Ultraviolet treatment device and ultraviolet treatment method

Abstract

Provided is an ultraviolet processing device and an ultraviolet processing method capable of efficiently forming hydroxyl groups by ultraviolet irradiation. An ultraviolet processing device according to an embodiment has an ultraviolet light source, a processing chamber, a gas supply portion, a temperature difference generation mechanism, and a stage. The processing chamber receives ultraviolet light from the ultraviolet light source. The gas supply portion supplies a water vapor mixed gas containing a mixed gas and water vapor to the processing chamber. The temperature difference generation mechanism causes a temperature difference in the water vapor mixed gas in the processing chamber. The stage holds a workpiece in a region in which the concentration of water vapor is relatively high due to convection of the water vapor mixed gas caused by the temperature difference in the processing chamber.

Description

Technical Field

[0001] This invention relates to an ultraviolet treatment apparatus and a method for treating workpieces by irradiating them with ultraviolet light. Background Technology

[0002] Previously, methods for treating workpieces such as substrates by irradiating them with ultraviolet light have been developed. When irradiating the workpiece with ultraviolet light, various gases are supplied to the periphery of the workpiece. For example, Patent Document 1 describes a structure capable of introducing multiple gases as processing gases into a processing chamber containing the workpiece. Furthermore, Patent Documents 2 and 3 describe processing apparatuses that introduce a gas containing water vapor into the processing chamber. When water vapor is introduced, the ultraviolet light reacts with water molecules, forming hydroxyl groups on the surface of the workpiece.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-144913

[0006] Patent Document 2: International Publication No. 2002 / 036259

[0007] Patent Document 3: Japanese Patent Application Publication No. 2008-43925 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] By forming hydroxyl groups, it is possible to modify insulating layers and other materials disposed on the surface of workpieces. For example, hydroxyl groups formed in insulating layers can improve the adhesion between the metal and the insulating layer. Therefore, there is a need for a technology that can efficiently form hydroxyl groups by ultraviolet irradiation.

[0010] In view of the above, the object of the present invention is to provide an ultraviolet treatment apparatus and an ultraviolet treatment method capable of efficiently forming hydroxyl groups by ultraviolet irradiation.

[0011] Technical solutions for solving the problem

[0012] To achieve the above objectives, one aspect of the present invention relates to an ultraviolet processing apparatus comprising an ultraviolet light source, a processing chamber, a gas supply unit, a temperature difference generating mechanism, and a mounting platform.

[0013] The processing chamber is exposed to ultraviolet light from the ultraviolet light source.

[0014] The gas supply unit supplies the processing chamber with a water vapor mixture containing a mixing gas and water vapor.

[0015] The temperature difference generating mechanism creates a temperature difference in the water vapor mixture within the processing chamber.

[0016] The stage in the processing chamber holds the workpiece in an area where it is irradiated by ultraviolet light and where the concentration of water vapor is relatively high due to convection of the water vapor mixture caused by the temperature difference.

[0017] In this ultraviolet processing apparatus, a temperature difference is created in the water vapor mixture supplied to the processing chamber, causing convection of the water vapor mixture. The workpiece is held in a region where the concentration of water vapor is relatively high due to this convection. Thus, a sufficient amount of water vapor is supplied to the vicinity of the workpiece, enabling the efficient formation of hydroxyl groups by ultraviolet irradiation. This, for example, can improve the adhesion of metals in wiring substrates.

[0018] The gas used for mixing can be an inactive gas.

[0019] The processing chamber may also include a processing space supplied with the water vapor mixture. In this case, the temperature difference generating mechanism may also locally heat or cool components in contact with the processing space.

[0020] The ultraviolet treatment apparatus may also include an entrance window that directs ultraviolet light from the ultraviolet light source into the processing space. In this case, the stage may also have a holding surface that is disposed opposite to the entrance window across the processing space and holds the workpiece.

[0021] The processing space can also be a space enclosed by an upper surface and a lower surface extending horizontally. In this case, the mixing gas can be a gas with a molecular weight greater than water. Additionally, the holding surface can also constitute the upper surface of the processing space. Furthermore, the entrance window can also constitute the lower surface of the processing space.

[0022] The gas used for mixing can be any one of nitrogen, neon, argon, krypton, and xenon.

[0023] The processing space can also be a space enclosed by an upper surface and a lower surface extending horizontally. In this case, the mixing gas can be a gas with a molecular weight smaller than water. Additionally, the holding surface can also constitute the lower surface of the processing space. Furthermore, the entrance window can also constitute the upper surface of the processing space.

[0024] The gas used for mixing can be either hydrogen or helium.

[0025] The distance between the entrance window and the workpiece can be greater than 0.1 mm and less than 3 mm.

[0026] The processing chamber and the mounting platform can also be configured such that the surface containing the holding surface in the processing space is substantially planar.

[0027] The temperature difference generating mechanism may also include a heating mechanism for heating the water vapor mixture in the processing chamber.

[0028] The heating mechanism can also be located on the platform or in the flow path of the water vapor mixture.

[0029] The ultraviolet processing apparatus may also include a light source chamber for housing the ultraviolet light source. Additionally, the temperature difference generating mechanism may include a cooling mechanism for cooling the atmosphere within the light source chamber.

[0030] One aspect of the present invention relates to an ultraviolet treatment method that involves irradiating the workpiece with ultraviolet light using the ultraviolet treatment device.

[0031] Invention Effects

[0032] As described above, according to the present invention, hydroxyl groups can be formed efficiently by ultraviolet irradiation. Furthermore, the effects described herein are not necessarily limited, and may include any of the effects described in this disclosure. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating a structural example of the ultraviolet processing apparatus according to the first embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram illustrating a structural example of a gas supply section.

[0035] Figure 3 This is a schematic diagram illustrating an example of the concentration gradient of water vapor accompanying convection.

[0036] Figure 4 This is a schematic diagram of an ultraviolet treatment device as a comparative example.

[0037] Figure 5 This is a schematic diagram illustrating a structural example of the ultraviolet processing apparatus according to the second embodiment.

[0038] Figure 6 This is a schematic diagram illustrating a structural example of the ultraviolet processing apparatus according to the third embodiment.

[0039] Figure 7 This is a schematic diagram illustrating a structural example of the ultraviolet processing apparatus according to the fourth embodiment. Detailed Implementation

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0041] <First Implementation Method>

[0042] [Overview of the Ultraviolet Treatment Device]

[0043] Figure 1 This is a schematic diagram illustrating a structural example of the ultraviolet (UV) processing apparatus according to the first embodiment of the present invention. The UV processing apparatus 100 is an apparatus for subjecting a workpiece W, which is a workpiece to be processed, to UV irradiation with UV light 1. In this disclosure, the workpiece W is a substrate on which an insulating layer made of resin material is formed on its surface. The insulating layer is, for example, a layer that serves as a base for forming a wiring pattern of metal. Therefore, a substrate, such as one before the metal wiring pattern is formed, becomes the workpiece W introduced into the UV processing apparatus 100.

[0044] The ultraviolet (UV) treatment apparatus 100 includes a gas supply unit 10, a lamp housing 20, a treatment chamber 30, a mounting platform 40, a heater 46, an exhaust unit 47, and a temperature sensor 48. The lamp housing 20 and the treatment chamber 30 are connected to form the main body of the UV treatment apparatus 100. Hereinafter, the vertical direction will be referred to as the Z-direction, and directions orthogonal to each other in a horizontal plane orthogonal to the vertical direction will be referred to as the X-direction and Y-direction. Figure 1 In the diagram, the up and down direction corresponds to the Z direction, and the left and right direction corresponds to the X direction.

[0045] The gas supply unit 10 is connected to the processing chamber 30 via a predetermined piping system and supplies gas to the processing chamber 30. Specifically, the gas supply unit 10 supplies the processing chamber 30 with a water vapor mixture gas 4, which contains a mixing gas and water vapor. The water vapor mixture gas 4 is used as the atmosphere gas in ultraviolet treatment where the workpiece W is irradiated with ultraviolet light.

[0046] Figure 2 This is a schematic diagram showing an example of the structure of the gas supply unit 10. The gas supply unit 10 humidifies the mixing gas 2 by passing it through water, and mixes it with water vapor 3. The gas supply unit 10 includes a gas source 11, an on / off valve 12, a flow controller 13, a humidification box 14, a supply pipe 15, a discharge pipe 16, and a needle valve 17.

