Method and device for determining processing conditions for plasma-based processing

Abstract

A method for determining processing conditions for plasma-based processing includes the following steps: an irradiation step of moving a head at a predetermined target speed while maintaining a predetermined target distance relative to an object, and irradiating plasma from the head to the surface of the object; a measurement step of measuring the surface state of the object after the irradiation step; a calculation step of repeatedly performing the irradiation step and the measurement step, and calculating the necessary speed required to saturate the surface state of the object by performing the irradiation step once, based on the number of times the irradiation step is performed until the surface state of the object is saturated; and a determination step of determining the necessary speed as the processing speed of the head.

Description

Technical Field

[0001] This specification discloses a method and apparatus for determining processing conditions for a plasma-based process. Background Art

[0002] A system has been proposed that includes: a process result estimation model that estimates the process result based on the monitoring output from a sensor that monitors process quantities during plasma processing and a pre-set prediction formula for the process result; and an optimal solution calculation model that calculates corrections to the process conditions based on the estimation results so that the process result reaches a target value (see, for example, Patent Document 1). In this system, the influence of interference can be suppressed by controlling the plasma process based on the solution (process conditions) generated by the optimal solution calculation model.

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-33228 Summary of the Invention

[0005] Problems to be solved by the invention

[0006] Thus, determining optimal treatment conditions for surface modification of an object during plasma-based treatment is considered an important issue in order to avoid yield degradation and improve productivity. For example, the head movement speed is the most important processing condition affecting the processing speed of plasma-based treatments, and it is desirable to determine the optimal speed using a simple method without using special equipment.

[0007] A main object of the present invention is to provide a method or apparatus for determining treatment conditions for plasma-based treatment, which can determine treatment conditions suitable for surface modification of an object in a simpler manner.

[0008] Technical solutions to problems

[0009] The present invention adopts the following means to achieve the above-mentioned main objects.

[0010] The gist of the method for determining treatment conditions for plasma-based treatment of the present invention is to include the following steps:

[0011] an irradiation step of moving the head at a predetermined target speed while maintaining a predetermined target distance from the object, and irradiating the surface of the object with plasma from the head;

[0012] a measuring step of measuring a surface condition of the object after the irradiation step;

[0013] a calculation step of repeatedly performing the irradiation step and the measurement step, and calculating a necessary speed required to saturate the surface condition of the object by performing the irradiation step once, based on the number of times the irradiation step is performed until the surface condition of the object is saturated; and

[0014] In the determination step, the required speed is determined as the processing speed of the head.

[0015] Effects of the Invention

[0016] In the plasma-based treatment condition determination method of the present invention, an irradiation step and a measurement step are repeatedly performed on an object. Next, based on the number of irradiation steps required to saturate the object's surface condition, the required speed required to saturate the object's surface condition with one irradiation step is calculated. This required speed is then determined as the processing speed of the head. This method allows for a simpler method to determine treatment conditions suitable for surface modification of the object. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a plasma processing device.

[0018] Figure 2 This is a schematic diagram of the structure of a plasma processing device.

[0019] Figure 3 This is a schematic diagram of the structure of the processing condition determination device.

[0020] Figure 4 This is an explanatory diagram showing a list of parameters used for plasma processing.

[0021] Figure 5 This is a flowchart showing an example of executing the head speed determination process.

[0022] Figure 6 This is an explanatory diagram showing the relationship between the number of repetitions of plasma treatment and the water contact angle of the treated surface.

[0023] Figure 7 This is a flowchart showing an example of executing the head distance determination process.

[0024] Figure 8 It is an explanatory diagram showing the relationship between the head distance and the water contact angle of the treatment surface.

[0025] Figure 9 It is a schematic structural diagram of a plasma processing apparatus according to another embodiment. DETAILED DESCRIPTION

[0026] Modes for carrying out the present invention will be described with reference to the accompanying drawings.

