JP2004214508A - Method and apparatus for forming wiring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming wiring which can form wiring uniformly without depending on step coverage of a conductive layer (seed layer) and width of a wiring groove, and to provide an apparatus for the same. <P>SOLUTION: The wiring forming method for forming wiring by burying a wiring material in the wiring groove 4 which is formed in the surface of a substrate W includes a conductive layer removing process for removing from the surface of the substrate W and side faces of the wiring groove 4 the conductive layer 7 between the barrier metal 6 and conductive layer 7, both of which are formed in advance on the surface of the substrate W and in the wiring groove 4; and a metal film forming process for forming a metal film 13 on the conductive layer 7 remaining on the bottom face of the wiring groove 4 after the conductive layer removing process. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for forming a wiring, and more particularly to a method for forming a wiring by embedding a conductive metal such as copper (Cu) in a fine wiring groove or connection hole provided on the surface of a substrate such as a semiconductor wafer. The present invention relates to a method and an apparatus therefor.
[0002]
[Prior art]
In recent years, a trend of using copper (Cu) having low electric resistivity and high electromigration resistance instead of aluminum or aluminum alloy as a wiring material for forming a circuit on a substrate such as a semiconductor wafer has become remarkable. . This copper wiring is generally formed by embedding copper in a fine recess provided on the surface of the substrate. As a method of forming the copper wiring, there are techniques such as chemical vapor deposition (CVD), sputtering, and plating. In any case, copper is formed on almost the entire surface of the substrate to form a chemical film. Unnecessary copper is removed by mechanical polishing (CMP: Chemical Mechanical Polishing).
[0003]
Copper has an electrical resistivity about 40% lower than aluminum, which is advantageous for the signal delay phenomenon, and further has much higher electromigration resistance than aluminum, which is also advantageous in improving the reliability of semiconductor devices. . In addition, since copper as a wiring material can be employed in a dual damascene method of integrally forming a connection hole (via hole) between a wiring and a multilayer wiring, a multilayer wiring structure can be formed at a relatively low cost. Can be.
[0004]
FIGS. 17, 18 and 19 are views showing a manufacturing example of this type of copper wiring board W in the order of steps.
As shown in FIG. 17A, a SiO 2 film is formed on a conductive film 1a of a semiconductor substrate 1 on which a semiconductor element is formed. ₂ And an insulating film 2 made of a low-k material or the like, and a fine concave portion 5 composed of a via hole 3 and a wiring groove (hereinafter referred to as a wiring groove) 4 is formed in the insulating film 2 by lithography and etching technology. A diffusion-suppressing barrier metal (barrier layer) 6 made of Ta, TaN, or the like is formed thereon. Then, as shown in FIG. 17B, a seed layer (conductive layer) 7 of copper or the like to be a power supply layer is formed on the surface of the barrier metal 6 by, for example, sputtering or CVD.
[0005]
Next, as shown in FIG. 17C, copper 8 as a wiring material is filled in the recesses (via holes 3 and wiring grooves 4) 5 of the substrate W by performing copper plating on the surface of the substrate W. Then, copper 8 is also deposited on the seed layer 7. After that, the copper 8, the seed layer 7, and the barrier metal 6 on the insulating film 2 are removed by chemical mechanical polishing (CMP), and the surface of the copper 8 filled in the recess 5 and the surface of the insulating film 2 are removed. Are made substantially coplanar. Thus, a wiring made of copper 8 is formed as shown in FIG.
[0006]
[Problems to be solved by the invention]
Here, when copper 8 is buried by electrolytic plating in minute recesses 5 provided on the surface of substrate W, it is necessary to form seed layer 7 on the surface of barrier metal 6 prior to electrolytic plating. . The purpose of forming the seed layer 7 is to reduce the copper ions in the plating solution by using the seed layer 7 as an electric cathode and to deposit copper 8 as a metal solid on the surface of the seed layer 7. To supply current.
[0007]
Therefore, if the step coverage (step coverage) of the seed layer 7 is not sufficiently good, a difference in the deposition rate of the copper 8 occurs depending on the film thickness of the seed layer 7, which is caused by poor filling of the copper 8 (voids, seams, etc.). Defect), and thus does not function as a wiring of a semiconductor device.
[0008]
In general, a PVD method (Physical Vapor Deposition) or the above-described CVD method is used as a method for forming a seed layer. However, in the case where the seed layer 7 is formed in the wiring groove and the via hole having the wiring rule of 0.13 μm or less and having a large aspect ratio by the PVD method, as shown in FIG. 18A, the step coverage of the seed layer 7 is reduced. Is remarkable. As a result, voids (voids) 10 as shown in FIG. 18B are generated in the copper wiring formed by plating, and the performance of the semiconductor device is reduced.
[0009]
In order to solve such a problem, attempts have been made to form a seed layer directly on a barrier metal by electroless plating instead of PVD. However, this method cannot form a smooth and uniform seed layer, so that when copper is formed by the subsequent electrolytic plating method, defects such as voids and seams are generated. Further, the CVD method has a very high raw material cost and is not yet suitable for practical use.
[0010]
Further, as shown in FIGS. 19A and 19B, copper is isotropically formed by plating, so that the narrow wiring groove 12 is larger than the wide wiring groove 11. The time required for embedding copper 8 is short. Therefore, when the embedding of the copper 8 into the wide wiring groove 11 is completed, excessive copper 8 is deposited on the narrow wiring groove 12 as shown in FIG. 19C. .
[0011]
As described above, when the copper 8 is formed unevenly on the substrate W, it is difficult to sufficiently planarize the surface of the substrate W even if chemical mechanical polishing (CMP) is performed in the next step. That is, as shown in FIG. 19 (d), the excessively deposited copper 8A remains on the substrate W without being sufficiently removed, while the copper 8B in the wide wiring groove portion is excessively removed. Polishing causes so-called dishing. Then, the copper remaining on the substrate W causes a short circuit between the wirings, and there is a problem in that the cross-sectional area of the wiring is reduced in the portion where dishing occurs, and the wiring resistance is increased.
[0012]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a wiring formation method capable of forming wiring with high uniformity without depending on the step coverage of a conductive layer (seed layer) and the width of a wiring groove. And an apparatus therefor.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 is a wiring forming method for forming wiring by embedding a wiring material in a wiring groove formed on a surface of a substrate, the method comprising: A conductive layer removing step of removing the conductive layer from the surface of the substrate and the side surface of the wiring groove among the barrier metal and the conductive layer formed in the wiring groove in advance, and forming a conductive layer on the bottom surface of the wiring groove after the conductive layer removing step. A metal film forming step of forming a metal film on the remaining conductive layer.
[0014]
According to the present invention, after removing the conductive layer, for example, by performing electroless plating, the conductive layer (seed layer) remaining on the bottom surface of the wiring groove is used as a starting point of the reaction to selectively use a metal as a wiring material. It becomes possible to deposit. As a result, even when the side surface of the wiring groove is not sufficiently covered with the conductive layer, it is possible to prevent the occurrence of defects such as voids due to the poor covering. Further, according to the present invention, the metal film can be uniformly formed in the wiring groove regardless of the width of the wiring groove. ) And dishing can be prevented.
