JP2003031778A - Method for manufacturing thin film device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device capable of connecting a new element from a rear surface of the device by using a release transfer technique. SOLUTION: A method for manufacturing a thin film device comprises the steps of releasing an element forming layer (3) formed on one substrate (1), and transferring the layer to other substrate (5). The method further comprises the steps of opening a connecting hole (37) at an exposed surface of the layer (3) inverted by transferring to allow an inner element to be connected, and forming a new element (38) on the exposed surface. Thus, wiring of an element forming layer to its exterior, connection of the electrode, thin film element or the like can be easily assured even by the manufacturing steps of one time release and transfer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device using an inter-substrate transfer technique for thin film elements.

[0002]

2. Description of the Related Art In a semiconductor application device such as a liquid crystal display (LCD) panel and an electroluminescence (EL) display, a plastic substrate is used as a base substrate for reasons such as prevention of deformation due to deformation and dropping and cost reduction. It may be desirable.

However, in manufacturing a thin film transistor used for a panel type display, a high temperature process is used.
Some plastic substrates and circuit elements such as EL elements cannot withstand high temperatures.

Therefore, the applicant manufactures a thin film semiconductor device on a heat-resistant basic substrate by a conventional semiconductor manufacturing technique including a high temperature process, and then forms an element forming film (layer) on which the thin film semiconductor device is formed from the substrate. A transfer technique is proposed in which a semiconductor application device is manufactured by peeling and adhering this to a plastic substrate. For example, Japanese Patent Laid-Open No. 10-
12529, JP-A-10-12530, JP-A-10-
It is described in detail in No. 12531 as "Peeling method" and the like.

[0005]

However, in the thin film device manufactured by using the peeling transfer technique, the element forming layer is relatively inverted upside down from the base substrate to the transfer substrate in the single transfer state. Therefore, the original upper surface of the element forming layer is in close contact with the transfer substrate, and the external wiring cannot be connected to the element forming layer as it is.

Therefore, the first transfer is performed from the basic substrate to the temporary transfer substrate, and the second transfer is performed from the temporary transfer substrate to the target transfer substrate (plastic substrate or the like) to form the basic substrate. The element formation layer is transferred to the transfer substrate so that the orientation is the same as that of the case. That is, the transfer is required twice in order to perform wiring connection and formation of other elements on the upper surface of the element formation layer.

Further, since the process is complicated with the multi-layer lamination of the thin film device, it is desirable that the number of transfer times be one.

Therefore, it is an object of the present invention to provide a method of manufacturing a thin film device, which can reduce the complexity of the process and the lengthening of the process due to the double transfer.

Another object of the present invention is to reduce the degree of stacking on one surface of a substrate of a thin film device.

[0010]

In order to achieve the above object, a method of manufacturing a thin film device of the present invention is a method of manufacturing a thin film device in which a thin film element formed on a base substrate is transferred to a transfer substrate. , A step of forming a separation layer having a property of peeling by applying required energy, a step of forming a transfer layer containing a thin film element on the separation layer, and a transfer to one surface of the transfer layer via an adhesive layer A step of joining the substrates, a step of applying the energy to the separation layer to cause peeling, and transferring the transfer layer to the transfer substrate, and a step of transferring and exposing the transfer layer exposed on the transfer substrate. A step of opening an exposed hole for connecting to the thin film element on the other surface, and a step of forming a new thin film element connected to the thin film element through the exposed hole on the other surface side of the transferred layer. And, including.

With this structure, the back surface of the transferred layer including the thin film element can also be used for forming the thin film device, and one transfer is required.

The thin film device manufacturing method of the present invention is a thin film device manufacturing method for transferring a thin film element formed on a base substrate to a transfer substrate. A step of forming a separation layer having, a step of forming a base layer on the separation layer, and a step of forming a transfer layer including a thin film element on one surface of the base layer, and an adhesive layer on the transfer layer. A step of joining the transfer substrate, a step of applying the energy to the separation layer to cause separation, and transferring the transfer layer to the transfer substrate; and a transfer layer exposed by being transferred to the transfer substrate. A step of opening an exposure hole for connecting to the thin film element on the other surface of the base substrate, and a new thin film element connected to the thin film element on the other surface side of the base substrate through the exposure hole. And a step of forming.

With this structure, it is possible to form elements, wirings, etc. on both surfaces of the base substrate of the transferred layer to be peeled off and transferred, and it is only necessary to transfer once.