[0047] Gas source 11 is the supply source for the mixed gas 2. Gas source 11 can be, for example, a gas cylinder containing the mixed gas 2 or a gas supply line installed in the facility. On / off valve 12 is connected to gas source 11 and opens / closes the supply path of the mixed gas 2. On / off valve 12 can be a ball valve, gate valve, etc. Flow controller 13 is connected to the downstream end of on / off valve 12 and controls the flow rate of the mixed gas 2. Flow controller 13 can be, for example, an MFC (Mass Flow Controller) that measures the mass flow rate of the mixed gas 2 for flow control.

[0048] Humidifier 14 is a tank for storing water (H2O). A certain amount of water, less than the tank's volume, is stored in humidifier 14. Supply pipe 15 is a pipe that supplies the mixing gas 2 to humidifier 14. One end of supply pipe 15 is connected to flow controller 13, and the other end is positioned in the water stored in humidifier 14 (below the water surface). Discharge pipe 16 is a pipe that discharges the gas from humidifier 14. One end of discharge pipe 16 is positioned above the water surface in humidifier 14, and the other end is connected to processing chamber 30. Needle valve 17 is externally connected between supply pipe 15 and discharge pipe 16 in humidifier 14.

[0049] The flow rate of the mixed gas 2, controlled by the flow controller 13, is supplied from the supply pipe 15 to the water in the humidification chamber 14. The mixed gas 2, which has passed through the water as bubbles, is released into the space above the water surface. In this process, a mixture of the mixed gas 2 and water vapor 3 (water vapor mixture 4) is generated. The water vapor mixture 4 accumulated above the water surface is discharged from the discharge pipe 16 and supplied to the treatment chamber 30.

[0050] Furthermore, by adjusting the needle valve 17, mixed gas 2 that has not passed through the water can be added to the water vapor mixture 4 discharged from the discharge pipe 16. This allows adjustment of the ratio of mixed gas 2 to water vapor 3 in the water vapor mixture 4. Additionally, the humidification chamber 14 can be configured to adjust the temperature of the stored water. This allows control of the saturated water vapor pressure, and enables precise adjustment of the ratio of mixed gas 2 to water vapor 3 in the water vapor mixture 4.

[0051] The mixing gas 2 is typically an inert gas. Here, an inert gas refers to a gas that is chemically stable and does not readily react with other elements or compounds, for example, during ultraviolet treatment performed by the ultraviolet treatment apparatus 100. In this embodiment, nitrogen (N2) will be primarily used as the mixing gas 2.

[0052] The specific structure of the gas supply unit 10 is not limited. For example, it can be configured to allow selection of the mixing gas 2 from a variety of gases. In addition, other gas sources can be appropriately provided so that any gas other than the water vapor mixed gas 4 (the humidifying gas of the mixing gas 2) can be supplied to the processing chamber.

[0053] return Figure 1 The light box 20 has a light box housing 21, an ultraviolet light source 22, and an entrance window 23, and is a chamber that houses the ultraviolet light source 22 and irradiates ultraviolet light into the processing chamber 30. In this embodiment, the light box 20 is equivalent to a light source chamber that houses the ultraviolet light source.

[0054] The lightbox housing 21 is a box-shaped shell constituting the lightbox 20, and it houses the ultraviolet light source 22 internally. The lightbox housing 21 has a connecting surface 24 and an opening 25. The connecting surface 24 is the outer surface of the lightbox housing 21 that connects to the processing chamber 30. Figure 1 In the diagram, the upper outer surface of the lamp housing 21 is called the connecting surface 24. An opening 25 is provided on the connecting surface 24 and is an opening for the passage of ultraviolet light 1 emitted from the ultraviolet light source 22.

[0055] Additionally, the lightbox housing 21 has a supply port 26a and an exhaust port 26b. The supply port 26a is for supplying the atmospheric gas used in the lightbox 20 and is connected to a gas supply source (not shown). The exhaust port 26b is for discharging the atmospheric gas used in the lightbox 20 and is connected to a recovery pipe (not shown). The atmospheric gas used in the lightbox 20 is a gas that substantially does not absorb ultraviolet light emitted by the ultraviolet light source 22, such as nitrogen.

[0056] The ultraviolet light source 22 is a light source capable of emitting ultraviolet light 1 and is disposed within the lamp housing 21. In this embodiment, a light source emitting vacuum ultraviolet (VUV) light is used as the ultraviolet light source 22. However, the present invention can also be applied even when using ultraviolet light 1 other than VUV. For example, an excimer lamp or a low-pressure mercury lamp can be used as the ultraviolet light source 22. Figure 1 Three ultraviolet light sources 22 are schematically illustrated. These ultraviolet light sources 22 are connected to a power source (not shown). Furthermore, the number and type of ultraviolet light sources 22 are not limited.

[0057] The entrance window 23, constructed from a component that allows ultraviolet light 1 to pass through, is located at the opening 25 of the lamp housing 21. For example, a plate-shaped component made of synthetic quartz glass can be used as the entrance window 23. Figure 1 As shown, in the ultraviolet processing apparatus 100, the interior space of the lamp box 20 and the interior space of the processing chamber 30 are divided by the entrance window 23. This allows for independent control of the atmosphere gas (nitrogen, etc.) in the lamp box 20 and the atmosphere gas (water vapor mixture 4, etc.) in the processing chamber 30. Furthermore, as described later, a processing space 33, divided by the entrance window 23, is formed in the processing chamber 30. Therefore, the entrance window 23 serves as a window for directing ultraviolet light from the ultraviolet light source 22 into the processing space 33.

[0058] The processing chamber 30 is a chamber where ultraviolet light enters from the ultraviolet light source 22 and treats the workpiece W with ultraviolet light. Inside the processing chamber 30 is a mounting stage 40 (described later), on which the workpiece W is fixed. Figure 1 As shown, the processing chamber 30 has a processing chamber housing 31 and a support platform 32. In addition, the processing chamber 30 includes a processing space 33 to which a water vapor mixture 4 is supplied.

[0059] The processing chamber housing 31 is a box-shaped housing that constitutes the processing chamber 30, configured to allow ultraviolet light to be drawn in from the lamp box 20. The processing chamber housing 31 has, for example, a structure with one side open, such that the entrance window 23 facing the lamp box 20 on the open side (lower side in the figure) is connected to the connection surface 24 of the lamp box housing 21.

[0060] Additionally, the processing chamber housing 31 has a supply port 35a and an outlet port 35b. The supply port 35a is for supplying atmospheric gas to the processing chamber 30, which contains a water vapor mixture 4, and is connected to... Figure 2 The exhaust pipe 16 of the gas supply unit 10 shown is connected. The exhaust port 35b is the exhaust port for discharging the atmospheric gas used in the processing chamber 30 containing the water vapor mixture 4, and is connected to the exhaust unit 47. The supply port 35a and the exhaust port 35b are respectively provided in positions communicating with the processing space 33. Furthermore, the size, shape, etc. of the supply port 35a and the exhaust port 35b are not limited.

[0061] The support platform 32 is a component that supports the mounting platform 40 inside the processing chamber housing 31, and has a facing surface 36 and a groove 37. The facing surface 36 faces the light box 20 (connecting surface 24 and entrance window 23). The support platform 32 is configured such that the facing surface 36 covers the cross-section of the internal space of the processing chamber housing 31 along the horizontal direction (X and Y directions). The groove 37 is a recess provided in the facing surface 36 for embedding the mounting platform 40. The support platform 32 can be constructed using, for example, metal plate components, block components, structural components, etc. There are no limitations on the type and material of the components constituting the support platform 32.

[0062] The stage 40 holds the workpiece W inside the processing chamber 30. The stage 40 has a holding surface 41 for holding the workpiece W, which is embedded in the groove 37 of the support stage 32 with the holding surface 41 facing the entrance window 23. Therefore, the holding surface 41 is arranged opposite to the entrance window 23 across the processing space 33. Furthermore, a holding mechanism (not shown) for holding the workpiece W on the holding surface 41 is provided on the stage 40. As the holding mechanism, a vacuum suction cup for adsorbing the workpiece W, a clamping member for pressing the outer edge of the workpiece W, etc., are used. Moreover, the specific structure of the holding mechanism is not limited. Ultraviolet light 1 emitted from the ultraviolet light source 22 irradiates the workpiece W held on the holding surface 41 through the entrance window 23.