[0015]
Here, the effects of the present invention will be described in more detail with reference to FIGS. FIG. 1 is a diagram showing a wiring forming process when the present invention is applied to a single damascene method and FIG. 2 is a dual damascene method. FIG. 3 is a view showing a wiring forming step when a wiring material is embedded in a substrate on which wiring grooves having different widths are formed by using the wiring forming method according to the present invention.
[0016]
In the step of removing the conductive layer (seed layer) 7 formed in advance on the barrier metal 6, not only the conductive layer 7 other than the bottom and side surfaces of the wiring groove 4 is selectively removed but also the step shown in FIG. As shown in FIG. 2B, the conductive layer 7 formed on the side surface of the wiring groove 4 needs to be selectively removed. This is because, when the conductive layer 7 is formed in the wiring groove 4 by using the PVD method, the unevenness of the coverage of the conductive layer 7 becomes remarkable particularly on the side surface of the wiring groove 4. By removing the conductive layer 7 thus formed, it becomes possible to form the metal film 13 in a state where the influence of the nonuniformity of the coverage is reduced (FIGS. 1C and 2C). , FIG. 2 (d)).
[0017]
Also, as shown in FIG. 3A, by using only the conductive layer 7 remaining on the bottom surfaces of the wiring grooves 11 and 12 as a reaction starting point for forming a metal film, even when the width of the wiring grooves is different, each wiring The time required to form the metal film 13 in the grooves 11 and 12 can be made equal. This is because if the metal film does not grow from the side surfaces of the wiring grooves 11 and 12, the time required to fill the metal grooves 13 into the wiring grooves 11 and 12 depends on the width of the wiring grooves 11 and 12. This is because the depth of the wiring groove is not equal to the time required by the metal film forming speed. As described above, according to the present invention, it is possible to prevent a local excessive metal from being formed, and to improve the uniformity of the metal film thickness on the substrate W. As a result, in the subsequent step of removing the metal film 13 and the barrier metal 6 by chemical mechanical polishing or the like, as shown in FIG. .
[0018]
The present invention according to claim 2, further comprising a first heat treatment step of heat treating the substrate after the conductive layer removing step and before the metal film forming step. 1. The wiring forming method according to item 1.
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to remove the residual stress which generate | occur | produced in the conductive layer and the barrier metal in the conductive layer removal process, and also it becomes possible to repair the flaw which arose in the conductive layer and the barrier metal.
[0019]
The invention according to claim 3 is the wiring forming method according to claim 1 or 2, further comprising a second heat treatment step of heat-treating the substrate after the metal film formation step.
According to the present invention, a bonding layer is formed between the metal component of the barrier metal and the metal component of the metal film at the interface between the barrier metal and the metal film by heat-treating the substrate on which the metal film is formed, It is possible to increase the adhesion of the film to the barrier metal. Further, as shown in FIGS. 2C and 2D, voids 10 and seams generated in the wiring (metal film) 8 can be repaired.
[0020]
The invention according to claim 4 further comprises, after the second heat treatment step, a metal film removing step of removing excess metal film and barrier metal from above the substrate. Wiring formation method.
[0021]
The invention according to claim 5 is the wiring forming method according to claim 4, further comprising a third heat treatment step of heat treating the substrate after the metal film removing step.
According to the present invention, the adhesion of the wiring to the barrier metal can be further improved. Further, in addition to such an effect, it is possible to reduce the residual stress of the wiring caused by an external force acting on the substrate during the metal film removing step of selectively removing the excess metal film and the barrier metal. .
[0022]
The present invention according to claim 6 is the wiring forming method according to any one of claims 1 to 5, wherein the conductive layer removing step is chemical mechanical polishing.
According to the present invention, the conductive layer formed on the surface of the substrate (the portion other than the wiring groove) can be removed by the chemical etching action by the chemical species in the polishing liquid and the mechanical polishing action by the polishing cloth. At the same time, the conductive layer formed on the side surface of the wiring groove can be removed by a mechanical polishing action using a polishing cloth.
[0023]
The present invention according to claim 7 is the wiring forming method according to any one of claims 1 to 5, wherein the conductive layer removing step is electrolytic polishing.
Since the speed at which the conductive layer is removed decreases as the distance from the ion exchanger increases, the speed at which the conductive layer is removed at the bottom surface of the wiring groove is smaller than at other portions on the substrate. Therefore, according to the present invention, the conductive layer formed on the surface of the substrate and the side surface of the wiring groove can be selectively removed from the conductive layer formed in advance on the barrier metal. Further, according to the electrolytic polishing, SiO 2 ₂ It is possible to obtain a sufficiently high processing speed without using such abrasive grains, and there is no risk of substrate contamination by the abrasive grains.
As described above, the conductive layer formed on the portion other than the bottom surface of the wiring groove can be selectively removed by using either chemical mechanical polishing or electrolytic polishing.
[0024]
The present invention according to claim 8 is the wiring forming method according to claim 4 or 5, wherein the metal film removing step is electrolytic polishing.
According to a ninth aspect of the present invention, there is provided the wiring forming method according to the fourth or fifth aspect, wherein the metal film removing step is a chemical mechanical polishing.
[0025]
The selective removal of the excess metal film formed on the wiring groove and the barrier metal on the insulating film between the wirings can be performed by one of CMP (chemical mechanical polishing), electrolytic polishing, or a combination thereof. preferable. When this step is performed by, for example, CMP, compared to the conventional damascene method as shown in FIG. 17, since a metal film is hardly formed in a portion other than the wiring groove on the substrate, the polishing liquid used for CMP is used. Can be greatly reduced.
[0026]
The present invention according to claim 10, wherein in the electropolishing, an ion exchanger is disposed on at least one of the conductive layer and a processing electrode or a power supply electrode, and the ion exchanger is brought close to or in contact with the conductive layer. And supplying a fluid to at least one of the conductive layer and the processing electrode or the power supply electrode, and applying a voltage between the power supply electrode and the processing electrode. 7. The wiring forming method according to 7 or 8.
[0027]
Advantageous Effects of Invention According to the present invention, it is possible to perform electropolishing on a substrate by electrochemical action while preventing a physical defect from being given to the substrate and impairing the characteristics of the substrate. The conductive layer formed on the side surface of the substrate can be selectively removed, and further, the deposits attached to the surface of the substrate can be removed (washed).
[0028]
The present invention according to claim 11, wherein the fluid is ultrapure water, pure water, or a liquid or an electrolyte having an electric conductivity of 500 µS / cm or less, wherein the wiring is formed according to claim 10 Is the way.
[0029]
The fluid supplied between the processing electrode and the feeding electrode and the substrate is ultrapure water, pure water, or a surfactant or the like added thereto, and has an electric conductivity of 500 μS / cm or less, preferably 50 μS / cm or less. More preferably, it is a liquid or electrolyte having a concentration of 0.1 μS / cm or less. The reason is that when the electric conductivity is 500 μS / cm or more, the processing speed inside the wiring groove is increased by the chemical etching action, so that it is difficult to selectively leave the conductive layer formed on the bottom surface of the wiring groove. This is because Here, the pure water is, for example, water having an electric conductivity of 10 μS / cm or less, and the ultrapure water is, for example, water having an electric conductivity of 0.1 μS / cm or less.
