JP3866012B2 - Electroless plating method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is an electroless plating suitable for use in wiring formation of a semiconductor substrate (including formation of a seed layer and an auxiliary seed layer formed for the purpose of reinforcing the seed layer) and formation of a wiring protective film. It relates to a method and a device.
[0002]
[Prior art]
Conventionally, aluminum or an aluminum alloy has generally been used as a material for forming a wiring circuit on a semiconductor substrate. However, as the degree of integration increases, it is required to use a material having higher conductivity as the wiring material. . For this reason, a method has been proposed in which copper or an alloy thereof is used as a wiring material, and this is plated on a semiconductor substrate to fill a wiring pattern groove formed on the substrate.
[0003]
Various methods such as CVD (Chemical Vapor Deposition) and sputtering are known as a method for filling the wiring pattern groove with copper or an alloy thereof, but when the material of the metal layer is copper or an alloy thereof, that is, In the case of forming a copper wiring, the cost is high in CVD, and in the case of sputtering, there is a disadvantage that embedding is impossible when the aspect is high (the ratio of the depth of the pattern is large). This is because the plating method is most effective.
[0004]
On the other hand, in the electroless plating equipment, each of these processing steps is used instead of the electroless plating equipment that performs electroless plating processing by providing a plurality of units for performing the conventional plating process, the pretreatment process accompanying the plating, and the cleaning process. There has been proposed an electroless plating apparatus that performs this in one unit. FIG. 5 is a diagram showing a schematic configuration of this type of electroless plating apparatus. As shown in the figure, in this electroless plating apparatus, a cover 83 is installed around a semiconductor substrate W placed and fixed on a holding means 81 that is rotationally driven by a motor M, and the semiconductor substrate W is indicated by a dotted line. The plating solution is supplied from the plating tank 87 to the upper center of the semiconductor substrate W by the pump P while being rotated by the motor M at the position, and the plating solution is spread over the entire upper surface of the semiconductor substrate W by the centrifugal force by the rotation. The plating solution dropped from the semiconductor substrate W is returned from the plating solution recovery part 85 of the cover 83 to the plating tank 87 and circulated.
[0005]
On the other hand, the semiconductor substrate W after plating is lowered and rotated to a position indicated by a solid line in the drawing, and by supplying cleaning water from a cleaning water supply means (not shown), the plating solution is washed away from the surface to the cleaning liquid recovery unit 86. Collect and drain.
[0006]
However, the conventional electroless plating apparatus has the following various problems.
(1) Since the plating solution is constantly dripped onto the surface to be plated of the semiconductor substrate, a large amount of the plating solution is circulated and used. In addition, when a large amount of plating solution is circulated and used, a large pump is required, and a liquid temperature maintenance device against the liquid temperature rise due to the heat generated by the pump is required, which not only increases the cost of the device but also increases the size of the device, and thus stores this device. Clean room costs will increase.
[0007]
(2) Since the plating solution is constantly circulated, by-products accumulate in the system due to the principle of electroless plating, and a stable plating process cannot be maintained. Further, in order to obtain a stable plating process, a plating solution analysis and solution adjusting device is required, which causes an increase in device cost and an increase in clean room cost.
[0008]
{Circle around (3)} Since the plating solution is circulated and used in large quantities, particles are likely to be generated from the respective constituent members of the apparatus, and it is necessary to install the filtering device F in the circulation path, resulting in an increase in apparatus cost and clean room cost.
[0009]
(4) When plating is performed while supplying the plating solution to only one place on the surface to be plated, the plating thickness of the portion where the plating solution has been dripped is thinner than the plating thickness of the other portions. Has been confirmed by experiments, and the in-plane uniformity of film thickness deteriorates. This is considered to be because only the portion where the plating solution is dropped is different in the reaction state due to the difference in the flow rate and thickness of the plating solution compared to the other portions.
[0010]
(5) In order to perform electroless plating, it is necessary to maintain the temperature of the reaction surface between the surface to be plated and the plating solution at a predetermined constant temperature, so a large amount of plating solution is optimal for the plating reaction. A procedure for constantly raising the temperature to the temperature is required, resulting in an increase in apparatus cost and an increase in clean room cost, and since the plating solution is always raised in temperature, the deterioration of the plating solution is promoted.
[0011]
{Circle around (6)} Since the semiconductor substrate is always rotated, the temperature drop becomes noticeable due to heat dissipation due to the peripheral speed of the semiconductor substrate, and a stable plating process cannot be obtained.