[0063] Processing space 33 is the internal space of processing chamber 30 where ultraviolet treatment of workpiece W is carried out in an atmosphere of water vapor mixed gas 4. For example... Figure 1 As shown, the space between the surface (lower surface 33b) formed by the connecting surface 24 of the light box housing 21 and the incident window 23 and the surface (upper surface 33a) formed by the opposite surface 36 of the support platform 32 and the holding surface 41 of the placement platform 40 becomes the processing space 33.

[0064] Heater 46 is a heating element installed inside the processing chamber 30. By operating heater 46, components connected to heater 46, as well as the water vapor mixture 4 within the processing chamber 30, are heated. Therefore, heater 46 functions as a heating mechanism for heating the water vapor mixture 4 within the processing chamber 30. Heater 46 is connected to a temperature controller (not shown).

[0065] exist Figure 1 In the ultraviolet treatment apparatus 100 shown, a heater 46 is provided on the stage 40. The heater 46 is embedded inside the stage 40, for example, to heat the entire stage 40. This allows for heating of the workpiece W held on the stage 40, for example, by heating the workpiece W while performing ultraviolet treatment. The heater 46 can be, for example, a tubular heater using heating wires (such as a sheathed heater). The specific structure of the heater 46 is not limited; for example, an oil heater can also be used.

[0066] In this way, heater 46 locally heats the components that are in contact with the processing space 33. Figure 1 In the example shown, the stage 40 in the component connected to the processing space 33 is locally heated. Therefore, when the heater 46 operates, a relatively high-temperature portion and a relatively low-temperature portion are generated in the component connected to the processing space 33. As a result, a temperature difference is generated in the water vapor mixture 4 within the processing space 33. In this embodiment, the heater 46 corresponds to a temperature difference generating mechanism that generates a temperature difference in the water vapor mixture within the processing chamber.

[0067] The exhaust section 47 is connected to the exhaust port 35b of the processing chamber 30, discharging the water vapor mixture 4 and other atmospheric gases from the processing chamber 30. The exhaust section 47 may include a flow meter such as an MFM (Mass Flow Meter) and be connected to an exhaust line (not shown). Furthermore, the structure of the exhaust section 47 is not limited, and it may also be equipped with a pressure gauge, flow control valve, etc.

[0068] Temperature sensors 48 are sensors that measure the temperature of various parts of the ultraviolet processing apparatus 100. Temperature sensors 48a, 48b, 48c, and 48d are respectively installed on the mounting platform 40, the support platform 32, the supply pipe 35a of the processing chamber 30, and the lamp housing 21. These temperature sensors 48 may be thermocouples, for example, but other types of temperature sensors may also be used. The values ​​detected by the temperature sensors 48 are used, for example, for controlling the heater 46 and monitoring the temperature.

[0069] [Ultraviolet radiation on the insulating layer and the formation of functional groups]

[0070] The following explains the effect of irradiating the insulating layer disposed on the surface of workpiece W with ultraviolet light 1. The resin material constituting the insulating layer contains a chain polymer composed of carbon atoms (C), oxygen atoms (O), hydrogen atoms (H), etc. The polymer contains single bonds (e.g., C=C, CO, CH, OH, etc.) and double bonds (e.g., C=O) between the atoms.

[0071] If the insulating layer is irradiated with ultraviolet light such as VUV, the insulating layer absorbs the energy of the ultraviolet light. At this time, a portion of the energy of the ultraviolet light becomes the excitation energy for the atoms constituting the polymer. As a result, the bonding state of the polymer changes, forming new functional groups. One example of a newly formed functional group is the hydroxyl group (COH). COH is a primary oxidation functional group, and for example, it readily bonds to copper atoms (Cu).

[0072] In Japanese Patent Application 2023-064090, the inventors described the effect of COHs formed on an insulating layer by VUV irradiation. For example, VUV absorption occurs not only on the surface of the insulating layer but also in a region at a depth of approximately tens of nm from the surface (hereinafter referred to as the surface region). The surface region, for example, extends from the surface of the insulating layer to a depth of approximately 20 nm to 40 nm. Therefore, when the insulating layer is irradiated with VUV, COHs are formed in the surface region extending from the surface of the insulating layer to its interior.

[0073] Here, we consider forming a copper film on an insulating layer containing CO through a sputtering process. The copper film can be used as a thickness layer for wiring patterns or as a seed layer for electroplating. In the sputtering process, Cu (metal) from the sputtering source reacts with the CO formed on the insulating layer to form COCu. COCu is a bond that connects the carbon chain C of the polymer to the Cu of the copper film, and functions as the bonding part between the insulating layer and the copper film.

[0074] Furthermore, as described above, CO₂ is formed from the surface to the interior of the insulating layer by VUV irradiation. Therefore, during the sputtering process, COCu is formed not only on the surface of the insulating layer but also inside the insulating layer, i.e., the surface region. Thus, by performing UV treatment to form CO₂ before sputtering the copper film, a bonding region between the insulating layer and the copper film can be formed from the surface to a depth of tens of nm. That is, a gradually changing, tight interface with bonding applied in the depth direction is formed in the surface region. This significantly improves the adhesion strength between the insulating layer and the copper film.

[0075] Furthermore, if the insulating layer is irradiated with ultraviolet light 1 in the air, oxygen molecules (O2) will be excited by ultraviolet light 1 during propagation in the air, generating ozone (O3) and ground-state oxygen atoms (O2). 1 D )), excited-state oxygen atoms (O(3 P These oxygen-derived products promote the oxidation of insulating layers containing hydroxyl groups (COH), such as C=O (carbonyl group) and COOH (carboxyl group) on the surface of the insulating layer. C=O, COOH, and other functional groups are difficult to bond with copper atoms (Cu).

[0076] When the insulating layer made of resin is irradiated with ultraviolet light 1, COH groups are formed in the insulating layer. This can, for example, improve the adhesion between the copper film used as a wiring layer and the insulating layer. On the other hand, if oxidation of the insulating layer progresses, functional groups such as C=O and COOH are formed. In this case, the adhesion between the copper film and the insulating layer may, for example, decrease.

[0077] [Introduction of water vapor mixture]

[0078] As a method to increase the ratio of COH formed in the insulating layer, a method of introducing a water vapor mixed gas 4 into the chamber where ultraviolet treatment is performed is considered. The water vapor mixed gas 4 is a humidifying gas that is humidified by mixing water vapor 3 with the mixing gas 2.

[0079] When the water vapor mixture 4 is irradiated with ultraviolet light 1, the water molecules (H2O) contained in the water vapor mixture 4 absorb ultraviolet light 1 and separate into oxidizing hydroxide ions (OH-) and reducing hydrogen ions (H+). Among them, OH- reacts with carbon chains that constitute the insulating layer (resin material) to form COH. In this way, by using the water vapor mixture 4, OH- can be directly supplied, thereby improving the COH generation efficiency in the insulating layer.

[0080] Furthermore, a gas other than oxygen is used as the mixing gas 2 in the mixed water vapor 3. This eliminates oxygen from the chamber and suppresses the formation of functional groups such as C=O and COOH. As a result, the proportion of COH formed in the insulating layer can be increased.

[0081] On the other hand, based on the structure of the apparatus for ultraviolet treatment, it is believed that due to the density difference between the water vapor 3 contained in the water vapor mixture 4 and the mixing gas 2, the concentration of water vapor 3 around the insulating layer decreases and becomes unstable. In this case, even if the water vapor mixture 4 is introduced, COH may not be formed efficiently.

[0082] [Concentration gradient of water vapor]

[0083] Therefore, the inventors, focusing on the fact that convection is generated by imparting a temperature difference to the water vapor mixture 4, can create a region where the concentration of water vapor 3 is relatively high, discovered a structure in which the workpiece W is held and irradiated with ultraviolet light 1. Hereinafter, the concentration gradient of water vapor 3 in the treatment chamber 30 of the ultraviolet treatment apparatus 100 according to the present invention will be described.

