JPH06302595A - Wiring formation system - Google Patents

Abstract

PURPOSE:To form a repair wiring having low resistivity causing no signal lag by irradiating a sample placed in a chamber with laser light in CVD gas atmosphere to form a repair wiring and after discharging the CVD gas to bring about vacuum, irradiating the sample with laser light condensed to have a width substantially equal to that of the wiring thereby annealing the sample. CONSTITUTION:A sample 19 placed in a chamber 13 filled with CVD gas is irradiated with laser light 2 to deposit the wiring material and then the movement of an XY stage 20 is controlled by a computor 22 thus forming a repair wiring. The CVD gas is then discharged to bring about vacuum in the chamber 13, and the sample 19 is shifted back and forth in the direction of the optical axis by means of a Z stage 20 so that the laser light 2 has an irradiation width substantially equal to the width of the wiring. The computor 22 controls the movement of the XY stage 21 to project the defocus laser light, thus obtained, only to the wiring part thus annealing the wiring. This constitution decreases the resistance of wiring and allows formation of the repair wiring of semiconductor device causing no signal lag.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for forming repair wiring on the surface of a semiconductor device, and particularly when a prototype semiconductor device has a partial defect. The present invention relates to a wiring forming apparatus suitable for identifying and repairing defective points. 2. Description of the Related Art In recent years, semiconductor devices have been highly integrated,
The number of wiring layers is also increasing. Therefore, semiconductor devices in the development process do not always operate as designed,
The characteristics are evaluated so that a complete operation can be provisionally obtained by cutting the wiring on the chip or connecting an arbitrary portion to identify a defective portion or repairing the defective portion. As a method for connecting any of these locations, the Extended Abstract of the Seventeenth Conference on Solid State Device and Materials, Tokyo (198)
5th year) pp. 193 to 196 (Extended Abstrac
ts of the 17-th Conference on Solid Sta
te Devices and Materials, Tokyo 1985 p
p193-196). That is,
In the CVD cell installed on the XY stage, Mo (C
O) ₆ vapor and atmospheric pressure Ar gas are introduced, and S in the CVD cell is introduced.
Initially several tens of μ on a Si substrate coated with io _2.
The Mo film is deposited by photochemical reaction by irradiating the second harmonic (wavelength: 257 nm) of W Ar ion laser, and then several tens of
Irradiating the fundamental wave (wavelength 515 nm) of 0 mW Ar ion laser to the Mo film deposited by photochemical reaction to locally generate thermal CV.
After performing D, the CVD cell is moved by an XY stage to form Mo wirings and connect arbitrary locations. In the above-mentioned prior art, the resistivity of the formed Mo wiring is 40 μΩ · cm, which is eight times larger than the bulk resistivity (5.4 μΩ · cm). Therefore, when it is used for repair wiring of a high-speed logic LSI used in a large-scale computer or the like, the signal is delayed and the characteristics cannot be evaluated. There is a method of increasing the film thickness of the wiring as a measure for reducing the resistance value of the wiring, but cracks are generated due to residual stress of the film formed by laser CVD, difference in expansion coefficient from the substrate, and the like. There is a limit to the increase in film thickness due to peeling and the like. 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 device for forming repair wiring having a small specific resistance without causing signal delay. The above-mentioned object is to provide a vacuum chamber, a local CVD means for forming wiring on a sample placed inside the vacuum chamber, and a wiring formed by the local CVD means locally. A laser CV using a laser as a local CVD means having a resistance lowering means for heating to
A laser irradiation unit configured by the D means for irradiating the wiring with a laser having a resistance reduced to a laser having a width substantially equal to the width of the wiring formed by the local CVD means, and the irradiated laser is scanned along the wiring. This is achieved by a wiring forming device including a scanning unit. The wiring whose resistance is reduced (annealed) by laser light irradiation is operated by irradiating the sample (semiconductor integrated circuit) with the laser light focused in advance in the CVD gas atmosphere. Has been formed. By exhausting the CVD gas surrounding the wiring and keeping the sample in a vacuum of 10 to ⁵ Torr or more, or in an atmosphere of an inert gas or a reducing gas, the wiring surface may be oxidized during the annealing process. To prevent. By irradiating the energy beam (laser light) focused to the same extent as the width of the wiring, uniform annealing and high-speed processing can be performed. This is because if the light is condensed within the width, the effect of re-evaporation becomes more remarkable than the effect of annealing and the wiring is damaged. The wiring that has been irradiated with an energy beam such as a laser is locally heated, and the specific resistance of the wiring is reduced by improving the crystallinity of the wiring material and removing impurities such as carbon and oxygen. Embodiments of the present invention will be described below with reference to the drawings. First, a first wiring forming apparatus according to the present invention will be described.
