JP3354191B2 - Laser film forming apparatus and laser film forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser film forming apparatus and a laser film forming method for forming a metal wiring on a semiconductor wafer by a laser CVD method.

[0002]

2. Description of the Related Art In a wiring technique by a laser CVD method, a metal carbonyl is converted to Ar ⁺ A direct drawing method in which a laser is locally thermally decomposed is generally used. This method has the advantages that a high film quality is obtained, the stability of the source gas is high, and the window into which laser light is introduced is less contaminated.

[0003] The result of laser CVD film formation is significantly affected by the source gas supply method. There are two types of source gas supply methods: a decompression method for forming a film in a vacuum atmosphere, and a carrier gas method for forming a film under an atmospheric pressure environment. Since the above-mentioned decompression method requires a leaktight vacuum vessel, there are problems such as an increase in equipment cost and a reduction in throughput due to evacuation time. Since the above carrier gas method does not require a vacuum atmosphere, workability is good and practicality is high. In particular, in recent years, the size of electronic devices to which laser CVD is applied has been increased in size, and the carrier gas method has been widely used in terms of throughput and workability.

[0004] Two conditions are required for good connection of the wiring of an electronic device. First, a high-quality film is formed and the electric resistance of the film is reduced. Second, since the reflectance of laser light is high and the thermal conductivity is high, it is good on aluminum where film formation is difficult. In the above carrier gas method, the difference in film quality and film formability depending on the type of gas is remarkable.

When hydrogen (H ₂ ) having a reducing action is used as a carrier gas, contamination of impurities (C, O, etc.) is suppressed, and a high film quality can be obtained. However, at the same time, nucleation is also suppressed, and the required rate of film formation is reduced.
The power must be high and aluminum wiring is susceptible to thermal damage. In addition, the contact resistance is increased due to the deterioration of the film-forming property, which is a hindrance to a good connection.

Another problem with hydrogen carriers is that they degrade the organometallics and cannot supply source gas with a stable quality. As the film is formed with a hydrogen carrier, the organic metal is subjected to the reduction action of hydrogen, and it becomes difficult to form the film gradually, even though the film forming conditions are set to the same, and eventually the film is completely formed. The phenomenon that it stops being performed occurs. For this reason, although the obtained film quality is high, hydrogen is not suitable as a carrier gas of the organic metal.

When an inert gas such as Ar, He, or N ₂ is used as a carrier gas, the source gas can be stably supplied for a long time without deteriorating the organic metal as in the case of using hydrogen. In addition, film formation on aluminum is facilitated because nucleation is facilitated. However, the quality of the film is low because decomposition products generated during the film formation are mixed into the film as impurities.

[0008]

As described above, in the conventional method using a single carrier gas, it is difficult to achieve both high film quality and good film forming property, and the device wiring is reduced by a metal film. Could not connect to resistor.

[0009] The present invention has been made in view of these circumstances, the laser the place of interest, which is adapted kills in the form forming the deposition of high quality by the laser beam under high workability atmospheric pressure It is to provide a film forming apparatus and a laser film forming method.

[0010]

