JP3249276B2 - Semiconductor device manufacturing method and thin film forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device such as a method of forming a conductive film such as a wiring, a method of connecting between wirings or a wiring or an element region provided on a semiconductor substrate and a lead, and the like. The present invention relates to a thin film forming apparatus for forming a conductive film.

[0002]

2. Description of the Related Art Wiring is formed on a semiconductor substrate, connecting between wirings, connecting an element region of the semiconductor substrate to another circuit, or multilayer wiring on a circuit substrate on which a plurality of semiconductor chips are mounted. Connection between them is one of the important manufacturing steps in forming a semiconductor device. In particular, as semiconductor devices become more highly integrated and miniaturized, forming multi-layer wiring on a circuit board and efficiently connecting the multi-layer wiring is necessary to form a highly accurate semiconductor device. Indispensable.

With reference to FIG. 21, a conventional connection method between multilayer wirings on a circuit board on which a plurality of semiconductor chips are mounted will be described. For example, a first layer wiring 2 having a desired pattern is formed on a silicon semiconductor substrate 1. This wiring 2
Is a two layer T with each layer being about 600 Å thick.
Cu having a thickness of about 3 μm sandwiched between the i layer and the two Ti layers
It has a laminated structure of Ti / Cu / Ti composed of layers,
The manufacturing method utilizes a vacuum evaporation method or a sputtering method. Subsequently, for example, a polyimide solution is applied to the entire surface of the semiconductor substrate and dried to form a polyimide insulating film 3. Then, after forming the contact holes 31 in the polyimide film 3 by using lithography, the polyimide film 3 serving as an interlayer insulating film is baked. Then on top of this
A second layer wiring 4 such as i / Cu / Ti or Al is formed in the same process as the first layer wiring. At this time, since the second layer wiring 4 is also formed in the contact hole 31, the first layer and the second layer wiring are electrically connected to each other. By repeating this process, further multilayer wirings are connected to each other.

In order to connect an integrated circuit formed in an element region of a semiconductor substrate to an external circuit, a connection formed in a non-element region around the semiconductor substrate and electrically connected to the integrated circuit. Pad electrodes are formed. A bump (protrusion) electrode may be formed on the pad electrode to join a lead connected to an external circuit to the pad electrode. Conventionally, the bump electrode has been formed by electrolytic plating of gold. FIG. 22 and FIG.
FIG. 2 is a cross-sectional view of a manufacturing process of the conventional bump electrode. For example, a plurality of Al pad electrodes 6 are formed in a non-element region around the silicon semiconductor substrate 1 by a sputtering method or the like.
The pad electrode 6 is electrically connected to a semiconductor element such as an integrated circuit formed on the semiconductor substrate 1. Next, an insulating protective film 7 made of SiO ₂ or the like is placed on the semiconductor substrate 1.
The protective film 7 is formed on the entire surface, and an opening is formed in a region where the pad 6 is formed (FIG. 22A).

Next, one or more conductive films 8 required for electrolytic plating are deposited by sputtering or the like so as to cover the exposed pads 6 and the protective film 7 (FIG. 22B). Next, a photosensitive polymer film 9 such as a photoresist having a thickness of about 20 μm is applied on the semiconductor substrate 1, and the polymer film 9 is formed.
Is exposed and developed to open only on the pad electrode 6 where the bump electrode is to be formed (FIG. 22C). After that, electroplating is performed by passing electricity through the conductive film 8 with an energizing pin or the like to form the gold bump electrode 10 (FIG. 23A). On this occasion,
A region where gold plating is not desired, such as the back side of the semiconductor substrate 1, must be covered with an insulator in advance. The unnecessary photosensitive polymer film 9 is removed, and the conductive film 8 other than under the bump electrode 10 is removed by etching using the gold bump electrode 10 as a mask to insulate between the bump electrodes (FIG. 23B).

[0006]

As described above, wiring processing requires processes such as photolithography, etching such as RIE, and photoresist stripping. Similarly, a complicated process is required when forming an opening in the interlayer insulating film necessary for electrically connecting the upper and lower wirings. In addition, when the bump electrode is formed by electrolytic plating, a complicated process is required because a film forming process by sputtering, a lithography process of forming a plating mask using a photoresist, an electrolytic plating process of forming a bump electrode, and the like are required. In order to add these steps to the final step of the wafer process,
There is a risk of lowering the yield and reliability. The present invention has been made under such circumstances, and is easy to manufacture.
Moreover, it is an object of the present invention to provide a method for manufacturing a semiconductor device in which a wiring or a connection electrode for connecting a wiring and another conductive layer is formed by a gas deposition method with a small number of steps. Another object of the present invention is to provide a thin film forming apparatus capable of forming a stable conductive film when forming a conductive film by using a gas deposition method.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, such as a semiconductor substrate or a circuit substrate, in which a conductive material in the form of fine particles is placed in a film forming chamber having a lower pressure than an evaporation chamber in which the fine particles of the conductive material are formed. A conductive film which is guided by an inert gas introduced into the evaporation chamber using the pressure difference between the evaporation chamber and the film formation chamber, and is used as a wiring or a connection electrode for connecting the wiring to another conductive layer. Is formed. Further, an inert gas rectifying means for rectifying the flow of the inert gas is attached to a tip of the means for introducing the inert gas provided in the evaporation chamber.