An example of the above is shown in FIG. The apparatus includes a laser oscillator 1 that oscillates a laser beam 2 and a sample 19 that reflects the laser beam 2.
Processing system including a dichroic mirror 3 for guiding the laser light 2 and an objective lens 4 for collecting and irradiating the laser light 2 on the sample 19, and an observation light source 5 and an observation light 8 having a wavelength close to the wavelength of the laser light 2. Filter 6 and observation light 8 for extracting light
Half mirror 7 for guiding the image on the sample 19, an imaging lens 9 for forming an image of the sample 19, a prism 1
0, an eyepiece lens 11, an observation optical system, a chamber 13 for accommodating a sample 19 to be formed with wiring, a window 12 for introducing a laser beam 2, a CVD
A gas supply / exhaust system comprising a gas introducing pipe 14 connected from a cylinder 16 containing a material gas via a valve 15 and an exhaust pipe 17 connected to a vacuum exhaust device (not shown) via a valve 18, , A Z stage 20 for mounting the sample 19 and moving the sample 19 in the optical axis direction for focusing with the laser light 2 and the observation light 8, and XY for moving the sample 19 in a plane perpendicular to the optical axis. A chamber 13 having a sample position specifying means composed of a stage 21;
The computer 22 controls the driving of the stage 20 and the XY stage 21, and the driving of the shutter 23 that opens and closes the optical path of the laser beam 2, respectively. Next, a procedure for forming wiring using the above apparatus will be described. First, the valve 15 is closed, the valve 18 is opened, and the inside of the chamber 13 is evacuated by a vacuum evacuation device (not shown) until the degree of vacuum reaches 10 to ⁶ Torr or more. Then, after closing the valve 18, the valve 15 is opened to introduce the CVD gas into the chamber 13 until the desired pressure is reached, and the valve 15 is closed to keep the CVD gas in the chamber 13. After that, the sample is moved to an arbitrary place by the XY stage 21 while observing the pattern on the sample 19 by the observation optical system. Next, the laser beam 2 is oscillated from the laser oscillator 1, the shutter 23 is opened, the laser beam 2 is condensed by the objective lens 4, and the sample 19 is irradiated with an arbitrary position. CVD
The gas is decomposed by the thermal energy of the laser light 2 to deposit the wiring material. The deposition moves along the movement of the XY stage 20 controlled by the computer 22 to a desired connection position at an arbitrary speed. The wiring is completed by closing the shutter 23 and stopping the irradiation of the laser light 2. After forming all the repair wiring, the valve 1
8 is opened and the chamber 1 is evacuated by a vacuum exhaust device (not shown).
The CVD gas exhaust 3, and at least 10 ~ ⁵ Torr vacuum. Then, the sample 19 is moved back and forth in the optical axis direction by the Z stage 20 so that the irradiation diameter of the laser beam 2 becomes approximately the same as the width of the wiring with respect to the wiring formed by the above method. The XY stage 21 is controlled by the computer 22 so that the defocused laser light thus obtained is irradiated only on the wiring portion, and the wiring is annealed by moving the XY stage 21 at an arbitrary speed. Next, the procedure for forming the wiring will be specifically described with reference to FIG. First, as shown in FIG. 2A, SiO is formed on the Si substrate 30.
₂ shows a sample in which an Al wiring layer 33 is formed via a film ₂ and a passivation film 32 is formed on the entire surface. The passivation film 32 on the Al wiring layer 33 in the portion that requires connection is subjected to windowing by a technique such as etching using a lithography technique, laser processing, or ion beam processing to form windowing portions 34a and 34b. This sample is shown in Figure 2.
As shown in (b), in the atmosphere of CVD gas 35 (for example, Mo
It is placed on (CO) ₆ vapor of 0.1 Torr and irradiated with the laser beam 2 (for example, the fundamental wave of Ar laser, power of 200 mW) focused on the window opening portion 34a. Then, the CVD gas 35 is decomposed by a thermochemical reaction to deposit the Mo film 36, and the sample is moved in the direction of the arrow at an arbitrary speed (for example, 0.1 mm).
/ Min) to the window opening portion 34b. In this way, as shown in FIG. 2C, the window opening 3 is formed by the Mo film 36.
The Al wirings at 4a and 34b are connected to each other. Next in FIG.
