JP2001085435A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bad influence on a device below an interconnection, when separating the interconnection by casting laser light on it. SOLUTION: When separating a drain interconnection 7a, 7b by casting laser light having high energy on a short-circuited section 9 using laser cutting equipment, the laser light is absorbed by an interlayer insulation film 6, and therefore laser energy passing through the interlayer insulation film 6 to be irradiated on a gate interconnection 5 and an active layer 3 is lowered sufficiently, preventing adverse effects of the laser light on a device (the gate interconnection 5, the active layer 3, a TFT 8) below the short-circuited section 9. As the interlayer insulation film 6 which absorbs the laser light, a silicon nitride oxide film, a silicon nitride film, or the like is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device and a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Liquid Crystal Display (LCD)
Display) includes a display pixel unit in which a large number of display pixels are arranged in a matrix, and a drive circuit unit that drives the display pixel unit. In addition, LCDs include an active matrix type having pixel driving elements for driving display pixels and a simple matrix type not using pixel driving elements. In an active matrix type LCD, a thin film transistor (TFT) formed on a transparent insulating substrate is used as a pixel driving element.

In recent years, it has become possible to obtain a TFT having high mobility by using a polycrystalline silicon film as an active layer. Therefore, a TFT using a polycrystalline silicon film as an active layer (polycrystalline silicon TFT) has come to be used not only as a pixel driving element but also as an active element constituting a driving circuit portion. An active matrix type LCD integrated with a drive circuit in which the display pixel portion and the drive circuit portion or only the drive circuit portion is constituted by a polycrystalline silicon TFT, and the display pixel portion and the drive circuit portion are formed on the same transparent insulating substrate. Is being developed.

In a display pixel portion of an LCD, wirings for selecting a display pixel and driving the display pixel are arranged in a grid pattern. The wiring is formed using a photolithography technique and an etching technique. However, if foreign matter adheres to a photomask used in the photolithography technique and the foreign matter extends between a plurality of wiring patterns, the etching technique is used. A short-circuit portion (defective portion) corresponding to the foreign matter is formed between wirings formed by using the method. In addition, a short-circuit portion may be formed due to direct attachment of conductive foreign matter between the wirings. For the same reason, a short-circuit portion may be formed between the wires of the drive circuit portion of the LCD. If such a short-circuit portion between the wirings is formed, a display pixel or a driving circuit causes an operation failure, and the LCD does not function.

Therefore, using a laser cutting device,
Irradiate high-energy laser light to short-circuited parts between wirings,
The function of the LCD is restored by separating the short-circuited portion by the thermal energy of the laser beam.

[0006]

However, when irradiating a laser beam to a short-circuited portion between wirings, the laser beam is applied to the interlayer insulating film below the laser-irradiated portion even if the laser energy is finely adjusted. The light may pass through and irradiate a wiring or an element (such as a transistor) thereunder, whereby the lower wiring may be cut or the element may be damaged due to heat energy. Therefore, the method of irradiating the laser beam to the short-circuit portion between the wirings and separating the laser light can be performed only when there is no wiring or element below the short-circuit portion between the wirings.

However, there are many cases where wires and elements are present below the short-circuited portion between the wires, and in such a case, it is required to separate the short-circuited portion. In particular, in an active matrix type LCD integrated with a driving circuit, since the wiring of the driving circuit portion is high in density, there is a high possibility that a wiring or an element exists below a short-circuited portion between the wirings, and laser light is applied between the wirings. At present, it is not possible to use a method of irradiating and cutting off the short-circuited portion.

[0008] Furthermore, the SOG (Spin On Gl
(Ass) or a film containing an organic material such as polyimide, when laser light is applied to the interlayer insulating film, the thermal energy of the laser light causes the organic material in the interlayer insulating film to evaporate and be released into the liquid crystal. There is also a problem that bubbles are generated by organic substances and display is disturbed.