[0030]
In addition, when performing electropolishing using only pure water or ultrapure water, cleaning after electropolishing is performed by preventing extra impurities such as an electrolyte from adhering or remaining on the surface of the substrate. Not only can the process be simplified, but there is also an advantage that the load of waste liquid treatment can be extremely reduced. Although the object of the present invention can be achieved by electrolytic polishing using an electrolytic solution, if it is desired to leave the conductive layer formed on the bottom surface of the wiring groove without removing as much as possible, the vicinity of the ion exchanger Electropolishing using ultrapure water, which is processed only in, is preferable.
[0031]
According to a twelfth aspect of the present invention, there is provided the wiring forming method according to any one of the first to eleventh aspects, wherein the metal film forming step is electroless plating or electrolytic plating.
Either electroless plating or electrolytic plating can be used to form a metal film to be a wiring isotropically, using the conductive layer left on the bottom of the wiring groove as a starting point of the reaction. Therefore, according to the present invention, it is possible to realize wiring formation in which the time required for embedding the wiring material does not depend on the width of the wiring groove. When electrolytic plating is used, the barrier metal must function as an electrode. Therefore, as the material of the barrier metal, it is preferable to use a conductive metal having a low electric resistivity such as α-tantalum (αTa).
[0032]
The present invention according to claim 13 is the wiring forming method according to claim 2, wherein the first heat treatment step is performed in a reducing atmosphere.
According to a fourteenth aspect of the present invention, there is provided the wiring forming method according to the third or fourth aspect, wherein the second heat treatment step is performed in a reducing atmosphere.
For example, in the case of a barrier metal containing Ta as a metal component, a natural oxide film (Ta _x O _y ) Is formed, and this natural oxide film causes an increase in electric resistance. According to the present invention, by performing the heat treatment of the substrate in a reducing atmosphere, the natural oxide film formed on the surface of the barrier metal during the heat treatment can be easily and reliably reduced.
[0033]
16. The wiring forming apparatus according to claim 15, wherein the wiring material is formed by embedding a wiring material in a wiring groove formed on a surface of the substrate, wherein the barrier metal is formed in advance on the surface of the substrate and the wiring groove. A conductive layer removing device for removing the conductive layer from the surface of the substrate and the side surface of the wiring groove, and a metal film forming device for forming a metal film on the conductive layer remaining on the bottom surface of the wiring groove And a wiring forming apparatus.
[0034]
According to a sixteenth aspect of the present invention, there is provided the wiring forming apparatus according to the fifteenth aspect, further comprising a heat treatment apparatus for heat treating the substrate.
According to a seventeenth aspect of the present invention, there is provided the wiring forming apparatus according to the fifteenth or sixteenth aspect, further comprising a metal film removing device for removing excess metal film and barrier metal from the substrate.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 4 is a plan view showing the overall configuration of the wiring forming apparatus according to the first embodiment of the present invention. In this embodiment, a barrier metal and a conductive layer (seed layer) are formed in this order in advance in the wiring groove of the substrate to be processed and the surface of the substrate. Further, copper (Cu) is used as a wiring material.
[0036]
As shown in FIG. 4, the wiring forming apparatus according to the present embodiment includes an electrolytic polishing apparatus 36 as a conductive layer removing apparatus for removing a conductive layer formed on the surface of a substrate, a cleaning machine 20 for cleaning the substrate, Three electroless plating apparatuses 100 as metal film forming apparatuses for forming a copper film (metal film) on the surface of a substrate, and a metal film removing apparatus for removing excess copper film and barrier metal formed on the surface of the substrate A CMP (chemical mechanical polishing) device 330, two dryers 22, and annealing devices 400A and 400B as heat treatment devices for heat treating the substrate. Further, the wiring forming apparatus according to the present embodiment includes a pair of cassettes 24 for storing substrates, first to third transfer robots 26A, 26B, and 26C for transferring substrates between the devices, and First and second temporary placement tables 28A and 28B for temporarily placing the substrates when transferring the substrates are provided. Hereinafter, each device will be described in order.
[0037]
FIG. 5 is a sectional view of an electrolytic polishing apparatus provided in the wiring forming apparatus according to the present embodiment. FIG. 6 is a plan view showing the electrode plate shown in FIG.
As shown in FIG. 5, the electropolishing apparatus 36 has a swing arm 44 swingable in a horizontal direction, and a vertically extending (face-down) suction holding of the substrate W which is suspended from a free end of the swing arm 44. A substrate holding portion 46, an electrode portion 48 having a processing electrode 50 and a power supply electrode 52, and a power supply 80 for applying a voltage between the processing electrode 50 and the power supply electrode 52.
[0038]
As shown in FIG. 6, the disk-shaped electrode unit 48 includes a plurality of processing electrodes 50 having a fan-like shape and a power supply electrode 52. The processing electrode 50 and the power supply electrode 52 are alternately arranged along the circumferential direction so that the surfaces (upper surfaces) of the processing electrode 50 and the power supply electrode 52 are exposed, and are separated from each other by a rib 48b made of an insulator. I have. As shown in FIG. 5, a film-like ion exchanger 56 that covers the upper surfaces of the processing electrode 50 and the power supply electrode 52 is attached to the upper surface of the electrode unit 48.
[0039]
The ion exchanger 56 is made of, for example, a nonwoven fabric provided with an anion exchange ability or a cation exchange ability. The cation exchanger preferably carries a strongly acidic cation exchange group (sulfonic acid group), but may also carry a weakly acidic cation exchange group (carboxyl group). The anion exchanger preferably carries a strongly basic anion exchange group (quaternary ammonium group), but may also carry a weakly basic anion exchange group (tertiary or lower amino group). Here, examples of the material form of the ion exchanger 56 include a nonwoven fabric, a woven fabric, a sheet, a porous material, and a short fiber.
[0040]
As shown in FIG. 5, the swing arm 44 moves up and down via a ball screw 62 in accordance with driving of a motor 60 for up and down movement. A swing motor 64 is connected to the lower end of the swing shaft 66 of the swing arm 44, and the swing arm 44 swings in the horizontal direction with the drive of the swing motor 64. I have. The substrate holding unit 46 is connected to a rotation motor 68 attached to a free end of the swing arm 44, and the substrate holding unit 46 rotates (rotates) with the rotation of the rotation motor 68. .
[0041]
The electrode section 48 is directly connected to the hollow motor 70, and the electrode section 48 rotates (rotates) with the driving of the hollow motor 70. A liquid supply hole 48a for supplying pure water, more preferably ultrapure water, is provided at the center of the electrode section 48. The liquid supply hole 48a is connected to a liquid supply pipe (not shown) extending inside the hollow portion of the hollow motor 70. Below the hollow motor 70, a power supply 80 for applying a voltage between the processing electrode 50 and the power supply electrode 52 is disposed. The anode and the cathode of the power supply 80 are electrically connected to the power supply electrode 52 and the processing electrode 50 via wires passing through the hollow portion of the hollow motor 70, respectively.
[0042]
After passing through the liquid supply hole 48a, the pure water or ultrapure water is supplied to the entire processing surface through the water-absorbing ion exchanger 56. Alternatively, a plurality of liquid supply holes 48a connected to the liquid supply pipe may be provided so that the liquid (pure water or ultrapure water) can be easily spread over the entire processing surface. Note that a liquid supply unit for supplying pure water or ultrapure water may be further provided above the electrode unit 48. In this case, pure water or ultrapure water can be simultaneously supplied to the surface of the substrate W from above and below the substrate W.
