Patent Application
20220406605
The various aspects and embodiments described herein pertain generally to a substrate liquid processing method and a substrate liquid processing apparatus.
Patent Document 1 describes a substrate liquid processing apparatus configured to perform electroless plating on a substrate (wafer) by using a processing liquid composed of a plating liquid.
Exemplary embodiments provide a technique enabling to improve uniformity of a plating film within a surface of a substrate in an electroless plating processing.
In an exemplary embodiment, there is provided a substrate liquid processing method of performing a liquid processing on a substrate by supplying a plating liquid onto the substrate. The substrate liquid processing method includes holding the substrate with a substrate holder; supplying the plating liquid onto a top surface of the substrate; covering the substrate with a cover body disposed above the held substrate, the cover body having a ceiling portion; and heating the plating liquid on the substrate by a heating unit provided in either one of at least the cover body and the substrate holder, in a state that the substrate is covered with the cover body. A gas exhausting operation of pushing out a reaction gas staying between the cover body and the substrate by moving either one of at least the cover body and the substrate holder vertically is performed in the heating of the plating liquid.
According to the exemplary embodiment, it is possible to improve the uniformity of the plating film within the surface of the substrate in the electroless plating processing.
Hereinafter, an exemplary embodiment of the present disclosure will be described with reference to the accompanying drawings.
First, referring to
As shown in
The plating unit 2 is configured to perform various processings on the substrate (wafer) W. The processings performed by the plating unit 2 will be described later.
The controller 3 is, for example, a computer, and includes an operation controller and a storage. The operation controller is configured as, for example, a CPU (Central Processing Unit) and configured to control the operation of the plating unit 2 by reading and executing a program stored in the storage. The storage is configured as a storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory) or a hard disk, and stores therein the program for controlling various processings performed in the plating unit 2. Further, the program may be recorded in a computer-readable recording medium 31, or may be installed from the recording medium 31 to the storage. The computer-readable recording medium 31 may be, for example, a hard disc (HD), a flexible disc (FD), a compact disc (CD), a magneto optical disc (MO), or a memory card. The recording medium 31 stores therein a program that, when executed by a computer for controlling an operation of the plating apparatus 1, causes the computer to control the plating apparatus 1 to perform a plating method to be described later.
Referring to
The plating unit 2 is equipped with a carry-in/out station 21; and a processing station 22 provided adjacent to the carry-in/out station 21.
The carry-in/out station 21 includes a placing section 211 and a transfer section 212 provided adjacent to the placing section 211.
In the placing section 211, a plurality of transfer containers (hereinafter, referred to as “carriers C”) each of which accommodates therein a plurality of substrates W horizontally is placed.
The transfer section 212 includes a transfer mechanism 213 and a delivery unit 214. The transfer mechanism 213 includes a holding mechanism configured to hold a substrate W, and is configured to be movable horizontally and vertically and pivotable around a vertical axis.
The processing station 22 includes a plurality of plating devices 5. In the present exemplary embodiment, the number of plating devices 5 provided in the processing station 22 is two or more, but may be one. The plating devices 5 are arranged on both sides of a transfer path 221 which is extended in a predetermined direction (on both sides in a direction perpendicular to a moving direction of a transfer mechanism 222 to be described later).
The transfer path 221 is provided with the transfer mechanism 222. The transfer mechanism 222 includes a holding mechanism configured to hold a substrate W, and is configured to be movable horizontally and vertically and pivotable around a vertical axis.
In the plating unit 2, the transfer mechanism 213 of the carry-in/out station 21 is configured to transfer the substrate W between the carrier C and the delivery unit 214. Specifically, the transfer mechanism 213 takes out the substrate W from the carrier C placed in the placing section 211, and then, places the substrate W in the delivery unit 214. Further, the transfer mechanism 213 takes out the substrate W which is placed in the delivery unit 214 by the transfer mechanism 222 of the processing station 22, and then, accommodates the substrate W in the carrier C of the placing section 211.