[0012]
(7) If the plating solution is to be supplied to the surface to be plated by spraying instead of dropping, the temperature control of the plating solution is uncertain and a stable plating process cannot be obtained.
[0013]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and its purpose is to reduce the amount of plating solution used, maintain a stable plating process, reduce the size and cost of the apparatus, and improve the film thickness. It is an object of the present invention to provide an electroless plating method and apparatus capable of achieving uniformity in the inside and preventing deterioration of the plating solution due to temperature rise.
[0014]
[Means for Solving the Problems]
  In order to solve the above problems, the invention described in claim 1The to-be-plated surface of the substrate is faced upward, and a weir member that surrounds the to-be-plated surface is opened on the to-be-plated surface,Supplying an electroless plating solution on the surface to be plated of the substrate, and performing an electroless plating process by holding the electroless plating solution on the surface to be plated for a predetermined timeWhenIs performed continuously. As a result, the surface to be plated can be treated with a small amount of electroless plating solution, a small pump can be used as a supply pump for the electroless plating solution, and the electroless plating equipment can be made compact and a clean room for storing it. Costs can be reduced. Moreover, since the electroless plating solution used is small, the temperature of the electroless plating solution can be easily raised and kept warm.
  The invention described in claim 2 is characterized in that the depth of the electroless plating solution held on the surface to be plated of the substrate is 10 mm or less.
[0015]
  Claim3The invention described in 1 is between the step of supplying the electroless plating treatment liquid and the step of holding the electroless plating treatment solution on the surface to be plated of the substrate for a predetermined time and performing the electroless plating treatment The electroless plating solution supplied on the surface to be plated of the substrateOver the entire surface to be platedA step of contacting the liquid is provided. As the step of bringing the electroless plating solution supplied to a part of the surface of the substrate into contact with the entire surface to be plated, the substrate is moved [ie, for example, the substrate supplied with the electroless plating solution is rotated. , Vibrating, swinging (moving), etc.] and moving the supplied electroless plating solution (scraping using a scraping member, blowing air to the liquid level, etc.) It is.
  The invention described in claim 4 is characterized in that the step of bringing the electroless plating solution into contact with the entire surface to be plated is a step of rotating the substrate for a time of 10 seconds or less.
[0016]
  Claim5According to the invention described in (2), the step of storing the electroless plating treatment liquid on the surface to be plated of the substrate for a predetermined time and holding the electroless plating treatmentAnd plating solutionIs performed in a stationary state. With this configuration, heat radiation due to the peripheral speed of the substrate does not occur as compared with the case where the processing is performed while rotating the substrate, the reaction temperature of each part can be made uniform, and a stable process can be obtained.
[0017]
  Claim6The invention described inInert gas is blown onto the surface to be plated until the electroless plating solution is in contact with the surface to be plated on the substrate.It is characterized by that.
[0019]
  Claim7The holding means for holding the substrate with the surface to be plated facing upward, and the periphery of the surface to be plated of the substrate held by the holding meansA dam member having a seal portion that seals with the upper surface of the substrate in contact with the surface to be plated openAnd saidSurrounded by weir membersAn electroless plating solution supply means for supplying and storing the electroless plating solution on the surface to be plated of the substrate is provided. This electroless plating apparatus can be used by replacing a pretreatment liquid, a catalyst treatment liquid, an electroless plating liquid, and the like as an electroless plating treatment liquid, and a series of electroless plating processes can be performed in a single cell.
[0020]
  Claim8The invention described inThe electroless plating treatment liquid supply means is configured to be installed at an upper portion of the surface to be plated and to distribute and supply the electroless plating treatment liquid.It is characterized by that.
As a result, the processing liquid can be simultaneously supplied substantially uniformly to the entire surface to be plated of the substrate.
[0021]
  Claim9The invention described in item 1 is characterized in that a heating means is provided in the vicinity of the substrate. As the heating means, for example, a back heater for heating the surface to be plated from the lower surface side of the substrate, or a lamp heater for heating from the upper surface side of the substrate is installed.
  The invention described in claim 10 is characterized in that the heating means is installed above the holding means.
  The invention described in claim 11 is characterized in that the electroless plating solution after use is disposable.