That is, in the method of manufacturing a semiconductor device according to the present invention, a step of forming a first wiring on a semiconductor substrate or a circuit board; a step of heating and evaporating a metal source; Contacting with an active gas to form fine metal particles; and transporting the fine metal particles onto the semiconductor substrate or circuit board by the inert gas,
A step of selectively forming metal columns by spraying the metal fine particles on the wiring, and a step of forming an interlayer insulating film on the semiconductor substrate or circuit board so that the metal columns are buried,
A step of exposing the tip of the metal pillar by etching the interlayer insulating film; and a step of forming a second wiring on the interlayer insulating film. The step of turning the evaporated metal source into fine metal particles comprises:
It may be performed at a pressure of 0 Torr to 5 atm.
In the step of selectively forming the metal pillar, the metal fine particles may be sprayed onto the first wiring via a nozzle, and the inner diameter of the nozzle may be 50 to 100 μm. In the step of selectively forming the metal pillar, the metal fine particles may be sprayed onto the first wiring via a nozzle, and the length of the nozzle may be 3 to 5 mm.
The gap between the tip of the nozzle and the semiconductor substrate or the circuit board may be 0.3 to 1 mm. The step of selectively forming the metal pillar is performed at 3 Torr.
It may be performed at the following pressure.

Further, the thin film forming apparatus of the present invention comprises a first vacuum chamber, a crucible for heating and evaporating a metal source disposed in the first vacuum chamber, and an inert gas in the first vacuum chamber. Means for introducing, a second vacuum chamber, a substrate disposed in the second vacuum chamber, on which the evaporated metal source is deposited, and a substrate from the first vacuum chamber to the second vacuum chamber. Transport means for transporting the active gas; and means for rectifying the inert gas, which is disposed in the first vacuum chamber and connected to a means for introducing the inert gas into the first vacuum chamber. The means for rectifying the active gas is disposed immediately below the crucible, and changes the direction of the flow of the inert gas derived from the means for introducing the inert gas to the surface of the molten metal of the crucible where the metal source is heated and melted. Coincide with the normal direction of the center point, and It is characterized by rectifying the normal heart point to the axis of symmetry of the flow of the inert gas. Further, the speed of the flow of the rectified inert gas is:
The vapor of the metal source generated from the molten metal surface may be cooled by the inert gas so as to be slower than the flow rate of the fine particles generated. As a means for rectifying the inert gas, a filter attached to an outlet of an inert gas introduction pipe used as a means for introducing the inert gas and having a main surface made of a fibrous substance may be used.

[0010]

The wiring and connection electrodes are easily formed by directly applying fine particles of a conductive material to a substrate such as a semiconductor substrate or a circuit substrate, so that the number of steps for forming these is reduced and the step coverage is reduced. By further changing the angle of the fine particles to the substrate as appropriate, the fine particles can be accurately deposited in a predetermined region. In addition, the flow rate of the inert gas introduced into the evaporating chamber is reduced so as not to disturb the gas flow due to the heat convection in the evaporating chamber by passing the gas through the inert gas rectifying means. As a result, the evaporating chamber is not sucked into the transport pipe. The generation of particles that stay and become coarser is suppressed.

[0011]

First, a semiconductor manufacturing apparatus for forming a conductive film by a gas deposition method used in this embodiment will be described with reference to FIG. The figure shows an evaporation chamber (chamber A) for forming metal fine particles as a first vacuum chamber, and a deposition chamber (chamber B) for depositing metal fine particles on a substrate such as a semiconductor substrate or a circuit substrate as a second vacuum chamber. FIG. 2 is a schematic view including a transfer pipe and a transfer pipe. A crucible 23 is provided in the chamber A, and a metal source 24 such as Au or Sn is contained therein. The crucible 23 made of quartz or the like is heated by a heating device 25, for example, an induction heating device with good controllability, and vaporizes the metal source 24 to form metal fine particles having a particle size of several hundred to several thousand angstroms. Heating device 25
When the metal source 24 is Au, the heating device 25
Heats the sauce to about 1400 ° C. In the case of Sn, the source is heated to about 1200 to 1300 ° C. In addition, Ag, Cu, W, Al, etc. are used as the source. An introduction pipe 26 for inserting an inert gas such as He or Ar is attached to the chamber A, and the inert gas is introduced into the chamber A. The pressure in chamber A is about 100 torr to 5 atm, preferably about 1 torr.
2 atm is appropriate.

A transfer pipe 27 for guiding the metal fine particles to the outside of the chamber is attached to the upper part of the chamber A. The transfer pipe 27 extends into the chamber B. This transfer pipe 2
At the tip of 7, the above-mentioned capillary nozzle 12 is attached. The diameter D of the thin tube nozzle 12 is about 50 to 100 μm, and the D / L may be 10 to 20 or more. Therefore, the length L is about 1 to 2 mm or more. A substrate 1 on which metal fine particles are deposited is placed in the chamber B, and the substrate 1 is heated by a heater 28 such as resistance heating. Further, a vacuum pump 29 is attached to the lower portion of the chamber B so that the pressure in the room can be reduced to several torr. The tip of the capillary nozzle 12 faces the surface of the substrate 1. The metal fine particles 13 accumulate due to the pressure difference between the evaporation chamber and the film forming chamber of this manufacturing apparatus. The diameter of the area of the deposited metal fine particles 13 in contact with the substrate 1 is
Depending on the inner diameter of the capillary nozzle 12, for example, when the inner diameter of the nozzle 12 is 100 μm, it becomes about 80 μm, and when it is 50 μm, it becomes about 30 μm. However, the deposited metal fine particles 13 may have a broad bottom depending on conditions, and may not be suitable for high integration of a semiconductor device. The spread of the skirt is affected by the flight speed of the metal fine particles that have flown out of the nozzle 12 and the distance between the nozzle and the substrate.