At least 1 after exhausting the CVD gas 35 as shown in (d)
The sample is exposed to a vacuum atmosphere of 0 to ⁵ Torr. Then, the sample is shifted back and forth in the direction of the optical axis so that the irradiation diameter of the laser beam 2 on the Mo film 36 becomes approximately the same as the Mo film 36, and the window opening portion 3 is formed.
The Mo film 36 deposited on 4a is irradiated and annealed.
Move the sample in the direction of the arrow,
4b, and only the Mo film 36 is shown in FIG.
Anneal as shown in FIG. In this method, since the laser beam 2 is irradiated with a diameter approximately equal to the width of the Mo film 36 when annealing is performed, annealing can be performed uniformly in a short time. When the converged laser light is irradiated a plurality of times, the deposited Mo film 36 is liable to peel and deteriorate, and stress stress is likely to remain in the film itself. The effect of annealing by this method is that the resistivity of the deposited Mo film is about 30 μΩ · cm, whereas the resistivity of the Mo film 38 after annealing is about 11 μΩ · cm.
The specific resistance can be reduced by about 40%. Mo before and after annealing
There is no significant change in membrane geometry. Therefore, the film thickness,
It is possible to improve the crystallinity of the Mo film and remove impurities such as carbon and oxygen by laser annealing without changing the wiring width. Further, by irradiating the Mo film 36 of the window openings 34a and 34b with the laser light 2 for several minutes, the contact portion between the Mo film 38 and the Al wiring is alloyed by a diffusion phenomenon due to heat and the contact resistance can be reduced. . Although the laser beam 2 is converged by the objective lens 4 here, a cylindrical lens 24 may be used as shown in FIG. That is, by using the objective lens 4 when forming the wiring and using the cylindrical lens 24 when performing the annealing, the laser light 2 is linearly condensed, and annealing can be performed with uniform energy with respect to the width of the wiring. According to this method, the sample 19 is not displaced from the focus position of the observation light 8, and therefore, there is an effect that the alignment at the time of annealing is facilitated. It should be noted that when performing annealing in this embodiment, the sample 19 was placed in a vacuum atmosphere.
Similar effects can be obtained in a reducing atmosphere or an inert gas atmosphere. Next, a second embodiment of the wiring forming apparatus of the present invention will be described with reference to FIG. With respect to the structure of the apparatus, the structures of the processing optical system and the observation optical system are the same as those described in FIG. Chamber 40
The window 12 for introducing the laser beam 2 to the upper part.
There is a nozzle 41 installed so that the CVD gas can be sprayed onto the sample 19, and the nozzle 41
A cylinder 16 containing the CVD gas and a valve 15 for adjusting the flow rate of the CVD gas are connected to the tip of the. Further, there is a nozzle 42 installed so that the reducing gas can be blown to the sample 19, and a cylinder 44 containing the reducing gas and a valve 43 for adjusting the flow rate of the reducing gas are connected to the tip of the nozzle 42. And the nozzles 41, 42
There is an exhaust pipe 45 for exhausting the CVD gas and the reducing gas so as to face with, and a valve 18 for adjusting the exhaust amount is connected to the exhaust pipe 45, so that the CVD gas or the reducing gas can be supplied in a fixed amount. It can be exhausted at. The sample 19 is a Z stage 20 which moves back and forth in the direction of the optical axis in order to focus the laser beam 2 and the observation beam 8,
It is mounted on the XY stage 21. Z stage 20
The XY stage 21 and the XY stage 21 are connected to a computer 22 and can be controlled to move to a predetermined position at an arbitrary speed. Next, a wiring forming procedure when the apparatus according to the second embodiment described above is used will be described. First, the valve 18 is opened with the valves 15 and 43 closed, and the chamber 40 is evacuated by a vacuum exhaust device (not shown) to a vacuum degree of at least 10 to ⁶ Torr. The sample 19 is moved to an arbitrary place by the XY stage 21 while observing the pattern of the sample 19 by the observation optical system during the exhaust. Thereafter, the valve 15 is opened and the CVD gas is blown onto the sample 19 from the nozzle 41.
The sprayed CVD gas is exhausted from the exhaust pipe 45,
The CVD gas exists only near the sample 19.