[0084] For reference Figure 1 As explained, the ultraviolet processing apparatus 100 is provided with a temperature difference generating mechanism (in this embodiment, a heater 46) that generates a temperature difference in the water vapor mixture 4 within the processing chamber 30. Furthermore, the platform 40 holding the workpiece W is configured such that the workpiece W is held in the processing chamber 30 in a region where it is irradiated with ultraviolet light 1 and where the concentration of water vapor 3 is relatively high due to convection of the water vapor mixture 4 caused by the temperature difference.

[0085] Figure 3 This is a schematic diagram illustrating an example of the concentration gradient of water vapor 3 accompanying convection. Figure 3 This is a partial map showing the processing space 33 formed in the processing chamber 30. The processing space 33 is the space enclosed by an upper surface 33a and a lower surface 33b extending horizontally. Here, the upper surface 33a refers to the surface located vertically above the processing space 33, and the lower surface 33b refers to the surface located vertically below the processing space 33.

[0086] Normally, gases heated inside a container become less dense due to thermal expansion and move upwards. Conversely, gases cooled are denser than heated gases and therefore move downwards. Creating a temperature difference within the container in this way generates convection due to gravity. Following the same principle, if a temperature difference is applied to the water vapor mixture 4 supplied to the processing space 33, convection of the water vapor mixture 4 will occur.

[0087] The water vapor mixture 4 is formed by mixing two gases with different molecular weights (water vapor 3 and mixing gas 2). Buoyancy corresponding to the molecular weights is generated by convection and acts on each of the two gases respectively. As a result, the concentrations of water vapor 3 and mixing gas 2 in the processing space 33 exhibit different distributions. It should be noted that, in this disclosure, molecular weight refers to the sum of the atomic weights of the gas molecules constituting the gas. Therefore, for gases with monatomic molecules (helium, argon, etc.), the atomic weight is directly referred to as the molecular weight.

[0088] In the water vapor 3 and the mixed gas 2, the buoyancy of gases with relatively large molecular weights (gases with relatively large densities) is relatively small, resulting in a higher concentration on the lower surface 33b side of the processing space 33. Conversely, the buoyancy of gases with relatively small molecular weights (gases with relatively small densities) is relatively large, resulting in a higher concentration on the upper surface 33a side of the processing space 33. Thus, due to the difference in molecular weight (density) between the water vapor 3 and the mixed gas 2 constituting the water vapor mixed gas 4, a concentration distribution is generated within the processing space 33. Furthermore, although the concentration distributions of the water vapor 3 and the mixed gas 2 differ, they are not separated.

[0089] In this embodiment, a gas with a molecular weight greater than that of water is used as the mixing gas 2. Nitrogen (molecular weight 28) is an example of such a mixing gas 2. The density of nitrogen under standard conditions (one atmosphere, 0°C) is 1.25 g / L. Furthermore, the density of water vapor 3 (molecular weight 18) under standard conditions is 0.804 g / L. Therefore, when using a water vapor mixture gas 4 (moistened nitrogen) that combines water vapor 3 and nitrogen, the relatively dense nitrogen gas becomes highly concentrated on the lower surface 33b side of the processing space 33, while the relatively less dense water vapor 3 becomes highly concentrated on the upper surface 33a side of the processing space 33.

[0090] exist Figure 3 In the diagram, when the molecular weight of the mixed gas 2 is greater than that of water, the concentration distribution of water vapor 3 generated by convection is schematically illustrated using a gradient. The more intense the color of the gradient, the higher the concentration of water vapor 3. Figure 3 As shown, in the processing space 33, the concentration of water vapor 3 is highest in the region adjacent to the upper surface 33a. It should be noted that the concentration of water vapor 3 decreases closer to the lower surface 33b, but the concentration of the mixed gas 2 (nitrogen, etc.) is higher closer to the lower surface 33b.

[0091] In this embodiment, the concentration of water vapor 3 is relatively high on the upper surface 33a side of the processing space 33. Therefore, in the ultraviolet processing apparatus 100, the workpiece W is held on the upper surface 33a side of the processing space 33, and ultraviolet light is incident from the lower surface 33b side. Specifically, the holding surface 41 that holds the workpiece W constitutes the upper surface 33a of the processing space 33. In addition, the entrance window 23 through which ultraviolet light 1 enters constitutes the lower surface 33b of the processing space 33. When viewed from the main body of the apparatus, the processing chamber 30 is arranged on the upper side, and the lamp box 20 is arranged on the lower side.

[0092] This structure allows the workpiece W to be maintained in areas where ultraviolet light 1 is irradiated and the concentration of water vapor 3 is relatively high. Consequently, the concentration of water vapor 3 around the insulating layer on the surface of the workpiece W can be stably increased. As a result, the supply of hydroxide ions (OH-) is maintained at a high level, which increases the ratio of hydroxyl groups (COH) formed in the insulating layer.

[0093] Furthermore, due to the high concentration of water vapor 3, the energy consumed in the ultraviolet light 1 irradiating the workpiece W, which is used to separate water vapor 3 (water molecules) into OH- and H+, increases. On the other hand, the energy of the ultraviolet light 1 reaching the insulating layer decreases. Therefore, for example, it is difficult to produce a situation where the parts that have already formed COH are further oxidized, and it is difficult to form functional groups such as C=O and COOH.

[0094] Thus, by irradiating ultraviolet light 1 in an atmosphere with a high density (partial pressure) of water vapor 3, the decrease in the COH ratio can be suppressed. That is, the modification on the surface of the workpiece W treated with ultraviolet light can be retained in the COH. This can also be described as suppressing the development of oxidation levels in the insulating layer.

[0095] Furthermore, as described above, the upper surface 33a and lower surface 33b of the processing space 33 are configured to extend in a horizontal direction. This avoids the formation of a concentration gradient of water vapor 3 (or mixed gas 2) along the horizontal direction. Moreover, in this disclosure, a surface extending in a horizontal direction refers to a surface that is substantially horizontally arranged. Therefore, the upper surface 33a and lower surface 33b do not need to be perfectly horizontal; for example, they can be slightly inclined from a horizontal plane as long as the workpiece W is appropriately subjected to ultraviolet treatment.

[0096] In addition, such as Figure 1 As shown, the processing chamber 30 and the mounting stage 40 are configured such that the surface containing the holding surface 41 (here, the upper surface 33a of the processing space 33) within the processing space 33 is substantially planar. Figure 1 In the ultraviolet treatment apparatus 100 shown, the support platform 32 and the mounting platform 40 are configured such that the opposing surface 36 of the support platform 32 disposed in the treatment chamber 30 is coplanar with the holding surface 41 of the mounting platform 40. As a result, the upper surface 33a of the treatment space 33 becomes substantially flat. Thus, there are no uneven areas on the upper surface 33a, and therefore no regions with locally high or low concentrations of water vapor 3 are created. Consequently, the concentration of water vapor 3 can be maintained uniformly over the entire workpiece W.

[0097] However, as described above, since water vapor 3 absorbs ultraviolet light 1, it is preferable that the irradiation distance d of ultraviolet light 1 in the processing space 33 be short in order to modify the insulating layer by irradiating it with ultraviolet light 1. Here, the irradiation distance d of ultraviolet light 1 is the interval between the incident window 23 and the workpiece W. In this embodiment, the irradiation distance d is set to 0.1 mm or more and 3 mm or less. By setting the irradiation distance d within this range, ultraviolet treatment that appropriately modifies the insulating layer can be achieved.

[0098] Furthermore, to ensure a gap by avoiding contact between the entrance window 23 and the workpiece W, the irradiation distance d is more preferably 0.5 mm or more, and to achieve sufficient ultraviolet light intensity, the irradiation distance d is more preferably 2 mm or less. Moreover, the irradiation distance d is not limited to the above-mentioned ranges, and can be appropriately set according to the type of workpiece W, the power of the ultraviolet light source 22, etc.

[0099] Thus, the processing space 33 becomes a thin plate-shaped space. In this case, by using the heater 46 to impart a temperature difference to the water vapor mixture 4, the water vapor mixture 4 also flows with an inclined concentration (concentration distribution) inside the processing space 33, where the water vapor 3 is concentrated on the upper surface 33a side and the mixed gas 2 (nitrogen, etc.) is concentrated on the lower surface 33b side.