[0043]
Here, the pure water is, for example, water having an electric conductivity of 10 μS / cm or less, and the ultrapure water is, for example, water having an electric conductivity of 0.1 μS / cm or less. Note that a liquid having an electric conductivity of 500 μS / cm or less may be used instead of pure water or ultrapure water. For example, a liquid obtained by adding a surfactant or the like to ultrapure water or pure water and having an electric conductivity of 500 μS / cm or less, preferably 50 μS / cm or less, and more preferably 0.1 μS / cm or less may be used. As described above, by supplying a liquid such as pure water or ultrapure water during processing, processing instability due to a processing product, gas generation, or the like can be removed, and uniform processing with good reproducibility can be obtained.
[0044]
Next, the operation of the electropolishing apparatus 36 configured as described above will be described.
First, the substrate W is sucked and held by the substrate holding unit 46 such that the processing surface faces downward. After moving the substrate holder 46 above the ion exchanger, the substrate holder 46 is lowered to bring the surface of the substrate W into contact with the ion exchanger. In this state, a predetermined voltage is applied between the processing electrode 50 and the power supply electrode 52 by the power supply 80, and the substrate holding unit 46 and the electrode unit 48 are rotated together. At the same time, pure water or ultrapure water is supplied to the upper surface of the electrode portion 48 from below the electrode portion 48 through the liquid supply hole 48a, and pure water or ultrapure water is supplied between the processing electrode 50 and the power supply electrode 52 and the substrate W. Fill with pure water. Thus, the conductive layer (seed layer) formed on the substrate W is electrolytically polished by the hydrogen ions or hydroxide ions generated by the ion exchanger 56. Here, pure water or ultrapure water is caused to flow inside the ion exchanger 56 to generate a large amount of hydrogen ions or hydroxide ions, and this is supplied to the surface of the substrate W to improve the efficiency. Electrolytic polishing can be performed.
[0045]
Since the processing speed, that is, the speed at which the conductive layer is removed, decreases as the distance from the ion exchanger increases, the processing speed at the bottom of the wiring groove becomes lower than at other portions of the substrate. Therefore, of the conductive layers formed in advance on the barrier metal, the conductive layers formed on the side surfaces of the wiring grooves and on the surface of the substrate can be selectively removed (FIGS. 1B and 2B). b), FIG. 3 (b)). Here, the surface of the substrate refers to a portion of the surface of the substrate where no wiring groove is formed, and is a concept including a portion where a barrier metal is formed.
[0046]
Next, the electroless plating apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view illustrating the overall configuration of the electroless plating apparatus according to the present embodiment. FIG. 8 is a cross-sectional view showing the relationship between the plating tank, the substrate holding unit, and the support unit when plating is performed by the electroless plating apparatus shown in FIG. FIG. 9 is an enlarged sectional view showing a vacuum seal material of the electroless plating apparatus shown in FIG.
[0047]
As shown in FIG. 7, in this electroless plating apparatus 100, a substrate (plated material) W such as a semiconductor wafer having a via hole or a wiring groove formed on a surface (plated surface) S faces downward (face down). It has a substrate holding unit 110 for holding by suction. The substrate holder 110 includes a disk-shaped holder 112 and a ring-shaped vacuum seal member 114 attached to an outer peripheral portion of the lower surface of the holder 112. This vacuum seal material 114 is made of an elastic material such as rubber, for example, and has an inner lip portion 114a and an outer lip portion 114b that protrude downward, as shown in detail in FIG. A concave portion 114c having a U-shaped cross section is formed between the inner lip portion 114a and the outer lip portion 114b. Further, the holding body 112 is fixed to a lower end of a rotating shaft 118, and is connected to a rotating motor 116 via the rotating shaft 118. The concave portion 114c of the vacuum seal material 114 communicates with a vacuum path 120 extending inside the holder 112, the rotating shaft 118, and the rotary motor 116, and the vacuum path 120 is connected to a vacuum source (not shown).
[0048]
According to such a configuration, the lower ends of the lip portions 114a and 114b of the vacuum sealing material 114 are pressed against the surface of the substrate W, and the space defined by the concave portion 114c and the surface of the substrate W is evacuated to thereby evacuate the substrate. The substrate W is suction-held by the substrate holding unit 110 in a state where the outer peripheral portion of W is sealed with the vacuum seal material 114. Furthermore, by driving the rotation motor 116 while holding the substrate W on the substrate holding unit 110, the substrate W can be rotated integrally with the substrate holding unit 110.
[0049]
Further, there is provided an inert gas introduction passage 122 extending inside the holding body 112, the rotating shaft 118, and the rotating motor 116 and opening at the lower surface of the holding body 112 surrounded by the vacuum seal material 114. Accordingly, when the substrate W is suction-held while the outer peripheral portion thereof is sealed with the vacuum seal material 114, the area surrounded by the vacuum seal material 114 ₂ An inert gas such as a gas can be introduced. Then, the plating solution that is about to enter the region surrounded by the vacuum seal material 114 is forcibly pushed back by the inert gas, thereby preventing the plating solution from entering the region surrounded by the vacuum seal material 114. This can be more reliably prevented.
[0050]
In this example, as shown in FIG. 9, a heating unit (heater) 124 for heating the substrate W is built in the holder 112. Then, the substrate W is heated by the heating unit 124 so that local temperature unevenness does not occur in the substrate W. Note that the heating unit 14 has a temperature control function, so that the substrate W can be heated to an arbitrary temperature. Then, the substrate W is immersed in a plating solution having a predetermined temperature, and the plating process is performed while the substrate W is heated by the heating unit 124 so as to have the same temperature as the plating solution. It is possible to prevent unevenness in temperature in S and prevent the plating temperature from changing during the plating process.
[0051]
The housing 130 is arranged so as to surround the periphery of the substrate holding part 110, and a ring-shaped support part 132 that protrudes inward and supports the peripheral edge of the substrate W from below is provided at the lower end of the housing 130. Further, an opening 134 through which the substrate W is taken in and out is provided on the peripheral wall of the housing 130. The housing 130 is rotatably connected to an outer peripheral portion of the vertical moving plate 138 via a bearing 140. The vertical moving plate 138 is connected to a cylinder rod 136 a of a reciprocating mechanism 136 attached to the rotary motor 116. As a result, the housing 130 moves up and down relatively with respect to the substrate holding unit 110 in accordance with the operation of the reciprocating mechanism 136, and holds the peripheral edge of the substrate W with the support unit 132 and the vacuum seal material 114. , So as to rotate integrally with the substrate holding unit 110.
[0052]
A plating tank 144 for holding a plating solution 142 is disposed below the housing 130. The plating tank 144 is made of, for example, Teflon (registered trademark) in order to reduce friction with the plating solution 142. A plating chamber 148 for storing the plating solution 142 is formed inside the plating tank 144. A plating solution supply path 146 is provided at the center of the bottom surface 148 a of the plating chamber 148, and the plating solution 142 is supplied to the plating chamber 148 through the plating solution supply path 146. The plating chamber 148 is surrounded by an overflow weir 150, and a plating solution discharge path 152 is provided outside the overflow weir 150. As a result, the plating solution 142 is introduced upward into the plating chamber 148 from the plating solution supply passage 146, overflows the overflow weir 150, and is discharged to the outside from the plating solution discharge passage 152.