The spread of the metal film formed by the fine metal particles will be described with reference to the characteristic diagrams shown in FIGS. FIG. 7 is a characteristic diagram showing the deposition rate of metal fine particles on the substrate and the dependence of the spread of the deposited metal fine particles on the substrate in the case of a nozzle having an inner diameter of 100 μmφ. (Torr), the vertical axis shows the film forming speed (μm / sec) of the metal fine particles and the diameter (μm) of the foot spread of the deposited metal fine particles (the diameter of the portion where the metal film is in contact with the substrate). At this time, the pressure of the evaporation chamber (chamber A) was 2 atm, and 1 torr · l / sec He
Gas is flowing. As shown in the deposition rate-pressure curve C, the deposition rate does not change much even when the pressure in the film formation chamber (chamber B) changes. On the other hand, the skirt spread is
As shown by the pressure curve D, the pressure increases as the pressure in the film forming chamber increases.

This is because the pressure in the evaporating chamber is as high as 2 atm even though the pressure in the film forming chamber is at most about 1 torr, so that even if the pressure in the film forming chamber changes, the deposition rate dependent on the differential pressure has almost no effect. Although it seems unlikely, in the deposition chamber, as the pressure increases, the mean free path of the metal fine particles becomes shorter,
The number of collisions between the residual gas in the film forming chamber and the fine metal particles ejected from the tip of the nozzle increases, and the metal particles are scattered. For example, assuming a case where a bump electrode is formed by metal fine particles on a 100 μm square electrode pad formed on a semiconductor substrate of a semiconductor device, this skirt spread is preferably smaller in diameter than about 100 μm. According to this condition, the pressure in the film forming chamber is 3
What is necessary is just torr or less.

FIG. 8 is a characteristic diagram showing the height of the metal particles deposited on the substrate and the dependence of the spread of the metal particles deposited on the substrate on the gap between the nozzle tip and the substrate. The horizontal axis indicates the gap (mm). ), The vertical axis indicates the deposition height (μm) of the metal fine particles and the diameter (μm) of the foot spread of the deposited metal fine particles. At this time, the differential pressure between the evaporation chamber and the film forming chamber is about 2 atm, and the nozzle is a multi-nozzle type in which a plurality of nozzles are assembled. In this embodiment, the gap is set to about 1 mm or less. However, the smaller the gap is, the smaller the gap is, as shown by the bottom spreading-gap curve F, and the deposition height is 0.3 m, as shown by the deposition height-gap curve E.
Since m is the highest, the distance between the substrate and the nozzle is most preferably about 0.3 mm. If the curve F is extended to the left, it seems that the skirt spread becomes smaller,
Actually, for example, when the value of the gap is smaller than about 0.1 mm, the metal fine particles scatter like a jet jet from a part that is slightly widened due to the conductance, and the skirt spread becomes large. Therefore, 0.3 mm
It is not preferable to make it smaller than the degree.

FIGS. 9 and 10 show the flared diameter (μ).
FIG. 7M is a characteristic diagram showing the dependence of the capillary nozzle length on m), wherein the horizontal axis represents the length of the nozzle (L in FIG. 6) and the vertical axis represents the diameter of the flared portion (μm). Higher integration of the semiconductor device cannot be expected if it spreads beyond the area where the metal fine particles are sprayed.
Also, because the manufacturing process cannot be controlled accurately,
Spread the skirt of deposited metal fine particles with a diameter of 100-150μ
m. For this purpose, as shown in these figures, the length L of the capillary nozzle is 3 to 5 mm.
It is preferable to set the degree. FIG. 9 shows that the nozzle inner diameter is 0.1
mm, and the gap between the nozzle and the substrate is 0.3 mm. In FIG. 10, the nozzle inner diameter is 0.1 mm, and the nozzle / substrate gap is 0.5 mm. As described above, the shape of the deposited film is
It is important that the controllability can be controlled by the inner diameter of the nozzle used and various conditions of gas deposition.

Next, an embodiment in which the manufacturing process can be greatly simplified by using the gas deposition technique will be described. FIG. 1 is a sectional view of a substrate according to a first embodiment of the present invention. The semiconductor device in this embodiment has a multi-chip structure in which a plurality of semiconductor chips are mounted on a circuit board having a multilayer wiring structure. The figure shows a substrate 1 made of AlN or the like used for the circuit substrate. Further, for example, a semiconductor substrate such as silicon may be used as the substrate 1 and the present invention may be applied to the formation of a multilayer wiring thereon. On the AlN circuit board 1 in this embodiment, a first wiring 2 having a predetermined pattern is formed, and an interlayer insulating film 3 is formed so as to cover the first wiring 2. Then, a second wiring 4 is provided on the interlayer insulating film 3. Although not shown, a third, fourth, or higher wiring may be formed on the wiring 4 via the next interlayer insulating film, or a protective insulating film may be formed immediately. As shown in this figure, an Au metal pillar 11 serving as a connection electrode is used to connect the first and second wirings. This connection electrode 11 is embedded in the interlayer insulating film 3 and electrically connects two upper and lower wirings.

