JPH01204448A - Wiring forming method - Google Patents

Abstract

PURPOSE:To prevent the yield of cracks, by forming a wiring by CVD using laser, and annealing the wiring in a vacuum atmosphere or in a non-oxidizing atmosphere of inactive gas atmosphere. CONSTITUTION:A wiring is an object of annearling with the projection of laser light 2. The wiring is formed by condensing and projecting the laser light 2 on a semiconductor device 100 and relatively scanning the light in a CVD gas atmosphere beforehand. The CVD gas surrounding the wiring is exhausted. The semiconductor device 100 is kept in a high vacuum state or in the atmosphere of inactive gas or reducing gas, and annealing is performed. The projecting power of the laser light 2 in annealing is low when the scanning is started. With the progress of the scanning, the power is increased to high value, i.e., the value required for the annearling. When the end of the scanning region is approached, the power is decreased to the value at the starting of the scanning. Thus, thermal shock due to rapid heating and rapid cooling of the wire that is formed with the laser CVD is decreased, and the yield of cracks is prevented.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for forming repair wiring on the surface of a semiconductor device), particularly when a prototype semiconductor device has a partial defect. The present invention relates to a wiring formation method suitable for repairing specified problems.

[Conventional technology]

In recent years, semiconductor devices have become highly integrated, and wiring layers are also becoming more multilayered. For this reason, a semiconductor device in the development process may not always operate as designed, and may be remanufactured using a photomask with a partially changed design, or a device may be remanufactured by cutting arbitrary wiring within the semiconductor device. Alternatively, the characteristics are evaluated by connecting arbitrary parts to identify good signal areas, or by repairing the parts so that complete operation can be temporarily obtained.

As a method of connecting any part of these, Extent Abstract of the Seventeenth Core 7 Arrangement e-on-O Solid State e-Device and Materials, Tokyo (1985) No. 19
Pages 5 to 196 (ExtendedAb-stra
cts of the 17th Confe
rence on 8o1id8t-site D
evices and Materials, Tokyo
1985 pp. 195-196). That is, Mo (CO), steam, and atmospheric pressure Ar gas were introduced into a CVD cell installed on an X-Y stage, and several 104 Ar ion lasers were first applied to the Si substrate coated with 810B in the CVD cell. the second of
F) Mo film was precipitated by photochemical reaction by irradiation with harmonics (wavelength 257 nm), then fundamental wave of Ar ion laser (wavelength 515?LWL) of several 10ofnW was irradiated with MogK deposited by photochemical reaction. and locally heat CvDt-
After this, the CVD cell is moved by an X-Y stage to form the wiring and connect it at any desired location.

[Problem to be solved by the invention] In the above conventional technology, the specific resistance of the formed Mo wiring is 40 μΩ.
・It is 8 times larger than the specific resistance of the country and the bulk (5.4 μΩ, m). For this reason, high-speed logic L used in large-scale computers, etc.
If used for SI repair wiring, the signal will be delayed and characteristics cannot be evaluated.

There is a method of increasing the wiring film thickness as a countermeasure to reduce the resistance value of the wiring, but it may cause cracks due to residual stress in the film formed by laser CVD, the difference in expansion coefficient with the substrate, etc. There is a limit to the ability to increase the film thickness by 1111 K, as generation and peeling occur.

Therefore, in order to reduce the resistance value of the wiring, it is essential to reduce the specific resistance of the wiring itself.

An object of the present invention is to provide a method for forming repair wiring with low resistivity and no signal delay.