By the way, the method of irradiating a laser beam to a short-circuit portion between wirings and separating the same can be used not only for LCDs but also for various semiconductor devices using a single crystal semiconductor substrate (bulk substrate). Had similar problems. In addition, not only can the short circuit between the wires be separated,
When irradiating a laser beam for cutting a laser fuse element used for a ROM (Programmable Read Only Memory), there is a similar problem as described above.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to irradiate a wiring layer with a laser beam and cut off the wiring layer, thereby adversely affecting devices below the wiring layer. Is to prevent

[0011]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a substrate on which a device is formed, a wiring layer formed on the substrate, A gist is a semiconductor device including a film formed between the device and a wiring layer and having a property of absorbing laser light.

Therefore, according to the present invention, when the wiring layer is irradiated with laser light, the wiring layer is cut off by the thermal energy of the laser light. At this time, since the laser light applied to the wiring layer is absorbed by a film having a property of absorbing the laser light, if the film sufficiently absorbs the laser light,
It is possible to sufficiently attenuate the laser energy of the laser light that passes through the film and irradiates the device below the wiring layer, thereby preventing the laser light from adversely affecting the device.

Next, according to a second aspect of the present invention, there is provided a substrate on which a device is formed, a wiring layer formed on the substrate, and a laser beam formed between the device and the wiring layer. The gist is a semiconductor device having a film having the following properties. Therefore, according to the present invention, when the wiring layer is irradiated with laser light, the wiring layer is cut off by the thermal energy of the laser light. At this time, since the laser light applied to the wiring layer is reflected by a film having a property of reflecting the laser light, if the laser light is sufficiently reflected by the film,
It is possible to sufficiently attenuate the laser energy of the laser light that passes through the film and irradiates the device below the wiring layer, thereby preventing the laser light from adversely affecting the device.

Next, a third aspect of the present invention is directed to the first aspect.
Alternatively, a gist of the present invention is a method of manufacturing a semiconductor device including a step of separating the wiring layer by irradiating the wiring layer with a laser beam in the semiconductor device according to claim 2. As described above, the separation of the wiring layer is performed by the LCD.
When a plurality of wiring layers are unnecessarily short-circuited in various semiconductor devices, such as when a short-circuited portion is cut off,
This is performed when, for example, a laser fuse element used for cutting is cut.

In the embodiments of the invention described below, the “device” described in the claims or the means for solving the problem includes a gate wiring 5, an active layer 3, and a TFT.
8 and 14, corresponding to the interlayer insulating film 11, and similarly "wiring layer"
Corresponds to the drain wirings 7a and 7b and the gate wiring 5.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view of a main part of the LCD of the first embodiment. FIG. 1 (b)
FIG. 2 is a sectional view taken along line AA in FIG.

The drive circuit unit 1 of the drive circuit integrated type active matrix type LCD includes a transparent insulating substrate 2, an active layer (active layer) 3, a gate insulating film 4, a gate wiring (scanning wiring) 5, an interlayer insulating film 6, and a drain. Wiring (data wiring) 7
a, 7b and TFT8.

The drive circuit unit 1 is formed on the same transparent insulating substrate (for example, a quartz substrate, a glass substrate, etc.) 2 as a display pixel unit (not shown). The active layer 3 is made of a polycrystalline silicon film and is formed on the transparent insulating substrate 2. On the active layer 3, a gate insulating film (for example, a silicon oxide film,
A gate wiring 5 is formed via a silicon nitride film 4). The interlayer insulating film 6 is formed on the transparent insulating substrate 2 including the active layer 3 and the gate wiring 5. Each drain wiring 7a, 7b is formed on the interlayer insulating film 6. Each drain wiring 7a, 7b and the active layer 3 are connected via a contact hole (not shown) formed in the interlayer insulating film 6. The active layer 3 and the gate wiring 5 constitute a top gate type polycrystalline silicon TFT 8 which is an active element of the drive circuit section 1.