Next, a method of manufacturing the semiconductor device will be described with reference to FIGS. First, Ti or T is deposited on the AlN substrate 1 by a vacuum deposition method or a sputtering method.
A barrier metal containing i is continuously deposited at about 1000 Å, Cu is deposited at about 3 μm, and Ni is deposited at about 3000 Å. This laminated Ni / Cu /
Using lithography on the Ti layer, for example, Ni
1, a mixed solution of HNO ₃ and CH ₃ COOH, and Ti and Cu are etched using a mixed solution of H ₂ O ₂ and C ₆ H ₈ O ₇ to form a first metal wiring 2 having a wiring width of 20 to 30 μm. I do. Next, an Au metal pillar 11 having a height of about 20 μm is deposited in a predetermined area of about 30 to 50 μm square on the first wiring 2 (FIG. 2A). Au metal pillar 11 deposited
In this method, Au fine particles 13 having an average particle diameter of about 500 angstroms vaporized in an inert gas into fine particles are sprayed together with He gas from the tip of the capillary nozzle 12 onto this predetermined area to locally deposit Au fine particles. It becomes. This method is called a gas deposition method, and is separated from an evaporation chamber for forming metal fine particles and a film formation chamber for placing a substrate on which a metal film such as a metal column is formed during deposition. ,
The pressure in the film forming chamber where the substrate is placed is lower than the pressure in the evaporation chamber where the metal fine particles are formed, and the metal fine particles are sprayed on the substrate by the pressure difference to form metal columns and the like.

At this time, if the temperature of the substrate is set to, for example, about 200 ° C. or more, the adhesion of the fine metal particles to the wiring surface is improved, and a material having a low contact resistance can be obtained. The diameter of the area of the metal column 11 in contact with the substrate is
For example, the inner diameter of the nozzle 12 is 100 μm.
m is about 80 μm, 50 μm is about 30 μm
become. The distance H from the tip of the nozzle 12 to the surface of the AlN substrate 1 is about 1 mm or less. Then, a polyimide solution having a viscosity of about 20,000 cp was
Drop on top, 500 rpm, 10 seconds and 1500 rpm
After spin rotation for 15 seconds at m, the solidified film was dried and solidified at 150 ° C. for 60 minutes in an N ₂ atmosphere to obtain a polyimide film 3.
(FIG. 2 (b)). Then, the entire surface is etched back with a choline solution to expose the tip of the Au metal pillar 11,
The final solidification is performed at 320 ° C. for 30 minutes to form a polyimide interlayer insulating film 3 having a thickness of about 30 μm (FIG. 2C). A second wiring 4 of a Ni / Cu / Ti laminate is formed on the interlayer insulating film 3.

On top of this, another wiring is formed thereon via an insulating protective film 5 or an interlayer insulating film (FIG. 1).
The metal column 11 made of Au fine particles has small crystal grains and a high specific resistance of about 5 μΩcm. Due to the heat resistance limit of the interlayer insulating film, even if recrystallization and crystal grain coarsening cannot be performed by high-temperature annealing after forming a multilayer wiring, the metal pillars have a height of 20 mm.
The resistance value is 1.4 mΩ when the diameter of the portion contacting with the substrate is approximately 30 μm, which does not affect the characteristics of the semiconductor device. Also, since there is no surface oxidation, A
The contact resistance between the u metal pillar and the second wiring is also small. Further, by etching back the polyimide, the tip of the metal pillar is exposed and planarized, so that the step of providing an opening in the interlayer insulating film can be omitted altogether. Furthermore, screen printing can also be used for forming the wiring thereon.
The combined use of this method further simplifies the process. However, since the upper limit of the firing temperature of the metal paste used for printing is limited to the upper temperature limit of the interlayer insulating film or less, the paste material is restricted.

Next, a second embodiment will be described with reference to FIGS. This is characterized in that the bump electrode formed on the electrode pad formed on the surface of the semiconductor substrate having the element region is formed by the gas deposition method described above. An electrode pad 6 is formed on the semiconductor substrate 1 and further covered with an insulating protective film 7. The electrode pad 6 is exposed from the insulating protective film 7. A photosensitive polymer film (photoresist) 9 having a thickness of about 20 μm is applied on the semiconductor substrate (FIG. 3A). Then, the polymer film is exposed and developed to form an opening 14 only in a portion of the electrode pad 6 where a bump electrode is to be formed.
(B)). Au is heated at a pressure of He gas of about 2 atm in the evaporation chamber A to generate Au fine particles. Next, the pressure of the film forming chamber B in which the semiconductor substrate 1 is placed is set lower than that of the evaporation chamber A. The fine particles 13 are conveyed together with He gas using the pressure difference between the two chambers, and are sprayed by the thin-tube nozzle 12 onto the semiconductor substrate 1 in an atmosphere reduced to several torr or less (see FIG. 6).

When the Au fine particles are sprayed on the semiconductor substrate 1, the capillary nozzle is aligned with the opening 14 shown in FIG.
The Au bump electrode 15 can be formed on the electrode pad 6 in the opening 14 by spraying fine particles from a place where the gap between the nozzle and the tip of the capillary nozzle is about 1 mm (FIG. 4A). Then, if the polymer film 9 used as a mask is removed, the surplus Au fine particles 16 deposited on the polymer film 9 are removed together, and individual bump electrodes 15 are formed (FIG. 4B). . FIG. 5 is a sectional view for explaining another method of this embodiment. In this example, a shielding plate 17 is used. When spraying metal fine particles on the semiconductor substrate 1, a shielding plate 17 having an opening 18 is provided between the semiconductor substrate 1 and the nozzle. The opening 18 is opposed to the electrode pad 6 on the semiconductor substrate 1 (FIG. 5A). When metal fine particles are sprayed on the semiconductor substrate 1 in this state, the bump electrodes 15 are formed on the electrode pads 6.
Is formed. The extra fine particles 16 attached to the shielding plate 17 are removed from the semiconductor substrate 1 together with the shielding plate 17.