[Means for solving the line layer]

The above purpose is achieved by using a vacuum device that maintains the wiring formed by laser CVD in a non-oxidizing or reducing atmosphere, and a means for relatively scanning and irradiating the wiring with a laser beam, and starting the scanning of the laser beam. Sometimes with low power, the irradiation power is increased to a required value as the scan progresses, and as the scan approaches the end, the irradiation power is lowered to perform annealing without causing cracks in the wiring and improve the film quality. This is achieved by improving the

[Effect]

The wiring to be annealed by laser light irradiation is formed in advance by relatively scanning the semiconductor device while focusing the laser light on the semiconductor device in a CVD gas atmosphere. This wiring can be oxidized by exhausting the CVD gas and performing annealing while keeping the semiconductor device in a high vacuum of 10" Torr or higher, or in an inert gas or reducing gas atmosphere. is prevented.

The irradiation power of the laser beam during annealing is low at the start of scanning, and is shifted to high power (a value necessary for annealing) as the scanning progresses.

Then, as the end of the scanning area approaches, the power is lowered to the level at the start of scanning. As a result, the thermal stress caused by rapid heating and cooling of wiring formed by laser CVD is greatly reduced.
Furthermore, the heat f! between the wiring and the underlying film! The stress caused by the difference in tensile modulus is also significantly reduced, so no cracks occur.

The wiring irradiated with laser light is locally heated. As a result, the compound that is one of the constituent materials of the wiring is decomposed, and metal components with low resistivity increase, thereby reducing the resistivity of the wiring.

[Fruitful example]

Embodiments of the present invention will be described below with reference to the drawings.

First, the most suitable device t'fI for carrying out the method of the present invention:
Shown in Figure 1.

The device includes a laser oscillator 1 that emits and loses laser light 2t;
A variable transmittance filter 3 that changes the irradiation power of the laser beam 2, its driving mechanism 4, a reflecting mirror 5 and a dichroic mirror 2-6 that reflect the laser beam 2 and guide it to the semiconductor device 100, and an optical path of the laser beam 2. A processing optical system consisting of a shutter 7 that opens and closes, a laser beam 2t and an objective lens 8 that condenses and irradiates the semiconductor device 100, an observation light source 9, and an observation light '#A.
A half mirror 11 for guiding the @ festival light 10 from 9 onto the semiconductor device 100, and an observation light 10 from the semiconductor device 100.
The reflected light 10' is transmitted to the imaging lens 12 and the television camera 1.
Prism leading to 5 14. An observation optical system consisting of a monitor 15 that displays an image captured by a television camera "y13," an irradiation power detection means consisting of a photodetector 16 and a display 17, and a control system for loading and unloading the semiconductor device 100 that is the target of wiring formation. loading chamber 1B, main chamber 19 provided with a window 51 for introducing laser light 2 and observation light 10t, loading chamber 18 domain chamber 19
A gate valve 20 that connects the loading chamber 18, a vacuum pump 21 and a valve 24 that evacuate the loading chamber 18, a vacuum gauge 2L for detecting the degree of visibility inside the loading chamber 18, Similarly, a vacuum system consisting of a vacuum pump 24 for evacuation of the main chamber 19 and a vacuum gauge 26 for detecting the degree of vacuum is provided in the loading chamber 18, and a semiconductor device 100 placed on a holder 27 is connected to the vacuum system. A transport means consisting of a transport arm 28 and its drive mechanism 29 for transporting the holder 27 between the chamber 18 and the main chamber 19;
installed in each direction of X, Y-Z, and 0 (three-dimensional direction)
A movable stage 30, a cylinder 52 containing CVD material gas, a valve 35, and piping 3 for gas introduction.
4, an annealing gas supply means consisting of a cylinder 35 containing an inert gas or reducing gas, a valve 36, and piping 37 for introducing gas as necessary, and the above-described variable transmittance. Controlling the drive mechanism s4 of the filter 3, the shutter 7, the drive mechanism 29 of the transport arm 2B, and the stage 50, taking in data from the display 17 of the photodetector 16, taking in force Loe data from the magnetic medium 38, A first controller 39 that performs
and the gate pulp 20 and valve 22.25 described above.
．． 55, 36, data acquisition from the vacuum gauges 25, 26, etc.) A device in which the light 2 consisting of four sounds is continuously oscillated is suitable. For example, Ar
There are V-za, Krv laser, eHe-NeL/-za, YAG laser (including harmonics), and so on.