[0053]
Here, the region of the bottom surface 148a of the plating chamber 148 facing the substrate W held by the substrate holding unit 110 has, for example, a bosh-shaped streamline, and has a quadratic curved surface that extends outward outward. I have. Thus, in a region having a quadratic curve of the bottom surface 148a, the plating solution 142 smoothly flows as a laminar flow along the bottom surface 148a, and generation of a local vortex in the middle of the flow is prevented. You. Further, a heating section having a shape along the quadratic curved surface of the bottom surface 148a may be buried at a position close to the bottom surface 148a inside the plating tank 144.
[0054]
In the electroless plating apparatus 100 according to this embodiment, the substrate W is inserted into the housing 130 from the opening 134 while the housing 130 is relatively lowered with respect to the substrate holding unit 110 by the reciprocating mechanism 136. The substrate W is placed on the support 132. In this state, the housing 130 is raised by the reciprocating mechanism 136, and the upper surface of the substrate W is pressed against the lower end of the vacuum seal material 114. Then, the space defined by the concave portion 114c of the vacuum seal material 114 and the surface of the substrate W is evacuated to suck and hold the substrate W while the outer peripheral portion of the substrate W is sealed with the vacuum seal material 114. In an area surrounded by the vacuum seal material 114, N ₂ An inert gas such as a gas is introduced. In this state, the substrate W is heated to a constant temperature equal to the temperature of the plating solution 142 introduced into the plating chamber 148 over the entire area by the heating unit 124 built in the substrate holding unit 110.
[0055]
The plating solution 142, which has been heated to a predetermined temperature in advance, is introduced into the plating chamber 148 via the plating solution supply path 146, and overflows from the overflow weir 150. At this time, the temperature of the plating solution 142 introduced into the plating bath 144 is, for example, about 25 to 90 ° C., preferably about 55 to 80 ° C., and the flow rate of the plating solution 22 is, for example, 1 to 30 L / min. It is preferably about 1 to 20 L / min, and more preferably about 1 to 10 L / min.
[0056]
In this state, the substrate W is lowered while rotating at a rotation speed of, for example, about 0 to 100 rpm, preferably about 0 to 50 rpm, more preferably about 0 to 20 rpm, and the substrate W is immersed in the plating solution 142 in the plating chamber 148. Then, as shown in FIG. 8, only the housing 130 is lowered, the support portion 132 is separated from the back surface of the substrate W, and the substrate W is sucked and held only by the substrate holding portion 110. Is subjected to copper plating.
[0057]
At this time, plating is performed in a state in which the support portion 132 that supports the substrate W from below is separated from the substrate W, so that the presence of the ring-shaped support portion 132 protruding downward from the surface (plated surface) S of the substrate W , H generated by electroless plating reaction ₂ The gas or the like is prevented from escaping from the surface (plated surface) S of the substrate W, and ₂ It is possible to improve the separation of the gas or the like from the surface (plated surface) S of the substrate W.
[0058]
In addition, by holding the substrate W by suction while the outer peripheral portion of the upper surface of the substrate W is sealed with the vacuum sealing material 114, it is possible to prevent the plating solution from infiltrating into the upper surface of the substrate W. The area surrounded by the vacuum seal material 114 ₂ By introducing an inert gas such as a gas and forcibly pushing back the plating solution which is going to enter the upper surface of the substrate W from the gap between the vacuum sealing material 114 and the substrate W, with the inert gas. In addition, it is possible to more reliably prevent the plating solution from entering the upper surface of the substrate W.
[0059]
It is preferable that the distance between the substrate W and the support portion 132 in a state where the support portion 132 supporting the substrate W from below is separated from the substrate W is such that the substrate W falls on the support portion 132 when the substrate W falls.
Then, after the plating process for a predetermined time is completed, the housing 130 is raised to support the substrate from below with the support portion 132, and after draining the liquid as necessary, the plating is performed in the reverse operation to the above. Is transported out of the housing 130.
[0060]
Note that, in this example, a ring-shaped support portion 132 is used, but a plurality of claws 160 are arranged outside the substrate W along the circumferential direction as shown in FIG. A step portion 160a may be provided on the upper surface of the extension portion extending in a hook shape toward the lower end of the claw 160, and the support portion 162 may be configured to support the substrate W from below with the step portion 160a. Even in this case, when the support portion 162 is separated from the substrate W during plating, the flow of the plating solution is disturbed with the rotation of the claw 160, and the plating solution contacts the surface (plated surface) S of the substrate W. It is possible to prevent the flow state of the plating solution from changing.
[0061]
FIG. 11 is a cross-sectional view illustrating another configuration example of the electroless plating apparatus 100 according to the present embodiment. This electroless plating apparatus 100 is different from the examples shown in FIGS. 7 to 9 in that a first plating chamber 164 bulging outward as a plating tank 144 for holding an electroless plating solution 142 and a bosh type And a plating chamber 148 composed of a second plating chamber 166 having a secondary curved surface extending outward and having a streamlined shape, and the first plating chamber 164 and the second plating chamber 166. The point is that the first rectifying plate 170 is disposed at the boundary, and the second rectifying plate 172 is disposed inside the second plating chamber 166. The rectifying plates 170 and 172 are for adjusting the flow of the plating solution 142 flowing through the inside of the plating chamber 148, and are formed of, for example, a punch plate having a large number of through holes 170a and 172a therein.
[0062]
For example, when the plating chamber 148 has a large volume, when plating is performed by bringing the surface (plated surface) S of the substrate W into contact with the plating solution 142 in the plating chamber 148, the entire surface S of the substrate W is covered. It is difficult to flow the plating solution 142 uniformly. According to the present embodiment, the rectifying plates 170 and 172 for adjusting the flow of the plating solution 142 are arranged inside the plating chamber 148, and the rectifying plates 170 and 172 reduce the flow of the plating solution 142 before reaching the surface of the substrate W. Thus, even if the volume of the plating chamber is increased, a uniform flow of the plating solution over the entire surface S of the substrate W can be formed.
[0063]
In this example, two rectifying plates 170 and 172 are arranged, and the plating solution 142 flowing inside the plating chamber 148 is rectified twice, so that the plating solution over the entire surface to be plated can be adjusted. Although a uniform flow is formed, it goes without saying that one or three or more sheets may be formed.
[0064]
As the current plates 170, 172, those in which the density and / or the diameter of the through holes 170a, 172a differ depending on the region may be used. For example, the density of the through holes 170a and 172a in the central portion of the rectifying plates 170 and 172 in which the plating solution 142 easily flows in a large amount is made coarser than the peripheral portion, or the diameter of the through holes 170a and 172a is made smaller to reduce the substrate. It is possible to prevent a region where the flow rate of the plating solution is large locally on the surface S of W.
[0065]
Here, an embodiment in which plating is performed using the electroless plating apparatus 100 described above with reference to FIGS. 7 to 11 will be described.
The composition of the plating solution used in this example is as follows.
CuSO ₄ ・ 5H ₂ O 5g / L
EDTA ・ 2Na 14g / L
HCHO (37%) 5mg / L
pH (adjusted with NaOH) 12.5
Additive appropriate amount
Further, the temperature of the plating solution is set to 60 ° C., and various conditions are set so that a plating rate of 100 nm / min is obtained.