In the plating unit 2, the transfer mechanism 222 of the processing station 22 is configured to transfer the substrate W between the delivery unit 214 and the plating device 5 and between the plating device 5 and the delivery unit 214. Specifically, the transfer mechanism 222 takes out the substrate W placed in the delivery unit 214 and carries the substrate W into the plating device 5. Further, the transfer mechanism 222 takes out the substrate W from the plating device 5 and places the substrate W in the delivery unit 214.
Now, a configuration of the plating device 5 will be described with reference to
The plating device 5 is configured to perform a liquid processing including an electroless plating processing. This plating device 5 includes a chamber 51; a substrate holder 52 disposed within the chamber 51 and configured to hold the substrate W horizontally; and a plating liquid supply 53 (processing liquid supply) configured to supply a plating liquid L1 (processing liquid) onto a top surface of the substrate W held by the substrate holder 52. In the present exemplary embodiment, the substrate holder 52 has a chuck member 521 configured to vacuum-attract a bottom surface (rear surface) of the substrate W. This chuck member 521 is of a so-called vacuum chuck type. Without being limited thereto, however, the chuck member 521 may be of a so-called mechanical chuck type configured to grip an edge portion of the substrate W with a chuck mechanism or the like. Furthermore, the substrate holder 52 may be equipped with a substrate holder elevating mechanism (not shown) configured to operate the substrate holder 52 in an up-and-down direction. The substrate holder elevating mechanism may be implemented by a cylinder or an actuator including a motor and a ball screw.
The substrate holder 52 is connected to a rotation motor 523 (rotational driving unit) via a rotation shaft 522. When the rotation motor 523 is driven, the substrate holder 52 is rotated along with the substrate W thereon. The rotation motor 523 is supported at a base 524 fixed to the chamber 51.
As depicted in
The plating liquid L1 is an autocatalytic (reduction) plating liquid for electroless plating. The plating liquid L1 contains a metal ion such as a cobalt (Co) ion, a nickel (Ni) ion, a tungsten (W) ion, a copper (Cu) ion, a palladium (Pd) ion or a gold (Au) ion, and a reducing agent such as hypophosphorous acid or dimethylamine borane. The plating liquid L1 may further contain an additive or the like. A plating film P (metal film, see
The plating device 5 according to the present exemplary embodiment further includes, as other processing liquid supplies, a cleaning liquid supply 54 configured to supply a cleaning liquid L2 onto the top surface of the substrate W held by the substrate holder 52, and a rinse liquid supply 55 configured to supply a rinse liquid L3 onto the top surface of the substrate W.
The cleaning liquid supply 54 is equipped with a cleaning liquid nozzle 541 configured to discharge the cleaning liquid L2 onto the substrate W held by the substrate holder 52, and a cleaning liquid source 542 configured to supply the cleaning liquid L2 to the cleaning liquid nozzle 541. Examples of the cleaning liquid L2 may include an organic acid such as a formic acid, a malic acid, a succinic acid, a citric acid or a malonic acid, or a hydrofluoric acid (DHF) (aqueous solution of hydrogen fluoride) diluted to the extent that it does not corrode a plating target surface of the substrate W. The cleaning liquid nozzle 541 is held by the nozzle arm 56 and configured to be movable along with the plating liquid nozzle 531.
The rinse liquid supply 55 is equipped with a rinse liquid nozzle 551 configured to supply the rinse liquid L3 onto the substrate W held by the substrate holder 52, and a rinse liquid source 552 configured to supply the rinse liquid L3 to the rinse liquid nozzle 551. The rinse liquid nozzle 551 is held by the nozzle arm 56 and configured to be movable along with the plating liquid nozzle 531 and the cleaning liquid nozzle 541. Examples of the rinse liquid L3 may include pure water (deionized water) or the like.