The distance h between the shielding plate 17 and the surface of the semiconductor substrate 1 may be about 1/10 or less of the distance H between the nozzle 12 and the surface of the semiconductor substrate 1 shown in FIG. Since the metal fine particles 13 coming out of the nozzle 12 have a large directionality, the shielding plate 17
Even if there is some space below the area, the adhesion area does not spread much, but if the distance h is too large, the shielding plate 17 will not serve as a mask. As a method of fixing the shielding plate between the nozzle and the substrate, there is a method of attaching a support to the shielding plate and fixing the support to the substrate. In this method, the positioning between the shielding plate and the electrode pad and the positioning between the nozzle and the electrode pad must be performed, and there are many difficult operations. On the contrary, there is a method of fixing the shielding plate to the nozzle.
The degree of alignment can be completed. FIG. 16 shows a method of spraying metal fine particles onto a substrate without using a shielding plate. The metal particles 13 are sprayed together with the inert gas molecules 35 toward the nozzle 12 onto the electrode pads 6 exposed from the insulating protective film 7 formed on the surface of the semiconductor substrate 1 such as a silicon semiconductor (see FIG. )). Metal fine particles 13
Is deposited on the electrode pad 6 to become the bump electrode 15, and the inert gas molecules 35 are scattered immediately after leaving the nozzle 12 (FIG. 16B). As shown in FIG. 5, if there is no mask as shown in FIG.
Since the upper bump electrode contacts, the processing becomes complicated thereafter.

Next, with reference to FIG. 6 and FIGS. 11 to 15, a method of embedding metal fine particles on a semiconductor substrate into fine connection holes and fine grooves according to a third embodiment will be described. He gas is introduced into the chamber A through the introduction pipe 26 to make the inside of the chamber A an inert gas atmosphere of about 2 atm. Next, for example, the crucible 23 is heated to about 1400 ° C. by the induction heating device 25 to vaporize Au as the metal source 24. The vaporized Au becomes metal fine particles 13 which are aggregates of metal. On the other hand, the inside of the chamber B in which the semiconductor substrate 1 is installed is set to 0.1 mm by the vacuum pump 29.
The pressure is reduced to about 1 torr. The Au metal fine particles are transported into the chamber B via the transport pipe 27 together with the He gas by a pressure difference between the chamber A and the chamber B. Fine contact holes 31 are formed in the insulating film 3 on the semiconductor substrate 1 (FIG. 11A).
The metal fine particles 13 are directly sprayed from the thin tube nozzle 12 to the contact holes 31 formed in the insulating film 3 on the semiconductor substrate 1 and are deposited therein (FIG. 11B). The flow is rectified together with the He gas in the thin tube nozzle, and the fine particles having a larger mass than the He gas start to deposit from the bottom of the contact hole 31 which is excellent in straightness and is a fine connection hole, and the metal column 11 grows (FIG. 11C). ).

During the growth of the metal columns, metal fine particles are sprayed by changing the spray angle with respect to the semiconductor substrate. FIG. 12 shows that the surface of the table 30 on which the substrate 1 is mounted is inclined with respect to the horizontal direction in the chamber B, and the metal fine particles are sprayed while rotating the table 12 around the nozzle 12 and a line extending vertically therefrom. . In FIG. 13, the nozzle 12 is inclined by an angle θ with respect to the normal direction of the substrate 1 on which the nozzle 12 is placed in the horizontal direction. Further, while rotating the nozzle together with the nozzle 12 while maintaining the angle θ between the nozzle 12 and the axis about the normal O extending vertically upward from the injection point of the metal fine particles on the substrate 1 injected from the nozzle 12, Inject particles. By controlling the injection angle of the fine particles having high linearity in this way, the injected fine metal particles can be deposited on the side wall of the contact hole 31. Note that, as shown in FIG.
7, a heating device 32 such as an electric resistance can be attached. By heating the nozzle or the transfer pipe in this way, the metal fine particles are heated and the adhesion to the substrate 1 is improved.

Although the cross-sectional shape of the tip of the nozzle 12 shown in FIGS. 12 to 14 is substantially circular, FIG. 15 uses the nozzle 12 having a slit-shaped cross-section at the tip. While scanning the nozzle 12 in the direction of the arrow, metal fine particles are sprayed over the entire surface including the groove formed on the substrate 1 and then the deposited film is polished to remove the film deposited other than the groove portion. The wiring pattern 33 is easily formed only inside the contact hole. At this time, if the heating device 34 is attached to the substrate 1 and heated, the adhesion of the metal fine particles is further improved. As described above, when the metal fine particles are used for forming a metal film of a semiconductor device, they are used for forming wiring patterns, forming metal columns used for connection between wirings, or forming bump electrodes and the like serving as signal input / output electrodes of semiconductor elements. Can be easily applied.

In the above embodiment of the present invention, a metal film formed by depositing fine metal particles is mainly used as a semiconductor substrate (semiconductor chip) on which semiconductor elements such as integrated circuits are formed.
The present invention is applied to, for example, the circuit board of a multi-chip type semiconductor device having a circuit board on which a plurality of semiconductor chips are mounted. In addition, by using the gas deposition method of the present invention, it is possible to embed the insulating material by spraying the insulating material into fine particles in an oxidizing gas atmosphere in addition to the conductive metal. An insulating substance may be put in a crucible in an evaporation chamber to form fine particles thereof, and the fine particles may be deposited on a substrate in a film formation chamber. It is also possible to form oxide particles by introducing an oxidizing gas such as oxygen and ozone from a gas line connected in the middle of the transfer pipe during the transfer of the metal fine particles, and to spray the oxide particles on the substrate. If the gas flow is properly designed, the oxidizing gas can be introduced directly into the evaporation chamber. As described above, according to the method of the present invention, the present invention is applicable not only to semiconductor devices but also to other electronic components. As described above, according to the gas deposition method, an inert gas is introduced into an evaporation chamber in which a crucible containing a metal source is arranged, and then the metal source in the crucible is heated and evaporated. The fine particles, which are the secondary agglomerates, are transported together with the inert gas by a pressure difference between the chambers to the reduced film formation chamber, and sprayed onto the substrate in the film formation chamber, whereby the metal source fine particle film can be deposited. In order to evaporate the metal source into fine particles,
An inert gas must be introduced into the evaporation chamber in which the crucible is located, and the evaporated metal source must be cooled by the inert gas. At this time, if the flow rate of the inert gas to be introduced is large,
The smoke (flow) of the fine particles fluctuates.

