JPH02116167A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a driving section with a necessary but minimum size by constructing a semiconductor substrate, a substrate, and an insulating film such that they are flush with each other. CONSTITUTION:Reecsses of necessary numbers are formed in a substrate 11, and a semiconductor substrate 12 having a smaller area than that 13 of the recess is placed on the substrate 11. Then, an insulating film 13 is formed such that a portion between the semiconductor substrate 12 and the recess is filled therewith. Finally, they are polished and flattened. There are further formed thereon elements such as transistors, diodes, resistors, and capacitors. Therefore, the driving section can be manufactured with a necessary but minimum size and an area occupied by wiring can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to large-area semiconductor devices such as liquid crystal displays, contact image sensors, liquid crystal optical shutter arrays, thermal heads, inkjet printers, and fluorescent display tubes, and methods for manufacturing the same. .

[Conventional technology]

In recent years, the development of large-area semiconductor devices such as liquid crystal flat displays, contact image sensors, liquid crystal optical shutter arrays, thermal heads, inkjet printers, and fluorescent display tubes has become active with the aim of downsizing input/output devices. Ta. The characteristics of these large-area semiconductor devices are that they consist of a large number of functional elements arranged one-dimensionally or two-dimensionally, which are the core of each function, formed on an insulating substrate such as glass or ceramics. It consists of a driving integrated circuit to be driven and a connection part that connects the functional element and the driving integrated circuit.

FIG. 4 is a perspective view of an example of a conventional contact type image sensor.

In the figure, 41 is an insulating substrate, 42 is a sensor array made of a photosensitive material such as amorphous silicon or cadmium selenide, 43 is a driving IC 144, which is a wire coming out from each sensor of the sensor array 42, and 45 is a wire. 44 and drive I
A bonding wire for connecting C43 is shown.

FIG. 5 is a perspective view of an example of a conventional liquid crystal display.

In the figure, 51 is an active matrix substrate made of an amorphous silicon or polycrystalline silicon thin film transistor array, 52 is a printed circuit board, and 53 is a driving IC 15.
4 indicates wiring from the driving IC to the active matrix substrate, and 55 indicates bonding wires for connecting the wiring 54 and the active matrix substrate 51. In this example of a liquid crystal display, the driving IC 53 is connected to T A B (T
It is connected to wiring using a connection method called apeAutomated Bonding. Thermal heads and inkjet printer heads have similar configurations.

[Problem to be solved by the invention]

The large area semiconductor device according to the above-mentioned conventional technology has the following problems. The biggest problem is the large number of wiring connections.For example, contact image sensors, liquid crystal optical shutter arrays,
In the case of one-dimensional input/output devices such as thermal heads and inkjet printers, even an A4 size device requires 2,000 to 4,000 wires. Even in the case of a display, 1000 to 2000 wirings are required. As the future trend is for resolution to become higher and higher,
It is thought that the number of wiring lines will also increase further. Regardless of the connection method used to connect these wiring lines and the driving IC, the large number of wiring lines increases the incidence of defects at the connection parts.
This will reduce the yield.

The next problem is the area occupied by the wiring and the driving IC.Normally, an IC chip has bonding pads lined up around its periphery for connection, especially when it comes to the area occupied by the wiring and driving IC.
C requires a large number of bonding pads, which makes the IC larger than necessary. Furthermore, since the wiring must be arranged in accordance with the bonding pad of the driving IC, the wiring occupies a considerably large area as shown in FIGS. 4 and 5. This extra area not only increases the overall size of the device, but also increases manufacturing costs. Therefore, as a way to overcome these drawbacks, research is actively being conducted on using thin film transistors made of amorphous silicon or polycrystalline silicon for the driving portion. This is because if thin film transistors are used, each functional element and a drive circuit can be manufactured at the same time, and connections can be eliminated. However, thin film transistors currently have drawbacks such as slower operating speed and poorer uniformity than single crystal silicon. Therefore, in terms of performance, conventional drive ICs
It is inferior to those using .

An object of the present invention is to provide a small, high-performance, low-cost semiconductor device and a manufacturing method thereof.