The method of manufacturing a thin film device according to the present invention is the method of manufacturing a thin film device in which a thin film element formed on a base substrate is transferred to a transfer substrate. Forming a separation layer that has, a step of forming a transfer layer including a thin film element on the separation layer, a step of bonding a transfer substrate to one surface of the transfer layer via an adhesive layer, the separation layer The step of transferring the transferred layer to the transfer substrate by applying the energy to the transfer substrate to cause peeling, and forming a new thin film element on the other surface side of the transferred layer. Protrusions are formed on a part of the substrate, whereby an opening is formed on the other surface of the transferred layer, so that the thin film element included in the transferred layer and the new thin film element can be connected.

With such a structure, it is possible to connect a new thin film element on the other surface side of the transferred layer to the thin film element in the transferred layer without the need to make holes in the substrate later. Become.

[0016] Preferably, the new thin film element includes a wiring layer, an electrode layer, and a thin film transistor. Therefore, 1
It is possible to form a wiring layer, an electrode layer, a thin film transistor, etc. on the flat back surface of the underlying layer of the element forming layer which is inverted with respect to the substrate by the round transfer.

Preferably, the material for the separation layer is selected so as to cause ablation in which the bonding force between atoms or molecules disappears or decreases upon irradiation with light such as a laser beam.

Preferably, the separation layer is a multilayer film including an amorphous silicon film and a metal film formed thereon. This facilitates separation within the separation layer and separation at the boundary between the separation layer and an adjacent layer.

Preferably, the separation layer contains amorphous silicon or silicon nitride, and the amorphous silicon contains hydrogen. As a result, when irradiated with light, hydrogen is separated (gasified), and the bonding force between molecules becomes weak.
Further, silicon nitride contains nitrogen, and when irradiated with a light beam, the nitrogen is separated to weaken the bonding force between molecules.

Preferably, the bonding layer between the transfer substrate and the transferred layer is a permanent adhesive.

The thin film device manufactured as described above is
For example, a thin film semiconductor device or an electro-optical device. The electro-optical device includes a liquid crystal display device, an EL device, an electrophoretic device, and the like, and it is convenient to apply them to an active matrix substrate using a plastic substrate thereof. In the present invention, the transfer substrate is not limited to the plastic substrate, and various types of substrates such as glass and ceramic can be used.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method of manufacturing a thin film device according to the present invention will be described below with reference to the drawings.

FIGS. 1A to 1E show a manufacturing process (process) of the thin film device according to the first embodiment of the present invention.

First, as shown in FIG. 1A, for example,
A light-transmitting heat-resistant substrate such as quartz glass that withstands about 1000 ° C. is used as the element formation substrate 1. In addition to quartz glass, soda glass, heat-resistant glass such as Corning 7059 and Nippon Electric Glass OA-2 can be used for the element forming substrate 1. The thickness of the element forming substrate 1 is not particularly limited, but is preferably about 0.1 mm to 0.5 mm, more preferably 0.5 mm to 1.5 mm. If the thickness of the element forming substrate 1 is too thin, the strength is lowered. On the contrary, if it is too thick, the irradiation light is attenuated when the transmittance of the element forming substrate 1 is low. However, when the transmittance of the irradiation light of the element forming substrate 1 is high, the thickness can be increased beyond the upper limit value. The separation layer 2 is formed on the element formation substrate 1.

The separation layer 2 causes peeling (also referred to as "intra-layer peeling" or "interfacial peeling") in the layer or at the interface by irradiation light such as laser light. That is, by irradiating with light of a certain intensity, the interatomic or intermolecular bonding force in the atoms or molecules of the material forming the separation layer 2 disappears or decreases, and ablation occurs.
It causes peeling. Also, by irradiation of irradiation light,
Gas may be released from the separation layer 2 to cause separation.
In some cases, the components contained in the separation layer 2 are released as a gas to be separated, and in other cases, the separation layer 2 absorbs light to become a gas and the vapor is released to be separated.

As the composition of the separation layer 2, for example, amorphous silicon (a-Si) can be used. Hydrogen (H) may be contained in this amorphous silicon. The hydrogen content is preferably about 2 at% or more, and more preferably 2 to 20 at%.
When hydrogen is contained, hydrogen is released by the irradiation of light, so that an internal pressure is generated in the separation layer 2, which promotes peeling. The hydrogen content depends on the film forming conditions, such as CVD.
When the method is used, it is adjusted by appropriately setting conditions such as gas composition, gas pressure, gas atmosphere, gas flow rate, gas temperature, substrate temperature, and power of light to be input. Other materials for the separation layer include silicon oxide or silicic acid compounds, silicon nitride, aluminum nitride, nitride ceramics such as titanium nitride, and organic polymer materials (those whose interatomic bonds are broken by light irradiation). , Metal, eg A
l, Li, Ti, Mn, In, Sn, Y, La, Ce,
Examples thereof include Nd, Pr, Gd or Sm, or an alloy containing at least one of these.