The variable transmittance filter 5 is a disc whose transmittance is changed continuously or at fixed angles in the circumferential direction), and when rotated by the drive mechanism 4, the transmitted light t (1) of the laser beam 2 is changed. Irradiation power) t-change.

The reflecting mirror 5 allows a certain percentage of the laser beam 2 to pass therethrough, and the power of the laser beam 2 transmitted therethrough and the dichroic filter 6, the objective lens 8, and the transmission of the laser beam 2 through the window 51 are reflected. If the rate is known, semiconductor device f10
The power of the laser beam 2 irradiated on the laser beam 2 can be easily determined. The dichroic mirror 6 has a characteristic of reflecting only the wavelength of the laser beam 2.

On the screen of the monitor 15, a marker (for example, an electronic line) indicating the irradiation position of the laser beam 2 is displayed. The contents of the processing data taken in from the magnetic medium 58 are stored in the semiconductor device 1.
The coordinates of the connection between the wiring in 00 and the wiring formed by laser CVD (the coordinate origin is a specific pattern (e.g. alignment mark) within 1Ω0 of the semiconductor device), the wiring formation route, the time of laser CVD and laser annealing. Laser light irradiation power, laser light scanning speed, introduction pressure of CVD material gas into the main chamber 19, introduction pressure of inert gas or reducing gas into the main chamber 19 (if necessary), various pre-processing The required degree of vacuum for the loading chamber 18 and the main chamber 19, etc. Next, the wiring method using this device will be explained.

First, while importing processing data from the magnetic medium 38,
The lid (not shown) of the loading chamber 18 is opened and the semiconductor device 100t is placed on the holder 27.

After closing the chamber, the valve 22 is opened to evacuate the inside of the loading chamber 18 to a high vacuum of 10'' Torr or more.

Incidentally, the main chamber 19 is preliminarily set at t cr' to 1 cr
' Exhausted to Torr. (The gate pulp 20 is closed, the valve 25 is open, and the valve 3L56 is closed) Next, the gate valve 20fc is opened, and the semiconductor device 100't'' holder 27 and the stage 30 are transferred to the transfer arm 28.
Place the gate pulp 20 on top, return the transfer arm 28, and remove the gate pulp 20.
Close. The inside of the main chamber 19 is 1(]'Tor again.
When a high vacuum of r or more is reached, close valve 25 and close valve 3.
3f. After opening the valve 63 and introducing the CVD material gas until it reaches a predetermined pressure, the valve 63 is closed and the CVD material gas is introduced into the chamber 19.
Confined inside. The CVD material gases used here include Cr(CO), , Ni(Co)4, Mo(CO
hmm. .

W(CO). metal carbonyl such as MOF@#V
VF● is a halogen compound. Although these are sublimable, their vapor pressure at room temperature is low, so the cylinder 32
If a heater is provided in the shield 63 and the pipe 64 and the CVD material gas is introduced while being heated, it will take only a short time.

During the introduction of the CVD material gas, the power of the laser beam 2 irradiated onto the semiconductor device R100 is adjusted based on the Loe data using the variable transmittance filter 5 and the photodetector 16. Further, after moving the stage 30 and positioning the reference position (for example, alignment mark) of the semiconductor device 100 directly below the objective lens 8, the stage 30 is moved so that the reference position and the marker on the monitor 15 match. , this position t is taken as the machining origin. Next, the stage 30 is moved based on the processing data to align the center of the contact hole previously formed in the semiconductor device 100 with the marker on the screen of the monitor 15.

