A pressuring module includes a stage having a mounting surface on which an object to be pressured is mounted; a plurality of pressure detecting sections that detect a pressure applied on the mounting surface; and a pressure varying section that varies a pressure distribution across a plane of the mounting surface, by differing a pressing force against the object to be pressured between a periphery and a central portion of the mounting surface in a plane direction of the mounting surface based on the pressure detected by the plurality of pressure detecting sections.

1. TECHNICAL FIELD

The present invention relates to a pressuring module, a pressuring apparatus, a substrate bonding apparatus, a substrate bonding method, and a bonded substrate.

2. RELATED ART

Japanese Patent Application Publication No. 2009-49066 describes a wafer bonding apparatus that bonds two wafers on which circuitry has been formed by heating and pressuring, thereby manufacturing a third-dimensional laminated semiconductor apparatus. When bonding a wafer larger than a chip, it is required to pursue bonding by creating a condition under which the entire wafer can be in press-contact. The wafer bonding apparatus uses a pressure profile control module to control the pressure.

However, depending on how the pressure profile control module is structured and controlled, a large difference is caused in pressure uniformity across the plane of the wafer in press-contact.

SUMMARY

Therefore, an aspect related to the innovations herein is to provide a pressuring module, a pressuring apparatus, a substrate bonding apparatus, a substrate bonding method, and a bonded substrate, which can solve the above-mentioned problems. This is achieved by combinations of the features of the claims According to a first aspect related to the innovations herein, provided is a pressuring module including a stage having a mounting surface on which an object to be pressured is mounted; a plurality of pressure detecting sections that detect a pressure applied on the mounting surface; and a pressure varying section that varies a pressure distribution across a plane of the mounting surface, by differing a pressing force against the object to be pressured between a periphery and a central portion of the mounting surface in a plane direction of the mounting surface based on the pressure detected by the plurality of pressure detecting sections.

According to a second aspect related to the innovations herein, provided is a pressuring apparatus having the above-explained pressuring modules provided to oppose each other.

According to a third aspect related to the innovations herein, provided is a substrate bonding apparatus including: the above-described pressuring module, and another stage provided to oppose the stage of the pressuring module, where the substrate bonding apparatus bonds a plurality of substrates mounted between the stage of the pressuring module and the another stage.

According to a fourth aspect related to the innovations herein, provided is a substrate bonding method including: mounting a plurality of substrates between mounting surfaces of a pair of opposing stages; detecting a pressure applied on the mounting surfaces using a plurality of pressure detecting sections; and varying a pressure by varying a pressure distribution across a plane of the mounting surfaces, by differing a pressing force against an object to be pressured between a periphery and a central portion of the mounting surfaces in a plane direction of the mounting surfaces based on the pressure detected by the plurality of pressure detecting sections.

According to a fifth aspect related to the innovations herein, provided is a bonded substrate resulting from the stated substrate bonding method.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1is a plan view schematically showing the entire structure of a bonding apparatus100including a pressuring apparatus240. The bonding apparatus100includes an atmosphere environment section102and a vacuum environment section202created inside a common casing101.

The atmosphere environment section102includes a plurality of substrate cassettes111,112, and113, and a control plate120. Operation of each element of each apparatus included in the bonding apparatus100is realized by control of the entire bonding apparatus100as well as the cooperative control or the integrated control performed by the control plate120controlling operation and the control operation sections provided for respective elements. The control plate120includes an operating section which a user can operate from outside when turning on the power switch of the bonding apparatus100or performing various settings thereto. The control plate120may also include a connecting section to connect to other installed appliances.

The substrate cassettes111,112, and113are for accommodating therein a substrate180to be bonded or having already been bonded by the bonding apparatus100. The substrate cassettes111,112, and113are detachably mounted to the casing101. Accordingly, the plurality of substrates180can be collectively mounted to the bonding apparatus100. It becomes also possible to collectively collect the substrates180finished being bonded by the bonding apparatus100.

The atmosphere environment section102includes a pre-aligner130, a provisional bonding apparatus140, a substrate holder rack150, a substrate removing section160, and a pair of robot arms171,172, which are respectively provided in the casing101. The temperature management is performed inside the casing101to maintain therein substantially the same temperature as in the environment in which the bonding apparatus100is installed. This facilitates accurate alignment by stabilizing the accuracy of the provisional bonding apparatus140.

The provisional bonding apparatus140is an apparatus to accurately align two opposing substrates180to superpose them, and so its adjustment range is very narrow. Therefore, prior to bringing substrates180into the provisional bonding apparatus140, the pre-aligner130is used to roughly grasp the position of the individual substrates180so that the substrates180can fall within the adjustment range allowed by the provisional bonding apparatus140. In the actual installment to the provisional bonding apparatus140, the substrates180are handed to the robot arm172by adjusting their orientations based on the roughly grasped position by the pre-aligner130. This process helps accurate alignment in the provisional bonding apparatus140.

The substrate holder rack150waits while accommodating therein a plurality of substrate holders190. The concrete configuration of the substrate holder190, designed to hold the substrates180by electrostatic suction, is detailed later.

The provisional bonding apparatus140includes a fixed stage141, a movable stage142, and an interferometer144. A heat insulating wall145and a shutter146are provided to surround the provisional bonding apparatus140. The space surrounded by the heat insulating wall145and the shutter146is subjected to temperature management by communicating to an air conditioner or the like, to maintain the alignment accuracy of the provisional bonding apparatus140.

The movable stage142of the provisional bonding apparatus140conveys the substrate180or the substrate holder190holding the substrate180. The fixed stage141, on the contrary, holds the substrate holder190or the substrate180in the fixed state.

The substrate removal section160removes the substrate180bonded by being sandwiched by the substrate holder190, from the substrate holder190taken out from the pressuring apparatus240detailed later. The substrate180, having been taken out from the substrate holder190, is returned and accommodated in the substrate cassette113by the robot arms172,171and the movable stage142. The substrate holder190, from which the substrate180has been taken out, is returned to the substrate holder rack150and waits.

The substrate180to be mounted to the bonding apparatus100may be a single silicon wafer, a compound semiconductor wafer, or the like, already provided with a plurality of periodic circuitry patterns. The mounted substrate180may also be a laminated substrate formed by laminating a plurality of wafers.

Among the robot arms171,172, the robot arm171located nearer the substrate cassettes111,112, and113conveys the substrate180between the substrate cassettes111,112,113, the pre-aligner130, and the provisional bonding apparatus140. The robot arm171also has a function of flipping one of the substrates180to be bonded. This robot arm171can facilitate bonding substrates180together by opposing respective surfaces on which circuitry, elements, terminals, or the like are formed.

On the other hand, the robot arm172located farther from the substrate cassettes111,112, and113conveys the substrate180and the substrate holder190between the provisional bonding apparatus140, the substrate holder rack150, the substrate removing section160, the substrate holder rack150, and the air lock chamber220. The robot arm172also carries in and out the substrate holder190to and from the substrate holder rack150.

The vacuum environment section202includes a heat insulating wall210, an air lock chamber220, a robot arm230, and a plurality of pressuring apparatuses240. The heat insulating wall210surrounds the vacuum environment section202, to maintain a high temperature within the vacuum environment section202, as well as to prevent heat radiation from fleeing to outside the vacuum environment section202. Accordingly, the effect of the heat of the vacuum environment section202onto the atmosphere environment section102can be restrained.

The robot arm230conveys the substrate180and the substrate holder190between any of the pressuring apparatuses240and the air lock chamber220. The air lock chamber220includes shutters222,224that open and close alternately, which are provided respectively for the atmosphere environment section102and the vacuum environment section202.