The thickness of the separation layer 2 is 1 nm to 20 μm.
The thickness is preferably about m, more preferably about 10 nm to 2 μm, and even more preferably about 40 nm to 1 μm. This is because if the thickness of the separation layer 2 is too thin, the uniformity of the formed film thickness is lost and unevenness occurs in the peeling. If the thickness of the separation layer 2 is too thick, the irradiation light required for the peeling is It is necessary to increase the power (light amount), and it takes time to remove the residue of the separation layer 2 left after the peeling.

The method for forming the separation layer 2 may be any method as long as it can form the separation layer 2 with a uniform thickness, and can be appropriately selected according to various conditions such as the composition and thickness of the separation layer 2. . For example, CVD (MOCCVD, low pressure CVD, EC
R-CVD method, vapor deposition, molecular beam deposition (MB), sputtering method, ion plating method, various vapor phase film forming methods such as PVD method, electroplating, immersion plating (dipping), electroless plating method, etc. It can be applied to various plating methods, Langmuir-Blodgett (LB) methods, spin coating, spray coating methods, coating methods such as roll coating methods, various printing methods, transfer methods, inkjet methods, powder jet methods and the like. Two or more of these methods may be combined.

Particularly, when the composition of the separation layer 2 is amorphous silicon (a-Si), it is preferable to form the film by CVD, particularly low pressure CVD or plasma CVD. Further, when the separation layer 2 is formed by using a ceramic by the sol-gel method or when it is made of an organic polymer material,
It is preferable to form a film by a coating method, particularly spin coating.

Preferably, an intermediate layer is formed between the separation layer 2 and an element formation layer 3 described later, or the separation layer 3 is formed.
It is advisable to form a plurality of layers including the intermediate layer. This intermediate layer prevents migration of components to or from a protective layer, an insulating layer, a transfer layer that physically or chemically protects the transfer layer during manufacture or use. It has at least one of the functions of a barrier layer and a reflective layer.

The composition of this intermediate layer can be appropriately selected according to the purpose. For example, in the case of the intermediate layer formed between the separation layer made of amorphous silicon and the transferred layer, silicon oxide such as SiO 2 may be used. Further, as the composition of the other intermediate layer, for example, Pt, Au, W, Ta,
Examples thereof include metals such as Mo, Al, Cr, Ti or alloys containing these as main components.

The thickness of the intermediate layer is appropriately determined according to the purpose of forming it. Usually, the thickness is preferably about 10 nm to 5 μm, more preferably about 40 nm to 1 μm.

As the method for forming the intermediate layer, various methods described for the separation layer 2 can be applied. The intermediate layer may be formed of a single layer, or may be formed of two or more layers using a plurality of materials having the same or different compositions.

On the separation layer 2, an element forming layer 3 on which electric elements such as thin film transistors are formed is formed. The element formation layer 3 includes an insulating layer 31 such as a silicon oxide film, which serves as a base layer for element formation, and an impurity-doped source / source layer.
It is composed of a silicon layer including a drain region, a gate insulating film 33, a gate wiring film 34, an interlayer insulating film 35, a source / drain wiring film 36, and the like.

For example, the insulating layer 31 is formed by depositing a silicon oxide film by the CVD method, and the silicon layer 32 is further formed. Next, the silicon layer 32 is patterned to form a transistor region. The silicon film is oxidized to form the gate oxide film 33. Ion implantation for the gate region is performed in the transistor region. Next, polysilicon in which impurities are diffused at a high concentration is deposited by the CVD method, and patterning is performed to form a gate wiring film 34. High-concentration impurity implantation is performed on the source / drain regions using the gate wiring to form the source / drain. A heat treatment for impurity activation is performed, and then a silicon oxide film is deposited by the CVD method to form an interlayer insulating film 35. Source·
A contact hole is opened in the interlayer insulating film 35 on the drain region. Polysilicon with a high concentration of impurities is used as C
The wiring film 36 is formed by depositing the metal film by the VD method or the scutter method and patterning it.

In this way, the element forming layer 3 is formed. In addition, as the thin film element included in the element forming layer 3, a pixel electrode, a connection pad, a resistor, a capacitor, or the like can be formed. The thin film transistor and the like can be formed according to, for example, the method described in Japanese Patent Publication No. 2-50630.

In the above case, the element forming layer 3 is the transferred layer, but the transferred layer is not limited to a thin film and may be a thick film such as a coating film or a sheet.

