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Claims  |
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What is claimed is:
1. A method for manufacturing a semiconductor device comprising: forming a metal film over a substrate; performing plasma treatment to the metal film in an atmosphere
containing oxygen to form a metal oxide film on a surface of the metal film; forming a base film over the metal oxide film; forming an element layer comprising a thin film transistor over the base film; forming a protective layer over the element
layer; selectively removing the metal film, the metal oxide film, the base film, the element layer, and the protective layer to form an opening; separating the base film, the element layer, and the protective layer from the substrate; and sealing the
base film, the element layer, and the protective layer by using flexible first and second films, wherein an electron density of the plasma treatment is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron
temperature of the plasma treatment is 0.5 eV or more and 1.5 eV or less around the substrate.
2. A method for manufacturing a semiconductor device comprising: forming a metal oxide film over a substrate by using plasma in an atmosphere containing oxygen; forming a base film over the metal oxide film; forming an element layer
comprising a thin film transistor over the base film; forming a protective layer over the element layer; selectively removing the metal oxide film, the base film, the element layer, and the protective layer to form an opening; separating the base
film, the element layer, and the protective layer from the substrate; and sealing the base film, the element layer, and the protective layer by using flexible first and second films, wherein an electron density of the plasma is 1.times.10.sup.11
cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of the plasma is 0.5 eV or more and 1.5 eV or less around the substrate.
3. A method for manufacturing a semiconductor device comprising: forming an insulating film over a substrate; forming a metal film over the insulating film; performing first plasma treatment to the metal film in an atmosphere containing
oxygen to form a metal oxide film on a surface of the metal film; forming a silicon oxide film over the metal oxide film; performing second plasma treatment to the silicon oxide film in an atmosphere containing nitrogen to nitride the surface of the
silicon oxide film; forming a silicon oxide film containing nitrogen over the silicon oxide film, the surface of the silicon oxide film being nitrided; forming an element layer comprising a thin film transistor over the silicon oxide film containing
nitrogen; forming a protective layer over the element layer; removing the insulating film, the metal film, the metal oxide film, the silicon oxide film, the surface of the silicon oxide film being nitrided, the silicon oxide film containing nitrogen,
the element layer, and the protective layer to form an opening; separating the silicon oxide film, the surface of the silicon oxide film being nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer from the
substrate; and sealing the silicon oxide film, the surface of the silicon oxide film being nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer by using flexible first and second films, wherein an electron
density of the first plasma treatment is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of the first plasma treatment is 0.5 eV or more and 1.5 eV or less around the substrate.
4. A method for manufacturing a semiconductor device comprising: forming an insulating film over a substrate; forming a metal oxide film over the insulating film by using plasma in an atmosphere containing oxygen; forming a silicon oxide film
over the metal oxide film; performing plasma treatment to the silicon oxide film in an atmosphere containing nitrogen to nitride the surface of the silicon oxide film; forming a silicon oxide film containing nitrogen over the silicon oxide film, the
surface of the silicon oxide film being nitrided; forming an element layer comprising a thin film transistor over the silicon oxide film containing nitrogen; forming a protective layer over the element layer; selectively removing the insulating film,
the metal oxide film, the silicon oxide film, the surface of the silicon oxide film being nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer to form an opening; separating the silicon oxide film, the
surface of the silicon oxide film being nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer from the substrate; and sealing the silicon oxide film, the surface of the silicon oxide film being nitrided, the
silicon oxide film containing nitrogen, the element layer, and the protective layer by using flexible first and second films, wherein an electron density of the plasma is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an
electron temperature of the plasma is 0.5 eV or more and 1.5 eV or less around the substrate.
5. A method for manufacturing a semiconductor device according to claim 3, wherein the atmosphere containing nitrogen is a mixed gas of N.sub.2 or NH.sub.3 and a rare gas, or a mixed gas of N.sub.2 or NH.sub.3, a rare gas, and H.sub.2.
6. A method for manufacturing a semiconductor device according to claim 4, wherein the atmosphere containing nitrogen is a mixed gas of N.sub.2 or NH.sub.3 and a rare gas, or a mixed gas of N.sub.2 or NH.sub.3, a rare gas, and H.sub.2.
7. A method for manufacturing a semiconductor device according to claim 1, wherein the atmosphere containing oxygen is a mixed gas of O.sub.2 or N.sub.2O and a rare gas, or a mixed gas of O.sub.2 or N.sub.2O, a rare gas, and H.sub.2.