When the substrate180and the substrate holder190are transported from the atmosphere environment section102to the vacuum environment section202, the shutter222at the atmosphere environment section102is first opened, and the robot arm172conveys the substrate180and the substrate holder190to the air lock chamber220. Next, the shutter222at the atmosphere environment section102is closed, and the shutter224at the vacuum environment section202is opened.

The air lock chamber220is provided with a heater221, using which the substrate180and the substrate holder190to be carried in are pre-heated prior to undergoing pressurized heating by the pressuring apparatus240. To be more specific, prior to carrying the substrate180and the substrate holder190into the pressuring apparatus240, they are heated the to a certain degree in the air lock chamber220making best use of the time required for exchanging its atmosphere, thereby improving the throughput of the pressuring apparatus240. It is desirable to start heating the inside of the air lock chamber220prior to carrying the substrate180and the substrate holder190into the air lock chamber220. This helps shorten the duration during which the substrate180and the substrate holder190have to stay in the air lock chamber220.

Subsequently, the robot arm230takes the substrate180and the substrate holder190out of the air lock chamber220, and mounts them to one of the pressuring apparatuses240. Each pressuring apparatus240pressures in the heat the substrate180carried in the pressuring apparatus240by being sandwiched by the substrate holder190. Accordingly, the substrate180is eternally bonded. The concrete processing and configuration are detailed later.

The pressuring apparatus240includes a main body to pressure the substrate180and the substrate holder190and a pressuring chamber in which the main body is installed. The robot arm230is provided within the robot arm chamber. In other words, the plurality of pressuring chambers, the robot arm chamber, and the air lock chamber220, which constitute the vacuum environment section202, are respectively partitioned, to be able to adjust their atmospheres independently from each other. In addition, as shown in the drawings, the vacuum environment section202is designed such that the plurality of pressuring chambers and the air lock chambers220align in the circumferential direction with the robot arm chamber at the center.

When carrying out the substrate180and the substrate holder190from the vacuum environment section202to the atmosphere environment section102, the above-described series of operations are executed in the reverse order. According to the series of operations, the substrate180and the substrate holder190can be carried in and out to and from the vacuum environment section202, without leaking any internal atmosphere of the vacuum environment section202towards the atmosphere environment section102.

Note that one of the plurality of pressuring apparatuses240can be replaced by a cooling apparatus. In this case, a cooling chamber in which the cooling apparatus is to be installed is also provided in the robot arm chamber's vicinity. The substrate180and the substrate holder190, after heated by the pressuring apparatus240, are transported into the cooling apparatus, and the cooling apparatus cools them to be a certain temperature. It is desirable that the cooling apparatus cools the cooling chamber in advance, prior to receiving the substrate180and the substrate holder190having been heated.

The following briefly explains the flow in which two substrates180are superposed onto each other and integrated. After the bonding apparatus100has started operating, the robot arm171carries the substrates180one by one to the pre-aligner130, thereby pre-aligning the substrates180. During this process, the substrates180whose bonding surface is downward are prioritized in pre-aligning. In parallel with the pre-aligning process, the robot arm172removes the substrate holder190accommodated with its surface to hold the substrate180oriented downward is removed from the substrate holder rack150, and carries it to the fixed stage141whose mounting surface is oriented downward. The fixed stage141fixes, by vacuum suction, the transported substrate holder190. Note that the fixed stage141is positioned above the movable stage142.

Thereafter, the robot arm171takes out the pre-aligned substrate180from the pre-aligner, orients its bonding surface downward using the reverse mechanism during the transportation, and provisionally places it over the plurality of push-up pins protruding from the movable stage142. The substrate180provisionally positioned over the push-up pins will be raised towards the fixed stage141by the push-up pins, to abut against the mounting surface of the substrate holder190already fixed to the fixed stage141. The substrate holder190receives power from the fixed stage141, to fix the substrate180by electrostatic suction.

Next, the substrates180whose bonding surface is oriented upward are pre-aligned. In parallel with this processing, the robot arm172takes out the substrate holder190whose surface to hold the substrate180is oriented upward is removed from the substrate holder rack150, and carries it to the movable stage142whose mounting surface is oriented upward. The movable stage142fixes, by vacuum suction, the transported substrate holder190. Note that push-up pins are retreated from the stage surface of the movable stage142when the substrate holder190whose surface to hold the substrate180is oriented upward is transported to the movable stage142.

Thereafter, the robot arm171takes out the pre-aligned substrate180from the pre-aligner, and mounts it on the mounting surface of the substrate holder190already fixed to the movable stage142. The substrate holder190receives power from the movable stage142, to fix the substrate180by electrostatic suction. In this way, pairs of a substrate holder190and a substrate180are fixed to their stages so that the bonding surfaces of the two substrates oppose each other.

When the substrates180are fixed with their bonding surfaces opposed to each other, the movable stage142is moved with precision by monitoring its position using the interferometer144, and the bonding surface of the mounted substrate180is aligned to the bonding surface of the substrate180held by the fixed stage141. After completion of this alignment, the movable stage142is moved towards the fixed stage141, and the substrates are provisionally bonded by contacting their bonding surfaces. The provisional bonding is pursued by integration by operating the suction mechanisms provided for the two opposing substrate holders190.

The two substrates180and the two substrate holders190integrated by the provisional bonding are transported to the air lock chamber220by means of the robot arm172. After transported to the air lock chamber220, the substrate180and the substrate holder190are mounted to the pressuring apparatus240by means of the robot arm230.

The two substrates180are heated and pressured by the pressuring apparatus240, thereby being bonded together and eternally integrated. Thereafter, the substrate180and the substrate holder190are taken out from the vacuum environment section202, to be carried in the substrate removing section160, to be separated from each other therein.

The bonded substrates180are transported to the substrate cassette113to be stored therein. The movable stage142is also used in transportation from the robot arm172to the robot arm171during this process. The substrate holder190is returned to the substrate holder rack150by means of the robot arm172.

The following explains the substrate holder190.FIG. 2is a perspective view showing a substrate holder190observed from above. In this drawing, the substrate180is held on the upper surface of the substrate holder190.FIG. 3is a perspective view showing the substrate holder190observed from below.

The substrate holder190includes a holder main body191, suction members192, and voltage applying terminals194, and forms a round plate whose diameter is size larger than the substrate180on the whole. The holder main body191is integrally formed by a highly rigid material such as ceramics or metal. The suction members192are formed by a ferromagnetic material, and are provided on the circumferential area of the surface to hold the substrate180, which is outside of the held substrate180. In this drawing, a total of six suction members192are provided, each pair of them provided at 120 degrees relative to each other. The voltage applying terminal194is embedded on the rear surface relative to the surface to hold the substrate180.

The holding surface of the holder main body191has a high level of planarity. In addition, the holder main body191has a plurality of aligning holes193formed from the front to rear surfaces of the holder main body191, outside the region at which the held substrate180is adhered by electrostatic suction. The holder main body191also has a plurality of insertion holes195formed from the front to rear surfaces of the holder main body191, inside the region at which the held substrate180is adhered by electrostatic suction. A push-up pin is inserted to each insertion hole195, to detach the substrate180from the substrate holder190.

The alignment holes193are fitted to the alignment pins of the fixed stage141or the like, and are used for aligning the substrate holder190. The suction members192are embedded in the concave region of the holder main body191, with their upper surface positioned at substantially the same plane as the holding surface. The voltage applying terminals194are embedded in the rear surface of the holder main body191. By supplying a voltage through the voltage applying terminals194, a potential difference is caused between the substrate holder190and the substrate180, thereby attaching the substrate180to the substrate holder190by electrostatic suction. Such members as the fixed stage141are provided with voltage supply terminals respectively, so as to sustain the electrostatic suction between the substrate180and the substrate holder190.