According to the first aspect of the present invention, there is provided a film forming method.
A table for placing the object and a translucent window member
A part of the table, which is arranged to face the table
In the space between the bar body and this cover body and the table
A first conduit for supplying a first gas, and the cover;
Between the body and the table, wherein the first gas is supplied.
Supplying the second gas to a space outside the space to be supplied
A second conduit for forming the film and the window
Laser irradiation for irradiating laser light through components
Lying in the laser film formation apparatus according to claim and means. The invention according to claim 2, wherein the table is an XY table
The laser film forming apparatus according to claim 1, wherein
It is in. In the invention according to claim 3, the cover body has a disk shape.
A base and a peripheral portion of the base protrude toward the table.
2. The device according to claim 1, further comprising an annular wall provided.
In the above-mentioned laser film forming apparatus. Invention, the mosquito claim 4
The bar body has a disk-shaped base and a lower surface side of the base.
A first annular wall protruding from a central portion of the side surface, and the first annular wall;
A second ring protruding from the periphery of the base outside the wall
2. The laser according to claim 1, further comprising:
Film forming equipment. According to a fifth aspect of the present invention, the first annular wall is more rigid than the first annular wall.
The height of the second annular wall is larger than that of the second annular wall.
5. The laser film forming apparatus according to claim 4, wherein
You. According to a sixth aspect of the present invention , at least one of the first conduits is provided.
The portion is a nozzle hole communicating with the space,
A laser film forming apparatus according to claim 1. In the invention according to claim 7, the plurality of nozzle holes are formed at predetermined intervals in a circumferential direction.
The laser deposition according to claim 6, characterized in that it is
In the device. The invention according to claim 8 is characterized in that the second pipe has a small number of pipes.
At least a part is a nozzle hole communicating with the space.
The laser film forming apparatus according to claim 1, wherein: In a ninth aspect of the present invention, the nozzle holes are arranged at predetermined intervals in a circumferential direction.
9. The recording device according to claim 8, wherein a plurality of the components are formed.
It is in the user film forming apparatus. The invention according to claim 10 is a light-transmitting window.
The cover body, which is partially equipped with a member, is
When the cover body and the object to be film-formed are
The raw material gas is supplied to the space between
Between the body and the object to be formed, and the source gas is supplied.
Supply the second gas to the space outside the space to be supplied
And applying the laser beam to the film-forming target through the window member.
Irradiation to form a film.
is there. In the invention according to claim 11, the object for film formation is an electronic device.
The laser according to claim 10, wherein the laser is a vise.
There is a film forming method. The invention of claim 12, wherein the raw material gas
11. An organic material comprising an organic metal.
In the laser film forming method described above. Invention, prior to claim 13
The raw material gas contains carbonyl.
A laser film forming method according to claim 10. Claim 14
The invention is characterized in that the laser light is visible light.
A laser film forming method according to claim 10. Claim 1
The invention according to claim 5, wherein the laser beam is an argon ion laser.
11. The laser film forming method according to claim 10, wherein:
It is in. According to a sixteenth aspect of the present invention, the film is formed by aluminum.
11. The semiconductor device according to claim 10, wherein the wiring is connected to a nickel wiring.
Laser film forming method.

[0011]

[0012]

[0013]

In the film formation while supplying the second gas, the second
Prevents outside air from flowing into the film deposition site due to gas flow
Is done.

[0014]

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

FIGS. 1 to 3 show a first embodiment of the present invention. The laser film forming apparatus shown in FIG. 1 employs an argon ion laser.
A laser oscillator 11 for outputting visible laser light L such as a laser is provided. The laser output from the laser oscillator 11
The light L is reflected by the mirror 12, focused by the objective lens 13, and enters the inside of the reaction vessel 14 through the window 15 formed on the upper surface thereof. An XY table 16 is provided inside the reaction vessel 14, and an electronic device 17 such as a semiconductor wafer as a film formation target is arranged on the XY table 16. Thereby, the laser light L focused by the objective lens 13 irradiates the upper surface of the electronic device 17.

The XY table 16 is driven in the XY directions by a drive unit 18 so that the laser light L can be scanned on the electronic device 17. The drive section 18 is driven and controlled by a drive signal from a control device 19.

The reaction vessel 14 is connected to one end of a first supply pipe 21 whose tip is opposed to a portion (film formation portion) of the electronic device 17 which is irradiated with the visible laser light L. Have been. In the middle of the first supply line 21, a reservoir 22 and a first mass flow controller 2 are provided.
The other end is connected to a supply source of an inert gas (not shown) such as nitrogen (N ₂ ). The reservoir 22 contains an organic metal 24 such as a metal carbonyl, and the organic metal 24 is heated by a heater 25. A certain amount of the inert gas that has passed through the first mass flow controller 23 is supplied to the above-described reservoir.
The raw material gas (source) is mixed with the vapor of the organic metal 24 in the bath 22.
Gas) and flows into the reaction vessel 14.

The reservoir 2 of the first supply line 21
One end of the second supply pipe 26 is connected to a position downstream of the second supply pipe 26. A control valve 27 and a second mass flow controller 28 are sequentially provided in the middle of the second supply line 26, and the other end is supplied with hydrogen (H ₂ ) as a reducing gas (not shown). In communication with the source. The control valve 27
Is opened, hydrogen can be mixed into the raw material gas flowing through the first supply pipe line 21, and the amount thereof can be controlled by the second mass flow controller 28.

The first mass flow controller 23 and the second mass flow controller 28 are controlled by a control signal from the control device 19. Thereby, the flow rate of the inert gas and the flow rate of the hydrogen are set respectively. Similarly, the control valve 27 is controlled to open and close by a control signal from the control device 19. Thereby, hydrogen can be appropriately mixed into the raw material gas flowing through the first supply pipe 21.