In this embodiment, copper (Cu) as a wiring material can be embedded in a wiring groove having a depth of about 1 μm by performing plating for about 10 minutes under the above-described conditions.
[0066]
Next, a CMP (chemical mechanical polishing) apparatus according to the present embodiment will be described with reference to FIG. FIG. 12 is a longitudinal sectional view schematically showing a main part of the CMP apparatus according to the present embodiment.
As shown in FIG. 12, a CMP apparatus 330 includes a polishing table 342 that forms a polishing surface by attaching a polishing cloth (polishing pad) 340 made of hard polyurethane or the like to the upper surface, and a polishing table 342 that forms a polishing surface on the substrate W. And a top ring 344 held toward the 342.
[0067]
When polishing the substrate W using such a CMP apparatus 330, the polishing table 342 and the top ring 344 are respectively rotated, and the polishing liquid is supplied from a polishing liquid supply nozzle 346 provided above the polishing table 342. Is supplied, the substrate W is pressed against the polishing cloth 340 of the polishing table 342 by the top ring 344 at a constant pressure. Then, the substrate W is polished flat and mirror-like by chemical mechanical polishing, which is a combined effect of the chemical polishing action of the chemical species contained in the polishing liquid and the mechanical polishing action of the polishing cloth.
[0068]
When the polishing is continued, abrasive grains and polishing debris adhere to the polishing cloth 340, and the characteristics of the polishing cloth 340 change to deteriorate the polishing performance. A dresser 348 is provided in the CMP apparatus 330 to recover the polishing force. The dresser 348 performs dressing (conditioning) of the polishing pad 340 when, for example, replacing the substrate W to be polished. In this dressing process, the dressing surface of the dresser 348 is pressed against the polishing cloth 340 of the polishing table 342 and is rotated, thereby removing abrasive grains and cutting debris adhering to the polishing surface and flattening the polishing surface. The polishing and dressing are performed, and the polished surface is regenerated.
[0069]
As described above, in the present embodiment, the removal of the conductive layer (seed layer) is performed by the electrolytic polishing device 36, but the conductive layer may be removed by the CMP device 330.
Here, the state of removing the conductive layer formed on the surface of the substrate and the side surface of the wiring groove using the CMP apparatus 330 will be described with reference to FIG. 13A is a cross-sectional view schematically showing a polishing cloth before dressing, FIG. 13B is a cross-sectional view schematically showing a polishing cloth after dressing, and FIG. 13C is formed on a substrate. FIG. 13D is a cross-sectional view schematically illustrating a state where the conductive layer is removed, and FIG. 13D is a cross-sectional view schematically illustrating the substrate after the conductive layer is removed.
[0070]
As shown in FIG. 13A, diamond abrasive grains 350 are fixed to the lower surface of the dresser 348. The shape and size of the diamond abrasive grains 350 are determined based on the depth and width of the wiring groove formed in the substrate. In other words, as shown in FIG. 13C, the unevenness (see FIG. 13B) formed on the polishing pad 340 by dressing is smaller than the depth of the wiring grooves 11 and 12 at the same time. The shape and size of the diamond abrasive grains 350 are determined so that the pitch is not more than the minimum width of the wiring grooves 11 and 12. According to the dresser 348 having such diamond abrasive grains 350, as shown in FIGS. 13C and 13D, the conductive layer 7 other than the bottom surfaces of the wiring grooves 11 and 12 can be removed. Become.
[0071]
In order to facilitate cleaning of the substrate after CMP, SiO ₂ It is preferable to use a polishing liquid containing no abrasive grains. Further, it is preferable to use a polishing cloth having a relatively small elastic modulus (a polishing cloth that is easily deformed). By using a polishing cloth having a relatively small elastic modulus, portions other than the wiring grooves, that is, the substrate surface can be easily removed by the chemical etching action by the chemical species in the polishing liquid and the mechanical polishing action by the polishing cloth. At the same time, the conductive layer on the side surface of the wiring groove can be easily removed by the mechanical polishing action of the polishing cloth.
[0072]
Next, the annealing apparatuses 400A and 400B according to the present embodiment will be described with reference to FIGS. FIG. 14 is a longitudinal sectional view schematically showing the annealing apparatus according to the present embodiment, and FIG. 15 is a transverse sectional view. Since both annealing apparatuses 400A and 400B have the same configuration, only annealing apparatus 400A will be described below.
[0073]
As shown in FIGS. 14 and 15, the annealing apparatus 400A includes a chamber 422 having a gate 420 for taking in and out the substrate W, a hot plate 424 disposed above the chamber 422, and a cool plate disposed below the chamber 422. And a plate 426. The hot plate 424 heats the substrate W to, for example, 400 ° C., and the cool plate 426 cools the substrate W by flowing, for example, cooling water.
[0074]
In the chamber 422, a plurality of elevating pins 428 that extend vertically through the inside of the cool plate 426 and that hold the substrate W thereon are arranged to be able to move up and down. Further, at positions opposed to each other with the hot plate 424 interposed therebetween, a gas introduction pipe 430 for introducing a gas for preventing oxidation between the substrate W and the hot plate 424 at the time of annealing and a gas introduction pipe 430 introduced from the gas introduction pipe 430. A gas exhaust pipe 432 for exhausting gas is provided.
[0075]
As shown in FIG. 15, an annealing apparatus 400A has an N filter having a filter 434a inside. ₂ H having a gas introduction path 436 and a filter 434b inside ₂ Gas introduction path 438 and N ₂ N flowing in the gas introduction passage 436 ₂ Gas and H ₂ H flowing in the gas introduction path 438 ₂ A mixer 440 for mixing the gas and a mixed gas introduction passage 442 through which the gas mixed by the mixer 440 flows are provided. The gas introduction pipe 430 described above is connected to the mixed gas introduction path 442.
[0076]
The substrate W having a wiring material formed on the surface thereof by the above-described electroless plating apparatus is carried into the chamber 422 through the gate 420 and is held by the lifting pins 428. Then, the elevating pins 428 are raised until the distance between the substrate W held by the elevating pins 428 and the hot plate 424 becomes, for example, about 0.1 mm to 1.0 mm. In this state, the substrate W is heated by the hot plate 424 to, for example, 400 ° C., and at the same time, a gas for preventing oxidation is introduced into the chamber 422 from the gas introduction pipe 430. The gas introduced into the chamber 422 flows between the substrate W and the hot plate 424 and is exhausted from the gas exhaust pipe 432. By doing so, annealing (heat treatment) can be performed in a reducing atmosphere, and an oxide film (for example, Ta) formed on the surface of the barrier metal can be formed. _x O _y ) Can be easily and reliably reduced. The processing time of this annealing is, for example, about several tens to 60 seconds. Further, the heating temperature of the substrate W is appropriately selected within a range of 100 to 600 ° C.
[0077]
After the annealing, the lift pins 428 are lowered until the distance between the substrate W held by the lift pins 428 and the cool plate 426 becomes, for example, about 0 mm to 0.5 mm. In this state, by introducing cooling water into the cool plate 426, the substrate W is cooled, for example, for about 10 to 60 seconds until the temperature of the substrate W becomes 100 ° C. or lower. Transport to In the present embodiment, N 2 is used as an antioxidant gas. ₂ Gas and a few% of H ₂ Although a mixed gas that is a mixture of gases is made to flow, ₂ You may make it flow only gas.