There is a slight difference in configuration between the substrate holder190mounted on the movable stage142and the substrate holder190mounted on the fixed stage141. Specifically, instead of providing the suction members192, a plurality of magnets are provided to correspond in position to the suction members192. By means of coupling of the suction members192to the magnets, the two substrates180are sandwiched, to integrate the two substrate holders190. Thus integrated two substrates180and two substrate holders190are occasionally referred to as “a substrate-holder pair.”

The following elaborates the structure of the pressuring apparatus240.FIG. 4is a front view schematically showing the entire configuration of the pressuring apparatus240. The pressuring apparatus240is installed in the pressuring chamber adjusted under the vacuum environment. The pressuring apparatus240is configured by an upper top plate31, an upper heat module41, and an upper pressure control module51which are installed at the ceiling, as well as a lower top plate32, a lower heat module42, a lower pressure control module52, and an elevation module60which are installed on the floor. The upper top plate31, the upper heat module41, and the upper pressure control module51form an upper pressuring module, and the lower top plate32, the lower heat module42, the lower pressure control module52form a lower pressuring module. Note that in the present embodiment, each of the upper pressuring module and the lower pressuring module can also function as a heating module, because the upper heat module41and the lower heat module42heat the upper top plate31and the lower top plate32.

A substrate-holder pair in which the two substrate holders190are integrated while sandwiching the two substrates180is carried onto the lower top plate32by means of the robot arm230. When the elevation module60is lifted up, the substrate-holder pair is brought into contact with the upper top plate31, sandwiched between the upper pressuring module and the lower pressuring module, and pressured and heated.

The upper pressuring module and the opposing lower pressuring module have the same structure as each other. The structure of them is briefly explained as follows, taking an example of the lower pressuring module.

FIG. 5is a diagrammatic sectional view of the configuration of a lower pressuring module. Note that the figure is a simplified diagram of the main structure, with some part thereof omitted.

The lower top plate32, which functions as a stage on which the substrate-holder pair is mounted, is a round plate made of silicon carbide, and is screwed to the lower heat module42at the periphery. The lower heat module42includes, inside its cylindrical shape, a plurality of heater plates401,402,403in contact with the surface of the lower top plate32opposite to the surface on which the substrate-holder pair is mounted. The heater plates401,402,403are heating sections, which are formed by copper for example, and electric heaters404are embedded in them respectively. A conductive wire405is used to supply power to the electric heater404, and a bead406made of ceramics for example is used to cover the conductive wire405for protection from high temperatures. A plurality of such beads406are combined to let the conductive wire405penetrate and introduce the conductive wire405from the heating space to the non-heating space.

During heating control, the heater plates401,402,403are heated by the electric heater404and convey the heat to the lower top plate32. During cooling control after completion of the heating, the heater plates401,402,403are cooled by a cooling tube407functioning as a cooler. The heater plates401,402,403are supported and fixed by the frame410formed radially from the central axis passing the center of the lower top plate32.

The frame410is supported by being linked to one end of each of the plurality of supporting columns411in the axial direction. The other end of each supporting column411is linked to a load cell412. Each load cell412is provided in contact with the exterior of the hollow pressuring section501, being one of the main elements of the lower pressure control module52, at the surface opposite to the surface linked to the supporting column411. The load cell412is a pressure detecting section, and straddles the hollow pressuring section501and the supporting column411, to detect the pressure applied from the hollow pressuring section501towards the supporting column411.

The internal space of the lower heat module42is divided between an upper heating space and a lower non-heating space by a heat shielding plate420provided parallel to the mounting surface of the substrate-holder pair of the lower top plate32. The heat shielding plate420is a partition having a function of preventing, as much as possible, conveyance of the heat in the heating space heated by the heater plates401,402,403to the non-heating space in which the hollow pressuring section501, the load cell412, or the like are provided which are susceptible to high temperatures. The heat shielding plate420has a penetration hole provided for passing the supporting column411therethrough. In other words, the supporting column411straddles the heating space and the non-heating space. The heat shielding plate420also has a penetration hole provided for passing the conductive wire405therethrough. Moreover, a cap421is provided around the penetration hole, to conduct the conductive wire405into a direction different from the direction in which it is extracted from the penetration hole.

A plurality of thermal reflectors422distant from each other are provided in parallel to the heat shielding plate420, between the heat shielding plate420and the hollow pressuring section501. Just as the heat shielding plate420, the thermal reflectors422also have penetration holes for passing the supporting column411therethrough. These thermal reflectors422are made of metal plate(s) such as aluminum. A multi-layer film is provided on the surface facing the heating space of at least one of the thermal reflectors, to reflect the wavelength of the radiation near the targeted heating temperature of the lower top plate32. The targeted heating temperature of the lower top plate32is 450 to 500 degrees centigrade when the substrate180to be bonded is a wafer. The thermal reflector422may be configured to be replaceable depending on the targeted heating temperature. This helps alleviate the heat conveyance from the heater plates401,402,403to the hollow pressuring section501. Not limited to the direction parallel to the heat shielding plate420, the thermal reflector(s)422may also be provided in parallel to the axial direction of the supporting column411. This helps alleviate leak of heat from the lower heat module42to outside.

The hollow pressuring section501is a pressure control section in a bag-like form made of a rubber sheet or the like, and is filled with a fluid. Some examples of the fluid are air, water, and oil. For example, hydrofluoroether having excellent environment characteristics may be used. The amount of fluid used to fill the inside is adjusted by controlling the valve502provided for the hollow pressuring section501and the supply tube503. Specifically, the other end of the supply tube503is connected to a pump not illustrated in the drawing. By controlling the pump together with the valve502, the amount of fluid inside the hollow pressuring section501can be increased or decreased. The hollow pressuring section501expands or contracts due to the amount of the internal fluid. Specifically, by adjusting the amount of fluid from or into the inside using the valve502, taking into consideration the pressure imposed on the lower pressure control module52from the elevation module60, the surface to be in contact with the plurality of load cells412can be controlled to be flat, have a form with a convex periphery, or a form with a convex center.

Not limited to a bag-like form made of an elastic material such as a rubber sheet, the hollow pressuring section501may have a form like a box with the planes to be in contact with the plurality of load cells412being deformable plate(s) as well as the planes facing the elevation module60and the circumference being rigid plate(s). In such an embodiment too, as long as the inside space is maintained just like an airtight bag, the internal pressure is adjustable by controlling the fluid to be in and out to and from the outside, thereby enabling to control the pressure with respect to surface in contact with the load cells412.

The following explains the shape and arrangement of the heater plates401,402,403.FIG. 6is a top view of the lower heat module42which reveals the shape and alignment of the heater plates401,402,403.

As shown in this drawing, by setting, as a center, the central axis passing the center of the lower top plate32, one round heater plate401is provided in the center, six heater plates402in a fan-like shape are provided to surround it, and 12 heater plates403in a fan-like shape are further provided to surround them. The fan-like shape of the heater plates402,403have an arc of a circle concentric with the heat plate401at the center.

The plane area covered by the heater plates401,402,403is larger than the area corresponding to the mounting surface of the substrate holder190mounted on the lower top plate32. This enables heating of the rear surface of the substrate holder190evenly. In addition, the heater plates401,402, and403are parallel to each other with a distance therebetween. Accordingly, even when the heater plates401,402,403are heated to be expanded by the electric heater404embedded therein, they are prevented from being in contact to each other. The interval between the heater plates401,402,403is pre-set taking into consideration the targeted heating temperature or the like. For example when the heater plates401,402,403are made of copper, the diameter of the lower top plate32is about 330 mm, and the targeted heating temperature is 450 degrees centigrade, the interval for the heater plates401,402,403is set to be about 1 mm.

The heating surface of each heater plate401,402,403has the same area as each other. Therefore, the diameter, the central angle or the like of the round shape or the fan-like shape are designed to yield the same area. In the example of the drawing, the diameter direction is divided in three stages. However, the number of stages in the diameter direction or the number of rounds or fans in one stage can be arbitrarily set. It is further preferable to equalize the thicknesses of the heater plates401,402, and403, to yield the same heat capacity therebetween.