In this embodiment, the opening and closing timing of the control valve 27 for mixing hydrogen into the raw material gas is set as follows. That is, FIGS. 2A and 2B show a perspective view and a cross-sectional view of the electronic device 17. In the figure, 17a is SiO ₂
A first aluminum wiring 17b and a second aluminum wiring 17c are formed discontinuously on the substrate 17a.

The first and second aluminum wirings 17
In the case where the first and second wirings 17b and 17c are connected by forming the metal film 20 shown in FIG. 2A, the position A (the starting position of the film formation) on the first aluminum wiring 17b, the first aluminum wiring 17
position B at the boundary between b and substrate 17a, position C at the boundary between second aluminum wiring 17c and substrate 17a, and position D on second aluminum wiring 17c (position at which film formation is completed)
Are input to the controller 19 in advance as position data. If the visible laser light L is scanned in the direction indicated by the arrow X in FIG.
Is controlled by the control device 19 to be closed between the position A and the position B, opened from the position B to the position C, and further closed between the position C and the position D.

Next, the first and second aluminum wirings 17b of the electronic device 17 are
The procedure for forming a film between 17c will be described. First, the laser light L
When the laser beam L is positioned so that the irradiation position of the laser beam L is located at the position A on the electronic device 17, the laser beam L is emitted as shown in FIG.
The XY table 16 is driven so as to scan in the direction indicated by the arrow X in FIG. When the laser light L is on the electronic device 17 between the position A and the position B, the control valve 27 is closed. Therefore, only the raw material gas is supplied into the reaction vessel 14, and no hydrogen is supplied. That is, when a film is formed on the first aluminum wiring 17b, hydrogen having a reducing action is not supplied, and nucleation of the film is not suppressed, so that heat is not excessively input by laser light. The metal film 20 can be formed on the first aluminum wiring 17b. Thus, the first aluminum wiring 17b is not thermally damaged, and the resistance is not increased.

The irradiation position of the laser beam L is between the position B and the position C in FIG.
When a film is formed on a, the control valve 27 is opened by a control signal from the control device 19. When the control valve 27 is opened, hydrogen is mixed into the organometallic gas flowing through the first supply pipe line 21 at a predetermined ratio. Hydrogen has a reducing action. For this reason, contamination due to carbon, oxygen, or the like is suppressed, so that the metal film 20 can be formed with high quality. Moreover, even if the nucleation is suppressed by hydrogen, the portion of the substrate 17a easily absorbs the laser light L, so that the film-forming property does not decrease and the contact resistance does not increase.

Next, when the laser beam L is irradiated between the position C and the position D, that is, when the second aluminum wiring 17c is irradiated, the control valve 27 is closed. Thereby,
Since hydrogen is prevented from being mixed into the raw material gas supplied to the reaction vessel 14, similarly to the case of forming a film on the first aluminum wiring 17b, it is possible to improve the laser output without increasing the laser output more than necessary. A film can be formed.

The second supply line 26 for supplying hydrogen
Is connected to the downstream side of the reservoir 23 so that hydrogen is mixed into the raw material gas in a timely manner, so that hydrogen does not flow in the reservoir 23. Therefore, the reservoir 2
Since the organic metal 24 in 3 does not change due to the reduction action of hydrogen, it is difficult to form a film even though the film is formed under the same film forming conditions. Absent.

FIG. 3 is a graph showing the state of film formation when the laser output and the mixing ratio of hydrogen are changed, and the resistance value of the film in that case. In this graph, x indicates that the film could not be formed, white circle indicates that the film was formed well, and black circle indicates that the film could be formed, but there was damage and the spatial resolution was poor. The numbers described next to the open circles and the black circles are resistance values (Ω). In addition, nitrogen gas was used as the inert gas, and the flow rate was 100 cc.
m (constant), and the scanning speed of the laser beam L is 2 μm /
s.