[0027] Figure 1 and Figure 2 1 is a schematic structural diagram of the plasma processing apparatus 10 . Figure 3 This is a schematic diagram of a plasma-based processing condition determination apparatus 50. The plasma processing apparatus 10 irradiates a workpiece W with plasma to modify the surface of the workpiece W. The workpiece W is, for example, a substrate. After adhesive is applied to the substrate, components are mounted. The plasma processing apparatus 10 improves the wettability (adhesive strength) of the substrate surface by performing plasma treatment on the substrate.

[0028] like Figure 1 、 2 As shown, the plasma processing apparatus 10 includes a head 20 and a head moving device 31 (see FIG. Figure 2 ), the head lifting device 32 for lifting the head 20, and the control device 40 for controlling the entire device (see Figure 2 ).

[0029] The head 20 includes a pair of electrodes, a holding member that holds the pair of electrodes so that the electrodes protrude into the reaction chamber, and a nozzle 21 having a discharge port communicating with the reaction chamber. The head 20 applies a voltage to the pair of electrodes and causes a processing gas to pass through the reaction chamber and be discharged from the nozzle 21, thereby blowing the plasma-formed processing gas (plasma gas) onto the surface of the workpiece W. The head moving device 31, for example, is composed of a ball screw mechanism and moves the head 20 in a direction parallel to the surface of the workpiece W. The head lifting device 32, for example, is composed of a ball screw mechanism and adjusts the distance between the discharge port (front end) of the nozzle 21 and the surface (upper surface) of the workpiece W by raising and lowering the head 20 in a direction perpendicular to the surface of the workpiece W.

[0030] The control device 40 is configured as a microprocessor centered around a CPU. In addition to the CPU, it also includes ROM, RAM, input / output interfaces, and a communication interface. Signals from the position sensor that detects the position of the head 20 are input to the control device 40 via the input / output interface. Control signals for the head 20, the head moving device 31, and the head lifting device 32 are output from the control device 40 via the input / output interface. Furthermore, the control device 40 communicates with the processing condition determination device 50 of this embodiment via the communication interface. The control device 40 controls the head 20, the head moving device 31, and the head lifting device 32 according to the processing conditions transmitted from the processing condition determination device 50, thereby performing plasma processing on the workpiece W.

[0031] The processing condition determination device 50 of this embodiment determines the processing conditions of the plasma treatment and is composed of a general-purpose computer having a CPU, ROM, RAM, a hard disk, an external storage device such as a flash memory drive (SSD), and various interfaces. A display device 57 such as a liquid crystal display and an input device 58 such as a keyboard and a mouse are connected to the processing condition determination device 50. In addition, a water contact angle measuring device 60 for measuring the water contact angle θ of the treatment surface of the workpiece W subjected to the plasma treatment is also connected to the processing condition determination device 50. As a functional block, Figure 3 As shown, the processing condition determination device 50 includes a processing unit 51 for determining the processing conditions for plasma processing, an input unit 52 for inputting various parameters required for determining the processing conditions, and a storage unit 53 for storing various information. Each functional block functions by integrating hardware such as a computer's CPU, ROM, RAM, external storage devices, and various interfaces, and software including installed programs.