A non-illustrated nozzle moving mechanism is connected to the nozzle arm 56 that holds the plating liquid nozzle 531, the cleaning liquid nozzle 541, and the rinse liquid nozzle 551 described above. This nozzle moving mechanism moves the nozzle arm 56 in a horizontal direction and an up-and-down direction. More specifically, as shown in
A cup 571 is disposed around the substrate holder 52. The cup 571 is formed into a ring shape when viewed from above, and configured to receive the processing liquid scattered from the substrate W when the substrate W is being rotated and configured to guide the received processing liquid to a drain duct 581 to be described later. An atmosphere blocking cover 572 is provided at an outer peripheral side of the cup 571 and configured to suppress diffusion of the ambient atmosphere around the substrate W in the chamber 51. The atmosphere blocking cover 572 is formed into a vertically extending cylindrical shape and has an open top. The cover body 6 to be descried later can be inserted into the atmosphere blocking cover 572 from above.
The drain duct 581 is provided under the cup 571. The drain duct 581 is formed into a ring shape when viewed from above, and serves to drain the processing liquid falling down after being received by the cup 571 and the processing liquid directly falling down from the vicinity of the substrate W. An inner cover 582 is provided at an inner periphery side of the drain duct 581. The inner cover 582 is disposed above the cooling plate 525, and serves to suppress diffusion of the processing liquid and the atmosphere around the substrate W. A guide member 583 configured to guide the processing liquid into the drain duct 581 is provided above an exhaust pipe 81 to be described later. Due to the presence of this guide member 583, the processing liquid falling from above the exhaust pipe 81 is suppressed from entering the exhaust pipe 81, and is received into the drain duct 581.
The substrate W held by the substrate holder 52 is covered by the cover body 6. The cover body 6 has a ceiling portion 61 and a sidewall portion 62 extending downwards from the ceiling portion 61. When the cover body 6 is located at a first gap position or a second gap position to be described later, the ceiling portion 61 is disposed above the substrate W held by the substrate holding unit 52, facing the substrate W with a relatively small gap therebetween.
The ceiling member 61 includes a first ceiling plate 611 and a second ceiling plate 612 provided on the first ceiling plate 611. A heater 63 (heating unit) to be described later is interposed between the first ceiling plate 611 and the second ceiling plate 612. The first ceiling plate 611 and the second ceiling plate 612 are configured to seal the heater 63 such that the heater 63 is not brought into contact with the processing liquid such as the plating liquid L1. More specifically, a seal ring 613 is provided at an outer peripheral side of the heater 63 between the first ceiling plate 611 and the second ceiling plate 612, and the heater 63 is sealed by the seal ring 613. Desirably, the first ceiling plate 611 and the second ceiling plate 612 have corrosion resistance against the processing liquid such as the plating liquid L1, and may be made of, for example, an aluminum alloy. Further, to improve the corrosion resistance, the first ceiling plate 611, the second ceiling plate 612 and the sidewall member 62 may be coated with Teflon (registered trademark).
The cover body 6 is connected to a cover body moving mechanism 7 via a cover body arm 71. The cover body moving mechanism 7 is configured to move the cover body 6 horizontally and vertically. More specifically, the cover body moving mechanism 7 is equipped with a rotation motor 72 configured to move the cover body 6 horizontally and a cylinder 73 (gap adjusting unit) configured to move the cover body 6 vertically. The rotation motor 72 is provided on a supporting plate 74 configured to be movable up and down with respect to the cylinder 73. Here, instead of the cylinder 73, an actuator (not shown) including a motor and a ball screw may be used.
As depicted in
As shown in
At the first gap position, the gap between the substrate W and the first ceiling plate 611 becomes a first gap g1 (see
At the second gap position, the gap between the substrate W and the first ceiling plate 611 becomes a second gap g2 (see
At the upper position, the gap between the substrate W and the first ceiling plate 611 becomes larger than the second gap g2, and the cover body 6 is located at a position above the second gap position. That is, the upper position is set to be a height position where the cover body 6 can be suppressed from interfering with an ambient structure such as the cup 571 or the atmosphere blocking cover 572 when the cover body 6 is rotated horizontally.
The cover body 6 is configured to be moved between the first gap position, the second gap position, and the upper position by the cylinder 73. That is, the cylinder 73 is configured to be capable of adjusting the gap between the substrate W and the first ceiling plate 611 to the first gap g1 or the second gap g2.