8. A method for manufacturing a semiconductor device according to claim 2, wherein the atmosphere containing oxygen is a mixed gas of O.sub.2 or N.sub.2O and a rare gas, or a mixed gas of O.sub.2 or N.sub.2O, a rare gas, and H.sub.2.
9. A method for manufacturing a semiconductor device according to claim 3, wherein the atmosphere containing oxygen is a mixed gas of O.sub.2 or N.sub.2O and a rare gas, or a mixed gas of O.sub.2 or N.sub.2O, a rare gas, and H.sub.2.
10. A method for manufacturing a semiconductor device according to claim 4, wherein the atmosphere containing oxygen is a mixed gas of O.sub.2 or N.sub.2O and a rare gas, or a mixed gas of O.sub.2 or N.sub.2O, a rare gas, and H.sub.2.
11. A method for manufacturing a semiconductor device according to claim 1, wherein a frequency of a power source for the plasma treatment is 2.45 GHz.
12. A method for manufacturing a semiconductor device according to claim 2, wherein a frequency of a power source for generating the plasma is 2.45 GHz.
13. A method for manufacturing a semiconductor device according to claim 3, wherein a frequency of a power source for generating the first and second plasma is 2.45 GHz.
14. A method for manufacturing a semiconductor device according to claim 4, wherein a frequency of a power source for generating the plasma and the plasma treatment is 2.45 GHz.
15. A method for manufacturing a semiconductor device according to claim 1, wherein potential of the plasma is 5V or less.
16. A method for manufacturing a semiconductor device according to claim 2, wherein potential of the plasma is 5V or less.
17. A method for manufacturing a semiconductor device according to claim 3, wherein potential of the first plasma treatment is 5V or less.
18. A method for manufacturing a semiconductor device according to claim 3, wherein potential of the second plasma treatment is 5V or less.
19. A method for manufacturing a semiconductor device according to claim 4, wherein potential of the plasma is 5V or less.
20. A method for manufacturing a semiconductor device according to claim 4, wherein potential of the plasma treatment is 5V or less.
21. A method for manufacturing a semiconductor device according to claim 3, wherein an electron density of the second plasma treatment is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of
the first plasma treatment is 0.5 eV or more and 1.5 eV or less around the substrate.
22. A method for manufacturing a semiconductor device according to claim 4, wherein an electron density of the plasma treatment is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of the
plasma treatment is 0.5 eV or more and 1.5 eV or less around the substrate. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention disclosed in this specification relates to a method for manufacturing a semiconductor device. In particular, the present invention relates to a method for manufacturing a semiconductor device in which an element layer is
peeled off a supporting substrate by using a peeling layer provided between the supporting substrate and the element layer.
2. Description of the Related Art
In recent years, development of a wireless chip that transmits and receives data has been actively advanced. The wireless chip is also referred to as an IC tag, an ID tag, an RF (Radio Frequency) tag, an RFID (Radio Frequency Identification)
tag, a wireless tag, an electronic tag, a wireless processor, a wireless memory, and the like. In this specification, the wireless chip may also be referred to as a semiconductor device.
In general, an RFID tag is constituted by an antenna and an IC chip, which is formed by an element layer including a transistor or the like provided over a silicon wafer. In recent years, however, technological development of an RFID tag using
an element layer provided over a glass substrate or the like has been advanced for cost reduction. However, in the case of using a technique for providing an element layer over a glass substrate, after forming an element layer over a glass substrate,
the element layer is required to be separated from the glass substrate, which is a supporting substrate, and to displace the element layer over a flexible substrate. The wireless chip is used by attaching to a surface of an article, embedding in an
article, or the like so as to be fixed. This is because it is desirable that the wireless chip itself has flexibility in a case of attaching or fixing the wireless chip to an article having curvature or flexibility.
Various techniques are known as a method for peeling an element layer provided over a supporting substrate. For example, there are a method for taking out an element layer by making a supporting substrate thin by grinding or polishing, a method
for removing a supporting substrate by chemical reaction or the like, a method for peeling an element layer provided over a supporting substrate, and the like. As a method for peeling an element layer provided over a supporting substrate, there is a
method that a separating layer is provided between a substrate and a layer to be transferred, and separation is made to occur in the separating layer by laser light irradiation through the substrate (see Reference 1: Japanese Patent Application Laid-Open
No. H10-125929). In addition, there is a method to separate an element layer from a supporting substrate by providing a peeling layer containing silicon between the element layer and the supporting substrate and removing the peeling layer with the use
of gas containing halogen fluoride (chemical formula: XF.sub.n (X is halogen other than fluorine and n is an integer number) (see Reference 2: Japanese Patent Application Laid-Open No. H8-254686).