[0032] Various parameters required for determining the processing conditions are input to the input unit 52. In this embodiment, the various parameters include "adhesive strength," "water contact angle," "surface free energy," "saturated contact angle," "number of irradiations," "heater on / off," "nozzle type," "adhesive type," "workpiece base material," "workpiece additives," "workpiece melting point," "workpiece thickness," "ambient temperature," "ambient humidity," "supply gas temperature," "surrounding gas flow," "surrounding gas volume," "electrode length," "internal nozzle usage time," and "requested processing speed." The "water contact angle" and "surface free energy" are indicators of the wettability of the workpiece surface. The "saturated contact angle" indicates the minimum value of the water contact angle. The "number of irradiations" indicates the number of plasma irradiations. The "heater on / off" indicates whether or not the shielding gas is heated to protect the processing portion. The "nozzle type" indicates the type of nozzle 21 used in the head 20. The "adhesive type" indicates the type of adhesive applied to the workpiece W (substrate) after the plasma treatment. The "workpiece base material" indicates a base material such as aluminum or polypropylene. "Additives to the workpiece" refers to materials such as glass fiber or rubber. "Ambient temperature" refers to the temperature around the workpiece during plasma treatment. "Ambient humidity" refers to the humidity around the workpiece during plasma treatment. "Supply gas temperature" refers to the temperature of the processing gas supplied to the plasma treatment device 10. "Surrounding gas flow" refers to the direction of the gas around the workpiece during plasma treatment. "Surrounding gas volume" refers to the volume of gas around the workpiece during plasma treatment. "Electrode length" refers to the length of the electrode inside the device. "Internal nozzle usage time" refers to the usage time of the internal nozzle of the device. "Requested processing speed" refers to the processing speed of the head requested by the user, that is, the lower limit speed Vmin of the workpiece. In addition, the above parameters are examples and can be appropriately determined according to the plasma treatment device 10 used or the type of plasma treatment performed.

[0033] As processing conditions for the plasma treatment, the processing unit 51 of the processing condition determination device 50 sets a target head speed Vtag, which is a target value for the moving speed of the head 20 in the X-axis direction, and a target head distance Ltag, which is a target value for the head distance L. The set target head speed Vtag and target head distance Ltag are transmitted to the control device 40 of the plasma processing apparatus 10. The control device 40 controls the head moving device 31 and the head lifting device 32 so that the head 20 moves at the target head speed Vtag while maintaining the target head distance Ltag. The control device 40 also controls the head 20 so that plasma is irradiated from the nozzle 21, thereby performing plasma treatment on the workpiece W.

[0034] Next, a procedure for determining the optimal values ​​of the target head speed Vtag and the target head distance Ltag (the execution head speed V and the execution head distance L) will be described.

[0035] Figure 5 is a flowchart showing an example of a head speed determination process performed by the processing unit 51. In the head speed determination process, the processing unit 51 first sets the target head distance Ltag based on the melting point of the material of the workpiece W, the supply gas temperature, the ambient temperature, etc. input by the input unit 52 (step S100). In the present embodiment, for the target head distance Ltag, the shortest head distance Lmin is set within a range in which the workpiece W does not melt even if the plasma is continuously irradiated. Next, the processing unit 51 sets a predetermined specified speed Vset as the target head speed Vtag (step S110). Here, the specified speed Vset is determined, for example, to be a speed near the maximum speed of the head moving device 31.

[0036] Next, the processing unit 51 sets the number of repetitions n to a value of 1 (step S120), and sends a command signal including the target head distance Ltag and the target head speed Vtag to the control device 40 (step S130). The control device 40 that receives the command signal controls the head moving device 31 and the head lifting device 32 in such a manner as to maintain the target head distance Ltag and move the head 20 at the target head speed Vtag, and controls the head 20 in such a manner as to irradiate the surface of the workpiece W with plasma (irradiation process). Furthermore, the processing unit 51 obtains the water contact angle θ relative to the treated surface of the workpiece W after the plasma treatment (step S140). The measurement of the water contact angle θ is performed, for example, as follows: a water drop is dripped onto the treated surface of the workpiece W by the water contact angle measuring device 60, the dripped water drop is photographed from the side, and the obtained image is processed to measure the water contact angle θ (measurement process).

[0037] Next, the processing unit 51 determines whether the number of repetitions n is greater than or equal to 2 (step S150). If the number of repetitions n is less than 2, that is, is 1, the number of repetitions n is increased by 1 (step S160), and the process returns to step S130 to repeatedly perform plasma treatment so that the plasma is irradiated onto the treated surface of the workpiece W in an overlapping manner, and obtain the water contact angle θ of the treated surface (step S140).