As shown in
As depicted in
The ceiling member 61 and the sidewall member 62 of the cover body 6 are covered by a cover body cover 64. The cover body cover 64 is provided on the second ceiling plate 612 of the cover body 6 with supporting members 65 therebetween. That is, a plurality of supporting members 65 protruded upwards from an upper surface of the second ceiling plate 612 is provided on the second ceiling plate 612, and the cover body cover 64 is placed on these supporting members 65. The cover body cover 64 is configured to be movable horizontally and vertically along with the cover body 6. Further, it is desirable that the cover body cover 64 has higher thermal insulation property than the ceiling member 61 and the sidewall member 62 to suppress a leakage of the heat within the cover body 6 to the vicinity thereof. For example, desirably, the cover body cover 64 may be made of a resin material. More desirably, the resin material has thermal resistance.
As shown in
In the present exemplary embodiment, a supply amount of the gas from the fan filter unit 59 when the plating liquid L1 on the substrate W is heated by the heater 63 is set to be smaller than a supply amount of the gas from the fan filter unit 59 when the plating liquid L1 is supplied onto the substrate W. More specifically, when the cover body 6 is located at the first gap position, a supply amount of the air from the fan filter unit 59 is set to be smaller than a supply amount of the air when the cover body 6 is located at the retreat position or the upper position.
The gas supplied from the fan filter unit 59 is exhausted by a gas exhaust mechanism 8. As illustrated in
Now, an operation of the present exemplary embodiment having the above-described configuration will be explained with reference to
The plating method performed by the plating apparatus 1 includes a plating processing on the substrate W. The plating processing is performed by the plating device 5. An operation of the plating device 5 to be described below is controlled by a control signal from the controller 3.
[Substrate Holding Process]
First, the substrate W is carried into the plating device 5, and the carried-into substrate W is held by the substrate holder 52, as illustrated in
[Substrate Cleaning Process]
Then, the substrate W held by the substrate holder 52 is subjected to a cleaning processing (process S2). In this case, the rotation motor 523 is first driven to rotate the substrate W at a preset rotational speed. Subsequently, the nozzle arm 56 located at the retreat position (the position indicated by the solid line in
[Substrate Rinsing Process]
Thereafter, the cleaned substrate W is subjected to a rinsing processing (process S3). In this case, the rinse liquid L3 is supplied from the rinse liquid nozzle 551 onto the substrate W being rotated, so that the front surface of the substrate W is rinsed. Thus, the cleaning liquid L2 remaining on the substrate W is washed away. The rinse liquid L3 supplied onto the substrate W is drained into the drain duct 581.
[Plating Liquid Accumulating Process]
Subsequently, as a plating liquid accumulating process, the plating liquid L1 is supplied onto to be accumulated on the rinsed substrate W (process S4). In this case, the rotational speed of the substrate W is reduced to be smaller than the rotational speed of the substrate W in the rinsing process. By way of example, the rotational speed of the substrate W may be set to be in the range from 50 rpm to 150 rpm. Accordingly, the plating film P to be described later, which is formed on the substrate W, can be uniformed. Further, in order to increase the accumulation amount of the plating liquid L1, the rotation of the substrate W may be stopped.
Then, as depicted in
Then, the nozzle arm 56 located at the discharge position is moved to the retreat position.
[Plating Liquid Heating Process]
Next, as a plating liquid heating process, the plating liquid L1 accumulated on the substrate W is heated. This plating liquid heating process includes a covering process of covering the substrate W with the cover body 6 (process S5), and a heating process of heating the plating liquid L1 while setting the gap between the substrate W and the first ceiling plate 611 to the first gap g1 (process S6). Further, it is desirable to maintain the rotational speed of the substrate W in the heating process equal to the rotational speed in the plating liquid accumulating process (or equal to stop the rotation of the substrate W). Further, as for the rotational speed of the substrate W in the heating process, the stop of the rotation and rotation at a low speed (for example, 20 rpm) may be repeated. Accordingly, the plating liquid L1 is agitated, so that the plating film P can be formed more uniformly.