The cooler tube407functioning as a cooler is provided to cool one or more of the heater plates401,402,403. For example, as the drawing shows, a pipe as the cooler tube407extends to be in contact with either of the heater plates402,403, and an external pump is controlled to circulate the cooling medium therein. The material of the pipe is desirably the same as the material of the heater plates401,402,403. If not exactly the same, if at least having the same linear expansion coefficient as the heater plates, the material is usable as a pipe because there will be no thermal slide due to temperature change at the contact surface.

FIG. 7is a top view of a lower heat module42which reveals the positional relation among the heater plates401,402,403, the frame410, and the supporting columns411. The frame410has such a shape that a plurality of arms elongate radially from the annular portion at the center. The heater plate401is fixed to the annular portion using a screw408, and the heater plates402and403are fixed to the arms using screws408. It is desirable that the screws408be arranged on the central line of the heater plates401,402,403, and either to be rotational symmetrical or bilaterally symmetrical.

The pressure from the hollow pressuring section501is conveyed to the heater plates401,402,403via the plurality of supporting column411and the frame410. Then, the heater plates401,402,403pressure the lower top plate32and heat it. If the hollow pressuring section501is considered as an actuator generating a pressing force in the axial direction of the supporting column411, the pressing force is conveyed in such an order starting from the supporting column411, the heater plate402, and to the lower top plate32, focusing on the supporting column411pressuring the heater plate402. In terms of the relation of the pressing surfaces thereof, the pressing surface of the supporting column411against to the heater plate402is smaller than the pressing surface of the heater plate402against the lower top plate32. In other words, the pressure is conveyed by spreading in the direction to convey, i.e., a localized pressure is gradually distributed. In this way, the pressure generated by the hollow pressing section501is conveyed towards the lower top plate32, thereby generating a constant pressing force onto the lower top plate32, or generating a pressure distribution that is intentionally smoothed out on the lower top plate32so as to pressurize the entire substrate180evenly. Although having a frame410between the heater plates401,402,403and the supporting column411in the present embodiment, the localized pressure is also conducted by being gradually distributed in the present embodiment in a vicinity of each supporting column411.

Although explaining the configuration of pressing the plurality of supporting columns411by a single hollow pressuring section501that expands or contracts by adjusting the amount of the internal fluid, the present embodiment can also be applied to the configuration of using an actuator that pressurizes each of the supporting columns411independently. In other words, even if the pressure generated by the actuator is limited to locally, the pressure can be gradually distributed, to pressurize the lower top plate32with a wide area.

The following explains the load cells412in contact with the exterior of the hollow pressuring section501, and interposed between the hollow pressing section501and the supporting columns411.FIG. 8shows both of a top view and a front view of a load cell412. Distortion gauges413, being a piezoelectric element, are attached to two portions on the upper surface of the load cell412. Likewise, distortion gauges413are attached to two portions on the lower surface. The output lines from the distortion gauges attached to the four portions are combined into the terminal section414at the side surface, to be connected to the outside via the conductive wire415.

In a vicinity of the center of the upper surface, a screw hole416to link the supporting column411is provided. Moreover, two screw holes417are also provided to be symmetrical to the screw hole416. The load cell412is fixed to the hollow pressuring section501via this screw hole417.

The pressure applied to each supporting column411can be detected by monitoring the output from the plurality of load cells412provided in the above manner. Adjustment of the pressure of the hollow pressuring section501or the lifting and lowering of the elevation module60can be pursued depending on the detected pressure. It is further possible to control to stop the pressurizing, when detecting an abnormal pressure exceeding the expected range.

The piezoelectric element can detect an applied pressure because it causes a potential difference according to the level of supplied pressure, and can be physically deformed if applied power. Therefore, when the pressure distribution is found in a certain area while detecting the pressure of the supporting column411, power can be supplied to the distortion gauge413of the load cell412in the area or an area other than the area, to increase the pressure to the supporting column411. By operating the load cell412as an auxiliary actuator in this way, more accurate pressure control can be realized. This is particularly preferable to evenly pressurize the substrate-holder pair mounted on the lower top plate32. In some cases, the hollow pressuring section501may be omitted when using the load cell412as an actuator. The position of the load cells412is not limited to as explained. Alternatively, the load cells412may be provided on the elevation module60to enable adjustment of the pressure applied to the lower pressure control module.

FIG. 9is a sectional view of the wiring of an electric heater404. Although the heater plate401is taken as an example in this embodiment, the heater plates402,403may also be configured in the same way.

As shown in this drawing, a conductive wire405is extracted from the electric heater404embedded in the heater plate401. In an environment that would not become too hot, the conductive wire is normally protected with a vinyl film. In the present embodiment, however, the heater plate401is heated up to 450 to 500 degrees centigrade, a vinyl film would not be an option. In addition, since the heating space and the non-heating space around the conductive wire are vacuum atmospheres, such a material as resin that generates a gas in the vacuum atmosphere cannot be used either. With these in view, a bead406made of an insulation material that would not emit a gas even under a vacuum atmospheric environment, as well as having a melting point higher than the temperature of the heating space is used as a protective material of the conductive wire405. One preferable material is ceramics. A plurality of the beads406protecting the conductive wire405are linked to each other across the heating space and the non-heating space to allow insertion of the conductive wire405therethrough, so that the conductive wire405can be bent.

Even though the heat insulating plate420separates between the heating space and the non-heating space, the heat insulating plate420is provided with a penetration hole423in which to insert the conductive wire405. A flange424is provided at the periphery of the penetration hole423. The flange424is an elevation formed by bending the heat insulating plate420in the insertion direction of the conductive wire405. The penetration section is constituted by the penetration hole423and the flange424.

The beads406are linked to each other with an interval therebetween so that the conductive wire405be bendable. In other words, the beads406respectively have a movable amount in which the beads406can move along the conductive wire405. If this movable amount exceeds the height “h” of the penetrating section, the conductive wire405may come in contact with the penetrating section directly. Therefore, the movable amount is set to be smaller than the height “h” of the penetrating section.

The following explains the structure of the elevation module60.FIG. 10is a diagrammatic sectional view of the configuration of the elevation module60. Note that the figure is a simplified diagram of the main structure, with some part thereof omitted.

The elevation module60is a two-stage structure composed of an upper part and a lower part, which are specifically the main EV section610near the lower pressure control module52and the sub EV section620near the floor. The main EV section610is fastened to the lower pressure control module52at the stage611. From the perspective of the whole elevation module60, this stage611is raised or lowered with respect to the floor, to raise or lower the lower pressure control module52, and further to pressure the substrate-holder pair.

The main EV section610is constituted by a single cylinder piston mechanism having a large diameter, and the sub EV section620is constituted by three cylinder piston mechanisms each having a small diameter, positioned at 120 degree intervals when observed from above. Here, it should be noted that the main EV section610and the sub EV section620interact with each other to raise or lower the stage611, and are not separate bodies simply stacked. The following explains each of these structures.

The main EV section610includes a main piston612having the stage611as its upper surface, a main cylinder613externally fitted onto the main piston, and a bellows614that is connected to the main cylinder613and follows the movement of raising and lowering of the main piston612. A main room615which is a space created between the main cylinder613and the main piston612is maintained air tight even when the main cylinder613is raised or lowered. A main valve616is connected to the main room615, to allow a fluid to flow in and out to and from outside. The main room615is filled with a fluid. By the main valve616controlling the flow-in and flow-out of the fluid, the amount of fluid in the main room615can be changed. The main piston612can be raised or lowered by changing the amount of fluid within the main room615.