However, the above conventional methods, that is, the methods for removing a supporting substrate by grinding, polishing, or dissolving has caused problems such as damage due to physical strength such as stress, and contamination. In addition,
according to such methods, it has been extremely difficult to reuse a substrate and the cost has been increased.
In the case where an element layer provided over a supporting substrate is separated by removing a peeling layer provided between the supporting substrate and the element layer, the quality of the peeling layer becomes important. Time required
for removing the peeling layer is affected depending on a material used for the peeling layer and an etchant used for removing the peeling layer. In addition, in a case where an element layer constituted by a thin film transistor or the like is provided
over a peeling layer, the property of the transistor may be affected and the reliability of a semiconductor device may be decreased depending on a material or the film quality of the peeling layer.
SUMMARY OF THE INVENTION
In view of the above problem, the present invention provides a manufacturing method of a semiconductor device at low cost and with high reliability.
According to one feature of the present invention, a method for manufacturing a semiconductor device includes the steps of forming a metal film over a substrate; forming a metal oxide film over the surface of the metal film by performing plasma
treatment to the metal film in an atmosphere containing oxygen; forming a base film over the metal oxide film; forming an element layer having a thin film transistor over the base film; forming a protective layer over the element layer; forming an
opening after selectively removing the metal film, the metal oxide film, the base film, the element layer, and the protective layer; separating the base film, the element layer, and the protective layer from the substrate; and sealing the base film, the
element layer, and the protective layer by using flexible first and second films, in which an electron density of plasma is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of the plasma treatment is
0.5 eV or more and 1.5 eV or less around the substrate.
According to another feature of the present invention, a method for manufacturing a semiconductor device includes the steps of forming a metal oxide film over a substrate by using plasma in an atmosphere containing oxygen; forming a base film
over the metal oxide film; forming an element layer having a thin film transistor over the base film; forming a protective layer over the element layer; forming an opening after selectively removing the metal oxide film, the base film, the element layer,
and the protective layer; separating the base film, the element layer, and the protective layer from the substrate; and sealing the base film, the element layer, and the protective layer by using flexible first and second films, in which an electron
density of the plasma is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of the plasma is 0.5 eV or more and 1.5 eV or less around the substrate.
According to another feature of the present invention, a method for manufacturing a semiconductor device includes the steps of forming an insulating film over a substrate; forming a metal film over the insulating film; forming a metal oxide film
over the surface of the metal film by performing plasma treatment to the metal film in an atmosphere containing oxygen; forming a silicon oxide film over the metal oxide film; nitriding the surface of the silicon oxide film by performing plasma treatment
to the silicon oxide film in an atmosphere containing nitrogen; forming a silicon oxide film containing nitrogen over the silicon oxide film the surface of which is nitrided; forming an element layer having a thin film transistor over the silicon oxide
film containing nitrogen; forming a protective layer over the element layer; forming an opening after selectively removing the insulating film, the metal film, the metal oxide film, the silicon oxide film the surface of which is nitrided, the silicon
oxide film containing nitrogen, the element layer, and the protective layer; separating the silicon oxide film the surface of which is nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer from the substrate;
and sealing the silicon oxide film the surface of which is nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer by using flexible first and second films, in which an electron density of plasma is
1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of at least one of the plasma treatments is 0.5 eV or more and 1.5 eV or less around the substrate.
According to another feature of the present invention, a method for manufacturing a semiconductor device includes the steps of forming an insulating film over a substrate; forming a metal oxide film over the insulating film by using plasma in an
atmosphere containing oxygen; forming a silicon oxide film over the metal oxide film; nitriding the surface of the silicon oxide film by performing plasma treatment to the silicon oxide film in an atmosphere containing nitrogen; forming a silicon oxide
film containing nitrogen over the silicon oxide film the surface of which is nitrided; forming an element layer having a thin film transistor over the silicon oxide film containing nitrogen; forming a protective layer over the element layer; forming an
opening after selectively removing the insulating film, the metal oxide film, the silicon oxide film the surface of which is nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer; separating the silicon oxide
film the surface of which is nitrided, the silicon oxide film containing nitrogen, the element layer, and the protective layer from the substrate; and sealing the silicon oxide film the surface of which is nitrided, the silicon oxide film containing
nitrogen, the element layer, and the protective layer by using flexible first and second films, in which an electron density of the plasma or the plasma treatment is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an
electron temperature of the plasma is 0.5 eV or more and 1.5 eV or less around the substrate.