If the CVD material gas was introduced at a predetermined pressure,
The shutter 7 is opened and the inside of the contact hole 106cL is irradiated with laser light 2t. (FIG. 2(a)) The wiring 103 in the contact hole 1064 is heated by laser irradiation, and the CVD material gas that comes in contact with it is thermally decomposed, and a conductive substance 107t is precipitated. (Fig. 2(b)) The conductive substance 107 obtained by decomposing the C'VD material gas is Cr(Co), (CrtNt (Go) in case of D)
For 4, Nle Mo (Co) * and MoF,
In the case of , it is current-W(Co)s, and in the case of previous, it is W. These also apply to the wiring that will be formed later.

After the contact hole to6at is completely filled, the shutter 7 is closed to stop laser irradiation. Then, the stage 30t moves and the contact holes 106 form a pair.
The center of b is aligned with the marker, the shutter 7t is opened again, and laser irradiation is performed to fill the conductive material.

When connecting multiple locations, repeat the above operation (alignment → laser irradiation) until all contact holes 106 are connected.
After filling with conductive material 107, wiring formation described below may be performed, or filling with conductive material 107 and wiring formation may be repeated for each pair.

Next, the filled contact holes 106 are connected to each other, that is, wiring is formed. After setting the irradiation power of the laser beam 2 to a predetermined value, the shutter 7 is opened to irradiate the filled portion of the contact hole 106b with the laser beam 2. At the same time, the stage 50t is moved, that is, relative scanning of the laser beam 2 is performed according to the wiring formation route of the processing data. As a result, the wiring 108 is placed on the semiconductor device 100 as shown in FIG.
is formed. The irradiation of the laser beam 2 and the movement of the stage 60 are stopped when the laser beam 2 reaches the filled portion of the contact hole 106α.

When all wiring 108 has been laid, the pulp 25 is opened and the CVD material gas in the main chamber 19 is exhausted. When the inside of the main chamber 19 reaches a high vacuum of 10'' Torr or more, laser annealing is performed.

As shown in FIG. 3, the irradiation power at the laser annealing starting point x1 is adjusted to P. This irradiation power P is the wiring 10
The value is such that even if the laser beam 8 is irradiated suddenly, the wiring 108 will not be cranked, and will vary depending on the material and dimensions of the wiring 108, the wavelength of the laser beam 2, etc. For example, the wiring width is about 15μ
When the Ar laser beam with a wavelength of 515 nm was irradiated to the Mo wiring of 200 mW or less, no cracks were observed in the wafer.

After adjusting the irradiation power P1t, the shutter 7t is opened and the stage 60 is moved along the wiring route to emit the laser beam 2.
scan relatively. As the scanning progresses, the irradiation power is increased until the predetermined position X! When this is reached, the value P is set so that the annealing effect is high. This irradiation power P is also the above-mentioned P1
Similarly, they differ depending on the material and dimensions of the arrangement a 108, the wavelength of the laser beam 2, etc. Figure 4 shows MO wiring f with a wiring width of approximately 15JM1.
Figure 3 shows the relationship between irradiation power and wiring resistance when laser annealing is performed using Ar laser light with a wavelength of 15 nm. Fourth
It can be seen that the wiring resistance can be reduced to t-175 or less by laser annealing with a drawing power of 9,500 mW or more. This is because the Mo0rCy compound that increases the resistivity in the Mo wiring is decomposed and the proportion of Mo as a metal increases.

When the irradiation position of the laser beam 2 reaches a predetermined position, the irradiation power is lowered, and the variable transmittance filter 5 is adjusted so that the scanning end point x4 is the same as the scanning start point.

Through this series of operations, the thermal shock of the wiring 108 due to rapid heating Φ caused by laser irradiation is reduced. And $10 distribution
The stress caused by the difference in thermal expansion coefficient between the base film 8 and the base film (vaxivation film 105) is also reduced, and the occurrence of cracks due to these factors can be prevented.

The irradiation power shown in Figure 3 c! 7. The file is recorded in advance on the guise medium 38 as processed data. Third
Although the figure shows the relationship with the irradiation position, it may also show the relationship with time. In addition, the irradiation power P.