As already mentioned, the sub EV section620has three cylinder piston mechanisms in the present embodiment. Each cylinder piston mechanism includes a sub piston621and a sub cylinder624externally fitted onto the sub piston621. The sub piston621is inserted into the piston guide617provided for the main cylinder613from outside the main cylinder613, to reach the inside of the main room615. In addition, a fixing section622to fix to the main piston612is provided at the end of the sub piston621positioned inside the main room615. The fixing section622fastens the sub piston621to the main piston612.

At the end opposite to the end provided with the fixing section622, the sub piston621includes a piston disc623externally fitting onto the sub cylinder624. The space in the sub cylinder624is divided by the piston disc623into an upper subroom625nearer the main cylinder613and a lower subroom626nearer the floor.

Both of the upper subroom625and the lower subroom626are maintained airtight. An upper sub valve627is connected to the upper subroom625using which a fluid comes in and out from outside. To the lower subroom626, a lower sub valve628is connected using which a fluid comes in and out to and from outside. The upper subroom625and the lower subroom626are filled with a fluid. Moreover, since the total volume of the upper subroom625and the lower subroom626is always constant, the volume ratio between the upper subroom625and the lower subroom626can be changed by conducting cooperative control on the upper sub valve627and the lower sub valve628.

When the volume of the upper subroom625is increased, the volume of the lower subroom626decreases to lower the sub piston621. Since the sub piston621is connected to the main piston612, the main piston612is also lowered. During this process, the main valve616is also subjected to cooperative control, to release to outside a fluid in an amount corresponding to the decrease in volume of the main room615caused in response to the lowering of the main piston612.

Conversely, if the volume of the lower subroom626is increased, the volume of the upper subroom625decreases to raise the sub piston621. This also raises the main piston612. During this process, the main valve616is also subjected to cooperative control, to flow, into the main room615, a fluid in an amount corresponding to the increase in volume of the main room615caused in response to the elevation of the main piston612.FIG. 11is a sectional view of the main piston612lifted by increasing the volume of the lower subroom626.

Note that the sub piston621also follows the movement of rising of the main piston612when the main piston612is raised by adjusting the amount of fluid within the main room615using the main valve616. Therefore in this case, it is possible to allow the change in volume of the upper subroom625and the lower subroom626occurring in response to the movement of the sub piston621following the movement of the main piston612, by cooperative control on the upper sub valve627and the lower sub valve628.

The fluid used to fill the main room615, the upper subroom625, and the lower subroom626is air, water, oil, etc. For example, hydrofluoroether having excellent environment characteristics may be used.

By configuring the elevation module60in two stages of the main EV section610and the sub EV section620, a variety in control is made possible depending on how to move the stage611. Specifically, when it is desirable to move it faster than a predetermined speed, the fluid in the sub EV section620is controlled, from which a larger displacement is obtained with a small volume of input and output fluid. When it is desired to apply a predetermined pressure or more, the fluid in the main EV section610is controlled, which experiences a smaller displacement even with a larger amount of input and output fluid. Control can also be directed to the fluid in the main EV section610when the stage611is to move slower than a predetermined speed.

According to the above-described embodiment of the pressuring apparatus240, the upper pressuring module having the same structure as the explained pressuring module is provided, and the elevation module60is used to bring into contact, to the upper pressuring module, the substrate-holder pair mounted to the lower pressuring module, thereby performing pressuring and heating. However, not limited to such an embodiment of installing an upper pressuring module on the ceiling, a plane disc may alternatively be installed on the ceiling, to simply press it from below, and can be still expected to yield a certain level of pressure consistency.

FIG. 12is a front view schematically showing another pressuring apparatus840. In the drawings on and afterFIG. 12, the same members as inFIG. 1through FIG.11are assigned the same reference numerals. The pressuring apparatus840is configured by the upper top plate31, the upper heat module41, and the upper pressure control module51which are installed at the ceiling, and the lower top plate32, the lower heat module42, the lower pressure control module52, and the elevation module60which are installed at the floor. The pressuring apparatus840is installed within the vacuum chamber in which a certain level of vacuum and cleanliness is maintained for the purpose of preventing the oxidation and contamination of the substrate22during the substrate bonding process.

The upper top plate31, the upper heat module41, and the upper pressure control module51form an upper pressuring module. The lower top plate32, the lower heat module42, and the lower pressure control module52form a lower pressuring module. Note that in the present embodiment, each of the upper pressuring module and the lower pressuring module can also function as a heating module, because the upper heat module41and the lower heat module42heat the upper top plate31and the lower top plate32.

An aligner, independent from the pressuring apparatus840, is used to align and superpose the two substrates22to be bonded, so that the electrodes to be bonded together are in contact with each other. These two substrates22are retained by being provisionally bonded together to prevent misalignment. Hereinafter, the substrates22and the substrate holders24in this state are referred to as “a substrate-holder pair.”

The substrate-holder pair is carried into the pressuring apparatus840by a robot arm and is mounted to the lower top plate32(FIG. 12). When the elevation module60is lifted up, the substrate-holder pair is brought into contact with the upper top plate31, sandwiched between the upper pressuring module and the lower pressuring module, and is subjected to substrate bonding processing by being pressured and heated. The upper pressuring module and the opposing lower pressuring module have the same structure. The structure of them is briefly explained as follows, taking an example of the lower pressuring module.

FIG. 13is a diagrammatic sectional view of the configuration of the lower pressuring module. The lower top plate32, which functions as a stage on which the substrate-holder pair is mounted, is a round plate made of silicon carbide, and is screwed to the lower heat module42at the periphery.

The lower heat module42includes, inside its cylindrical body, a plurality of heater plates401,402,403in contact with the surface of the lower top plate32opposite to the surface on which the substrate-holder pair is mounted. The heater plates401,402,403heat the lower top plate32. The heater plates401,402,403are formed by a material having a favorable heat conductivity (e.g., copper), and electric heaters404are embedded in them respectively. A conductive wire405is used to supply power to the electric heater404, and a bead406made of ceramics for example is used to cover the conductive wire405for protection from high temperatures.

During heating control, the heater plates401,402,403are heated by the electric heater404and convey the heat to the lower top plate32. During cooling control after completion of the heating, the heater plates401,402,403are cooled by a cooling tube407functioning as a cooler. The heater plates401,402,403are supported and fixed by the frame410formed radially from the central axis passing the center of the lower top plate32.

The frame410is supported by being linked to one end of each of the plurality of first supporting columns418and second supporting columns431. The other end of each of the plurality of first supporting columns418and second supporting columns431is connected to either a first pressure detecting section419or a second pressure detecting section432. Each first pressure detecting section419is provided to contact with the exterior of the hollow pressuring section501of the lower pressure control module52, at the surface opposite to the surface linked to the first supporting columns418. The first pressure detecting sections419detect pressure applied from the hollow pressuring section501towards the first supporting columns418. The first pressure detecting section419may be a load cell.

Each second pressure detecting section432is provided to contact with the lower plate, being the main body of the lower pressure control module52, at the surface opposite to the surface linked to the second supporting columns431. The second pressure detecting section432detects pressure applied from the main body of the lower pressure control module52towards the second supporting columns431. The second pressure detecting section432may be a load cell.

The internal space of the lower heat module42is divided between an upper heating space and a lower non-heating space by a heat shielding plate420provided parallel to the mounting surface of the substrate-holder pair of the lower top plate32. The heat shielding plate420is a partition having a function of preventing, as much as possible, conveyance of the heat in the heating space heated by the heater plates401,402,403to the non-heating space in which the hollow pressuring section501, the first pressure detecting section419, or the like are provided which are susceptible to high temperatures. The heat shielding plate420has a penetration hole provided for passing the first supporting column418and the second supporting columns431therethrough. In other words, the first supporting columns418and the second supporting columns431straddle the heating space and the non-heating space. The heat shielding plate420also has a penetration hole provided for passing the conductive wire405therethrough.