  The invention described in claim 12 is characterized in that the electroless plating apparatus has a cooling means for cooling the substrate.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The electroless plating apparatus according to this embodiment is used to form a seed layer or wiring made of a copper layer by performing electroless copper plating on the surface of a semiconductor substrate W, for example. An example of this plating process will be described with reference to FIG.
[0023]
As shown in FIG. 1A, the semiconductor substrate W is made of SiO on the conductive layer 1a of the substrate 1 on which the semiconductor element is formed.₂The contact hole 3 and the wiring groove 4 are formed by lithography / etching technique, the barrier layer 5 made of TiN or the like is further formed thereon, and the seed layer 7 is formed thereon by electroless copper plating. Is formed. The seed layer 7 may be formed in advance by sputtering or the like, and an auxiliary seed layer may be formed on the seed layer 7 by electroless copper plating in order to reinforce it. Then, as shown in FIG. 1B, the surface of the semiconductor substrate W is plated with copper so that the contact holes 3 and the grooves 4 of the semiconductor substrate W are filled with copper, and a copper layer 6 is deposited on the insulating film 2. . Thereafter, the copper layer 6 on the insulating film 2 is removed by chemical mechanical polishing (CMP), and the surface of the copper layer 6 filled in the contact hole 3 and the wiring groove 4 as shown in FIG. The surface of the insulating film 2 is made substantially flush with the surface of the insulating film 2, and a wiring protective film 8 is formed on the exposed metal surface.
[0024]
FIG. 2 is a schematic configuration diagram of an electroless plating apparatus configured using one embodiment of the present invention. As shown in the figure, this electroless plating apparatus has a holding means 11 for holding a semiconductor substrate W as a member to be plated on its upper surface, and a surface to be plated (upper surface) of the semiconductor substrate W held by the holding means 11. A weir member (plating solution holding mechanism) 31 that abuts the peripheral portion and seals the peripheral portion, and a plating solution (electroless plating treatment solution) on the surface to be plated of the semiconductor substrate W whose peripheral portion is sealed by the dam member 31 ) A shower head (electroless plating treatment liquid (dispersion) supply means) 41, a cleaning liquid supply means 51 installed near the upper periphery of the holding means 11 and supplying a cleaning liquid to the surface to be plated of the semiconductor substrate W; A recovery container 61 for recovering the discharged cleaning liquid (plating waste liquid), a plating liquid recovery nozzle 65 for sucking and recovering the plating liquid held on the semiconductor substrate W, and a mode for driving the holding means 11 to rotate. It is constructed (rotation driving means) to and a M. Each member will be described below.
[0025]
The holding means 11 is provided with a substrate mounting portion 13 for mounting and holding the semiconductor substrate W on the upper surface thereof. The substrate placement unit 13 is configured to place and fix the semiconductor substrate W. Specifically, a vacuum suction mechanism (not shown) that vacuum-sucks the semiconductor substrate W to the back side thereof is installed. On the other hand, on the back surface side of the substrate mounting portion 13, a back surface heater (heating means) 15 that is planar and warms the plated surface of the semiconductor substrate W from the lower surface side is installed. The back heater 15 is constituted by a rubber heater, for example. The holding means 11 is rotationally driven by a motor M and is configured to be moved up and down by an elevating means (not shown).
[0026]
The weir member 31 has a cylindrical shape, and a seal portion 33 for sealing the outer peripheral edge of the semiconductor substrate W is provided at the lower portion thereof, and is installed so as not to move up and down from the illustrated position.
[0027]
The shower head 41 has a structure in which the supplied plating solution is dispersed in a shower shape and supplied to the surface to be plated of the semiconductor substrate W substantially uniformly by providing a number of nozzles at the tip. The cleaning liquid supply means 51 has a structure for ejecting the cleaning liquid from the nozzle 53.
[0028]
The plating solution recovery nozzle 65 is configured to be able to move up and down and turn, and its tip is configured to descend to the inside of the weir member 31 on the peripheral surface of the upper surface of the semiconductor substrate W so as to suck the plating solution on the semiconductor substrate W. Has been.
[0029]
Next, the operation of this electroless plating apparatus will be described. First, the holding means 11 is lowered from the state shown in the figure to provide a gap with a predetermined dimension between the weir member 31 and the semiconductor substrate W is placed and fixed on the substrate platform 13. For example, a φ8 inch wafer is used as the semiconductor substrate W.