The drain wirings 7a and 7b are made of various conductive materials (for example, various metals such as polycrystalline silicon, silicide, and aluminum alloy, and various high-melting metals (for example, titanium, tungsten, molybdenum, etc.)). Each of the drain wirings 7a and 7b is short-circuited via a short-circuit portion (defective portion) 9. That is, although each of the drain wirings 7a and 7b is formed by using the photolithography technique and the etching technique, foreign matter adheres to a photomask used in the photolithography technique,
When the foreign matter extends between the wiring patterns corresponding to the drain wirings 7a and 7b, a short-circuit portion 9 corresponding to the foreign matter is formed between the drain wirings 7a and 7b formed by using the etching technique. . In addition, when a conductive foreign substance directly adheres between the drain wirings 7a and 7b, a short-circuit portion 9 made of the foreign substance may be formed. When such a short-circuit portion 9 is formed, the drive circuit unit 1 causes an operation failure and does not function as an LCD.

For this purpose, a high-energy laser beam (for example, a KrF excimer laser, an ArF excimer laser, an F ₂ excimer laser, etc.) is applied to the short-circuited portion 9 using a laser cutting device, and the short-circuited portion 9 is irradiated with the thermal energy of the laser beam. It is necessary to recover the malfunction of the drive circuit unit 1 and restore the function of the LCD by disconnecting the LCD.
However, when irradiating the laser light to the short-circuited portion 9, even if the laser energy is finely adjusted, the laser light is irradiated to the laser-irradiated portion under the short-circuited portion 9.
Is irradiated to the gate wiring 5 and the active layer 3 thereunder, and the gate wiring 5 may be cut off or the active layer 4 may be damaged by heat energy.

Therefore, in the first embodiment, a silicon oxynitride film (SiON) is used as the interlayer insulating film 6.
The silicon oxynitride film has a short wavelength laser beam (for example, KrF
Excimer laser, ArF excimer laser, F ₂ excimer laser, etc.), the laser light applied to the short-circuit portion 9 is absorbed by the interlayer insulating film 6 and transmitted through the interlayer insulating film 6 to pass through the gate wiring 5. And the laser energy of the laser light applied to the active layer 3 is sufficiently attenuated. Therefore, when the short-circuit portion 9 is irradiated with laser light and cut off, the laser light can be prevented from adversely affecting devices (gate wiring 5, active layer 3, TFT 8) below the short-circuit portion 9. .

FIG. 2 shows PECVD (Plasma Enhanced Ch).
Oxygen flow ratio (oxygen / (nitrogen + oxygen)) when forming a silicon oxynitride film using emical vapor deposition
FIG. 9 is a characteristic diagram showing measurement results of an absorption coefficient with respect to a KrF excimer laser in a case where is changed.

As shown in FIG. 2, as the oxygen flow rate ratio increases, the absorption coefficient for the KrF excimer laser decreases. Here, an interlayer insulating film 6 made of a silicon oxynitride film is used.
When the film thickness of 7000 is set to 7000 ° and the energy transmittance of the KrF excimer laser is set to 50%, the absorption coefficient becomes 7 × 1.
0 ³ cm ⁻¹ and FIG. 2 shows that it is appropriate to set the oxygen flow rate ratio to about 0.1 (energy transmittance = absorption coefficient × film thickness of interlayer insulating film 6).

The reason why the energy transmittance is set to 50% is as follows. (1) The interlayer insulating film 6 having an energy transmittance of less than 50%
If the laser energy to be absorbed by the laser beam is too large, the interlayer insulating film 6 may be ruptured. (2) Even if the energy transmittance is 50%, if the film thickness of the interlayer insulating film 6 is 7000 Å, the laser light does not adversely affect the devices (gate wiring 5, active layer 3, TFT 8) below the short-circuited portion 9. Up to this, the laser light can be absorbed by the interlayer insulating film 6.

As described above, the absorption coefficient of the silicon oxynitride film can be arbitrarily set in accordance with the thickness of the interlayer insulating film 6 and the wavelength of the laser beam by appropriately setting the composition ratio of oxygen and nitrogen. It is also possible to prevent destruction of the interlayer insulating film 6 due to absorption of laser light.