The hollow pressuring section501is a hollow pressure controller and is filled with a fluid. Some examples of the fluid are air, water, and oil. The hollow pressuring section501adjusts the amount of filled fluid, by controlling the valve502provided between the hollow pressuring section501and the supply tube503. The hollow pressuring section501can control the pressure of the internal fluid by adjusting the amount of filled fluid.

The pressure of the fluid in the hollow pressuring section501is detected and monitored using a pressure sensor436. It is further possible to control to stop the pressurizing, when detecting an abnormal pressure exceeding the expected range.

The hollow pressuring section501may have a bag-like form made of a rubber sheet or the like. The hollow pressuring section501expands or contracts due to the amount of the internal fluid, thereby enabling to control the pressure against the surface in contact with the plurality of first pressuring detecting section419. The hollow pressuring section501may have a form like a box with the planes to be in contact with the plurality of first pressure detecting sections419being deformable plate(s) as well as the planes facing the elevation module60and the periphery being rigid plate(s). In such an embodiment too, as long as the internal pressure is maintained just like an airtight bag, the internal pressure is adjustable by controlling the fluid to be in and out to and from the outside, thereby enabling to control the pressure with respect to surface in contact with the plurality of first pressure detecting sections419. Specifically, by adjusting the amount of fluid from or into the inside using the valve502, taking into consideration the pressure imposed on the lower pressure control module52from the elevation module60, the surface to be in contact with the plurality of first pressure detecting sections419can be controlled to be flat, have a form with a convex periphery, or a form with a convex center.

FIG. 14andFIG. 15show a conceptual sectional view of the shape of the hollow pressuring section501. The hollow pressuring section501includes a lower plate510, an upper plate511, and a hollow chamber512created therebetween. As already described, the hollow chamber512is filled with a fluid supplied from the supply tube503. The upper plate511is provided with grooves514on the outer periphery as a concentric circle with its center being the center of the upper plate511. When the upper plate511is deformed, the grooves514can alleviate the stress concentration at the periphery of the upper plate511.

FIG. 14conceptually shows how the upper plate511is deformed when the pressure of the fluid introduced into the hollow chamber512is raised. When the pressure of the internal fluid in the hollow pressuring section501is high, the upper plate511expands, thereby deforming towards the exterior of the hollow chamber512. The deformation of the upper plate511is the largest at the central portion and gradually decreases towards the periphery.

FIG. 15conceptually shows how the upper plate511is deformed when the pressure of the fluid in the hollow chamber512is lowered. When the pressure of the internal fluid in the hollow pressing section501is low, the upper plate511is deflated, thereby deforming towards the inside of the hollow chamber512. In this case too, the deformation of the upper plate511is the largest at the central portion and gradually decreases towards the periphery, with the deformation direction reversed to the case ofFIG. 14.

FIG. 16is a top view of the lower heat module42, which reveals the shape and position of the heater plates401,402,403. As shown inFIG. 16, by setting, as a center, the central axis passing the center of the lower top plate32, one round heater plate401is provided in the center, six heater plates402in a fan-like shape are provided to surround it, and 12 heater plates403in a fan-like shape are further provided to surround them. The fan-like shape of the heater plates402,403have an arc of a circle concentric with the heat plate401at the center.

The plane are covered by the heater plates401,402,403is larger than the area corresponding to the mounting surface of the substrate holder24mounted on the lower top plate32. This enables heating of the rear surface of the substrate holder24evenly. In addition, the heater plates401,402, and403are parallel to each other with a distance therebetween. Accordingly, even when the heater plates401,402,403are heated to be expanded by the electric heater404embedded therein, they are prevented from being in contact to each other. The interval between the heater plates401,402,403are pre-set taking into consideration the targeted heating temperature or the like. For example when the heater plates401,402,403are made of copper, the diameter of the lower top plate32is about 350 mm, and the targeted heating temperature is 450 degrees centigrade, the heater plates401,402,403are set to be about 5 mm.

The heating surface of each heater plate401,402,403has the same area as each other. Therefore, the diameter, the central angle or the like of the round shape or the fan-like shape are designed to yield the same area. In the example of the drawing, the diameter direction is divided in three stages. However, the number of stages in the diameter direction or the number of rounds or fans in one stage can be arbitrarily set. It is further preferable to equalize the thicknesses of the heater plates401,402, and403, to yield the same heat capacity.

The cooler tube407functioning as a cooler is provided to cool one or more of the heater plates401,402,403. For example, as the drawing shows, the cooler tube407extends to be in contact with either of the heater plates402,403, and an external pump is controlled to circulate the cooling medium therein. The material of the cooling tube is desirably the same as the material of the heater plates401,402,403. If not exactly the same, if at least having the same expansion coefficient as the heater plates, the material is usable as a cooler tube because there will be no thermal slide due to temperature change at the contact surface.

FIG. 17is a top view of a lower heat module42which reveals the positional relation among the first supporting column418and the second supporting column431. The frame410has such a shape that a plurality of arms elongate radially from the annular portion at the center. The heater plate401is fixed to the annular portion using a screw408, and the heater plates402and403are fixed to the arms using screws408. It is desirable that the screws408be arranged on the central line of the heater plates401,402,403, and either to be rotational symmetrical or bilaterally symmetrical.

The pressure from the hollow pressuring section501is conveyed to the heater plates401,402,403via the plurality of first supporting columns418and the frame410. Then, the heater plates401,402,403pressure the lower top plate32and heat it. If the hollow pressuring section501is considered as an actuator generating a pressing force in the axial direction of the first supporting column418, the pressing force is conveyed in such an order starting from the first supporting column418, the heater plate402, and to the lower top plate32, focusing on the first supporting column418pressuring the heater plate402.

The plurality of first pressure detecting section419can detect the pressure applied to each first supporting column418, to monitor the output from the hollow pressuring section501. Adjustment of the pressure of the hollow pressuring section501or the lifting and lowering of the elevation module60can be pursued depending on the detected pressure. It is further possible to control to stop the pressurizing, when detecting an abnormal pressure exceeding the expected range.

As for the second supporting column431, it is provided on a circumferential portion of the hollow pressuring section501and is installed over the lower plate being the main body of the lower pressure control module52via the second pressure detecting section, as shown inFIG. 17. Since the main body of the lower pressure control module52is made of a rigid material, unlike the upper plate511of the hollow pressuring section501which is elastic deformable, the second supporting column431can directly convey the pressure from the elevation module60to the heater plate403. In turn, the heater plate403conveys the applied pressure to the lower top plate32.

According to this arrangement, the second pressure detecting section432, which is provided between the second supporting column431and the lower plate of the lower pressure control module52, can detect the pressure supplied from the elevation module60to the lower top plate32. Adjustment of the pressure of the hollow pressuring section501or the lifting and lowering of the elevation module60can be pursued depending on the detected pressure. It is further possible to control to stop the pressurizing, when detecting an abnormal pressure exceeding the expected range.

As inFIG. 14in which the upper plate511experiences an upward expansion, the pressure given by the hollow pressuring section501to the lower top plate32via the first supporting column418is larger than the pressure given by the elevation module60to the lower top plate32via the second supporting column431. The deformation of the upper plate511is the largest at the central portion and gradually decreases towards the periphery, and so the pressure given by the hollow pressuring section501to the lower top plate32is the largest at the central portion, and gradually decreases towards the periphery.

If the upper plate511experiences an inward depression in the direction of the hollow chamber512as shown inFIG. 15, the pressure given by the hollow pressuring section501to the lower top plate32via the first supporting column418is smaller than the pressure given by the elevation module60to the lower top plate32via the second supporting column431. The deformation of the upper plate511is the largest at the central portion and gradually decreases towards the periphery, and so the pressure given by the hollow pressuring section501to the lower top plate32is the smallest at the central portion, and gradually increases towards the periphery.