[0038] If the processing unit 51 determines in step S150 that the number of repetitions n is greater than or equal to 2, it subtracts the currently acquired water contact angle θ from the previously acquired water contact angle (previous θ) to calculate the water contact angle change Δθ (step S170). Furthermore, the processing unit 51 determines whether the water contact angle change Δθ is near 0 (step S180). This determination is to determine whether the water contact angle θ has reached the saturated contact angle θth as a result of repeated plasma treatment of the treatment surface of the workpiece W. If the processing unit 51 determines that the water contact angle change Δθ is not near 0, it determines that the water contact angle θ has not reached the saturated contact angle θth, increases the number of repetitions n by 1 (step S160), and repeats the processes of steps S130 and S140.

[0039] On the other hand, when the processing unit 51 determines that the water contact angle change Δθ is near 0, it sets the required speed Vreq as the value obtained by dividing the specified speed Vset (target head speed Vtag) by the value obtained by subtracting 1 from the number of repetitions n (step S190). Here, the required speed Vreq is the moving speed of the head 20 required to saturate the surface condition (water contact angle θ) of the processed surface of the workpiece W (reach the saturated contact angle θth) by performing a single plasma treatment (irradiation step). Figure 6 This is an explanatory diagram showing the relationship between the number of repetitions of plasma treatment and the water contact angle of the treated surface. As shown in the figure, it can be seen that when the head 20 is moved at a high-speed target head speed Vtag (prescribed speed Vset) to perform plasma treatment, when the number of repetitions n of the plasma treatment is the fifth time, the change in the water contact angle Δθ becomes a value close to 0 (the slope of the water contact angle θ is approximately 0), and the saturated contact angle θth is reached at the fourth time before it. Therefore, by moving the head 20 at the necessary speed Vreq (= Vset / (n-1)) obtained by dividing the prescribed speed Vset by the value 4 required to reach the saturated contact angle θth, the surface of the workpiece W can be modified to the saturated contact angle θth through a single plasma treatment. As a result, the processing speed of the plasma treatment can be optimized by a simple method.

[0040] After the processing unit 51 has set the required speed Vreq in this manner, it determines whether the required speed Vreq is greater than the lower speed limit Vmin (step S200). Here, the lower speed limit Vmin is the lower limit of the processing speed requested by the user based on the production tact, etc. If the processing unit 51 determines that the required speed Vreq is greater than the lower speed limit Vmin, it sets the required speed Vreq as the execution head speed V (step S210), and the execution head speed determination process ends. On the other hand, if the processing unit 51 determines that the required speed Vreq is not greater than the lower speed limit Vmin but is less than the lower speed limit Vmin, it sets the lower speed limit Vmin as the execution head speed V (step S220), and the execution head speed determination process ends.

[0041] Figure 7 This is a flowchart illustrating an example of the head distance determination process. The head distance determination process is executed after the head speed determination process. During the head distance determination process, the processing unit 51 determines whether the required speed Vreq set in the head speed determination process is less than the lower speed limit Vmin (step S300). If the processing unit 51 determines that the required speed Vreq is not less than the lower speed limit Vmin but is greater than the lower speed limit Vmin, the processing unit 51 sets the shortest head distance Lmin set in step S100 of the head speed determination process as the head distance L (step S310), and terminates the head distance determination process.

[0042] On the other hand, if the processing unit 51 determines that the required speed Vreq is less than the lower speed limit Vmin, it sets the lower speed limit Vmin as the target head speed Vtag (step S320) and sets the head distance Lmin used in step S100, for example, to the target head distance Ltag (step S330). Next, the processing unit 51 transmits a command signal including the target head distance Ltag and the target head speed Vtag to the control device 40, causing the plasma to be irradiated onto the processing surface of the new workpiece W (step S340). Furthermore, the processing unit 51 obtains the water contact angle θ relative to the processed surface of the workpiece W after the plasma treatment from the water contact angle measuring device 60 (step S350).