<Covering Process of Covering Substrate with Cover Body>
First, the substrate W is covered with the cover body 6 (process S5). In this case, the rotation motor 72 of the cover body moving mechanism 7 is first driven, so that the cover body 6 located at the retreat position (the position indicated by the solid line in
Then, as shown in
To elaborate, as shown in
<Heating Process>
Subsequently, the plating liquid L1 accumulated on the substrate W is heated (process S6). The heating of the plating liquid L1 is performed for a predetermined time period which is set to allow the temperature of the plating liquid L1 to reach a preset temperature. If the temperature of the plating liquid L1 is raised up to a temperature where a component of the plating liquid L1 is precipitated, the component of the plating liquid L1 is precipitated on the top surface of the substrate W, so that the plating film P begins to be formed.
Meanwhile, in this heating process, a reaction gas (hydrogen or the like) is generated from the plating liquid L1 with the growth of the plating film.
The reaction gas generated from the plating liquid L1 stays gradually between the substrate W and the cover body 6, so a concentration of the reaction gas in the central portion of the substrate W increases in the surface of the substrate W. In the surface of the substrate W, if the concentration of the reaction gas in the plating liquid L1 W increases in the central portion of the substrate, the precipitation of the plating component is accelerated thereat, so that the plating film on the central portion of the substrate W becomes thick, whereas the plating film on the outer periphery of the substrate W becomes thin. As a result, the plating film is formed on the substrate W in a non-uniform manner.
However, according to the plating device 5 of the present exemplary embodiment to be described below, a gas exhausting operation is performed in the heating process. The gas exhausting operation is an operation of pushing out the reaction gas staying between the cover body 6 and the substrate W by vertically moving either one of at least the cover body moving mechanism 7 configured to move the cover body 6 and the substrate holder elevating mechanism (not shown) configured to move the substrate holder 52 up and down.
In the heating process, by vertically moving either one of at least the cover body moving mechanism 7 and the substrate holder elevating mechanism, the concentration of the reaction gas staying between the substrate W and the cover body 6 can be dispersed. Accordingly, the increase of the concentration of the reaction gas in the central portion of the substrate W can be suppressed.
Thus, in the surface of the substrate W, the precipitation of the plating component can be performed uniformly, so that the plating film can be formed in the uniform manner.
Here, the gas exhausting operation will be described in detail. In the gas exhausting operation, the cylinder 73 of the cover body moving mechanism 7 is moved from the state in which the cover body 6 is located at the first gap position g1, as shown in
In this way, by moving the cover body 6 up and down, the reaction gas staying between the substrate W and the cover body 6 is dispersed, so that the increase of the concentration of the reaction gas in the central portion of the substrate W can be suppressed. Therefore, in the surface of the substrate W, the precipitation of the plating component can be performed uniformly, and the uniform plating film can be formed.
Further, the gas exhausting operation may be performed multiple times in the process of heating the plating liquid L1 on the substrate W. The uniformity of the plating film on the substrate W can be improved by increasing the repetition number of the gas exhausting operation based on a characteristic of the plating liquid L1 or a required thickness of the plating film.
In addition, the gas exhausting operation may be performed such that the substrate W is not exposed between the bottom surface of the ceiling portion 61 and the lower end 621 of the sidewall portion 62. Accordingly, the exposure of the front surface of the substrate W to the atmosphere outside the cover body 6 can be suppressed, so that the plating film on the substrate W can be suppressed from being oxidized.
<Cover Body Retreating Process>
Upon the completion of the heating process, the cover body moving mechanism 7 is driven to locate the cover body 6 at the retreat position (process S7). In this case, the cylinder 73 of the cover body moving mechanism 7 is first driven to raise the cover body 6 located at the second gap position to the upper position. Then, the rotation motor 72 of the cover body moving mechanism 7 is driven, allowing the cover body 6 located at the upper position to be revolved horizontally and located at the retreat position.