As a method of forming the silicon oxynitride film, there are a PECVD method, a method of implanting nitrogen ions into the silicon oxide film by an ion implantation method, and a method of exposing the silicon oxide film to nitrogen plasma. Any method may be used. As described in detail above, according to the first embodiment, the device (gate wiring 5, active layer 3, TF) under the short-circuited portion 9 of the drain wirings 7a, 7b.
Since the short-circuited portion 9 of the drive circuit section 1 can be simply and reliably separated without adversely affecting T8), the yield of the LCD can be improved.

The present invention is not limited to the above-described first embodiment, but may be embodied as follows. Even in such a case, the same operation or effect as that of the first embodiment can be obtained. Obtainable. (1) The first embodiment is applied to the drive circuit unit 1 of an active matrix type LCD integrated with a drive circuit. However, since the silicon oxynitride film has a visible light transmission property, the display in the transmission type LCD is performed. It can also be used for an interlayer insulating film in a pixel portion. That is, the interlayer insulating film 6 made of the silicon oxynitride film can be formed not only on the drive circuit section 1 in the drive circuit integrated type active matrix type LCD but also on the entire surface of the transparent insulating substrate 2 including the display pixel section. .

Here, silicon in the interlayer insulating film 6,
The composition ratios of nitrogen and oxygen do not need to be uniform throughout the interlayer insulating film 6 and may vary in the film thickness direction, or the composition ratios of the drive circuit unit 1 and the display pixel unit are different. The composition ratio distribution may be generated in the drive circuit unit 1 or the display pixel unit.

It is not necessary that the entire thickness of the interlayer insulating film 6 has a property of absorbing laser light, but only a part of the interlayer insulating film 6 having a property of absorbing laser light. . For example, the interlayer insulating film 6 may have a multilayer structure including a plurality of insulating films, and at least one insulating film of the multilayer structure may have a property of sufficiently absorbing laser light.

(2) Examples of the film having the property of absorbing laser light include a silicon nitride film (SiN), indium oxide (In ₂ O ₃ ), zinc oxide (ZnO), etc., in addition to the silicon oxynitride film. The interlayer insulating film 6 may be formed from these films. However, a film that does not transmit visible light (for example,
In the case where the interlayer insulating film 6 is formed of amorphous silicon, titanium nitride (TiN), zirconium nitride (ZrN), or the like, the interlayer insulating film 6 cannot be arranged in a display pixel portion of a transmission type LCD.

(3) FIG. 3A is a plan view of a main part of an LCD according to a second embodiment of the present invention. FIG.
FIG. 3B is a sectional view taken along line AA in FIG.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The second embodiment is different from the first embodiment shown in FIG.
An interlayer insulating film (for example, SOG, polyimide or the like) 11 containing an organic substance is formed on a transparent insulating substrate 2 containing
The point is that an interlayer insulating film 6 having a property of absorbing laser light is formed on the interlayer insulating film 11, and drain wirings 7a and 7b are formed on the interlayer insulating film 6.

When the interlayer insulating film 11 is irradiated with a laser beam, the organic matter in the interlayer insulating film 11 is vaporized and released by the thermal energy of the laser beam, and bubbles are generated by the organic material inside the liquid crystal, which hinders display. Sometimes. However, since the interlayer insulating film 6 is interposed between the interlayer insulating film 11 and the drain wirings 7a and 7b, the laser energy of the laser light transmitted through the interlayer insulating film 6 and irradiated onto the interlayer insulating film 11 is sufficiently attenuated. Thus, it is possible to prevent the organic matter in the interlayer insulating film 11 from being vaporized.

FIG. 4 is a sectional view of a main part of the display pixel section 12 in the LCD according to the second embodiment. The display pixel unit 12 includes:
Transparent insulating substrates 2 and 13, active layer 3, gate insulating film 4, gate wiring 5, interlayer insulating films 6 and 11, TFT 14, transparent pixel electrode (transparent display electrode) 15, alignment films 16 and 17, liquid crystal layer 18, transparent A counter electrode 19 and a contact hole 20 are provided.

