 701 partially masked with a resist 702 using an ion implantation apparatus.
[0041]
FIG. 7B is a diagram showing the silicon region 703 implanted with helium ions formed by the above-described process.
[0042]
By the above-described ion implantation step, a silicon region 703 having a peak at a predetermined depth in the single crystal silicon substrate 701 and implanted with helium ions having a distribution in the depth region before and after that is formed. The distribution in the depth direction of the concentration of helium ions in the silicon region 703 implanted with helium ions is shown in the figure as a graph.
[0043]
In FIG. 7C, a thermal process is performed after removing the resist 702 of the semiconductor device obtained in the above-described process, and the helium ions in the silicon region 703 into which helium ions are implanted are gasified to form the voids 704. It is a process. Further, in the thermal process when forming the epitaxial silicon layer 705, silicon on the surface side from the gap 704 is single-crystallized from an amorphous state, and the single-crystal silicon in that portion has an insulating gap 704 immediately below, This is a region where an SOI device can be formed.
[0044]
8A to 8C are perspective views showing an example of a method for manufacturing the semiconductor device according to the present invention shown in FIG.
[0045]
FIG. 8A shows a process of implanting fluorine ions into the single crystal silicon substrate 801 partially masked with the resist 802 using an ion implantation apparatus.
[0046]
FIG. 8B is a diagram showing a silicon region 803 implanted with fluorine ions, formed by the above-described process.
[0047]
By the above-described ion implantation process, a silicon region 803 having a peak at a predetermined depth in the single crystal silicon substrate 801 and fluorine ions having a distribution in the depth region before and after that is formed. The distribution in the depth direction of the concentration of fluorine ions in the silicon region 803 into which fluorine ions are implanted is shown in the drawing as a graph.
[0048]
FIG. 8 (c) shows that after removing the resist 802 of the semiconductor device obtained in the previous step, a thermal process is performed to react the fluorine ions in the silicon region 803 into which fluorine ions have been implanted with silicon and gasify them. This is a step of forming the gap 804. Furthermore, in the thermal process when forming the epitaxial silicon layer 805, silicon on the surface side from the gap 804 is single-crystallized from an amorphous state, and the single-crystal silicon in that portion has an insulating gap 804 immediately below, This is a region where an SOI device can be formed.
[0049]
The gap obtained in this way is characterized by the fact that it is possible to dissipate very efficiently by filling it with a cooling medium such as helium gas, ammonia gas, freon gas, etc. and circulating it. This is the same as the embodiment.
[0050]
In the embodiment of the present invention, helium is used as a raw material as an implanted ion that becomes a gas that fills the gap, but other elements such as hydrogen, nitrogen, neon, argon, krypton, xenon, and radon may also be used. Obviously, similar effects can be obtained, and these are also within the scope of the present invention.
[0051]
Similarly, fluorine is used in the present invention as the implanted ions that react with silicon and gasify to form voids. However, the same effect can be obtained by using other elements such as chlorine and germanium. it is obvious. When germanium is used, it is applied that germanium oxide obtained by oxidation can be easily sublimated at around 1000 degrees.
[0052]
Furthermore, although single crystal silicon is typically used as the substrate material, it is added that the effect is not changed at all even when other semiconductor materials, germanium, gallium arsenide, indium arsenide, indium phosphide, gallium aluminum arsenide, or the like are used.
[0053]
And the surface of the SOI substrate formed in this way becomes a wavy shape due to the influence of the void hidden under the water surface, but can be easily flattened using a chemical mechanical polishing method (CMP method) or the like, Even if it is necessary, it can be dealt with.
[0054]
In addition, even when the ion implantation depth cannot be increased so much, a single crystal thin film having a desired thickness can be formed by performing epitaxial growth after forming the void.
[0055]
Furthermore, since the wiring formed on this structure uses a gas having a dielectric constant lower than that of silicon dioxide as the insulating layer of the SOI structure, the wiring parasitic capacitance is remarkably reduced, and higher frequency propagation is possible. is there.
[0056]
【The invention's effect】
By using the semiconductor device according to the present invention, a fundamental solution to the problem of heat dissipation that has been a problem with conventional SOI substrates has been achieved. Furthermore, since the parasitic capacitance is smaller than that of the conventional SOI structure, it has become possible to realize faster elements and wiring.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a semiconductor device according to the present invention.
FIG. 2 is a perspective view showing an embodiment of a semiconductor device according to the present invention.
3 is a perspective view showing an example of a manufacturing method of the semiconductor device according to the present invention shown in FIG. 1. FIG.
4 is a perspective view showing an example of a manufacturing method of the semiconductor device according to the present invention shown in FIG. 2;
5 is a perspective view showing an example of a manufacturing method of the semiconductor device according to the present invention shown in FIG. 2. FIG.
6 is a perspective view showing an example of a manufacturing method of the semiconductor device according to the present invention shown in FIG. 1. FIG.
7 is a perspective view showing an example of a manufacturing method of the semiconductor device according to the present invention shown in FIG. 2; FIG.
8 is a perspective view showing an example of a manufacturing method of the semiconductor device according to the present invention shown in FIG. 2;
FIG. 9 is a cross-sectional view showing an example of a conventional method for manufacturing a semiconductor device.
[Explanation of symbols]
101 single crystal silicon substrate 102 void 201 having helium gas single crystal silicon substrate 202 void region 301 single crystal silicon substrate 302 resist 303 silicon region 304 in which helium ions are implanted 401 void having helium gas 401 single crystal silicon substrate 402 resist 403 helium Ion implanted silicon region 404 Void 501 Single crystal silicon substrate 502 Resist 503 Fluorine ion implanted silicon region 504 Void 601 Single crystal silicon substrate 602 Resist 603 Helium ion implanted silicon region 604 Void having helium gas 605 Epitaxial silicon layer 701 Single crystal silicon substrate 702 Resist 703 Helium ion implanted silicon region 704 Void 705 Epitaxial silicon 801 single-crystal silicon substrate 802 resist 803 fluorine ions implanted silicon region 804 gap 805 epitaxial silicon layer 901 single crystal silicon substrate 902 oxygen ions 903 oxygen ion implanted silicon region 904 of silicon dioxide thin film

Claims (3)

In a method for manufacturing a semiconductor device, in a specific section at a specific depth of a single crystal silicon substrate, a void that communicates with the outside of the substrate is formed.
Introducing into the single crystal silicon substrate, using an ion implantation method, a raw material that reacts with silicon of the single crystal silicon substrate to gasify;
Said single crystal silicon substrate and the raw material, by heat application, the steps that form a said gap by promoting the reaction of the silicon and the raw material of the single crystal silicon substrate,
And a step of single-crystallizing silicon of the single-crystal silicon substrate immediately above the gap . In a method for manufacturing a semiconductor device, in a specific section at a specific depth of a single crystal silicon substrate, a void that communicates with the outside of the substrate is formed.
Introducing into the single crystal silicon substrate, using an ion implantation method, a raw material that reacts with silicon of the single crystal silicon substrate to gasify;
Said single crystal silicon substrate and the raw material, by heat application, the steps that form a said gap by promoting the reaction of the silicon and the raw material of the single crystal silicon substrate,
And a step of performing epitaxial growth on silicon of the single crystal silicon substrate in the gap . The semiconductor device according to claim 1 or 2,
A method for manufacturing a semiconductor device, wherein the raw material to be gasified is either fluorine or chlorine.

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