[0100] Because the processing space 33 is narrow, water vapor 3 can more easily contact the workpiece W. Furthermore, a layer with a high concentration of the mixed gas 2 is formed on the lower surface 33b side where ultraviolet light 1 is incident. The mixed gas 2, being an inert gas such as nitrogen, absorbs almost no ultraviolet light 1. Therefore, the layer with a high concentration of the mixed gas 2 functions as a region within the processing space 33 where ultraviolet light 1 absorption is low. Thus, for example, the distance between the incident window 23 and the workpiece W (irradiation distance d) can be increased without reducing the irradiation intensity of ultraviolet light 1 on the workpiece W, ensuring an appropriate irradiation distance d.

[0101] The following describes an experiment evaluating the adhesion strength between the insulating layer and the copper film, using a workpiece that has undergone ultraviolet treatment in the ultraviolet treatment apparatus 100 as a sample. The workpiece W, which has undergone ultraviolet treatment, has an insulating layer formed on a support substrate. CCL (Copper Clad Laminate) is used as the support substrate. An epoxy film is used as the insulating layer.

[0102] Workpiece W is introduced into the ultraviolet (UV) treatment device 100 and irradiated with VUV while a water vapor mixture 4 is supplied. An excimer irradiation device is used as the VUV light source. In the experiment, the irradiation distance d of UV 1 is set to 1 mm.

[0103] In addition, a copper film is formed on the UV-treated workpiece W using a sputtering apparatus. The sputtered copper film has a thickness of 300 nm. Then, a copper plating layer is formed by electrolytic copper plating. The copper plating layer has a thickness of 30 μm. After the copper plating layer is formed, an annealing treatment is performed.

[0104] Annealed samples were used as the test objects to evaluate the adhesion between the insulating layer and the copper film (sputtered copper film + copper plating layer). In the experiment, a 1 cm wide incision was cut into the copper film, and the copper film was peeled off using a peel tester to measure the adhesion strength [N / cm]. The maximum adhesion strength was recorded when the copper film was peeled off at a speed of 50 mm / s.

[0105] In addition, the copper film formed on the insulating layer was peeled off from the insulating layer, and the interface of the copper film was measured by X-ray photoelectron spectroscopy (XPS). Based on the O1s spectrum measured here, the ratio of the peak representing COCu (529.9 nm) to the peak representing C=O (531.6 nm) was calculated (hereinafter referred to as the O1s ratio). The O1s ratio is the ratio of COH to C=O (carbonyl group) and COOH (carboxyl group). It can be said that the higher this value, the higher the proportion of COH formed on the insulating layer.

[0106] [Example 1: Relationship between water vapor quantity and sealing strength]

[0107] Table (1) shows the experimental results under the condition of changing the amount of water vapor 3 contained in the water vapor mixture 4. In this experiment, moist nitrogen mixed with nitrogen and water vapor 3 was used. Here, the relative humidity of water vapor 3 at 25°C is used as an indicator of the amount of water vapor 3 in the water vapor mixture 4.

[0108] Here, the method for adjusting the water vapor mixture gas 4 (humidifying gas) in this experiment will be explained. In this experiment, the experimental setup was configured in a cleanroom with the room temperature adjusted to 25°C, and the experiment was conducted there. The water vapor mixture gas 4 was generated by including water vapor produced using a heated ultrasonic sprayer in the mixing gas 2 (original gas). Here, the sprayed water was heated to 40°C before spraying, and the mist-like water droplets were removed using a hollow fiber air filter. Then, the gas with the water droplets removed was passed through a radiator to reach the same temperature as room temperature. In this way, due to the decrease in temperature, the amount of saturated water vapor decreased, and a gas with a relative humidity of 100% was obtained. This gas was mixed with the mixing gas 2 (dried nitrogen, etc.) dried in any ratio, and the moisture content was measured using a dew point meter before being introduced into the treatment chamber 30, and then used in the experiment. At this time, the mixing amount of the mixing gas 2 was adjusted based on the dew point meter measurement, thereby adjusting the relative humidity of the water vapor 3.

[0109]

[0110] The highest temperature is the highest temperature in the processing space 33, which is the temperature of the stage 40 where the heater 46 is installed. The lowest temperature is the lowest temperature in the processing space 33. Here, the temperature of the part of the housing (light box housing 21 and processing chamber housing 31) facing the processing space 33 with the lowest temperature is recorded as the lowest temperature. The temperature difference is the temperature difference in the processing space 33, which is the difference between the highest temperature and the lowest temperature. The VUV irradiation time is the time [seconds] of VUV irradiation. In any of the experiments shown in Table (1), the highest temperature is 150°C, the lowest temperature is 30°C, the temperature difference is 120°C, and the VUV irradiation time is 6 seconds.

[0111] In experiments 11-20 shown in Table (1), the relative humidity of water vapor 3 contained in the water vapor mixture 4 was varied from 10% to 100% in 10% increments. For example, in experiment 11, nitrogen was set to 90% and water vapor 3 was set to 10%, but the sealing strength was the lowest at 0.07. In addition, the O1s ratio was also the lowest at 0.

[0112] Increasing the relative humidity of water vapor 3 increases both the sealing strength and the O1s ratio. For example, from experiment number 12 (relative humidity of water vapor 3 20%) to experiment number 14 (relative humidity of water vapor 3 40%), the increases in sealing strength and O1s ratio are significant. Furthermore, in experiment number 18 (relative humidity of water vapor 3 80%), the sealing strength is 0.3 and the O1s ratio is 0.28, both being maximum values. Thus, the greater the sealing strength, the greater the increase in the O1s ratio.

[0113] Furthermore, if the relative humidity of water vapor 3 is higher than that in Experiment 14 (40% relative humidity of water vapor 3), the changes in sealing strength and O1s ratio become relatively small. In the experiments described below, the relative humidity of water vapor 3 was basically set to 40%. It should be noted that when the relative humidity of water vapor 3 is set to 90% and 100% (Experiments 19 and 20), it is not possible to measure the sealing strength and O1s ratio.

[0114] According to the results in Table (1), the relative humidity of water vapor 3 in the water vapor mixture 4 is preferably 20% or more and 80% or less. Furthermore, from the viewpoint of suppressing water droplet formation and achieving sufficient sealing strength, the relative humidity of water vapor 3 in the water vapor mixture 4 is more preferably set to 40% or more and 60% or less. However, the relative humidity of water vapor 3 in the water vapor mixture 4 is not limited to the range described here and can be appropriately set according to the type of workpiece W, etc.

[0115] [Example 2: Relationship between temperature difference and sealing strength]

[0116] Table (2) shows the experimental results under conditions where the temperature difference within the treatment chamber 30 was varied. In any of the experiments shown in Table (2), the relative humidity of the water vapor 3 was 40%, and the VUV irradiation time was 6 seconds.

[0117]

[0118] In experiments 21-25 shown in Table (2), ultraviolet treatment was performed with the lowest temperature of the treatment space 33 set to 30°C and the highest temperature (temperature of heater 46) set to 50°C, 80°C, 120°C, 150°C, and 180°C, respectively. In experiment 21, with the lowest temperature difference, the sealing strength was 0.1, the lowest. If the highest temperature (temperature difference) is increased, the sealing strength and O1s ratio increase. For example, in experiments 22 (highest temperature 80°C, temperature difference 50°C) to 23 (highest temperature 120°C, temperature difference 90°C), the increase in sealing strength and O1s ratio is large. In addition, in experiment 24 (highest temperature 150°C, temperature difference 120°C), the sealing strength was 0.29. It should be noted that the sealing strength in experiment 25 (highest temperature 180°C, temperature difference 150°C) is the same as that in experiment 24. Thus, it can be seen that when the heater 46 is placed on the platform 40, a temperature difference of about 120°C is sufficient to improve the sealing strength.

[0119] According to the results in Table (2), when the heater 46 is installed on the mounting table 40, the temperature difference in the processing chamber 30 (processing space 33) is preferably set to 90°C or higher and 150°C or lower, more preferably 100°C or higher and 120°C or lower. Furthermore, when the heater 46 is installed on the mounting table 40 as in this embodiment, it is also possible to consider that the workpiece W is heated and set the maximum temperature (temperature difference) to be relatively small. In addition, the temperature difference in the processing chamber 30 is not limited to the range described herein and can be appropriately set according to the type of workpiece W, etc.