If the upper plate511is made flat through adjustment of the pressure of the fluid inside the hollow pressuring section501, the pressure given by the hollow pressuring section501to the lower top plate32via the first supporting column418will be the same as the pressure given by the elevation module60to the lower top plate32via the second supporting column431, thereby equalizing the pressure over the plane of the lower top plate32. In other words, the pressure distribution on the plane of the lower top plate32can be finely adjusted, by adjusting the pressure of the fluid in the hollow pressuring section501. Therefore, even when there is not enough flatness on the front surface or the rear surface of the substrates22to be bonded, substrate bonding can be pursued by the fine adjustment of the pressure using the hollow pressuring section501to provide even pressure across the plane of the substrate22.

FIG. 18is a diagrammatic sectional view of the structure of the elevation module60. The elevation module60is a two-stage structure composed of an upper part and a lower part, which are specifically the main EV section610near the lower pressure control module52and the sub EV section620near the floor. The main EV section610is fastened to the lower pressure control module52at the base611. From the perspective of the whole elevation module60, this base611is raised or lowered with respect to the floor, to raise or lower the lower pressure control module52, and further to pressure the substrate-holder pair.

The main EV section610is constituted by a single cylinder piston mechanism having a large diameter, and the sub EV section620is constituted by three cylinder piston mechanisms each having a small diameter, positioned at 120 degree intervals when observed from above. Here, it should be noted that the main EV section610and the sub EV section620interact with each other to raise or lower the base611, and are not separate bodies simply stacked. The following explains each of these structures.

The main EV section610includes a main piston612having the base611at its upper surface, a main cylinder613externally fitted onto the main piston, and a bellows614that is connected to the main cylinder613and follows the movement of raising and lowering of the main piston612. A main room615which is a space created between the main cylinder613and the main piston612is maintained air tight even when the main cylinder613is raised or lowered. A main valve616is connected to the main room615, to allow a fluid to flow in and out to and from outside. The main room615is filled with a fluid. By the main valve616controlling the flow-in and flow-out of the fluid, the amount of fluid in the main room615can be changed. The main piston612can be raised or lowered by changing the amount of fluid within the main room615.

The main cylinder613is provided with a pressure sensor632. The pressure sensor632detects the pressure of the fluid in the main room615and monitors it. Adjustment of the pressure of the main room615can be pursued depending on the detected pressure, to adjust the lifting and lowering of the elevation module60. It is further possible to control to stop the pressurizing, when detecting an abnormal pressure exceeding the expected range.

As already mentioned, the sub EV section620has three cylinder piston mechanisms in the present embodiment. Each cylinder piston mechanism includes a sub piston621and a sub cylinder624externally fitted onto the sub piston621. The sub piston621is inserted into the piston guide617provided for the main cylinder613from outside the main cylinder613, to reach the inside of the main room615. In addition, a fixing section622to fix to the main piston612is provided at the end of the sub piston621positioned inside the main room615. The fixing section622fastens the sub piston621to the main piston612.

At the end opposite to the end provided with the fixing section622, the sub piston621includes a piston disc623externally fitting onto the sub cylinder624. The space in the sub cylinder624is divided by the piston disc623into an upper subroom625nearer the main cylinder613and a lower subroom626nearer the floor.

Both of the upper subroom625and the lower subroom626are maintained airtight. An upper sub valve627is connected to the upper subroom625using which a fluid comes in and out to and from outside. To the lower subroom626, a lower sub valve628is connected using which a fluid comes in and out to and from outside. The upper subroom625and the lower subroom626are filled with a fluid. Moreover, since the total volume of the upper subroom625and the lower subroom626is always constant, the volume ratio between the upper subroom625and the lower subroom626can be changed by conducting cooperative control on the upper sub valve627and the lower sub valve628.

The lower subroom626is provided with a pressure sensor634. The pressure sensor634detects the pressure of the fluid in the lower subroom626and monitors it. Adjustment of the pressure of the lower subroom626can be pursued depending on the detected pressure, to adjust the lifting and lowering of the elevation module60. It is further possible to control to stop the pressurizing, when detecting an abnormal pressure exceeding the expected range.

The upper subroom625may also be provided with a pressure sensor, with which the pressure of the liquid in the upper subroom625can be detected and monitored.

FIG. 19is a sectional view showing the state in which the main piston is raised by lifting the sub piston. By increasing the volume of the lower subroom626, the volume of the upper subroom625decreases, to raise the sub piton621. Since this sub piston621is connected to the main piston612, the main piston612is also elevated. During this process, the main valve616is also subjected to cooperative control, to flow, into the main room615, a fluid in an amount corresponding to the increase in volume of the main room615caused in response to the elevation of the main piston612.

Conversely, if the volume of the upper subroom625is increased, the volume of the lower subroom626decreases to lower the sub piston621. This also lowers the main piston612. During this process, the main valve616is also subjected to cooperative control, to release to outside a fluid in an amount corresponding to the decrease in volume of the main room615caused in response to the lowering of the main piston612.

Note that the sub piston621also follows the movement of rising of the main piston612when the main piston612is raised by adjusting the amount of fluid within the main room615using the main valve616. Therefore in this case, it is possible to allow the change in volume of the upper subroom625and the lower subroom626occurring in response to the movement of the sub piston621following the movement of the main piston612, by cooperative control on the upper sub valve627and the lower sub valve628.

The fluid used to fill the main room615, the upper subroom625, and the lower subroom626is air, water, oil, etc. For example, hydrofluoroether having excellent environment characteristics may be used.

By structuring the elevation module60in two stages of the main EV section610and the sub EV section620, a variety in control is made possible depending on how to move the stage611. Specifically, when it is desirable to move it faster than a predetermined speed, the fluid in the sub EV section620is controlled, from which a larger displacement is obtained with a small volume of input and output fluid. When it is desired to apply a predetermined pressure or more, the fluid in the main EV section610is controlled, which experiences a smaller displacement even with a larger amount of input and output fluid. Control can also be directed to the fluid in the main EV section610when the stage611is to move slower than a predetermined speed.

The pressuring apparatus840includes a position sensor for detecting the position of the lower top plate32. The position sensor may be designed to directly detect the position of the lower top plate32, or may be designed to detect the position of the main piston612. When the position sensor is designed detect the position of the main piston612, the control section may convert the detected value to the position of the lower top plate32, and use it to control the position of the lower top plate32. The pressuring apparatus840can adjust the moving up and down of the elevation module60depending on the detected position. It is further possible to control to stop the moving up or down of the elevation module60, when detecting an abnormal position outside the expected range.

FIG. 20is a block diagram of a pressuring control system700of the pressuring apparatus840. The pressuring control system700includes an integral control section to control the entire lower top plate, and a section to control the inner section of the lower top plate. The integral control section to control the entire lower top plate includes a common instruction setting section710, a position controller722, a pressure controller724, and a control switcher726. The section to control the inner section of the lower top plate includes a common instruction setting section710, a pressure controller742, and a control switcher744.

The instruction setting section710sets a position instruction, a pressure instruction, and an instruction to generate a difference in pressure, to be given to the position controller722, the pressure controller724, and the pressure controller742. For example, such information as targeted position setting, a raising speed of the lower top plate32, or the like may be inputted to the instruction setting section710to facilitate setting. The targeted pressure setting, the pressuring speed or the like may also be inputted to the instruction setting section710to facilitate setting.

The position controller722controls the electromagnetic valve for sub EV728and the main valve for main EV616, based on the deviation (ΔZ=Zt−ZT) between the targeted position setting (Zt) for the position instruction712and the position value (ZT) for the lower top plate32detected by the position sensor730. The electromagnetic valve for sub EV728adjusts the amount of the fluid flowing into the sub cylinder624according to the control signal, to raise or lower the main piston612thereby controlling the position of the lower top plate32. The main valve616adjusts the amount of the fluid flowing into the main cylinder613according to the control signal, to raise or lower the main piston612thereby controlling the position of the lower top plate32.