FIG. 17 is an enlarged sectional view showing the evaporating chamber A of FIG. 6 and illustrating the movement of the evaporated metal source. The inert gas is supplied to the evaporation chamber A by the inert gas introduction pipe 26. If the flow rate of the supplied inert gas is high,
A wobble 37 shown by a dotted line in the flow 36 of the metal fine particles.
Occurs. The wobble 37 occurs in the flow 36 of fine particles because the flow rate of the supplied inert gas is faster than the flow 36 of fine particles moving on the upward flow of the inert gas due to thermal convection. This wobble 37
Occurs regardless of the temperature of the crucible 23. for that reason,
The fine particles that have not been sucked into the transport tube 27 due to the wander are deviated from the transport tube 27 as shown by an arrow 361,
Due to the heat convection in the evaporation chamber A, circulation is performed as shown by an arrow 362, which comes into contact with newly generated fine particles and coarsens. The coarse particles may be sucked into the transfer pipe 27 and supplied to the film forming chamber B, and may be deposited on the substrate.

Next, as a fourth embodiment, a thin film forming apparatus capable of suppressing such fluctuation of the flow of fine particles will be described with reference to FIGS. 18 is a perspective view showing the inside of the evaporation chamber, FIG. 19 is a perspective view of a fine particle film formed from fine particles, and FIG. 20 is a characteristic diagram showing the shear strength of the fine particle film formed on the substrate. As in the first embodiment, the thin film forming apparatus using the deposition method includes an evaporation chamber A, a film formation chamber B in which a substrate on which a fine particle film is formed is disposed, and an introduction pipe for introducing an inert gas into the evaporation chamber A. 26 and a transport pipe 27 for sending fine particles from the evaporation chamber A to the film formation chamber B (see FIG. 6). FIG. 18 shows the inside of the evaporation chamber.
A crucible 23 having an inner diameter of 10 mm is arranged in the evaporation chamber, into which Au as a metal source is put. The crucible 23 is heated by resistance heating or induction heating, and
Evaporates. When the molten Au was heated to a surface temperature of 1400 ° C., H was introduced through the inert gas introduction pipe 26.
When e gas is introduced into the evaporating chamber, the evaporated Au is cooled by He gas, condensed, and has a particle size of several hundreds to several hundreds.
Fine particles 13 of 0 Å are formed.

The evaporating chamber and the film forming chamber B are connected by a transfer pipe 27, He gas is introduced into the evaporating chamber, and the pressure in the evaporating chamber is set to 1 atm. Then, a vacuum pump is connected to the film forming chamber B, and a vacuum is drawn to about 0.3 Torr, whereby H from the evaporation chamber using the pressure difference between the evaporation chamber and the film forming chamber to the film forming chamber is used.
e gas flow is possible. Fine particles 1 formed in the evaporation chamber
3 is formed on the substrate in the film forming chamber B from the nozzle attached to the tip of the transfer tube 27 while riding on the flow of the He gas to form an Au fine particle film, which is a conductive film intended by the present invention. Can be. This embodiment is characterized in that an inert gas straightening means is attached to the tip of an inert gas introduction pipe 26 for supplying He gas to the evaporation chamber. This inert gas rectification means comprises a filter 39. Filter 3
Reference numeral 9 denotes a cylindrical container having an outer diameter of 120 mm and an inner diameter of 60 mm and having a hollow central portion and having a hollow section, and a woven fabric 40 whose upper part is woven with stainless steel fibers. The woven fabric is not limited to stainless steel, but may be glass fiber or other materials. Diameter is 100μ for stainless fiber
m, and the aperture ratio is about 50%. The cylindrical container of the filter 39 is attached to the tip of the inert gas introduction tube 26, and is disposed immediately below the crucible 23 so that the woven fabric 40 of stainless steel fiber faces upward.

The crucible 23 is arranged above the filter 39, and it is advantageous that the center line of the filter 39 coincides with the center line of the crucible 23. A transport pipe 27 is disposed above the crucible 23, and a suction port 38 at the tip thereof is provided.
It faces the crucible 23. It is advantageous that the center line of the crucible 23 coincides with the center line of the transport tube 27. He supplied to the evaporation chamber from the inert gas introduction pipe 26
The gas is introduced into the filter 39 and flows through the woven fabric 40 toward the upper crucible 23. Au of the crucible 23 is
The particles are heated and evaporated, and are cooled to He gas to generate the fine particles 13, sent from the suction port 38 to the transfer pipe 27, and supplied to the film formation chamber B through the transfer pipe 27. This introduction pipe 26
He passes through the filter 39 at about 5 m / sec, but exits the filter 39 at 0.2 m / sec.
Slow down to a degree. When the suction port 38 of the transport pipe 27 is arranged at a position about 50 mm directly above the crucible 23,
Under the above-described fine particle generation conditions in which the temperature of the molten Au surface is increased to 1400 ° C.,
The velocity of the flow of the fine particles due to the thermal convection of the He gas toward the suction port 38 is about 1 m / sec. Therefore, He supplied to the evaporation chamber through the filter 39
Since the flow velocity of the gas is lower than this, the flow of the He gas is not disturbed. In addition, the flow of the fine particles toward the suction port 38 of the transport pipe 27 can maintain high symmetry with respect to the center of the crucible 23.