[0030]
Next, the holding means 11 is raised and its upper surface is brought into contact with the lower surface of the dam member 31 as shown in the figure, and at the same time, the outer periphery of the semiconductor substrate W is sealed by the seal portion 33 of the dam member 31. At this time, the surface of the semiconductor substrate W is in an open state.
[0031]
Next, the semiconductor substrate W itself is directly heated by the back surface heater 15 to, for example, set the temperature of the semiconductor substrate W to 70 ° C. (maintain until the end of plating), and then a plating solution heated to, for example, 50 ° C. is ejected from the shower head 41. Then, the plating solution is poured over substantially the entire surface of the semiconductor substrate W. Since the surface of the semiconductor substrate W is surrounded by the dam member 31, all of the injected plating solution is held on the surface of the semiconductor substrate W. The amount of the plating solution to be supplied may be a small amount so as to be 1 mm thick (about 30 ml) on the surface of the semiconductor substrate W. The depth of the plating solution held on the surface to be plated may be 10 mm or less, and may be 1 mm as in this embodiment. If a small amount of plating solution is supplied as in this embodiment, the heating device for heating the plating solution can be small. In this embodiment, since the temperature of the semiconductor substrate W is heated to 70 ° C. and the temperature of the plating solution is heated to 50 ° C., the surface to be plated of the semiconductor substrate W becomes, for example, 60 ° C. The temperature can be optimized for the reaction. If the semiconductor substrate W itself is heated in this way, the temperature of the plating solution that requires a large amount of power consumption for heating does not have to be raised so high. Therefore, it is possible to prevent the material from changing. The power consumption for heating the semiconductor substrate W itself may be small, and since the amount of the plating solution stored on the semiconductor substrate W is small, the heat of the semiconductor substrate W by the back heater 15 can be easily performed. The capacity is small and the device can be made compact. If means for directly cooling the semiconductor substrate W itself is also used, it is possible to change the plating conditions by switching between heating and cooling during plating. Since the plating solution held on the semiconductor substrate is small, temperature control can be performed with high sensitivity.
[0032]
Then, the semiconductor substrate W is instantaneously rotated by the motor M to uniformly wet the surface to be plated, and then the surface to be plated is plated while the semiconductor substrate W is stationary. Specifically, the semiconductor substrate W is rotated at 100 rpm or less for 1 second so that the surface to be plated of the semiconductor substrate W is uniformly wetted with a plating solution, and then is kept stationary to perform electroless plating for 1 minute. The instantaneous rotation time is at most 10 sec.
[0033]
After the plating process is completed, the tip of the plating solution recovery nozzle 65 is lowered to the vicinity of the inside of the weir member 31 at the peripheral edge of the surface of the semiconductor substrate W, and the plating solution is sucked. At this time, if the semiconductor wafer W is rotated at a rotation speed of, for example, 100 rpm or less, the plating solution remaining on the semiconductor substrate W can be collected in the portion of the dam member 31 at the peripheral edge of the semiconductor substrate W by the centrifugal force. The plating solution can be recovered with good and high recovery rate. Then, the holding means 11 is lowered to separate the semiconductor substrate W from the weir member 31, the rotation of the semiconductor substrate W is started, and the cleaning liquid (ultra pure water) is supplied from the nozzle 53 of the cleaning liquid supply means 51 to the surface to be plated of the semiconductor substrate W. By spraying and cooling the surface to be plated, the electroless plating reaction is stopped by diluting and washing. At this time, the cleaning liquid sprayed from the nozzle 53 may be applied to the weir member 31 to simultaneously clean the weir member 31. The plating waste liquid at this time is collected in the collection container 61 and discarded.
[0034]
The plating solution that has been used once is not reused but is disposable. As described above, since the amount of the plating solution used in this apparatus can be very small as compared with the conventional case, the amount of the plating solution to be discarded is small even without being reused. In some cases, the plating solution recovery nozzle 65 may not be installed, and the used plating solution may be recovered in the recovery container 61 as a plating waste solution together with the cleaning solution.
[0035]
Then, after the semiconductor substrate W is rotated at high speed by the motor M and spin-dried, it is taken out from the holding means 11.
[0036]
FIG. 3 is a schematic configuration diagram of an electroless plating apparatus configured using another embodiment of the present invention. In the figure, the difference from the above embodiment is that a lamp heater (heating means) 17 is installed above the holding means 11 instead of providing the back heater 15 in the holding means 11, and the lamp heater 17 and the shower head 41. -2. That is, for example, a plurality of ring-shaped lamp heaters 17 having different radii are installed concentrically, and a large number of nozzles 43-2 of the shower head 41-2 are opened in a ring shape from the gaps between the lamp heaters 17. The lamp heater 17 may be composed of a single spiral lamp heater, or may be composed of lamp heaters having various other structures and arrangements.