Next, as shown in FIG. 1B, an adhesive is applied on the element forming layer 3 by spin coating or the like,
The adhesive film 4 is formed. Place the transfer substrate 5 on this,
To join.

As the adhesive, various curable adhesives such as a reaction curable adhesive, a thermosetting adhesive, a photo-curable adhesive and an anaerobic curable adhesive can be used. The composition is appropriately selected such as epoxy type, acrylate type and silicone type.

The transfer substrate 5 may be one having inferior properties such as heat resistance and corrosion resistance unless there is a high temperature process in the subsequent steps. It may have flexibility and elasticity. Examples of such a material include various synthetic resins and various glass agents. The synthetic resin may be either a thermoplastic resin or a heat-effective resin, and for example, other materials such as polyethylene, polypropylene, ethylene-propylene copolymer, etc. are applicable. As the glass material, for example, quartz glass, alkali silicate glass, soda lime glass, and others can be used.

The transfer substrate 5 is, for example, one that constitutes an independent device such as a liquid crystal cell, or a color filter, an electrode layer, a dielectric layer, an insulating layer or a semiconductor element. It may be a part of the device.

Next, as shown in FIG. 1C, the entire surface is irradiated with laser light from the first substrate side 1 to weaken the bonds of atoms and molecules in the separation layer 2. Further, the hydrogen in the separation layer 2 is molecularized and separated from the crystal bond, and the base substrate side 1 and the element formation layer 3 are separated. This allows
The element forming layer 3 as the transferred layer is transferred to the transfer substrate 5.

Next, as shown in FIG. 1D, a very flat underlying insulating film 31 corresponding to the source / drain regions of the element forming layer 3 is patterned to form contact holes with a diameter of about 20 to 30 μm. Open. For the patterning, photolithography, an ink jet method, a dropping of an etching solution, laser etching, or the like can be applied.

Next, as shown in FIG. 1 (e), for example,
The transparent electrode ITO 38 is laminated on the base layer 31 and patterned to form pixel electrodes, terminal electrodes and the like. Such a substrate is used as a pixel substrate of a liquid crystal display or an EL display.

Although the transparent electrode is formed as the thin film element in the first embodiment, the invention is not limited to this. For example, various things such as a pixel electrode, a connection terminal, a wiring, a thin film transistor, a dielectric, and an EL light emitting body can be formed.

2 (a) to 2 (e) show a second embodiment of the present invention. In the figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and description of such parts will be omitted.

In this second embodiment, the base substrate 3
Instead of forming the opening 37 (see FIG. 1D) in the subsequent step 1), the base substrate 1 uses a substrate in which the protrusion 1a is formed in a portion corresponding to the opening 37. After forming the separation film 2 on the base substrate 1, a silicon oxide film 31 as a base layer is deposited to a predetermined thickness. This silicon oxide film 31 is flattened by etching back to the separation film 2.
For the etch back, mechanical polishing and etching can be used. After that, the same process as in the first embodiment is performed to form the element forming layer 3 (FIG. 2A). After that, the transfer substrate 5 is adhered (FIG. 2B), and the base substrate 1 is peeled off (FIG. 2C). The base layer 3 is formed by the protrusions 1a of the base substrate 1.
1 is formed with an opening 37 connectable to the element forming layer (FIG. 2D). Using this opening 37, the underlayer 31
The thin film element 38 formed on the back side of the element and the element of the element forming layer 3 formed on the front side are electrically connected (see FIG. 2).
(E)). Such a panel is used as a pixel substrate of a liquid crystal display or an EL display. The thin film element 38 includes a pixel electrode, a connection terminal, a wiring, a thin film transistor, a dielectric, E
It is possible to form various things such as an L luminous body.

Since the base substrate 1 on which the projections 1a are formed can be repeatedly used, it is convenient to use a relatively expensive base substrate efficiently.

As described above, according to the above-described embodiments,
The element forming layer 3 is transferred and formed on the transfer substrate 5 made of plastic or the like without the step of using the temporary transfer substrate. Since the transfer process is performed only once, the manufacturing process is simplified. Further, the back surface of the thin film element base substrate, which is not normally used, is used. Since this surface is a flat surface, it can be easily used in the subsequent process.

Further, the above steps can be used in ordinary thin film transistor manufacturing equipment and are in good condition.

[0051]

As described above, in the present invention, the wiring is drawn out to the back side of the base of the element forming film, so that the wiring and the electrode between the element forming film and the outside can be formed even by the manufacturing process by one transfer. It is possible to easily secure the connection of the thin film element and the like.