FIG. 19 (a) shows the shape of the fine particle film (conductive film) on the substrate when using a thin film forming apparatus without the filter when the nozzle has an inner diameter of 100 μm and a length of 30 mm. FIG. 19B shows the shape of the fine particle film (conductive film) on the substrate when the thin film forming apparatus of this embodiment in which a filter is installed is used. As shown in the figure, the fine particle film 11 on the substrate 1 formed using the thin film forming apparatus provided with a filter is formed uniformly without coarse particles adhering thereto. The fine particle film formed by this apparatus eliminates the fluctuation of the smoke of the fine particles in the evaporation chamber, and
Since the gas is rectified, there are almost no coarse particles.
On the other hand, the coarse particles 41 are unnecessarily attached to or contained in the fine particle film 11 on the substrate 1 formed using the thin film forming apparatus without a filter. The smoke of the fine particles in the evaporation chamber of this apparatus fluctuates (for example, once / sec, and the fluctuation width is 0.1 mm / sec.).
2 mm), the fine particles which have not been directly sucked into the transport pipe 27 are convected in the evaporating chamber to be coarsened. The coarse particles are sucked into the transport pipe 27 and are mixed in the deposited fine particle film. In the case of a fine particle film in which coarse particles are mixed, the bonding strength between the fine particle film and the substrate is reduced because the bonding area with the substrate surface is extremely reduced.

FIG. 20 shows the shear strength of the fine particle film (conductive film) formed on the substrate. The vertical axis indicates the shear strength (kg
f / mm ² ), and the horizontal axis represents the fine particle film formed by the thin film forming apparatus without using the filter, and the right axis represents the fine particle film formed by the thin film forming apparatus of this embodiment using the filter. Au melting surface (molten surface) temperature is 1
The measurement was performed on three fine particle films obtained at 400 ° C., 1450 ° C., and 1500 ° C., respectively. The pressure in the evaporation chamber was set to 2 atm.
000 cc of He gas was passed. The average shear strength of the fine particle film formed by the thin film forming apparatus without using a filter is 1 kgf / mm ² (0.05 to 10.2 kgf / m ² ).
m ² ), but the shear strength of the fine particle film formed by the thin film forming apparatus of this example using a filter was 1 on average.
It is greatly improved to 0 kgf / mm ² or more. A
The shear strength of the conductive film obtained on the substrate by u plating is also shown by the dotted line in the figure. As described above, when a filter is used as an inert gas rectifying unit in a thin film forming apparatus, the shear strength of a conductive film formed from metal fine particles can be equal to that of a conductive film formed by Au plating.

In the above embodiment, a filter is used as the inert gas rectifying means. However, a plurality of pipes are bundled with their outlets aligned, and connected to an inert gas inlet pipe. The outlet points in the direction of the crucible above. Also in this method, the flow of the inert gas is rectified. Further, the shape of the filter of the embodiment shown in FIG. 18 is a donut shape, but may be a disk shape in the present invention.

[0035]

As described above, the present invention provides a method for forming a metal film such as a wiring, a connector for connecting the wiring or a bump electrode by spraying a metal fine particle carried by an inert gas onto a substrate. However, a semiconductor device having stable characteristics can be provided by a simple process without requiring a complicated process. Further, the metal film can be selectively formed on the substrate by controlling the injection angle of the metal fine particles without using a mask or a shielding plate. Also,
By rectifying the inert gas introduced into the evaporation chamber, a fine particle film free of coarse particles can be formed, and the adhesion to the substrate is greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a circuit board used in a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the semiconductor device according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a manufacturing process of the semiconductor device according to the second embodiment.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the semiconductor device according to the second embodiment.

FIG. 5 is a sectional view showing the manufacturing process of the semiconductor device according to the second embodiment;

FIG. 6 is a schematic sectional view of a semiconductor manufacturing apparatus according to the present invention.

FIG. 7 is a characteristic diagram showing the deposition rate of metal fine particles used in the semiconductor device according to the present invention and the pressure dependence of the expansion of the tail in the film forming chamber.

FIG. 8 is a characteristic diagram showing the dependence of the deposition height and foot spread of metal fine particles used in the semiconductor device according to the present invention on the gap between the nozzle tip and the substrate.

FIG. 9 is a characteristic diagram showing the nozzle length dependence of the foot spread of metal fine particles used in the semiconductor device according to the present invention.

FIG. 10 is a characteristic diagram showing the nozzle length dependence of the foot spread of metal fine particles used in the semiconductor device according to the present invention.

FIG. 11 is a sectional view showing the manufacturing process of the semiconductor device of the third embodiment.

FIG. 12 is a sectional view of a substrate used in a semiconductor device according to a third embodiment.

FIG. 13 is a sectional view of a substrate used for a semiconductor device according to a third embodiment.

FIG. 14 is a sectional view of a substrate used in a semiconductor device according to a third embodiment;

FIG. 15 is a sectional view of a substrate used in a semiconductor device according to a third embodiment.

FIG. 16 is a cross-sectional view of a substrate and a nozzle used in the semiconductor device of the present invention.

FIG. 17 is a sectional view of an evaporation chamber of the thin film forming apparatus of the present invention.

FIG. 18 is a perspective view of an evaporation chamber of a thin film forming apparatus according to a fourth embodiment.

FIG. 19 is a perspective view of a fine particle film formed by the thin film forming apparatus of the present invention.

FIG. 20 is a characteristic diagram showing a shear strength of a fine particle film formed by the thin film forming apparatus of the present invention.