[0078]
Next, the operation of the wiring forming apparatus according to the present embodiment configured as described above will be described.
As shown in FIGS. 1A, 2A, and 3A, the substrate processed by the wiring forming apparatus according to the present embodiment includes a barrier metal 6 and a conductive layer on the surface of the substrate W. (Seed layer) 7 is a substrate formed in this order in advance. In the present embodiment, Cu, Cu alloy, Ag, Ag alloy, Au, and Au alloy are preferably used as the conductive layer or the wiring material. By using such a metal, the wiring resistance inside the semiconductor device can be significantly reduced as compared with the conventional aluminum wiring, and the electromigration resistance also improves, thereby improving the performance of the semiconductor device. It is possible to do. In the following example, a case where a copper film (Cu) is formed as a wiring material will be described.
[0079]
First, in FIG. 4, a substrate to be processed is stored in a pair of cassettes 24 in advance. The substrates stored in these cassettes 24 are taken out one by one by a first transfer robot 26A, temporarily placed on a first temporary table 28A, and then transferred to an electropolishing device 36. In the electrolytic polishing device 36, the above-described electrolytic polishing is performed, and the conductive layer 7 formed on the surface of the substrate W and the side surface of the wiring groove is removed (FIGS. 1B, 2B, and 3B). )reference).
[0080]
Next, the substrate W processed by the electrolytic polishing device 36 is transferred to the cleaning machine 20 by the second transfer robot 26B. In the cleaning machine 20, a cleaning liquid such as pure water is supplied to the substrate W, whereby the substrate W is cleaned. The cleaned substrate W is then transported to an annealing device 400A, where an oxide film (for example, Ta) formed on the surface of the barrier metal by an annealing process (heat treatment) in a reducing atmosphere. _x O _y ) Is reduced, and at the same time, defects such as residual stress and scratches generated in the barrier metal and the conductive layer are removed. Thereafter, the substrate W is once placed on the second temporary placement table 28B by the second transfer robot 26B, and then transferred to the electroless plating apparatus 100 by the third transfer robot 26C. In the electroless plating apparatus 100, copper is deposited as a wiring material using the conductive layer 7 remaining on the bottom of the wiring groove as a starting point of the reaction. As described above, since the conductive layer 7 formed on the side surface of the wiring groove is removed by the electrolytic polishing device 36 before plating is performed on the substrate, copper (metal film) is removed from the inside of the wiring groove and the wiring. It is formed only near the upper side of the groove (see FIGS. 1 (c), 2 (c) and 3 (c)).
[0081]
The substrate W on which the copper is formed is transferred to the annealing device 400B by the third transfer robot 26C and the second transfer robot 26B. In the annealing device 400B, the substrate W is subjected to the annealing process (heat treatment) as described above. By this annealing treatment, the adhesion between the copper and the barrier metal 6 can be improved, and as shown in FIGS. 2C and 2D, voids (cavities) generated inside the copper are repaired. can do.
[0082]
Next, the substrate W is once mounted on the second temporary table 28B by the second transfer robot 26B, and then transferred to the CMP apparatus 330. In the CMP apparatus 330, the excess copper and the barrier metal 6 formed on the surface of the insulator are removed, and the surface of the copper filled in the wiring groove and the surface of the insulating film are substantially flush with each other (FIG. 1A ), FIG. 2 (e)).
[0083]
The substrate W that has been processed by the CMP device 330 is transported to the annealing device 400B by the second transport robot 26B, and the substrate W is again annealed by the annealing device 400B. By the third annealing, the adhesion between the copper and the barrier metal can be further enhanced, and the residual stress generated inside the copper by the processing in the CMP apparatus 330 can be reduced.
[0084]
Next, after the substrate W is again cleaned by the cleaning device 20, the substrate W is transported to the dryer 22 by the second transport robot 26B, and spin-dried by the dryer 22 to dry the substrate W. Then, the substrate W is transferred from the dryer 22 to the cassette 24 by the first transfer robot 26A, and the substrate W is stored at the position originally stored in the cassette 24, whereby a series of processing is completed.
[0085]
In this example, the conductive layer formed on the surface of the substrate W and the side surface of the wiring groove is removed by the electrolytic polishing device 36, but the conductive layer is removed by the CMP device 330 instead of the electrolytic polishing device 36. Is also good. Although the removal of excess copper and barrier metal is performed by the CMP device 330, an electrolytic polishing device 36 may be used instead, or the electrolytic polishing device 36 and the CMP device 330 are combined. You may.
[0086]
Next, a wiring forming apparatus according to a second embodiment of the present invention will be described with reference to FIG.
The difference between the above-described first embodiment and the second embodiment is that an electroplating apparatus is used as a metal film forming apparatus instead of the electroless plating apparatus. The other configuration is the same as that of the wiring forming apparatus according to the first embodiment, and thus the description thereof will not be repeated.
[0087]
FIG. 16 is a cross-sectional view schematically showing an electrolytic plating apparatus used in the wiring forming apparatus according to the present embodiment. The electrolytic plating apparatus 370 is for plating a surface of a substrate to form a wiring material such as copper. As shown in FIG. 16, the electrolytic plating apparatus 370 includes a cylindrical plating tank 382 that opens upward and holds a plating solution 380 therein, and a substrate W that is detachably held downward while holding the substrate W detachably. And a substrate holder 384 disposed at a position to close the upper end opening of the 382. Inside the plating tank 382, a flat anode plate 386 which is immersed in a plating solution 380 and serves as an anode electrode is horizontally disposed, and the substrate W serves as a cathode. At the center of the bottom of the plating tank 382, a plating liquid jet tube 388 that forms a jet of the plating liquid upward is connected, and a plating liquid receiver 390 is arranged outside the upper part of the plating tank 382.
[0088]
In the electroplating apparatus 370 having such a configuration, the substrate W is held and disposed downward by the substrate holding portion 384 above the plating tank 382, and a predetermined distance is provided between the anode plate (anode) 386 and the substrate (cathode) W. The plating solution 380 is ejected upward from the plating solution ejection tube 388 while applying the voltage of. As described above, the jet of the plating solution 380 is applied perpendicularly to the lower surface (plated surface) of the substrate W, and a plating current is caused to flow between the anode plate 386 and the substrate W. A film is formed.
[0089]
The basic operation of the wiring forming apparatus according to the present embodiment is the same as the operation of the wiring forming apparatus according to the above-described first embodiment.
In both cases of the first embodiment and the second embodiment, three plating apparatuses as metal film forming apparatuses are provided, and the throughput is improved. In general, since the plating process takes a long time, a vertical type plating apparatus that performs a plating process in a state where the substrates are placed vertically may be employed in order to process a large number of substrates in a small area.
[0090]
【The invention's effect】
As described above, according to the present invention, after the conductive layer is removed, the conductive layer (seed layer) remaining on the bottom surface of the wiring groove is used as a wiring material by performing, for example, electroless plating, using the conductive layer (seed layer) remaining on the bottom surface of the wiring groove as a starting point of the reaction. Can be selectively deposited. As a result, even when the side surface of the wiring groove is not sufficiently covered with the conductive layer, it is possible to prevent the occurrence of defects such as voids due to the poor covering. Further, according to the present invention, the metal film can be uniformly formed in the wiring groove regardless of the width of the wiring groove. ) And dishing can be prevented.