[Means to solve the problem]

The semiconductor device of the present invention includes a substrate, a recess provided in the substrate, one or more semiconductor substrates embedded in the recess and having an area smaller than the recess, and a connection between the semiconductor substrate and the recess. It is characterized by having an insulating film to be buried, the semiconductor substrate, and elements such as transistors, diodes, and capacitors formed on the substrate.

The method for manufacturing a semiconductor device of the present invention includes the steps of forming one or more recesses in a substrate, placing one or more semiconductor substrates having an area smaller than the recesses in the recesses, and at least the semiconductor substrate. a step of forming an insulating film in the gap between the semiconductor substrate and the recess, a step of polishing the semiconductor substrate and the insulating film until the surfaces of the semiconductor substrate, the insulating film, and the base plate become flat; The method is characterized in that it includes a step of forming elements such as transistors, diodes, and capacitors in an insulating film.

[Effect]

In the present invention, a necessary number of recesses are formed on a substrate, a semiconductor substrate having a smaller area than the recesses is placed, and then an insulating film is formed over the recesses to fill at least the space between the semiconductor substrate and the recesses. Finally, this is polished to make it planar; the important thing here is to polish until the surface of the substrate is exposed. Normally, the insulating film formed in this way gradually loses transparency when the film thickness exceeds several microns, so if it is not scraped off, it will not transmit light even if a transparent substrate such as glass is used. This makes it difficult to use for applications such as liquid crystal displays and contact image sensors. This is not the case in cases where an opaque substrate is used. In subsequent steps, elements such as transistors, diodes, and capacitors are formed on the semiconductor substrate, insulating film, and substrate to complete the semiconductor device.

In the present invention, since the surfaces of the semiconductor substrate, the substrate, and the insulating film are made on the same plane, the elements on the semiconductor substrate and the elements on the insulating film can be connected simultaneously in one photolithography process. Can be done. Therefore, there is no need for a connection process as in conventional devices. Further, there is no need to create a bonding pad, the drive section can be made with the minimum necessary size, and the area occupied by the wiring can be significantly reduced.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(C) are cross-sectional views shown in the order of steps for explaining an embodiment of the present invention.

First, as shown in FIG. 1(a), a necessary number of recesses as shown in the figure are formed on a glass substrate 11, and a semiconductor substrate 12 is cut out from a silicon wafer or a gallium arsenide wafer. Place it in the recess.

Next, as shown in FIG. 1(b), as the insulating film 13, 6
A glass powder that melts at a temperature of about 00 to 700° C. is dispersed in a solvent and is applied on top of this, and is melted at the above temperature to fill the gap between the concave portion of the substrate and the semiconductor substrate.

Next, as shown in FIG. 1(c), the surface is polished to form a flat surface. The polishing method is almost the same as the usual polishing method for silicon or glass.

Next, elements such as transistors, diodes, resistors, and capacitors are formed on this. The formation of these elements follows a normal silicon process or gallium arsenide process. However, in cases where heat-resistant glass is used for this substrate, high-temperature processes reaching 1000°C, such as thermal oxidation, cannot be used, so the gate insulating film and passivation insulating film can be formed using sputtering, thermal decomposition, etc. 600°C
A low-temperature oxide film of about 100% is used.

FIG. 2 is a perspective view of an active matrix liquid crystal display to which the present invention is applied.

In the figure, 21 is a glass substrate, 22 is a silicon substrate,
23 is a drive circuit section in the silicon substrate 23, 24 is an insulating film, 25 is a scanning circuit wiring connecting each drive circuit section, 26
2 is an active matrix section made of thin film transistors made of amorphous silicon or polycrystalline silicon, 27 is a drain line of the active matrix, and 28 is a gate line.

In this figure, the drain line 27 and the gate line 28 correspond to the wiring part of the conventional example, but in the present invention, these wirings are created as part of the processing process of the silicon substrate 22 at the same time as the scanning circuit wiring 25. There are no connections as there is no connection. Furthermore, since this is a so-called photolithography process, it is possible to achieve much higher density wiring than conventional wiring techniques, and the area occupied by the wiring portion on the device is extremely small compared to conventional examples. Furthermore, there is no bonding pad on the silicon substrate, which was conventionally required, and the silicon substrate 22
9 The present invention, which is smaller than C, can be applied in various ways.