[0043] After obtaining the water contact angle θ, the processing unit 51 determines whether the obtained water contact angle θ is an angle close to the saturation contact angle θth (step S360). The saturation contact angle θth is, for example, the water contact angle obtained in step S140 when an affirmative determination is made in step S180 during the aforementioned head speed determination process. If the processing unit 51 determines that the water contact angle θ is not an angle close to the saturation contact angle θth, the processing unit 51 subtracts a predetermined amount ΔL from the current target head distance Ltag as a new target head distance Ltag (step S370), returns to step S340, performs plasma treatment on the new workpiece W at the target head distance Ltag and the target head speed Vtag (=Vmin), and obtains the water contact angle θ of the treated surface of the workpiece W after the plasma treatment (step S350).

[0044] In this manner, the processing unit 51 gradually shortens the target head distance Ltag in step S360 until the water contact angle θ reaches an angle close to the saturated contact angle θth, while simultaneously performing plasma processing on a new workpiece W. Furthermore, when the processing unit 51 determines that the water contact angle θ has reached an angle close to the saturated contact angle θth, it sets the currently set target head distance Ltag as the set execution head distance L (step S380), and terminates the execution head distance determination process. Figure 8 : is an explanatory diagram showing the relationship between the head distance and the water contact angle of the processing surface. When the required speed Vreq is less than the lower limit speed Vmin, the target head speed Vtag is determined to be the lower limit speed Vmin. In this case, when the above-mentioned shortest head distance Lmin is determined as the execution head distance Ltag, the surface of the processing surface of the workpiece W cannot be modified to the saturation contact angle θth through a single plasma treatment. Therefore, in this embodiment, on the basis of determining the target head speed Vtag to be the lower limit speed Vmin, while gradually shortening the target head distance Ltag, plasma treatment is performed on a new workpiece W each time and the water contact angle θ of the processing surface of the workpiece W is measured, thereby determining the optimal head distance that can complete the surface modification of the workpiece W through a single plasma treatment at the lower limit speed Vmin. In this way, it is possible to correspond to the processing speed of the head 20 requested by the user.

[0045] Here, the correspondence between the main elements of the embodiment and the main elements of the present invention described in the claims is described. Specifically, the head 20 of this embodiment corresponds to the head, and the workpiece W corresponds to the object. Furthermore, the plasma processing apparatus 10 corresponds to the irradiation unit that performs the irradiation process, the water contact angle measuring apparatus 60 corresponds to the measurement unit that performs the measurement process, the processing unit 51 that performs steps S150 to S190 of the head speed determination process corresponds to the calculation unit, and the processing unit 51 that performs step S210 of the head speed determination process corresponds to the determination unit.

[0046] The present invention is not limited to the above-described embodiments, and can be implemented in various forms within the technical scope of the present invention.

[0047] For example, in the above-described embodiment, the plasma processing apparatus 10 of this embodiment includes a head moving device 31 for horizontally moving the head 20 and a head lifting device 32 for vertically lifting the head 20. However, a plasma processing apparatus 110 according to another embodiment includes a multi-jointed robot for moving the head 20 in a three-dimensional space. Figure 9 This is a schematic structural diagram of a plasma processing apparatus according to another embodiment. As shown in the figure, the multi-joint robot of the plasma processing apparatus 110 according to another embodiment is configured as a vertical multi-joint robot having a base B, first to fourth links L1 to L4 connected in series relative to the base B, first to fifth joint axes J1 to J5 connecting the links, and a head 20 connected to the front end link (fourth link L4). Thus, even if the processing surface of the workpiece W is a curved surface, the head 20 can be moved while maintaining the head distance L while irradiating the workpiece W with plasma. In addition, the multi-joint robot is not limited to a vertical multi-joint robot, and may be any type of robot such as a horizontal multi-joint robot.

[0048] In the method for determining processing conditions for a plasma-based process of the present invention, the required speed may be calculated in the calculation step based on a value obtained by dividing the target speed by the number of executions. This allows the required speed to be determined through simpler calculations.