[0037]
Even with this configuration, the plating solution can be supplied almost uniformly in a shower form from the nozzles 43-2 onto the surface to be plated of the semiconductor substrate W, and the heating and heat insulation of the semiconductor substrate W can be directly and uniformly performed by the lamp heater 17. Yes. In the case of the lamp heater 17, in addition to the semiconductor substrate W and the plating solution, the surrounding air is also heated, so that there is an effect of keeping the temperature of the semiconductor substrate W.
[0038]
In order to directly heat the semiconductor substrate W by the lamp heater 17, the lamp heater 17 with relatively high power consumption is required. Instead, the lamp heater 17 with relatively low power consumption and the back surface heater shown in FIG. 15, the semiconductor substrate W may be heated mainly by the back heater 15, and the plating solution and the surrounding air may be kept warm mainly by the lamp heater 17. Similarly to the above-described embodiment, a temperature control may be performed by providing a means for cooling the semiconductor substrate W directly or indirectly.
[0039]
Next, plating was actually performed using the electroless plating apparatus shown in FIG. 2 and the conventional electroless plating apparatus shown in FIG. 5, and the results were compared. The experimental conditions and results are shown below.
[0040]
[Electroless Cu plating sample]
A φ8 inch semiconductor substrate in which a TaN (30 nm) barrier layer and a Cu (50 nm) seed layer (solid film) are formed on silicon.
[0041]
[Plating specifications]
(1) Plating method according to the present invention
Step: The semiconductor substrate W is set on the holding means 11 heated by the back heater 15 (70 ° C.), the weir member 31 is set on the semiconductor substrate W, and then the plating solution (50 ° C.) with the semiconductor substrate W stationary. Is supplied from the shower head 41 by 30 ml for 5 sec. Next, the semiconductor substrate W is rotated for 1 second at 100 rpm, the plating solution is uniformly wetted on the surface of the semiconductor substrate W, and is held for 1 minute in a stationary state. Thereafter, the plating solution is recovered by the plating solution recovery nozzle 65, and then the weir member 31 is separated from the surface of the semiconductor substrate W, and the cleaning solution (ultra pure water) is applied to the surface of the semiconductor substrate W for 30 sec while rotating the semiconductor substrate W (800 rpm). Supply for a while and rinse with water to stop the plating reaction. The supply of the cleaning liquid is stopped, and the semiconductor substrate W is taken out by spin drying (1000 rpm, 30 sec).
[0042]
(2) Conventional plating method
Step: The semiconductor substrate W is set on the holding means 81, and the plating solution at 70 ° C. is continuously dropped onto the center of the semiconductor substrate W for 1 min (600 ml / min) while rotating the semiconductor substrate W at 40 rpm. After the dropping of the plating solution, the cleaning solution (ultra-pure water) is supplied onto the surface of the semiconductor substrate W for 30 seconds while the semiconductor substrate W continues to rotate, and the plating reaction is stopped. Then, the semiconductor substrate W is taken out from the holding means 81 and dried by a separate dryer.
[0043]
FIG. 4 is a diagram showing the results of measuring the film thickness on the X-axis of the semiconductor substrate W electrolessly plated by the above methods. As shown in the figure, the film thickness of the plating method according to the present invention is uniform over the entire semiconductor substrate W, whereas the film thickness at the center of the semiconductor substrate W is extremely thin in the conventional plating method. It was confirmed that the in-plane uniformity of the plating film thickness was improved in each step by the plating method according to the present invention.
[0044]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. For example, the electroless plating apparatus according to the present invention is not limited to the formation of a seed layer or a copper layer for wiring, but can also be used for forming a wiring protective film.
[0045]
Furthermore, the electroless plating apparatus according to the present invention can also be used for a pretreatment step and a catalyst treatment step of electroless plating. That is, for example, in the above embodiment, the electroless plating solution is supplied from the shower head 41 to the surface to be plated of the semiconductor substrate W to perform the electroless plating. However, the electroless plating solution is supplied from the shower head 41 before the electroless plating solution supply step. By supplying other electroless plating solution used for the electroplating pretreatment step and the catalyst treatment step, these treatment steps can be performed in the electroless plating apparatus together with the electroless plating step.