When the cover body 6 is raised from the first gap position, the supply amount of the air from the fan filter unit 59 is increased to be returned to the supply amount of the air in the plating liquid accumulating process (process S4). Accordingly, the flow rate of the air flowing around the substrate W is increased, so that the gas vaporized from the plating liquid L1 can be suppressed from rising and diffusing.
In this way, the plating liquid heating process (processes S5 and S6) for the substrate W is completed.
[Substrate Rinsing Process]
Subsequently, the substrate after being subjected to the plating liquid heating process is rinsed (process S8). In this case, the rotational speed of the substrate W is first increased to be higher than the rotational speed in the plating processing. By way of example, the substrate W is rotated at the same rotational speed as that in the substrate rinsing process (process S3) prior to the plating processing. Next, the rinse liquid nozzle 551 positioned at the retreat position is moved to the discharge position. Then, the rinse liquid L3 is supplied from the rinse liquid nozzle 551 onto the substrate W being rotated, so that the front surface of the substrate W is rinsed. As a consequence, the plating liquid L1 left on the substrate W is washed away.
[Substrate Drying Process]
Thereafter, the rinsed substrate W is subjected to a drying processing (process S9). In this case, the rotational speed of the substrate W is increased to be higher than the rotational speed in the substrate rinsing process (process S8), for example, so that the substrate W is rotated at a high speed. Accordingly, the rinse liquid L3 remaining on the substrate W is removed by being scattered off, and the substrate W having the plating film P formed thereon is obtained, as shown in
[Substrate Taking-Out Process]
Then, the substrate W is taken out from the substrate holder 52, and carried out of the plating device 5 (process S10).
In this way, the series of processes S1 to S10 of the plating method for the substrate W using the plating apparatus 1 are completed.
As stated above, according to the apparatus and method described above, by moving either one of at least the cover body 6 and the substrate holder 52 vertically in the middle of heating the plating liquid L1, the reaction gas staying between the substrate W and the cover body 6 is dispersed. Thus, it is possible to suppress the increase of the concentration of the reaction gas in the central portion of the substrate W.
Accordingly, within the surface of the substrate W, the precipitation of the plating component can be performed uniformly, and the uniform plating film can be formed
In addition, the gas exhausting operation may be performed multiple times while heating the plating liquid L1 on the substrate W. By increasing the repetition number of the gas exhausting operation in consideration of the characteristic of the plating liquid L1 or the required thickness of the plating film, the uniformity of the plating film on the substrate W can be improved.
Furthermore, the gas exhausting operation may be performed such that the substrate W is not exposed between the bottom surface of the ceiling portion 61 and the lower end 621 of the sidewall portion 62. Accordingly, it is possible to suppress the front surface of the substrate W from being exposed to the atmosphere outside the cover body 6, so that the oxidation of the plating film on the substrate W can be suppressed.
The above exemplary embodiment has been described for the example where the plating liquid L1 supplied on the substrate W is heated by the heater 63 provided in the cover body 6. However, instead of providing the heater in the cover body 6, a heater (not shown) may be provided inside the substrate holder 52 to heat the plating liquid L1 on the substrate W. Alternatively, it may also be possible to provide heaters in both the cover body 6 and the substrate holder 52.
In addition, in the above-described exemplary embodiment, a second heater (not shown) may be provided in the sidewall portion 62 of the cover body 6. In this configuration, the temperature rise of the plating liquid L1 on the substrate W can be accelerated.
It will be appreciated that the present disclosure is not limited to the above-described exemplary embodiments and modification examples, and that various modifications may be made without departing from the scope of the present disclosure. Furthermore, various other exemplary embodiments may be conceived by appropriately combining the constituent components disclosed in the above-described exemplary embodiments and modification examples. Some components may be deleted from all the constituent components shown in the exemplary embodiments and modification examples. In addition, the constituent components disclosed in the different exemplary embodiments and modification examples may be appropriately combined.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-197924 | Oct 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/039018 | 10/16/2020 | WO |