[0049] Furthermore, in the method for determining treatment conditions for a plasma-based treatment of the present invention, the measuring step may include measuring a water contact angle on the surface of the object as the surface condition of the object. This allows for more accurate measurement of the surface condition of the object.

[0050] Furthermore, in the plasma-based processing condition determination method of the present invention, the target distance may be determined in the determination step based on the melting point of the object. This allows the target distance of the head to be determined at an appropriate distance, thereby preventing damage to the workpiece due to plasma irradiation.

[0051] Alternatively, in the plasma-based treatment condition determination method of the present invention, in the determination step, if the required speed is lower than a lower speed limit, the lower speed limit is determined as the target speed of the head, a required distance is derived to saturate the surface state of the object measured in the measurement step when the irradiation step is performed at the lower speed limit, and the derived required distance is determined as the target distance. In this manner, even when the head speed cannot be reduced, by optimizing the head distance, it is possible to achieve satisfactory surface modification of the object in a single plasma treatment.

[0052] In the above-described embodiment, the present invention is provided in the form of a processing condition determination method, but may also be provided in the form of a processing condition determination device.

[0053] Industrial applicability

[0054] The present invention can be utilized in the manufacturing industry of plasma processing equipment, etc.

[0055] Description of Reference Numerals

[0056] 10, 110 plasma processing device, 20 head, 21 nozzle, 31 head moving device, 32 head lifting device, 40 control device, 50 processing condition determination device, 51 processing unit, 52 input unit, 53 storage unit, 57 display device, 58 input device, 60 water contact angle measuring device, B base, J1~J5 first to fifth joint axes, L1~L4 first to fourth connecting rods, W workpiece.

Claims

1. A method for determining treatment conditions for a plasma-based treatment, comprising the following steps: an irradiation step of moving the head at a predetermined target speed while maintaining a predetermined target distance from the object, and irradiating the surface of the object with plasma from the head; a measuring step of measuring a surface condition of the object after the irradiation step; a calculation step of repeatedly performing the irradiation step and the measurement step, and calculating a necessary speed required to saturate the surface condition of the object by performing the irradiation step once, based on the number of times the irradiation step is performed until the surface condition of the object is saturated; and In the determining step, the required speed is determined as a processing speed of the head.

2. The method for determining treatment conditions for a plasma-based treatment according to claim 1, wherein: In the calculation step, the required speed is calculated based on a value obtained by dividing the target speed by the number of executions.

3. The method for determining treatment conditions for a plasma-based treatment according to claim 1, wherein: In the measuring step, a water contact angle of the surface of the object is measured as the surface state of the object.

4. The method for determining treatment conditions for a plasma-based treatment according to claim 2, wherein: In the measuring step, a water contact angle of the surface of the object is measured as the surface state of the object.

5. The method for determining treatment conditions for a plasma-based treatment according to any one of claims 1 to 4, wherein: In the determining step, the target distance is determined based on the melting point of the object.

6. The method for determining treatment conditions for a plasma-based treatment according to any one of claims 1 to 4, wherein: In the determination process, when the required speed is lower than the lower limit speed, the lower limit speed is determined as the target speed of the head, the required distance required to saturate the surface state of the object measured in the measurement process when the irradiation process is performed at the lower limit speed is derived, and the derived required distance is determined as the target distance.

7. A processing condition determination device comprising: an irradiation unit that moves a head at a predetermined target speed while maintaining a predetermined target distance from an object, and irradiates the surface of the object with plasma from the head; a measuring unit that measures a surface condition of the object after irradiation by the irradiation unit; a calculation unit that repeatedly performs irradiation by the irradiation unit and measurement by the measurement unit, and calculates a necessary speed required to saturate the surface state of the object by performing the plasma treatment once, based on the number of times the plasma treatment is performed until the surface state of the object is saturated; and The determination unit determines the required speed as a processing speed of the head.

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