[0120] [Example 3: Relationship between the type of gas used in the mixture and the strength of the seal]

[0121] This concludes the explanation focusing on the case where nitrogen is used as the mixing gas 2, which has a molecular weight greater than that of water. Other inert gases with a molecular weight greater than that of water may also be used as the mixing gas 2. In this embodiment, any one of the aforementioned nitrogen, neon, argon, krypton, and xenon is used as the mixing gas 2.

[0122] It should be noted that gases with molecular weights greater than water, such as carbon monoxide (CO) and carbon dioxide (CO2), have high VUV absorption. Furthermore, air and oxygen (O2) contain oxygen molecules that promote the oxidation of the insulating layer, so they are preferable to avoid using them to increase the COH ratio. Additionally, it is believed that hydrocarbon gases such as methane and ethane, and processing gases such as SF6, will decompose during VUV irradiation. Based on these reasons, as described above, nitrogen and rare gases are preferably used for mixing gas 2.

[0123] Table (3) shows the experimental results when the type of mixed gas 2 was changed. In any of the experiments shown in Table (3), the relative humidity of water vapor 3 was 40%, the highest temperature was 150°C, the lowest temperature was 30°C, the temperature difference was 120°C, and the VUV irradiation time was 6 seconds.

[0124]

[0125] In experiments 31-34 shown in Table (3), neon (Ne: molecular weight 20), argon (Ar: molecular weight 40), krypton (Kr: molecular weight 83.7), and xenon (Xe: 131.3) were used as the mixing gas 2, respectively. The sealing strength in experiment 31, which used neon with the smallest molecular weight, was 0.18, which was less than the sealing strength of 0.29 when nitrogen with a larger molecular weight was used (refer to experiment 24 in Table (2)). On the other hand, in experiment 32, which used argon with a larger molecular weight than nitrogen, the sealing strength was greater than when nitrogen was used. It can be seen that, overall, the larger the molecular weight of the mixing gas 2, the greater the sealing strength.

[0126] For example, the molecular weight (20) of neon is relatively close to that of water (18), so the effect of increasing the concentration of water vapor 3 is considered limited. Furthermore, argon, krypton, and xenon have sufficiently large molecular weights compared to water, and it is believed that they fully utilize the effect of increasing the concentration of water vapor 3. As for the mixing gas 2, nitrogen is preferred, for example, in terms of suppressing the cost of ultraviolet treatment. Additionally, to further improve the sealing strength compared to nitrogen, argon, a relatively inexpensive rare gas, can be used.

[0127] [Comparative Example]

[0128] Figure 4 This is a schematic diagram of an ultraviolet treatment device as a comparative example. Figure 4The ultraviolet treatment apparatus 110 shown has a treatment chamber 111 on the lower side of the main body and a lamp box 112 on the upper side. Furthermore, a columnar support platform 114 is provided in the treatment chamber 111, which supports and holds a workpiece W from below. Therefore, the platform 113 is supported near the center of the treatment space 115 in a floating state from its lower surface. An entrance window 116 is provided on the upper surface of the treatment space 115, facing the workpiece W (platform 113). Ultraviolet light emitted from the ultraviolet light source 117 inside the lamp box 112 irradiates the workpiece W through the entrance window 116. Additionally, a heater 118 is provided on the platform 113.

[0129] A water vapor mixture 4 containing nitrogen and water vapor 3 is supplied to the processing space 115. In this case, when the heater 118 is activated, the water vapor mixture 4 convection occurs within the processing space 115, and the concentration of water vapor increases near the upper surface of the processing space 115 (along the surface of the entrance window 116). On the other hand, the concentration of nitrogen increases near the lower surface of the processing space 115 (the surface of the fixed support 114). Furthermore, near the center of the processing space 115 where the workpiece W is held, it is considered that there is almost no concentration difference between water vapor and nitrogen.

[0130]

[0131] The table (comparative examples) shows the experimental results for samples treated with ultraviolet light using the ultraviolet treatment device 110. For example, in experiments 1-7, the results were obtained by setting the relative humidity of water vapor 3 to a relatively low 20%, the temperature difference to 120°C, and increasing the VUV irradiation time by 3 seconds each time from 0 to 18 seconds. In experiment 3, where the VUV irradiation time was set to 6 seconds, the adhesion strength was the highest. This value is comparable to that obtained using... Figure 1 The values ​​of the ultraviolet treatment device 100 (experiment number 12 in Table (1)) are the same.

[0132] In experiments 8, 9, and 10, the VUV irradiation time was set to 6 seconds, and the relative humidity of water vapor 3 was set to 40%, 60%, and 80%, respectively. Even with this variation in the relative humidity of water vapor 3, the sealing strength fluctuated unstablely around 0.1, but no tendency was observed for the sealing strength to increase with the increase in the relative humidity of water vapor 3.

[0133] As described above, the stage 113 of the ultraviolet treatment apparatus 110 differs from the stage 40 of the ultraviolet treatment apparatus 100 in that it is not configured to hold the workpiece W in an area where the concentration of water vapor 3 is relatively high. Therefore, it is considered that a high concentration of water vapor 3 cannot be stably supplied to the periphery of the workpiece W, and the effect of efficiently forming COH cannot be expected.

[0134] In the ultraviolet treatment apparatus 100 of this embodiment, a temperature difference is generated in the water vapor mixture 4 supplied to the treatment chamber, causing convection of the water vapor mixture 4. The workpiece W is held in a region where the concentration of water vapor 3 is relatively high due to this convection. As a result, a sufficient amount of water vapor 3 is supplied to the vicinity of the workpiece W, thus enabling the efficient formation of hydroxyl groups (COH) by ultraviolet irradiation.

[0135] For example, in manufacturing wiring substrates for mounting semiconductor components, techniques are required to improve the adhesion strength between the insulating layer made of resin material and the wiring layer made of conductive material such as metal. Furthermore, in recent years, there has been a trend towards using metal sputtering to achieve drying of the manufacturing process.

[0136] In this embodiment, a region with a higher concentration of water vapor 3 is generated by convection due to the temperature difference accompanying the water vapor mixture 4, and a workpiece W with an insulating layer is disposed in this region. By increasing the concentration of water vapor 3 around the workpiece W in this way, the generation efficiency of COH based on ultraviolet irradiation can be improved. As a result, COH can be formed efficiently and stably from the surface of the insulating layer to its interior surface region. Therefore, even when a copper film is formed directly on the surface of the insulating layer by sputtering, for example, the adhesion strength between the insulating layer and the copper film can be improved. As a result, the reliability of the wiring substrate can be significantly improved.

[0137] <Second Implementation Method>

[0138] The ultraviolet treatment apparatus according to the second embodiment of the present invention will be described. In the following description, parts that have the same structure and function as those in the ultraviolet treatment apparatus 100 described in the above embodiment will be omitted or simplified.

[0139] In the above embodiment, a structure that generates a temperature difference in the water vapor mixture 4 within the processing chamber 30 by means of a heater 46 provided on the mounting platform 40 has been described. The location of any mechanism that generates a temperature difference in the water vapor mixture 4 within the processing chamber 30 is not limited.

[0140] Figure 5 This is a schematic diagram illustrating a structural example of the ultraviolet treatment apparatus according to the second embodiment. The ultraviolet treatment apparatus 200 is envisioned as a device using a mixed gas 2 with a molecular weight greater than water, with the treatment chamber 30 positioned on the upper side and the lamp box 20 positioned on the lower side. Furthermore, in the ultraviolet treatment apparatus 200, and... Figure 1 Compared to the ultraviolet treatment device 100 shown, a heating unit 60 is provided instead of the heater of the heating platform 40.

[0141] The heating unit 60 includes a unit housing 61 and a unit heater 62. The unit housing 61 is the shell constituting the heating unit 60, and is constructed, for example, using a metal structural component. The unit heater 62 is disposed inside the unit housing 61 and is a heating element that heats the entire unit housing 61. For example, a sheathed heater can be used as the unit heater 62. The unit housing 61, heated by the unit heater 62, exchanges heat with the water vapor mixture 4, thereby locally heating the water vapor mixture 4. Furthermore, a temperature sensor 48e is provided in the heating unit 60 for measuring its temperature.