[Brief description of the drawings]
FIG. 1 is a view showing a wiring forming step when a wiring forming method according to the present invention is applied to a single damascene method.
FIG. 2 is a diagram showing a wiring forming step when the wiring forming method according to the present invention is applied to a dual damascene method.
FIG. 3 is a view showing a step of embedding a wiring material in a substrate on which wiring grooves having different widths are formed by using the wiring forming method according to the present invention.
FIG. 4 is a plan view showing the overall configuration of the wiring forming apparatus according to the first embodiment of the present invention.
FIG. 5 is a cross-sectional view of the electropolishing apparatus according to the first embodiment of the present invention.
FIG. 6 is a plan view showing the electrode plate shown in FIG.
FIG. 7 is a cross-sectional view showing the overall configuration of the electroless plating apparatus according to the first embodiment of the present invention.
8 is a cross-sectional view showing a relationship between a plating tank, a substrate holding unit, and a support unit when plating is performed by the electroless plating apparatus shown in FIG.
FIG. 9 is an enlarged sectional view showing a vacuum sealing material of the electroless plating apparatus shown in FIG.
FIG. 10 is a perspective view showing another example of the configuration of the support provided in the electroless plating apparatus according to the first embodiment of the present invention.
FIG. 11 is a sectional view showing another configuration example of the electroless plating apparatus according to the first embodiment of the present invention.
FIG. 12 is a longitudinal sectional view schematically showing a main part of the CMP apparatus according to the first embodiment of the present invention.
13A is a cross-sectional view schematically showing a polishing cloth before dressing, FIG. 13B is a cross-sectional view schematically showing a polishing cloth after dressing, and FIG. 13D is a cross-sectional view schematically showing a state in which the conductive layer formed on the substrate is removed, and FIG. 13D is a cross-sectional view schematically showing the substrate after the conductive layer is removed.
FIG. 14 is a longitudinal sectional view schematically showing an annealing apparatus according to the first embodiment of the present invention.
FIG. 15 is a transverse sectional view of the annealing apparatus shown in FIG.
FIG. 16 is a sectional view schematically showing an electrolytic plating apparatus according to a second embodiment of the present invention.
FIG. 17 is a diagram showing a conventional example of manufacturing a copper wiring board in the order of steps.
FIG. 18 is a diagram showing a conventional example of manufacturing a copper wiring board in the order of steps.
FIG. 19 is a view showing one conventional production example of a copper wiring board in order of steps.
[Explanation of symbols]
1 semiconductor substrate
2 Insulating film
3 beer hall
4,11,12 Wiring groove
5 recess
6 Barrier metal (barrier layer)
7 Conductive layer (seed layer)
8 Copper
10 void
13 Metal film
20 washing machine
22 dryer
24 cassettes
26A, 26B, 26C Transfer robot
28A, 28B temporary table
36 Electropolishing equipment (conductive layer removing equipment)
44 Swing arm
46 PCB holder
48 electrodes
50 Processing electrode
52 feeding electrode
56 ion exchanger
60 Vertical movement motor
62 ball screw
66 Swing axis
68 Motor for rotation
70 Hollow motor
80 power supply
100 Electroless plating equipment (metal film forming equipment)
110 substrate holder
112 Holder
114 Vacuum sealing material
116 rotating motor
118 Rotation axis
120 vacuum path
122 Inert gas introduction path
124 heating unit
130 housing
132 support
134 opening
136 reciprocating mechanism
142 plating solution
144 plating tank
146 Plating solution supply path
148 Plating room
150 Overflow Weir
152 Plating solution discharge path
160 claws
162 support
164 First plating room
166 2nd plating room
170,172 Rectifier plate
330 CMP (Chemical Mechanical Polishing) Equipment
340 polishing cloth (polishing pad)
342 polishing table
344 Top Ring
346 Polishing liquid supply nozzle
348 dresser
350 diamond abrasive
400A, 400B annealing equipment (heat treatment equipment)
420 gate
422 chamber
424 hot plate
426 Cool plate
428 lifting pin
430 gas inlet pipe
432 gas exhaust pipe
434a, 434b Filter
436 N ₂ Gas introduction path
438 H ₂ Gas introduction path
440 mixer
370 Electroplating equipment
380 plating solution
382 Plating tank
384 substrate holder
386 anode plate
388 Plating solution injection tube
390 Plating solution receiver

Claims (17)

A wiring forming method for forming a wiring by embedding a wiring material in a wiring groove formed on a surface of a substrate,
A conductive layer removing step of removing the conductive layer from the surface of the substrate and a side surface of the wiring groove, of the barrier metal and the conductive layer formed in advance on the surface of the substrate and the wiring groove; A metal film forming step of forming a metal film on the conductive layer remaining on the bottom surface of the wiring groove. The method according to claim 1, further comprising a first heat treatment step of heat-treating the substrate after the conductive layer removing step and before the metal film forming step. 3. The method according to claim 1, further comprising a second heat treatment step of heat-treating the substrate after the metal film formation step. 4. The wiring forming method according to claim 3, further comprising a metal film removing step of removing excess metal film and barrier metal from above the substrate after the second heat treatment step. The method according to claim 4, further comprising a third heat treatment step of heat treating the substrate after the metal film removing step. The method according to claim 1, wherein the conductive layer removing step is chemical mechanical polishing. The wiring forming method according to claim 1, wherein the conductive layer removing step is electrolytic polishing. The method according to claim 4, wherein the metal film removing step is electrolytic polishing. 6. The wiring forming method according to claim 4, wherein the metal film removing step is chemical mechanical polishing. In the electrolytic polishing, an ion exchanger is arranged on at least one of the conductive layer and the processing electrode or the power supply electrode,
Bringing the ion exchanger close to or in contact with the conductive layer,
Supply fluid to at least one between the conductive layer and the processing electrode or the power supply electrode,
The method according to claim 7, further comprising a step of applying a voltage between the power supply electrode and the processing electrode. The method of claim 10, wherein the fluid is ultrapure water, pure water, or a liquid or an electrolyte having an electric conductivity of 500 μS / cm or less. The method according to any one of claims 1 to 11, wherein the metal film forming step is electroless plating or electrolytic plating. 3. The method according to claim 2, wherein the first heat treatment is performed in a reducing atmosphere. The method according to claim 3, wherein the second heat treatment is performed in a reducing atmosphere. A wiring forming apparatus for forming wiring by embedding a wiring material in a wiring groove formed on a surface of a substrate,
A conductive layer removing device for removing the conductive layer from the surface of the substrate and the side surface of the wiring groove, of the barrier metal and the conductive layer formed in advance on the surface of the substrate and the wiring groove, and remaining on the bottom surface of the wiring groove; A wiring forming apparatus, comprising: a metal film forming apparatus for forming a metal film on a conductive layer. 16. The wiring forming apparatus according to claim 15, further comprising a heat treatment apparatus for heat treating the substrate. 17. The wiring forming apparatus according to claim 15, further comprising a metal film removing device for removing excess metal film and barrier metal from above the substrate.

Images