FIGS. 3A to 3C are cross-sectional views of other examples of semiconductor devices to which the present invention is applied.

In the example shown in FIG. 3(a), two types of silicon substrates, an n-type silicon substrate 32 and a p-type silicon substrate 33, are embedded in one recess of a glass substrate 31, and the gap between the recess and the recess is filled with an insulating film 34. It is filled with By using such a variety of substrates, new effects occur. In this example, a so-called CMO3 (compensated field effect transistor) can be easily manufactured. When forming CMO3, normally it is necessary to form a p or n well by ion implantation, but if separate substrates are used in this way, this process can be omitted.

In the example shown in FIG. 3(b), two
This is an example in which a silicon substrate 35 and a gallium arsenide substrate 36 are embedded in two recesses, respectively.

In this example, for example, a combination of a high-speed gallium arsenide transistor and a silicon transistor, a combination of a silicon transistor and a light emitting diode, a semiconductor laser, a photodiode, etc. is possible, and a large-area optical integrated circuit can be realized.

The example shown in FIG. 3(C) uses a silicon substrate 37 as the substrate, and the same application as that shown in FIG. 3(b) can be considered.

〔Effect of the invention〕

First, regarding the effects related to the manufacturing method, the method for manufacturing a semiconductor device of the present invention eliminates the need for connection methods such as wire bonding and TAB that were required in conventional semiconductor devices of this type, resulting in improved yields. I was able to make improvements. Specifically, conventional wire bonding has a defect rate of about 0.5%, and 2,000 to 3,000 wires are defective.
If there were genuine connections, several defects would have been inevitable and a repair process would have been necessary, but this can be completely avoided with the present invention. Furthermore, the process of aligning connection paths between electrode terminals, which is required in the TAB method, is no longer necessary.

Next, the effects related to semiconductor devices, which are also related to the manufacturing method, are that the wiring density can be increased and that the device can be made smaller because there is no need to provide connection pads on the semiconductor substrate. In addition, since the semiconductor substrate is a single crystal, it is significantly superior in terms of uniformity of operating speed compared to examples using thin film transistors.

Specifically, the same functions can be achieved with a fraction of the area occupied by conventional wiring sections, connection sections, and drive ICs. Furthermore, compared to devices using thin-film transistors, we were able to achieve speed and uniformity that is more than an order of magnitude higher.

As explained above, according to the present invention, it is possible to manufacture a small and low-cost semiconductor device.

DESCRIPTION OF SYMBOLS 11... Substrate, 12... Semiconductor substrate, 13... Insulating film, 21... Glass substrate, 22... Silicon substrate, 23... Drive circuit part, 24... Insulating film, 25・・・
- Wiring for scanning circuit, 26... active matrix section, 27... drain line, 28... gate line.

Agent Patent Attorney Susumu Uchihara

[Brief explanation of drawings]

FIGS. 1(a) to (c) are cross-sectional views shown in the order of steps for explaining one embodiment of the present invention, FIG. 2 is a perspective view of a contact type image sensor to which the present invention is applied, and FIG. a) ~ (C)
4 is a sectional view for explaining another embodiment of the present invention, FIG. 4 is a perspective view of an example of a conventional contact type image sensor, and FIG. 5 is a perspective view of an example of a conventional liquid crystal display. ! Two dolphins and spears! A map of a bamboo flower area with a bamboo curtain

Claims (2)

[Claims] (1) a substrate, a recess provided in the substrate, one or more semiconductor substrates filled in the recess and having an area smaller than the recess, and an insulating film filling between the semiconductor substrate and the recess; . A semiconductor device comprising: the semiconductor substrate; and elements such as transistors, diodes, and capacitors formed on the substrate. (2) forming one or more recesses in the substrate; placing one or more semiconductor substrates smaller in area than the recesses in the recesses; and at least forming a gap between the semiconductor substrate and the recesses. a step of forming an insulating film; a step of polishing the semiconductor substrate and the insulating film until the surfaces of the semiconductor substrate, the insulating film, and the substrate become flat; and forming a transistor, a diode, and a capacitor on the semiconductor substrate and the insulating film. A method for manufacturing a semiconductor device, comprising the step of forming an element such as.