[0142] Heating unit 60 is a unit for heating the water vapor mixture 4, and is disposed in the flow path of the water vapor mixture 4. Figure 1 In the example shown, a heating unit 60 is provided on the upper surface 33a side of the processing space 33, near the outlet 35b. Furthermore, the location of the heating unit 60 is not limited; for example, it can be provided on the lower surface 33b side of the processing space 33, or near the supply port 35a. Alternatively, the heating unit 60 can be provided in the central portion of the processing space 33.

[0143] Thus, even when the heating unit 60 is installed in the flow path of the water vapor mixture 4, for example, similar to the case where a heater is installed on the platform 40, a temperature difference can be imparted to the water vapor mixture 4 within the processing space 33 to induce convection. In this embodiment, the heating unit 60 is equivalent to a temperature difference generating mechanism that generates a temperature difference in the water vapor mixture within the processing chamber.

[0144] [Example 4: Relationship between temperature difference and sealing strength when using a heating unit]

[0145] Table (4) shows the experimental results under the condition that the temperature difference inside the processing chamber 30 is changed using the heating unit 60. The samples used in the experiment are the same as those used in Examples 1-3 above. In addition, the highest temperature in Table (4) is the temperature of the heating unit 60, and the lowest temperature is the temperature of the lowest part of the shell facing the processing space 33. In any of the experiments shown in Table (4), the relative humidity of water vapor 3 is 40%, and the VUV irradiation time is 6 seconds.

[0146]

[0147] In experiments 41-47 shown in Table (4), with the minimum temperature of the processing space 33 set to 30°C, the maximum temperature (temperature of the heating unit 60) was set to 50°C, 80°C, 120°C, 150°C, 180°C, 210°C, and 240°C for ultraviolet treatment. In this experiment, if the maximum temperature (temperature difference) is increased, the sealing strength and O1s ratio increase. In experiment 47 (maximum temperature 240°C, temperature difference 210°C), both the sealing strength and O1s ratio are the highest.

[0148] Thus, when using the heating unit 60, for example, compared to the case of heating the stage 40, the impact on the heating of the workpiece W is lower. Therefore, the temperature of the heating unit 60 can be set to a relatively high temperature, increasing the temperature difference. As a result, a high degree of adhesion between the insulating layer and the copper film can be achieved.

[0149] <Third Implementation Method>

[0150] In the above embodiment, as a mechanism for generating a temperature difference in the water vapor mixture 4 within the processing chamber 30, a heating mechanism for heating the water vapor mixture 4 is used. Figure 1 heater 46, Figure 5 The case of the unit using heater 62) has been described. As a structure that generates a temperature difference in the water vapor mixture 4, a mechanism for local cooling of the components connected to the processing space 33 can also be used.

[0151] Figure 6 This is a schematic diagram illustrating a structural example of the ultraviolet treatment apparatus according to the third embodiment. The ultraviolet treatment apparatus 300 is envisioned to use a mixed gas 2 with a molecular weight greater than water, with the treatment chamber 30 positioned on the upper side and the lamp box 20 positioned on the lower side. Furthermore, in the ultraviolet treatment apparatus 300, besides… Figure 1 In addition to the ultraviolet treatment device 100 shown, a cooling unit 70 is also provided inside the lamp box 20.

[0152] The cooling unit 70 is a cooling mechanism that cools the atmosphere inside the lamp housing 20. The cooling unit 70 cools the atmosphere gas (e.g., nitrogen) used in the lamp housing 20 inside the lamp housing 20. As a result, the entrance window 23 constituting the lower surface 33b of the processing space 33 and the lamp housing 21 are cooled, and the water vapor mixture 4 inside the processing space 33 can be locally cooled.

[0153] In addition, such as Figure 6As shown, in the ultraviolet treatment apparatus 300, a heater 46 installed on the mounting platform 40 locally heats the water vapor mixture 4 within the treatment space 33. This allows for the easy generation of a large temperature difference through the combined use of localized cooling and heating. In this embodiment, the cooling unit 70 and the heater 46 on the mounting platform 40 constitute a temperature difference generating mechanism that creates a temperature difference in the water vapor mixture within the treatment chamber.

[0154] The cooling unit 70 includes a cooling pipe 71 and a cooling pipe holder 72. The cooling pipe 71 is a piping through which refrigerant flows, and is constructed, for example, using a pipe made of a metal with high thermal conductivity. The cooling pipe holder 72 is a structural component that holds the cooling pipe 71, for example, by exposing the surface of the cooling pipe 71. Alternatively, the cooling pipe holder 72 may also be configured as a heat transfer component that provides a medium for heat exchange between the atmospheric gas inside the lamp box 20 and the cooling pipe 71. Figure 6 In the example shown, a cooling pipe 71 is provided along the inner periphery of the upper side of the space inside the light box 20. This allows for direct cooling not only of the atmospheric gas used in the light box 20, but also of the components on the lower surface 33b side of the processing space 33. Furthermore, the structure of the cooling unit 70 is not limited.

[0155] [Example 5: Relationship between temperature difference and sealing strength when using a heating unit]

[0156] Table (5) shows the experimental results under the condition of varying the temperature difference within the processing chamber 30 using the cooling unit 70. The samples used in the experiment were the same as those used in Examples 1-3 above. The highest temperature in Table (5) is the temperature of the stage 40, and the lowest temperature is the temperature of the lamp housing 21 constituting the lower surface 33b of the processing space 33 (measured by the temperature sensor 48d). The lowest temperature was varied by controlling the temperature of the cooling unit 70. In addition, the relative humidity of the water vapor 3 was 40%, and the VUV irradiation time was 6 seconds.

[0157]

[0158] In experiments 51-55 shown in Table (5), ultraviolet treatment was performed with the highest temperature of the treatment space 33 set to 150℃ and the lowest temperatures set to 25℃, 20℃, 15℃, 10℃, and 5℃. In this experiment, it was found that if the lowest temperature is lowered, i.e., if the temperature difference is increased, the sealing strength and O1s ratio increase. It should be noted that in experiments 54 (lowest temperature 10℃, temperature difference 140℃) and 55 (lowest temperature 5℃, temperature difference 145℃), the sealing strength and O1s ratio are the same.

[0159] Thus, by using the cooling unit 70, even under a fixed maximum temperature, the temperature difference of the water vapor mixture 4 in the processing space 33 can be increased, thereby improving the sealing strength. Furthermore, the ultraviolet light source 22 inside the lamp box 20 needs to be cooled to dissipate its heat; therefore, the cooling unit 70 also functions as a mechanism for cooling the ultraviolet light source 22. Conversely, any device equipped with a cooling mechanism for the ultraviolet light source 22 can be configured to increase the temperature difference within the processing chamber 30. Therefore, even when there is an upper limit to the maximum temperature, the sealing strength can be sufficiently improved.

[0160] <Fourth Implementation Method>

[0161] In the above embodiments, an example of using a gas with a molecular weight greater than that of water as the mixing gas 2 constituting the water vapor mixture 4 has been described. However, it is not limited to this; the mixing gas 2 may also be a gas with a molecular weight smaller than that of water.

[0162] When the molecular weight of the mixed gas 2 is smaller than that of water, the relationship between the concentration distributions of water vapor 3 and the mixed gas 2 in the treatment space 33 is the same as when the molecular weight of the mixed gas 2 is larger than that of water (refer to...). Figure 3 The concentration distribution is reversed compared to the previous method. That is, the relatively dense water vapor 3 becomes highly concentrated on the lower surface 33b side of the processing space 33, while the relatively less dense mixed gas becomes highly concentrated on the upper surface 33a side of the processing space 33. In this embodiment, the processing chamber 30 and the light box 20 are configured based on this concentration distribution.

[0163] Figure 7 This is a schematic diagram illustrating a structural example of the ultraviolet treatment apparatus according to the fourth embodiment. The ultraviolet treatment apparatus 400 is envisioned to use a mixed gas 2 with a molecular weight smaller than water. Therefore, in the ultraviolet treatment apparatus 400, the treatment chamber 30 is disposed on the lower side, and the lamp box 20 is disposed on the upper side. This can also be described as, for example, using... Figure 1 The structure of the ultraviolet treatment device 100 shown is configured with its top and bottom reversed.