In this state, the laser light 2 is condensed by the objective lens 4 and irradiated on an arbitrary place of the sample 19, and the thermal energy decomposes the CVD gas to deposit the wiring material. This deposition moves at an arbitrary speed along the movement of the XY stage 21 controlled by the computer 22 to a position where connection is desired. Then, after forming the desired wiring, the shutter 23 is closed to interrupt the optical path of the laser beam 2 and the wiring forming process is completed. Then, after forming all the repair wirings, the valve 15 is closed to stop the supply of the CVD gas. Next, the valve 43 is opened and the reducing gas is sprayed from the nozzle 42 onto the sample 19. The blown reducing gas is exhausted from the exhaust pipe 45, and the reducing gas exists only near the sample 19. In this state, the irradiation diameter of the laser beam 2 with respect to the wiring formed by the above method is set to be approximately the same as the width of the wiring.
The sample 19 is moved back and forth in the optical axis direction by the Z stage 20. In this way, the XY stage 21 is controlled by the computer 22 so that only the wiring portion is irradiated with the laser light 2 with the laser light 2 defocused, and the wiring is annealed by moving the XY stage 21 at an arbitrary speed. As a result, the crystallinity of the wiring is improved and carbon
Impurities such as oxygen can be removed, and the specific resistance can be reduced. Further, according to the present embodiment, it is not necessary to completely exhaust the CVD gas after forming the wiring, so that there is an effect that the transition to the annealing process after forming the wiring can be performed quickly. Although Mo (CO) ₆ is used as the wiring material for precipitating Mo, MoCl ₅ , MoF ₆ or the like may be used. Further, W (CO) ₆ or WF ₆ , Ni (CO) ₄ is used to deposit W as another wiring material, and Ni (CO) ₄ is used to deposit Ni, and the fundamental wave of the Ar laser (wavelength 514 is used as the laser light for performing deposition annealing). 0.5 nm) and the second harmonic of Ar laser (wavelength 257n
It is possible to use a combination in which Al is deposited from Al (CH ₃ ) ₂ and Cd (CH ₃ ) ₂ is deposited from Cd (CH ₃ ) ₂ using m) and annealing is performed by the fundamental wave of an Ar laser. However, the present invention is not limited to these. According to the present invention, since the resistance value of the wiring formed by laser CVD can be reduced to near the resistance value of the bulk of the wiring material, a semiconductor device in which signal delay becomes a problem can be obtained. It can be used to form repair wiring. Further, since only the above wiring is irradiated with an energy beam such as a laser, only a necessary portion can be repaired without giving a thermal influence to the surrounding completed element, so that the yield of the element is not deteriorated. The effect is that it can be repaired mechanically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a first embodiment of a wiring forming device of the present invention. FIG. 2 is a diagram illustrating a wiring forming process of the present invention. FIG. 3 is a cross-sectional view showing an application of the first embodiment of the wiring forming apparatus of the present invention. FIG. 4 is a sectional view showing a second embodiment of the wiring forming apparatus of the present invention. [Explanation of Codes] 1 ... Laser oscillator, 2 ... Laser light, 4 ... Objective lens, 13 ... Chamber, 16 ... CVD gas cylinder, 19 ... Sample, 20 ... Z stage, 21 ... XY stage, 22 ... Computer , 33 ... Al wiring layer, 34a, 34b ... Window opening, 36 ... Mo film, 38 ... Annealed Mo film, 24 ... Cylindrical lens, 41, 42 ... Nozzle.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shuzo Sano             Stock, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Production Engineering Research Laboratory, Hitachi, Ltd. (72) Inventor Katsuro Mizukoshi             Stock, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Production Engineering Research Laboratory, Hitachi, Ltd.

Claims (1)

[Claims] 1. A vacuum chamber, a local CVD means for forming wiring on a sample placed inside the vacuum chamber, and the local CV
A wiring forming device, comprising: a resistance lowering means for locally heating the wiring formed by the D means to reduce the resistance. 2. The local CVD means is a laser CV using a laser.
The wiring forming apparatus according to claim 1, wherein the wiring forming apparatus is configured by D means. 3. The resistance lowering means irradiates a laser focused on the wiring with the same width as the width of the wiring formed by the local CVD means onto the wiring, and the irradiated laser relatively along the wiring. The wiring forming apparatus according to claim 1, further comprising a scanning unit that scans. 4. The local CVD means is a laser CV using a laser.
A laser irradiator configured to irradiate the wiring with a laser focused by the D-means and having the same resistance as the width of the wiring formed by the local CVD means; 2. The wiring forming apparatus according to claim 1, wherein the wiring forming apparatus comprises a scanning unit configured to scan along a line, and the laser CVD unit and the laser irradiation unit include the same laser light source.