From the measurement results, the following became clear. That is, it was confirmed that good film formation results were obtained when the laser output was 30 mW and 40 mW, and that the resistance value of the film was lowest when the mixing ratio of hydrogen was 20% at each laser output. Was done. Therefore, when supplying hydrogen to form a film from the position B to the position C, if the supply amount is set to 20% with respect to the flow rate of the source gas, a film having a low resistance value can be formed. Become.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the laser light L output from the laser oscillator 11 is
Is reflected by the half mirror 12a and introduced into the reaction vessel 14, the intensity of the reflected light L 'from the electronic device 17 is detected by the photodetector 41, and the detection signal is sent to the control device 1
9 is input. The intensity of the reflected light L ′ detected by the photodetector 41 differs depending on the irradiation site of the electronic device 17.
In other words, the intensity of the reflected light from the first and second aluminum wirings 17b and 17c is higher than the intensity of the reflected light from the substrate 17a. As in the first embodiment, hydrogen can be mixed into the source gas at the appropriate time.

FIGS. 5 and 6 show a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, a cover 31 is used instead of the reaction vessel 14 shown in the first embodiment.
The cover body 31 includes a disc-shaped base 32 and the base 32.
A first annular wall 33 protruding from the center of one side surface on the lower surface side of the first annular wall 33, and the base portion 32 outside the first annular wall 33.
And a second annular wall 34 protruding from a peripheral portion of the second member. The cover body 31 is arranged above the XY table 16 so as to face the upper surface of the electronic device 17 at a predetermined interval.

The first annular wall 33 forms a first space portion 35 with its inner peripheral surface, and the second annular wall 34 has an inner peripheral surface and an outer peripheral surface of the first annular wall 33. Form the second space 36. Assuming that the protrusion dimension of the first annular wall 33, that is, the height dimension is H1, and the height dimension of the second annular wall 34 is H2, H1 <H2 is set.

A through hole 37 penetrating in the thickness direction is formed in a central portion of the base portion 32 corresponding to the first space portion 35, and a light transmitting window member 38 is provided in the through hole 37. ing. A first annular passage 39 is formed around the through hole 37. In the first annular passage 39, first nozzle holes 41 communicating with the first space 35 are formed at predetermined intervals in a circumferential direction. The first supply passage 21 for supplying the raw material gas from the reservoir 22 is connected to the first annular passage 39.

A second annular passage 42 is formed in a portion of the base 32 corresponding to the second space 36.
In the second annular passage 42, second nozzle holes 43 communicating with the second space 36 are formed at predetermined intervals in the circumferential direction. The second annular passage 42 is connected to a second supply pipe 26 for supplying hydrogen as a reducing gas.

When a film is formed using the cover body 31 having the above structure, the first space 35 formed by the first annular wall 33 is opposed to the film formation portion of the electronic device 17. The electronic device 17 is positioned. In this state, when a film is formed between the position A and the position B shown in FIG. 2A, the source gas is supplied from the first supply pipe 21 to the first space 35. Further, the control valve 27 provided in the second supply pipe 26 is closed, and the supply of hydrogen is stopped.

On the other hand, the electronic device 17 is driven in the direction of arrow X, and the raw material gas is thermally decomposed by the laser beam L which has passed through the window member 38 and illuminated the position A.
Therefore, metal film 20 is generated between positions AB on first aluminum interconnection 17b.

When a film is formed between the position B and the position C, the control valve 27 is opened and the second supply line 26
Hydrogen is supplied to the space 36 of. The hydrogen gas flowing out into the second space 36 flows into the first space 35 through a gap between the lower end surface of the first annular wall 33 and the upper surface of the substrate 17a as shown by an arrow in FIG. And then partly out of the wave. Therefore, contamination due to carbon, oxygen, or the like is suppressed by the reducing property of hydrogen, and film formation with high film quality is performed.

Hydrogen flows out of the second space portion 36 and flows out of the first space portion.
Is mixed with the raw material gas by flowing into the space portion 35.
That is, it is mixed with the source gas in the vicinity of the film formation site. Therefore, since the quality is not degraded by the reducing gas before the organic metal in the source gas is supplied to the film formation site, the film can be formed on the film formation region with high quality film.

When a film is formed between the positions C and D, the control valve 27 is closed to stop the supply of the hydrogen gas, and only the raw material gas is supplied to form the film in the same manner as between the positions AB. Done.

The cover body 31 has a double structure of a first annular wall 33 and a second annular wall 34, and is provided outside the first annular wall 33 provided inside. The second
The annular wall 34 is formed to have a larger height dimension. Therefore, even if the distance between the lower end surface of the second annular wall 34, which is the lowermost end of the cover body 31 shown in FIG. It is difficult to reach the site. In particular, the second space 3
At the time of film formation while supplying hydrogen gas to 6, the flow of the hydrogen gas can prevent the outside air from flowing into the first space 35, that is, the film formation site. As a result, the handling of the electronic device 17 can be improved.