[0046]
In the above-described embodiment, plating is performed in a state where the plating solution is held on the surface to be plated and is stationary, but may be slowly rotated to such an extent that uneven plating does not occur.
[0047]
In addition, the present invention is not limited to the shower head as long as the plating solution can be distributed and supplied to the surface to be plated. For example, a nozzle that supplies the plating solution while performing a swinging operation or a translation operation may be provided.
[0048]
In the above-described embodiment, cleaning is performed by supplying the cleaning liquid in a state in which the holding unit 11 is separated from the dam member 31 in the cleaning step after plating. However, the cleaning liquid is supplied in a state in which the holding unit 11 is not separated from the dam member 31. The cleaning may be performed by overflowing the cleaning liquid from the top of the weir member 31. By supplying the cleaning solution, the plating solution remaining in the interior is diluted, and at the same time, the solution temperature is lowered, whereby the electroless plating reaction is stopped. Instead of lowering the holding means 11, the weir member 31 may be pulled up to separate them.
[0049]
When the semiconductor substrate W is heated by the back heater 15 (especially from the start of heating until the plating solution is contacted), an inert gas such as argon (Ar) is used to prevent oxidation on the surface to be plated of the semiconductor substrate W. It is preferable to blow gas. If a seed layer by sputtering, for example, is exposed on the surface of the semiconductor substrate W, the surface may be oxidized if it is heated. It is particularly effective when used in a case where it is intended to be formed on a layer.
[0050]
In the above embodiment, the back heater 15 and the lamp heater 17 are used as the heating means for the semiconductor substrate W. However, a heater may be installed at another position near the substrate. In addition to using a heater or using a heater, the temperature of the atmosphere in which electroless plating is performed is substantially equal to the electroless plating temperature (temperature suitable for plating the surface to be plated, which is the reaction surface). Heat treatment can be prevented and the processing temperature can be kept constant. In this case, a heated gas may be supplied around the substrate.
[0051]
In the above embodiment, the step of instantaneously rotating the substrate was used as the step of contacting the electroless plating solution supplied onto the surface to be plated of the substrate. Any process may be used as long as the electroless plating solution is in contact with the entire surface to be plated by moving the electroless plating solution. That is, the process of moving the substrate includes, for example, vibrating the substrate supplied with the electroless plating solution, or shaking (moving) the substrate, and the process of moving the supplied electroless plating solution. For example, the electroless plating solution may be scraped and leveled using a leveling member, or may be blown to the liquid level.
[0052]
In the above-described embodiment, an example in which electroless plating is performed on a semiconductor substrate has been shown, but it goes without saying that the present invention can also be applied to the case where electroless plating is performed on various substrates other than the semiconductor substrate.
[0053]
【The invention's effect】
As described in detail above, the present invention has the following excellent effects. (1) Since the surface to be plated is treated by storing and holding the electroless plating solution on the surface to be plated for a predetermined time, the surface to be plated can be treated with a small amount of electroless plating solution, The cost can be reduced, and a small pump can be used as a supply pump for the electroless plating treatment solution, so that the electroless plating apparatus can be made compact and the cost of the clean room for housing it can be reduced. In addition, since the electroless plating solution used is small, the electroless plating solution can be easily heated and kept warm, and there is no need to constantly heat up a large amount of the electroless plating solution. Deterioration of the processing liquid is not promoted.
[0054]
(2) Since the amount of electroless plating solution to be used may be small, it does not increase the cost even if it is discarded as it is, and a new electroless plating solution can always be used and the composition of the treatment solution can be made constant. By-products generated in the case of recycling do not accumulate in the system, and stable plating and other processing can be performed easily, eliminating the need for plating solution analyzers and solutions, reducing equipment costs and clean rooms Cost can be reduced. Further, since the electroless plating solution is not circulated and used in large quantities, it is difficult for particles to be generated from the constituent members of each device, and a filtering device is not required.
[0055]
(3) Since the treatment is performed by holding the electroless plating solution on the surface to be plated, each part of the surface to be plated is treated as compared with the case where the treatment is performed while the electroless plating solution is dropped on the surface to be plated. The conditions can be made the same, and the in-plane uniformity of the formed plating film thickness can be achieved. In particular, when the process is performed while the substrate is stationary, heat is not radiated due to the peripheral speed of the substrate as compared with the case where the process is performed while the substrate is rotated, and the reaction temperature can be made uniform without a temperature drop. A process is obtained.