According to another feature of a method for manufacturing a semiconductor device in the above structures, the atmosphere containing nitrogen is a mixed gas of N.sub.2 or NH.sub.3 and a rare gas, or a mixed gas of N.sub.2 or NH.sub.3, a rare gas,
and H.sub.2.
According to another feature of a method for manufacturing a semiconductor device in the above structures, the atmosphere containing oxygen is a mixed gas of O.sub.2 or N.sub.2O and a rare gas, or a mixed gas of O.sub.2 or N.sub.2O, a rare gas,
and H.sub.2.
According to another feature of a method for manufacturing a semiconductor device in the above structures, a frequency of a power source for generating the plasma is 2.45 GHz.
According to another feature of a method for manufacturing a semiconductor device in the above structures, potential of the plasma is 5V or less.
In this specification, an element layer means a layer at least provided with an element typified by a thin film transistor (TFT). Various integrated circuits such as a CPU (central processing unit), a memory, or a microprocessor can be provided
by using the element such as a thin film transistor. In addition, the element layer can also have a mode including an antenna as well as a thin film transistor. For example, the element layer composed of a thin film transistor performs an operation by
using an AC voltage generated at an antenna and transmission to a reader/writer can be performed by modulating an AC voltage that is applied to the antenna. Note that the antenna may be formed in the element layer along with the thin film transistor or
may be formed separately from the thin film transistor and provided so as to be electrically connected thereto subsequently.
By applying the present invention, a semiconductor device provided over a flexible substrate can be manufactured in high yields. In addition, a semiconductor device can be provided with low cost by using a method for manufacturing a
semiconductor device according to the present invention.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description along with the accompanied drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIGS. 1A to 1E are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 1);
FIGS. 2A to 2D are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 1);
FIG. 3 is a view showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 2);
FIG. 4 is a view showing a film forming apparatus (Embodiment Mode 3);
FIG. 5 is a view showing a film forming apparatus (Embodiment Mode 1);
FIGS. 6A to 6C are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 4);
FIGS. 7A and 7B are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 4);
FIG. 8 is a view showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 4);
FIGS. 9A and 9B are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 4);
FIGS. 10A and 10B are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 4);
FIG. 11 is a view showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 4);
FIGS. 12A to 12D are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 5);
FIGS. 13A to 13D are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 5);
FIGS. 14A to 14C are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 5);
FIGS. 15A to 15C are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 5);
FIGS. 16A to 16D are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 6);
FIGS. 17A to 17D are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 9);
FIGS. 18A to 18C are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 9);
FIGS. 19A to 19C are views each showing a method for manufacturing a semiconductor device according to the present invention (Embodiment Mode 9);
FIGS. 20A to 20C are a diagram and views each explaining a usage pattern of a semiconductor device according to the present invention (Embodiment Mode 10);
FIG. 21 is a view explaining a usage pattern of a semiconductor device according to the present invention (Embodiment Mode 11);
FIGS. 22A to 22H are views each explaining a usage pattern of a semiconductor device according to the present invention (Embodiment Mode 11); and
FIGS. 23A to 23E are views each explaining a usage pattern of a semiconductor device according to the present invention (Embodiment Mode 7).
DETAILED DESCRIPTION OF THE INVENTION
Embodiment Modes of the present invention will be explained below with reference to the accompanying drawings. However, it is to be easily understood that various changes and modifications will be apparent to those skilled in the art.
Therefore, unless such changes and modifications depart from the scope of the invention, they should be construed as being included therein. Note that identical portions are used in common in different figures in embodiment modes of the present
invention that will be explained below.
Embodiment Mode 1
In this embodiment mode, one constitution example of a method for manufacturing a semiconductor device according to the present invention will be explained with reference to drawings.