[Brief description of drawings]

FIG. 1 is a process diagram illustrating a first embodiment of the present invention.

FIG. 2 is a process drawing explaining a second embodiment of the present invention.

[Explanation of symbols]

1 substrate 2 separation layers 3 Element formation layer 4 Adhesive layer 5 Transfer board

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/336 H05B 33/02 29/786 H01L 29/78 627D H05B 33/02 F term (reference) 2H092 GA00 GA55 JA01 JA24 KA05 MA05 MA07 MA10 MA16 MA30 NA25 PA01 3K007 AB18 EB00 FA01 5C094 AA43 BA03 BA29 BA43 CA19 DA14 DA15 DB04 EA04 EA07 GB10 5F110 AA16 BB01 CC10 DD01 DD02 DD03 DD12 EE09 EE45 FF02J23HL22 HL23HL23H02 GG23GG5202 NN23 NN33 NN34 NN35 NN36 QQ03 QQ11 QQ16 QQ19 QQ30

Claims (14)

[Claims] 1. A method of manufacturing a thin film device for transferring a thin film element formed on a base substrate to a transfer substrate, the method comprising forming a separation layer on the base substrate, the separation layer having a characteristic of peeling by applying required energy. A step of forming a transferred layer including a thin film element on the separation layer, a step of joining a transfer substrate to one surface of the transfer layer via an adhesive layer, and a step of applying the energy to the separation layer and peeling the transfer layer. To produce
Transferring the transferred layer to the transfer substrate; opening an exposure hole for connecting to the thin film element on the other surface of the transferred layer exposed by being transferred to the transfer substrate; And a step of forming a new thin film element connected to the thin film element through the exposed hole on the other surface side of the transfer layer. 2. A method of manufacturing a thin film device for transferring a thin film element formed on a base substrate to a transfer substrate, the method comprising forming a separation layer on the base substrate, the separation layer having a characteristic of peeling by applying required energy. A step of forming an underlayer on the separation layer and forming a transferred layer including a thin film element on one surface of the underlayer; and a step of joining a transfer substrate on the transferred layer via an adhesive layer, Applying the energy to the separation layer to cause separation,
A step of transferring the transferred layer to the transfer substrate; and a step of opening an exposure hole for connecting to the thin film element on the other surface of the base substrate of the transferred layer exposed by being transferred to the transfer substrate. Forming a new thin film element connected to the thin film element through the exposure hole on the other surface side of the base substrate. 3. A method of manufacturing a thin film device for transferring a thin film element formed on a base substrate to a transfer substrate, the method comprising forming a separation layer having a characteristic of peeling by applying required energy on the base substrate. A step of forming a transferred layer including a thin film element on the separation layer, a step of joining a transfer substrate to one surface of the transfer layer via an adhesive layer, and a step of applying the energy to the separation layer and peeling the transfer layer. To produce
Including a step of transferring the transferred layer to the transfer substrate, and a step of forming a new thin film element on the other surface side of the transferred layer, forming a protrusion on a part of the base substrate, According to the above, the method of manufacturing a thin film device, wherein an opening is formed on the other surface of the transferred layer so that the thin film element included in the transferred layer and the new thin film element can be connected. 4. The method for manufacturing a thin film device according to claim 1, wherein the new thin film element includes a wiring film, an electrode, a terminal, and a thin film transistor. 5. The separation layer loses or reduces bonding force between atoms or molecules upon irradiation with light.
5. A method of manufacturing a thin film device according to any one of 1. 6. The separation layer comprises a plurality of membranes.
6. A method of manufacturing a thin film device according to any one of 5 to 5. 7. The method of manufacturing a thin film device according to claim 1, wherein the separation layer contains amorphous silicon or silicon nitride. 8. The method of manufacturing a thin film device according to claim 6, wherein the plurality of films include an amorphous silicon film and a metal film formed thereon. 9. The amorphous silicon contains hydrogen.
A method of manufacturing a thin film device according to claim 7. 10. The method for manufacturing a thin film device according to claim 1, wherein the adhesive layer is a permanent adhesive. 11. The method of manufacturing a thin film device according to claim 1, wherein the thin film device is a semiconductor device. 12. An active matrix substrate manufactured by using the method according to claim 1, wherein a plurality of thin film transistors connected to a plurality of pixel electrodes arranged two-dimensionally are manufactured. 13. An electro-optical device using the active matrix substrate according to claim 11. 14. The electro-optical device according to claim 13, wherein the electro-optical device is a liquid crystal display device, an electroluminescence device, or an electrophoretic device.