[0057]
  (Four)If the electroless plating solution supply means is installed at the top of the surface to be plated and dispersed to supply the electroless plating solution, the electroless plating treatment is applied almost uniformly to the entire surface of the substrate to be plated. The solution can be supplied simultaneously, and the temperature control of the electroless plating solution can be performed stably.
[0058]
  (Five)The holding means for holding the substrate and the periphery of the surface to be plated are sealed.Weir memberWhen,Weir membersoSurroundedSince the electroless plating apparatus comprises an electroless plating treatment liquid supply means for supplying and storing the electroless plating treatment liquid on the surface to be plated of the substrate, the pretreatment liquid as the electroless plating treatment liquid, The catalyst treatment solution, electroless plating solution, and the like can be used interchangeably. Therefore, a series of electroless plating steps can be performed in a single cell, and the apparatus can be made compact.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a plating process.
FIG. 2 is a schematic configuration diagram of an electroless plating apparatus configured using an embodiment of the present invention.
FIG. 3 is a schematic configuration diagram of an electroless plating apparatus configured using another embodiment of the present invention.
FIG. 4 is a diagram showing a film thickness measurement result of a semiconductor substrate W electrolessly plated by each method of the present invention and the conventional example.
FIG. 5 is a schematic configuration diagram of a conventional electroless plating apparatus.
[Explanation of symbols]
W Semiconductor substrate (substrate)
11 Holding means (substrate holding means)
13 Substrate placement part
15 Back heater (heating means)
31 Weir member (Plating solution holding mechanism)
33 Sealing part
41 Shower head (electroless plating solution supply means)
51 Cleaning liquid supply means
53 nozzles
61 Collection container
65 Plating solution recovery nozzle
M motor
17 Lamp heater (heating means)
41-2 Shower head
43-2 Nozzle

Claims (12)

The surface to be plated of the substrate faces upward, and the dam member surrounding the surface to be plated is brought into contact with the surface to be plated, and the electroless plating process is performed on the surface to be plated of the substrate surrounded by the dam member electroless that the step of supplying a liquid, and performing the electroless plating treatment liquid was held sump predetermined time on the surface to be plated of the substrate by electroless plating, and performing in succession Plating method. 2. The electroless plating method according to claim 1, wherein the depth of the electroless plating treatment liquid retained on the surface to be plated of the substrate is 10 mm or less. Between the step of supplying the electroless plating solution and the step of storing and holding the electroless plating solution on the surface of the substrate for a predetermined time to perform the electroless plating treatment, 3. The electroless plating method according to claim 1, further comprising a step of bringing the electroless plating solution supplied onto the plating surface into contact with the entire surface to be plated . The electroless plating method according to claim 3, wherein the step of bringing the electroless plating solution into contact with the entire surface to be plated is a step of rotating the substrate for a time of 10 seconds or less. 2. The step of storing and holding the electroless plating solution on the surface to be plated of the substrate for a predetermined time and performing the electroless plating treatment is performed in a state where the substrate and the plating solution are stationary. The electroless plating method according to 2 or 3 or 4 . 6. The electroless plating according to any one of claims 1 to 5, wherein an inert gas is blown onto the surface to be plated before the electroless plating solution is contacted on the surface to be plated of the substrate. Method. Holding means for holding the substrate with the surface to be plated facing upward;
A dam member having a seal portion that seals in a state where the surface to be plated of the substrate is in contact with the upper surface around the surface to be plated of the substrate held by the holding means; and
An electroless plating apparatus comprising: an electroless plating solution supply means for supplying and storing an electroless plating solution on a surface to be plated of the substrate surrounded by the dam member . 8. The electroless plating process according to claim 7, wherein the electroless plating solution supply means is installed on an upper surface of the surface to be plated and dispersed to supply the electroless plating solution. apparatus. The electroless plating apparatus according to claim 7, wherein a heating unit is provided in the vicinity of the substrate. The electroless plating apparatus according to claim 9, wherein the heating unit is installed above the holding unit. The electroless plating apparatus according to any one of claims 7 to 10, wherein the electroless plating solution after use is disposable. The electroless plating apparatus according to any one of claims 7 to 11, wherein the electroless plating apparatus has a cooling means for cooling the substrate.

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