Although the change from P, , P, to Psi is shown continuously, it may be changed stepwise.

For windings in which a plurality of wires 108 are formed, the stage 60 is moved again to align the scanning start point of the next wire 108, and all the wires 108 are laser annealed using the above procedure. (FIG. 2(d)) After transferring the gate pulp 2, the stage 50 is returned to the position when transporting 1 ttoa of semiconductors.
0t-open, transfer arm 28 to semiconductor device 100
The holder 28 is transported to the fc crawling chamber 18. Next, the gate pulp 20 is closed, the loading chamber 18 is opened to the atmosphere, the semiconductor device 100 is taken out, and wiring formation is completed.

In this example, laser annealing was performed in a vacuum, but after evacuating the main chamber 19 to a high vacuum, the valve 3
It is also possible to open cylinder 35 and introduce an inert gas or reducing gas, and carry out the process in this atmosphere.

Further, the wiring 108 formed by laser CVD in this embodiment is C
Since the VD material gas is obtained by thermal decomposition, it is formed with a width larger than the condensing diameter of the laser beam 2. Therefore, by defocusing the condensing diameter of the laser beam 2 during laser annealing, and by irradiating the entire width of the wiring 108, the entire wiring 108 can be uniformly annealed.

Furthermore, if a heater is provided on the stage 30 or the holder 27, or a heating rung is provided in the main chamber 19, laser annealing is performed while heating the entire semiconductor device t100 to an extent that does not adversely affect its characteristics. Wiring resistance can be reduced by low-power laser irradiation. In addition, the interval between the rise and fall of the irradiation power (31 in Fig. 3)
Jez w JS J4 ) can be shortened, so the region where the resistance is sufficiently reduced becomes longer.

〔Effect of the invention〕

As described above, according to the present invention, the resistance value of wiring formed by laser CVD can be significantly reduced, and therefore it can be applied to identifying and repairing defective locations in semiconductor devices where signal delay is a problem.

Further, since annealing is performed by irradiating only the above-mentioned wiring with a laser beam, a reduction in resistance can be achieved without having a thermal effect on the surrounding completed elements.

Furthermore, the stress caused by laser irradiation is reduced to 7t.
Since annealing is performed, no cracks will occur in the wiring. [Repair yield of semiconductor devices will be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment for forming wiring according to the present invention, FIG. 2 is a diagram showing a wiring forming process according to the present invention, and FIG. 3 is a diagram showing changes in irradiation power in laser annealing according to the present invention. 4 are diagrams showing the relationship between irradiation power and wiring resistance during laser annealing. 1- Laser generator, 2... Laser light, 6... Transparent.
Variable transmittance filter, 5 - Reflection mirror, 7 - Shutter, 8 - Objective lens, 16 - Photodetector, 18
...Loading chamber, 19...Main chamber, 20-...Gate pulp, 21.24...True! pump, 30...stage, 51...window, 52...
CVD material gas cylinder, 38...Miss medium, 39-1
Component cI-2, 100...Semiconductor device, 105--Wiring, 106--Contact hole, 107--Conductive material, 108--Wiring. body) two countries

Claims (1)

[Claims] 1. A method for additionally forming wiring for identifying or repairing a defective portion on the surface of a semiconductor device, including a step of forming the wiring by at least CVD using a laser, and the wiring using the laser. 1. A wiring forming method, comprising: an annealing step. 2. The wiring forming method according to claim 1, wherein the step of annealing the wiring is performed in a non-oxidizing atmosphere such as a vacuum atmosphere or an inert gas atmosphere. 3. The wiring forming method according to claim 1, wherein the step of annealing the wiring is performed in a reducing atmosphere. 4. The wiring forming method according to claim 1, wherein in the step of annealing the wiring, the laser irradiation power is increased at the start of scanning, and the laser irradiation power is decreased as the scanning approaches the end.