FIG. 21 is a cross-sectional view of a substrate used for a conventional semiconductor device.

FIG. 22 is a sectional view of a manufacturing process of a conventional semiconductor device.

FIG. 23 is a sectional view showing a manufacturing process of a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (circuit board and semiconductor substrate) 2 1st wiring 3 Interlayer insulating film 4 2nd wiring 5, 7 Insulating protective film 6 Electrode pad 8 Electroplating conductive film 9 Photosensitive polymer film 10 Gold electrode 11 Metal pillar DESCRIPTION OF SYMBOLS 12 Capillary nozzle 13 Metal fine particle 14 Contact hole of photosensitive polymer film 15 Bump electrode 16 Extra metal fine particle 17 Shielding plate 18 Opening of shielding plate 19 Au thin film 20 Bonding wire 21 Bonding agent 23 Crucible 24 Metal source 25, 28, 32, 34 Heating device 26 Inert gas introduction pipe 27 Transfer pipe 29 Vacuum pump 30 Substrate supporting substrate 31 Contact hole of insulating film 33 Wiring pattern 35 Inert gas molecule 36, 361, 362 He gas flow 37 He gas Of the flow of water 38 Suction port of the conveying pipe 39 Filter 40 Stainless steel woven fabric of the filter 41 Coarse particles

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hidemitsu Egawa 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Pref. (56) References JP-A-4-83882 (JP, A) JP-A-2-22102 (JP, A) JP-A-4-251945 (JP, A) JP-A-4-171923 JP-A-61-100950 (JP, A) JP-A-62-85445 (JP, A) JP-A-62-102543 (JP, A) JP-A-6-216258 (JP, A) JP-A-6-169161 (JP, A) JP-A-6-93418 (JP, A) JP-A-6-101026 (JP, A) JP-A-6-65757 (JP, A) JP-A-5-315287 ( JP, A) JP-A-5-132756 (JP, A) JP-A-5-47777 (JP JP-A-4-352387 (JP, A) JP-A-4-130632 (JP, A) JP-A-4-26769 (JP, A) JP-A-2-290095 (JP, A) 2-113553 (JP, A) JP-A-62-291138 (JP, A) JP-A-61-53717 (JP, A) JP-A-61-3431 (JP, A) JP-A-60-235440 (JP, A) A) JP-A-50-64767 (JP, A) JP-A-61-69961 (JP, A) JP-A-1-153553 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) H01L 21/3205 H01L 21/285 H01L 21/60 H01L 21/768

Claims (12)

(57) [Claims] A step of forming a first wiring on a semiconductor substrate or a circuit board; a step of heating and evaporating a metal source; and bringing the evaporated metal source into contact with an inert gas to form metal fine particles. Transferring the metal fine particles onto the semiconductor substrate or circuit substrate by the inert gas, and spraying the metal fine particles on the first wiring to selectively form metal columns; and A step of forming an interlayer insulating film on the circuit board so that the metal pillars are buried; a step of etching the interlayer insulating film to expose a tip portion of the metal pillar; Forming a wiring. 2. The method according to claim 1, wherein the step of forming the evaporated metal source into fine metal particles is performed at a pressure of 100 Torr to 5 atm. 3. The step of selectively forming the metal pillar,
2. The method according to claim 1, wherein the fine metal particles are sprayed onto the first wiring via a nozzle, and the inside diameter of the nozzle is 50 to 100 μm. 3. 4. The step of selectively forming the metal pillar,
3. The method according to claim 1, wherein the metal fine particles are sprayed onto the first wiring via a nozzle, and the length of the nozzle is 3 to 5 mm. 4. 5. The semiconductor device according to claim 2, wherein a gap between a tip of the nozzle and the semiconductor substrate or the circuit substrate is 0.3 to 1 mm. Manufacturing method. 6. The step of selectively forming the metal pillar,
The method according to claim 1, wherein the method is performed at a pressure of 3 Torr or less. 7. A first vacuum chamber; a crucible for heating and evaporating a metal source disposed in the first vacuum chamber; a means for introducing an inert gas into the first vacuum chamber; A vacuum chamber, a substrate disposed in the second vacuum chamber, on which the evaporated metal source is deposited, and a transport unit for transporting an inert gas from the first vacuum chamber to the second vacuum chamber. Means for rectifying the inert gas which is disposed in the first vacuum chamber and which is connected to means for introducing the inert gas into the first vacuum chamber; means for rectifying the inert gas, The direction of the flow of the inert gas, which is disposed directly below the crucible and is derived from the means for introducing the inert gas, coincides with the normal direction of the center point of the molten metal surface of the crucible where the metal source is heated and melted. And the normal of this center point is Thin film forming apparatus characterized by rectifying to the symmetry axis of the scan of the flow. 8. The flow rate of the rectified inert gas is lower than the flow rate of fine particles generated by cooling the vapor of the metal source generated from the molten metal surface by the inert gas. The thin film forming apparatus according to claim 7, wherein: 9. A means for rectifying the inert gas, wherein a space having an obstacle in a gas flow direction of a gas supply pipe used when the inert gas is supplied to the first vacuum chamber. The thin film forming apparatus according to claim 7, wherein the thin film is supplied to the first vacuum chamber through the first vacuum chamber. 10. The method according to claim 10, wherein the inert gas is supplied to the first vacuum chamber from a gap between the metal fibers while the metal fibers are filled in the gas supply pipe as the obstacle. The thin film forming apparatus according to claim 9. 11. The thin film forming apparatus according to claim 9, wherein one end of the gas supply pipe has an annular cylindrical shape. 12. The thin film forming apparatus according to claim 9, wherein the obstacle is a filter whose surface is made of stainless steel fiber.