If the distance d between the cover body 31 and the electronic device 17 can be increased, the electronic device 17
Even if the electronic device 17 is moved even if the surface is uneven, it is possible to prevent the electronic device 17 from hitting the lower end surface of the cover body 31. Therefore, at the time of film formation, the electronic device 17
Can be prevented from being damaged by the cover body 31.

In each of the above embodiments, the first and second supply pipes are connected to the reaction vessel or the cover body to supply the raw material gas and the reducing gas. The gas and the reducing gas may be supplied directly to the film-forming portion. In short, the material gas can be supplied to the film-forming portion and the reducing gas can be supplied in a timely manner. Good.

[0041]

According to the present invention, suitable film formation can be performed.
And the handling of electronic devices
It is possible to aim up.

[0042]

[0043]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an entire apparatus showing a first embodiment of the present invention.

FIG. 2A is an enlarged perspective view of a part of the electronic device, and FIG. 2B is a cross-sectional view of a state where a metal film is formed.

FIG. 3 is a graph similarly showing a relationship between a mixture ratio of hydrogen and a film formation state.

FIG. 4 is an overall configuration diagram of a device according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an entire apparatus according to a third embodiment of the present invention.

FIG. 6 is a bottom view of the cover body as viewed from the lower surface side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Laser oscillator, 14 ... Reaction container, 16 ... Electronic device (film-forming object), 19 ... Control device, 21 ... First supply conduit, 23 ... Reservoir, 24 ... Organic metal, 26 ... Second
Supply pipe, 27 control valve, 31 cover body, 33 first annular wall, 34 second annular wall, 35 first space portion, 36 second space portion.

Claims (16)

(57) [Claims] 1. A table for arranging a film formation target.
And a translucent window member provided in a part thereof, and spaced apart from the table.
A first gas is placed in a space between the cover and the table, and a space between the cover and the table.
A first conduit for supplying, a between the cover and body table, the first
Second gas in a space outside the space to which the gas is supplied.
A second pipe line for supplying the laser beam and the film-forming target through the window member.
A laser irradiation unit for irradiating the laser light . 2. The method according to claim 1, wherein the table is an XY table.
The laser film forming apparatus according to claim 1, wherein: Wherein the cover body includes a disc-shaped base, the facing table side projecting from the periphery of the base portion
The ray according to claim 1, further comprising an annular wall.
The film forming equipment. 4. The cover body has a disk-shaped base portion and a first portion protruding from a central portion of one side surface on the lower surface side of the base portion.
And an outer peripheral wall of the base portion outside the first annular wall.
And a second annular wall provided.
The laser film forming apparatus as described in the above. 5. The second annular wall rather than the first annular wall.
The feature is that the wall has a larger height dimension
The laser film forming apparatus according to claim 4, wherein 6. At least a portion of said first conduit is a front conduit.
A nozzle hole communicating with the space.
Item 2. A laser film forming apparatus according to Item 1. 7. The nozzle hole is formed at predetermined intervals in a circumferential direction.
7. The ray according to claim 6, wherein the number is formed.
The film forming equipment. 8. The apparatus according to claim 8, wherein at least a part of said second conduit is provided
Claims, characterized in that the serial space is Roh nozzle hole communicating
Item 2. A laser film forming apparatus according to Item 1. 9. The nozzle hole is formed at predetermined intervals in a circumferential direction.
9. The ray according to claim 8, wherein a number is formed.
The film forming equipment. 10. A cover partially including a translucent window member.
When the body is placed facing away from the film-forming target,
The raw material gas is supplied to the space between the bar and the object to be formed.
At the same time as the supply, between the cover body and the film formation target,
Gas in the space outside the space where the feed gas is supplied.
While irradiating the laser beam onto the film formation object through the window member.
And forming a film. 11. The film forming object is an electronic device.
The method according to claim 10, wherein 12. The raw material gas contains an organic metal.
The method according to claim 10, wherein 13. The raw material gas contains carbonyl.
The method for forming a laser film according to claim 10, wherein
Law. 14. The method according to claim 14, wherein the laser light is visible light.
The laser film forming method according to claim 10, wherein: 15. The laser beam is an argon ion laser
The laser deposition according to claim 10, wherein
Method. 16. An aluminum wiring is formed by said film formation.
The laser deposition according to claim 10, wherein the connection is made.
Method.