First, a metal film 11 is formed over a surface of a substrate 10 (FIG. 1A). The metal film 11 may be formed in a single layer or a plurality of layers to be stacked. Note that an insulating film may be provided over the substrate 10 before
forming the metal film 11. It is preferable to provide an insulating film between the substrate 10 and the metal film 11 particularly when the contamination from the substrate may occur.
As for the substrate 10, a glass substrate, or a heat resistant plastic substrate or the like that can withstand heat treatment in a manufacturing process of a semiconductor device is preferably used. There is no limitation to the area or shape
of the substrate in using such a substrate, and thus, a rectangular substrate having one side of 1 meter or more, for example, is used as the substrate 10, so as to enhance the productivity extremely. Such merit is great advantages as compared with a
circular silicon substrate. Note that of course it is possible to use a quartz substrate, or a metal substrate or a stainless steel substrate where an insulating film is formed over one surface for the substrate 10. However, these substrates are
infinitely inferior to a glass substrate in terms of the cost of the substrate itself, which is not preferable. This is apparent particularly when a large-sized substrate is required, which is not preferable also in consideration of mass production. In
this embodiment mode, a glass substrate is used as the substrate 10.
As the metal film 11, a film made of one or more of elements such as tungsten (W), molybdenum (Mo), titanium (Ti), tantalum (Ta), niobium (Nb), nickel (Ni), cobalt (Co), zirconium (Zr), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd),
osmium (Os), and iridium (Ir), or an alloy material or a compound material containing the element as the main component is formed in a single layer or a stacked layer. In addition, these materials can be formed by using a known means (a sputtering
method or various CVD methods such as a plasma CVD method). In this embodiment mode, tungsten (W) is formed to be 20 to 40 nm thick by a sputtering method as the metal film 11.
As the insulating film provided between the substrate 10 and the metal film 11, a single layer structure of an insulating film at least having oxygen or nitrogen such as silicon oxide (SiO.sub.x), silicon nitride (SiN.sub.x), a silicon oxide film
containing nitrogen (SiO.sub.xN.sub.y film) (x>y) (x and y are positive integers), or a silicon nitride film containing oxygen (SiN.sub.xO.sub.y film) (x>y) (x and y are positive integers), or a stacked structure thereof can be used. These
insulating films can be formed by using a known means (a sputtering method or various CVD methods such as a plasma CVD method). In this embodiment mode, a silicon oxide film containing nitrogen is formed to be 50 to 150 nm thick as the insulating film
provided between the substrate 10 and the metal film 11.
Next, high-density plasma treatment is performed to the metal film 11 in an atmosphere containing oxygen to form a metal oxide film 12 over a surface of the metal film 11 (FIG. 1B). The metal oxide film 12 is formed of an oxide of metal that
constitutes the metal film 11. For example, when a tungsten film is used as the metal film 11, a tungsten oxide film is formed as the metal oxide film 12 over a surface of the tungsten film by performing high-density plasma treatment. In this
embodiment mode, a layer made of the metal film 11 and the metal oxide film 12 is referred to as a peeling layer 19.
In this specification, high-density plasma treatment is characterized in that an electron density of plasma is 1.times.10.sup.11 cm.sup.-3 or more and 1.times.10.sup.13 cm.sup.-3 or less and an electron temperature of plasma is 0.5 eV or more and
1.5 eV or less. Although the electron density of plasma is high, the electron temperature around an object (the metal film 11) formed over the substrate is low. Thus, plasma damages to the substrate can be prevented. In addition, since the electron
density of plasma is as high as 1.times.10.sup.11 cm.sup.-3 or more, the oxide formed by oxidation treatment is superior in evenness of film thickness and it is possible to form a dense film. In addition, since the electron temperature of plasma is as
low as 1.5 eV or less, the oxidation treatment can be performed at a lower temperature than conventional plasma treatment or thermal oxidation method. For example, the plasma oxidation treatment can be performed sufficiently even when the plasma
treatment is performed at a lower temperature by at least 100.degree. C. than a strain point of a glass substrate (typically, temperatures at 250 to 550.degree. C.). As a power source frequency for generating plasma, a microwave (2.45 GHz) is used.
In addition, potential of plasma is as low as 5V or less; thus, excessive dissociation of raw material molecules can be suppressed.
Note that plasma is a state in which an electron is separated from an atom or a molecule, and an ion and an electron are mixed. On the whole, a charge of plasma is neutral. In addition, a plasma density generally means an electron density or an
ion density, that is, the number of the charged particles per unit volume. In this specification, a plasma | | |