An active layer 3 is formed on the transparent insulating substrate 2, and a gate wiring 5 is formed on the active layer 3 via a gate insulating film 4. The active layer 3 and the gate wiring 5 form a pixel driving element. Top gate type polycrystalline silicon TFT
14 are configured. On the transparent insulating substrate 2 including the TFT 14, interlayer insulating films 11 and 6 are formed in this order, and on the interlayer insulating film 6, a transparent pixel electrode 15 is formed.
The transparent pixel electrode 15 is connected to the active layer 3 of the TFT 14 via a contact hole 20 formed in each of the interlayer insulating films 6 and 11. An alignment film 16 is formed on the transparent pixel electrode 15 and the interlayer insulating film 6. On the other hand, a transparent counter electrode 19 is formed on the transparent insulating substrate 13, and an alignment film 17 is formed on the transparent transparent counter electrode 19.
Each of the transparent insulating substrates 2 and 13 has a respective alignment film 16 and 17
Are arranged to face each other, and a liquid crystal is sealed in a gap between the alignment films 16 and 17 to form a liquid crystal layer 18.

Here, the interlayer insulating film 11 is provided for flattening the surface of the transparent pixel electrode 15 to enable a good display. The display pixel unit 12 thus configured
According to the method, the interlayer insulating film 6 is interposed between the interlayer insulating film 11 and the transparent pixel electrode 15 so that the transparent pixel electrode 15
Irradiating the laser beam to separate unnecessary short-circuit parts,
When the alignment film 16 on the transparent pixel electrode 15 is irradiated with laser light to correct a luminescent spot to a dark spot, the laser energy of the laser light transmitted through the interlayer insulating film 6 and applied to the interlayer insulating film 11 is sufficient. And the organic matter in the interlayer insulating film 11 can be prevented from evaporating. Therefore, the organic matter in the interlayer insulating film 11 is not vaporized and released by the thermal energy of the laser beam, and the generation of bubbles due to the organic matter inside the liquid crystal layer 18 can be prevented.

(4) FIG. 5A is a plan view of a main part of an LCD according to a third embodiment of the present invention. FIG.
FIG. 5B is a sectional view taken along line AA in FIG.
In the third embodiment, the same components as those in the first embodiment have the same reference numerals, and a detailed description thereof will be omitted.

The third embodiment differs from the first embodiment shown in FIG. 1 in that the active layer 3 and the gate wiring 5
Interlayer insulating film 21, reflective film 2 on transparent insulating substrate 2 including
Second, the interlayer insulating film 23 is formed in this order, and the drain wirings 7a and 7b are formed on the interlayer insulating film 23.

The reflection film 22 is made of a material having a property of reflecting laser light (for example, various metals such as an aluminum alloy, various high-melting metals (for example, titanium, tungsten,
Molybdenum, etc.). Therefore, the laser beam applied to the short-circuit portion 9 is applied to the interlayer insulating film 2.
3, the light is reflected by the reflective film 22 and hardly reaches the interlayer insulating film 21 and the lower side thereof.
The laser energy of the laser light transmitted through 1 to 23 and applied to the gate wiring 5 and the active layer 3 is sufficiently attenuated. Therefore, when the short-circuit portion 9 is irradiated with the laser beam and separated,
The laser beam can be prevented from adversely affecting devices (gate wiring 5, active layer 3, TFT 8) below the short-circuited portion 9.

What kind of interlayer insulating films 21 and 23 are used
Insulating film (for example, silicon oxide film, silicon nitride film, etc.)
Etc.). Each interlayer insulating film 21, 23
Means that the reflective film 22 is formed of a conductive material
The gate wiring 5 and the drain wiring 7 via the reflection film 22
a, 7b are provided to prevent a short circuit.
You. Therefore, an insulating material (for example, alumina
(Al_TwoO_Three), Iron oxide (Fe _TwoO_Three) Etc. in the reflective film 22
Is formed, the interlayer insulating films 21 and 23 are provided.
No need. By the way, various metals including refractory metals
PVD (Physical Vapor D)
eposition) method may be used.