[0164] In this embodiment, the concentration of water vapor 3 is relatively high on the lower surface 33b side of the processing space 33. Therefore, in the ultraviolet processing apparatus 400, the workpiece W is held on the lower surface 33b side of the processing space 33, and ultraviolet light is incident from the upper surface 33a side. Specifically, the holding surface 41 that holds the workpiece W constitutes the lower surface 33b of the processing space 33. In addition, the entrance window 23 through which ultraviolet light 1 enters constitutes the upper surface 33a of the processing space 33. With this structure, the workpiece W can be held in an area where ultraviolet light is irradiated and the concentration of water vapor 3 is relatively high. As a result, the concentration of water vapor 3 around the insulating layer on the surface of the workpiece W can be stably increased.

[0165] [Example 6: Sealing strength when using a mixed gas with a molecular weight smaller than water]

[0166] As the mixed gas 2 with a molecular weight smaller than water, either hydrogen or helium is used. Table (6) shows the introduction of the mixed gas 2 with a molecular weight smaller than water. Figure 7 The experimental results were obtained using the ultraviolet treatment device 400 shown. The samples used in the experiments were the same as those used in Examples 1-3 above. In any of the experiments shown in Table (6), the relative humidity of water vapor 3 was 40%, the maximum temperature was 150°C, the minimum temperature was 20°C, the temperature difference was 120°C, and the VUV irradiation time was 6 seconds.

[0167]

[0168] Experiment 61, shown in Table (6), was conducted for comparison and is an example of using nitrogen gas with a molecular weight greater than water in the ultraviolet treatment device 400. The results of experiment 61 are observed and compared with those in… Figure 1 Compared to the experiment conducted in the ultraviolet treatment apparatus 100 shown (refer to experiment number 24 in Table (2)), the sealing strength was lower. This is believed to be because the concentration of nitrogen gas around the workpiece W is higher than that of water vapor 3, thus reducing the efficiency of COH generation.

[0169] In experiments 62 and 63, hydrogen (H2: molecular weight 2) and helium (He: molecular weight 4) were used as the mixed gas 2, respectively, with a molecular weight smaller than water. Under these conditions, the adhesion strength was significantly improved compared to using nitrogen. Experiment 62, using hydrogen, showed the highest adhesion strength, more than four times that of the nitrogen-using experiment. For example, when hydrogen molecules reach the surface of the workpiece W, the diffusion coefficient is small, allowing them to penetrate the resin. In this case, it is believed that hydrogen molecules become the raw material for COH bonding within the resin, thus further improving the adhesion strength.

[0170] Thus, even when using a mixed gas 2 with a molecular weight smaller than water, COH can be efficiently formed by holding the workpiece W in the region where the concentration of water vapor 3 is higher within the processing chamber 30. Furthermore, when using hydrogen, the hydrogen becomes a raw material for COH within the resin, thus further improving the bonding strength is expected.

[0171] <Other Implementation Methods>

[0172] The present invention is not limited to the embodiments described above, and can be implemented in various other ways.

[0173] In the above description, ultraviolet treatment performed by an ultraviolet treatment apparatus was used to modify the insulating layer before sputtering a copper film or the like. This invention is not limited to sputtering film formation and can be applied to other processes that form metals or metal compounds on a resin surface.

[0174] For example, this invention can be used for various pretreatments such as pretreatment for vacuum evaporation (automotive rearview mirrors, etc.), pretreatment for CVD (Chemical Vapor Deposition) (semiconductor devices, etc.), pretreatment for ALD (Atomic Layer Deposition) (all-solid-state batteries, etc.), pretreatment for direct bonding of metal plates and resin plates (fuel cells, etc.), and pretreatment for plating (printed substrates, etc.). The hydrogen in the COH formed on the resin surface is replaced by metal or metal compounds, forming covalent bonds with oxygen. This significantly improves the adhesion between the resin material and the metal or metal compound. It should be noted that because the molecular radius of the replaced hydrogen is very small, it is temporarily absorbed by the resin and then disappears through the resin. Therefore, no residual effects from hydrogen remain.

[0175] Furthermore, the present invention is not limited to the pretreatments described above, and can be used for any modification treatment performed by forming COH (hydroxyl groups) in the insulating layer. For example, by forming a large number of hydrophilic COH functional groups, the hydrophilicity of the insulating layer can be significantly improved. Thus, for example, treatment using hydrophilic solutions can be appropriately performed. Moreover, the present invention can be applied to any treatment requiring the formation of COH functional groups.

[0176] At least two of the feature portions described above can be combined. That is, the various feature portions described in each embodiment can be arbitrarily combined without distinguishing between the embodiments. In addition, the various effects described above are merely illustrative and not limiting, and other effects may also be achieved.

[0177] Marker description

[0178] W…workpiece; 4…water vapor mixture; 10…Gas Supply Department; 20…lightbox; 22…Ultraviolet light source; 23…entry window; 30…processing room; 33…processing space; 33a…upper surface; 33b…lower surface; 40…stage; 41…Keep the surface intact; 46… heaters; 60… heating units; 70…cooling unit; 100, 200, 300, 400… Ultraviolet treatment devices.

Claims

1. An ultraviolet treatment device, comprising: Ultraviolet light source; The processing chamber receives ultraviolet light from the ultraviolet light source; The gas supply unit supplies the processing chamber with a water vapor mixture containing a mixing gas and water vapor; A temperature difference generating mechanism that creates a temperature difference between the water vapor mixture in the processing chamber; and A stage is used in the processing chamber to hold the workpiece in an area where it is irradiated by ultraviolet light and where the concentration of water vapor is relatively high due to convection of the water vapor mixture caused by the temperature difference.

2. The ultraviolet treatment apparatus according to claim 1, wherein, The gas used for mixing is an inactive gas.

3. The ultraviolet treatment apparatus according to claim 1, wherein, The processing chamber includes a processing space supplied with the water vapor-gas mixture. The temperature difference generating mechanism locally heats or cools the components in contact with the processing space.

4. The ultraviolet treatment apparatus according to claim 3, wherein, The ultraviolet processing device also includes an entrance window that allows ultraviolet light from the ultraviolet light source to enter the processing space. The stage has a holding surface that is disposed opposite to the entrance window across the processing space and holds the workpiece.

5. The ultraviolet treatment apparatus according to claim 4, wherein, The processing space is the space enclosed by an upper surface and a lower surface that extend horizontally. The gas used for mixing is a gas with a molecular weight greater than that of water. The retaining surface forms the upper surface of the processing space. The entrance window forms the lower surface of the processing space.

6. The ultraviolet treatment apparatus according to claim 5, wherein, The gas used for mixing is any one of nitrogen, neon, argon, krypton, and xenon.

7. The ultraviolet treatment apparatus according to claim 4, wherein, The processing space is the space enclosed by an upper surface and a lower surface that extend horizontally. The gas used for mixing is a gas with a molecular weight smaller than that of water. The retaining surface forms the lower surface of the processing space. The entrance window forms the upper surface of the processing space.

8. The ultraviolet treatment apparatus according to claim 7, wherein, The gas used for mixing is either hydrogen or helium.

9. The ultraviolet treatment apparatus according to claim 4, wherein, The distance between the entrance window and the workpiece is more than 0.1 mm and less than 3 mm.

10. The ultraviolet treatment apparatus according to claim 4, wherein, The processing chamber and the mounting platform are configured such that the surface containing the holding surface in the processing space is substantially planar.

11. The ultraviolet treatment apparatus according to claim 1, wherein, The temperature difference generating mechanism includes a heating mechanism for heating the water vapor mixture in the processing chamber.

12. The ultraviolet treatment apparatus according to claim 11, wherein, The heating mechanism is disposed on the platform or in the flow path of the water vapor mixture.

13. The ultraviolet treatment apparatus according to claim 1, wherein, The ultraviolet processing device also includes a light source chamber for housing the ultraviolet light source. The temperature difference generating mechanism includes a cooling mechanism for cooling the atmosphere inside the light source chamber.

14. A method for ultraviolet treatment, The workpiece is irradiated with ultraviolet light using the ultraviolet treatment device according to claim 1.

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