However, a material that does not transmit visible light (for example,
In the case where the interlayer insulating film 6 is formed of various metals including a high melting point metal, the interlayer insulating film 6 cannot be arranged in the display pixel portion of the transmissive LCD. However, the reflective film 2 is made of a material that transmits visible light (for example, a dielectric multilayer film or the like).
In the case where No. 2 is formed, the reflection film 22 can be arranged in the display pixel portion of the transmission type LCD.

(5) Not only the case where the short-circuited portion 9 between the drain wirings 7a and 7b is cut off by irradiating the laser light, but also the short-circuited portion (not shown) between the plurality of gate wirings 5 is irradiated with the laser light and cut off. It may be applied in the case. in this case,
In addition to employing a top gate TFT as in the above embodiment, a bottom gate TFT in which a gate wiring 5 is directly formed on a substrate 2 is employed. It is conceivable to disconnect the wiring 5.

(6) Driving Circuit The present invention may be applied not only to the driving circuit section or display pixel section of an active matrix type LCD integrated with a drive circuit, but also to the driving circuit section or display pixel section of a simple matrix type LCD. In this case, the active layer 3 may be formed of not only a polycrystalline silicon film but also an amorphous silicon film.

(7) In various semiconductor devices using a single crystal semiconductor substrate (bulk substrate) as well as an LCD,
The present invention may be applied to a case where a short-circuit portion between wirings is irradiated with laser light to be separated. (8) In addition to separating the short circuit between the wires,
It may be applied when irradiating a laser beam for cutting a laser fuse element used for M.

[Brief description of the drawings]

FIG. 1A is a plan view of a main part of a first embodiment embodying the present invention. FIG. 1B is a sectional view taken along a line AA in FIG.
Line sectional view.

FIG. 2 is a characteristic diagram for explaining the operation of the first embodiment.

FIG. 3A is a plan view of a main part of a second embodiment embodying the present invention. FIG. 3B is a sectional view taken along line AA in FIG.
Line sectional view.

FIG. 4 is a sectional view of a main part of a second embodiment according to the present invention;

FIG. 5A is a plan view of a main part of a third embodiment that embodies the present invention. FIG. 5B is a sectional view taken along the line AA in FIG.
Line sectional view.

[Explanation of symbols]

 2: transparent insulating substrate 3: active layer 5: gate wiring 6, 11: interlayer insulating film 7a, 7b: drain wiring 8, 14, TFT 22: reflective film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H01L 29/78 619A F term (Reference) 2H092 JB73 KB25 MA47 MA50 NA16 NA29 4M118 AA10 CA33 CA34 EA05 5F004 AA06 BB04 DB08 DB09 DB10 EB02 FA02 5F033 GG04 HH04 HH09 HH18 HH19 HH20 HH25 QQ53 QQ60 QQ64 QQ90 RR03 RR06 RR08 RR22 RR25 SS15 TT04 VV00 XX36 5F110 NN27 BB02 BB05 NN02 BB03 NN03 02 FF02 NN03 GG03 NN QQ30

Claims (3)

[Claims] 1. A semiconductor device comprising: a substrate on which a device is formed; a wiring layer formed on the substrate; and a film formed between the device and the wiring layer and having a property of absorbing laser light. A semiconductor device characterized by the above-mentioned. 2. A semiconductor device comprising: a substrate on which a device is formed; a wiring layer formed on the substrate; and a film formed between the device and the wiring layer and having a property of reflecting laser light. A semiconductor device characterized by the above-mentioned. 3. The manufacturing of a semiconductor device according to claim 1, further comprising a step of irradiating the wiring layer with the laser beam in the semiconductor device according to claim 1 or 2 to separate the wiring layer. Method.