The electromagnetic valve for sub EV728includes an upper sub valve627and a lower sub valve628. So as to raise the main piston612, the sub piston621is raised by controlling the lower sub valve628thereby adjusting the amount of the fluid flowing into the lower subroom. So as to lower the main piston612, the sub piston621is lowered by controlling the upper sub valve627thereby adjusting the amount of the fluid flowing into the upper subroom.

The position controller722is a PDD (proportional, differential, differential operation) controller. By enhancing the D (differential) operation control, the main piston612can approximate to the targeted position setting more quickly in the fixed command control, and the main piston612can follow the targeted position setting more quickly in the follow-up control.

The pressure controller724controls the electromagnetic valve for sub EV728and the main valve for main EV616, based on the deviation (ΔP=Pt−P2) between the targeted pressure setting (Pt) for the pressure instruction714and the pressure (P2) given to the lower top plate32from the elevation module60detected by the second pressure detecting section432, thereby raising or lowering the main piston612, to control the pressure of the lower top plate32(i.e., pressuring power with respect to the substrate-holder pair).

The pressure controller724is a PI (proportional, integrating operation) controller. By the PI operation control, it becomes possible to give moderate pressure to the substrate-holder pair.

The control switcher726switches control between the position control and the pressure control. In other words, the control switcher726selects one of the control signals issued from the position controller722and the pressure controller724, to control the electromagnetic valve for sub EV728and the main valve616. For example, when there is a sufficient distance left before the substrate-holder pair mounted on the lower top plate32reaches the upper top plate31, the processing time can be reduced by adopting the signal from the position controller722to control the elevation module60, to raise the lower top plate32quickly, to cause it to approach the upper top plate31. On the contrary, when the upper top plate31and the lower top plate32are to sandwich the substrate-holder pair and pressure it, it is better to adopt the control signal from the pressure controller724to control the elevation module60, in an attempt to realize accurate pressuring to the targeted pressure value.

In addition, the control switcher726monitors the pressure value detected by the pressure sensor634installed in the sub cylinder624and the pressure value detected by the pressure sensor632installed in the main cylinder613. When the pressure sensor634or the pressure sensor632has detected an abnormal pressure, the control switcher726can close the electromagnetic valve for sub EV as well as the main valve616to stop the moving up or down of the elevation module60, to prevent breakage of the pressuring apparatus840in an emergency.

The position sensor730detects the position of the lower top plate32and feeds it back, as needed. The deviation (ΔZ=Zt−ZT) between the targeted position setting (Zt) for the position instruction712and the detected value (ZT) fed back by the position sensor730will be the input value to the position controller722. The second pressure detecting section432detects the pressure given from the elevation module60to the lower top plate32and feeds it back, as needed. The deviation (ΔP=Pt−P2) between the targeted pressure setting (Pt) for the pressure instruction714and the detected value (P2) fed back by the second pressure detecting section432will be the input value to the pressure controller724.

The pressure controller742controls the valve502of the hollow pressuring section501, based on the deviation (ΔPd=Pd−P1+P2) being the result of subtracting, from the targeted difference in pressure setting (Pd) for the instruction to generate difference in pressure716, the difference (P1−P2) between the pressure (P1) detected by the first pressure detecting section419and the pressure (P2) detected by the second pressure detecting section432, in an attempt to adjust the amount of the fluid flowing into the hollow pressuring section501. The pressure (P2) detected by the second pressure detecting section432is applied to the periphery of the lower top plate32from the elevation module60, and the pressure (P1) detected by the first pressure detecting section419is applied to the central portion of the lower top plate32from the hollow pressuring section501. Therefore, the control of the difference in pressure is to control the pressure distribution in the plane of the lower top plate32, i.e., to control the evenness in the plane of the pressure applied to the substrate-holder pair.

Whether to flow in or out the fluid of the hollow pressuring section501can be controlled to yield the obtained difference in pressure (P1−P2) of no greater than a predetermined value (e.g., 0.05 MPa). It is also possible to control whether to flow in or out the fluid of the hollow pressuring section501to yield the difference in pressure (P1−P2) of zero. The predetermined range of difference in pressure can be designated by an instruction to generate difference in pressure, depending on each purpose of control.

The control switcher744monitors the pressure value detected by the pressure sensor436installed in the hollow pressuring section501. When the pressure sensor436has detected an abnormal pressure, the control switcher744can close the valve502to stop controlling the fluid of the hollow pressuring section501, to prevent breakage of the pressuring apparatus840in an emergency.

The first pressure detecting section419detects the pressure given to the lower top plate32by the hollow pressuring section501via the first supporting column418and feeds it back, as needed. The deviation (ΔPd=Pd−P1+P2) being the result of subtracting, from the targeted difference in pressure setting (Pd) for the instruction to generate difference in pressure716, the difference (P1−P2) between the pressure (P1) detected by the first pressure detecting section419and the pressure (P2) detected by the second pressure detecting section432will be the input value to the pressure controller742.

The following explains the process in which the lower top plate32of the pressuring apparatus840is controlled by means of the pressure control system as shown inFIG. 20. First, as shown inFIG. 12, the elevation module60is lowered, to mount the substrate-holder pair on the lower top plate32. In this state, the substrate-holder pair is greatly distanced from the upper top plate31, and so the controller switcher726selects to control the elevation module60using the position controller722.

The position controller722adjusts the lower sub valve628by the PDD operation based on the deviation (ΔZ=Zt−ZT), to control the fluid of the sub EV section620that is greatly displaced by flowing in a small volume of fluid, to quickly raise the elevation module60. When detecting that the lower top plate32is approaching a predetermined position based on the position data (ZT) fed back from the position sensor730, the position controller722adjusts the main valve616by the PDD operation, and switches to control the fluid of the main EV section610which is hardly displaced even by flowing in a large volume of fluid, in an attempt to raise the elevation module60.

When the distance between the substrate-holder pair to the upper top plate31has reached 10 mm (corresponding to a predetermined position (Zt)), the control switcher726switches to pressure control from position control. In other words, it selects to control the elevation module60using the pressure controller724. Following this, the pressure controller724adjusts the main valve616by the PI operation based on the deviation (ΔP=Pt−P2), to control the fluid of the main EV section610to raise the elevation module60.

Simultaneously, the pressure controller742adjusts the valve502of the hollow pressuring section501by the PI operation, based on the deviation (ΔPd=Pd−P1+P2) being the result of subtracting, from the targeted difference in pressure setting (Pd) for the instruction to generate difference in pressure716, the difference (P1−P2) between the pressure (P1) detected by the first pressure detecting section419and the pressure (P2) detected by the second pressure detecting section432, in an attempt to control the amount of the fluid flowing into the hollow pressuring section501thereby controlling the pressure of the hollow pressuring section501.

For example, by setting the targeted difference in pressure setting (Pd) to 0 to control the fluid to flow in or out of the hollow pressuring section501to yield the difference in pressure (P1−P2) of 0, the pressure ((P1) detected by the first pressure detecting section419will follow the pressure (P2) detected by the second pressure detecting section432, and so the pressure can be constant across the plane of the lower top plate32, as well as preventing the breakage of the hollow pressuring section501during the pressuring process. When the targeted difference in pressure setting (Pd) is set to a certain value, the pressure (P1) detected by the first pressure detecting section419can be controlled to maintain the difference in pressure (Pd) between it and the pressure (P2) detected by the second pressure detecting section432. Therefore, it becomes possible to pursue pressuring while maintaining a constant pressure distribution between the central portion and the periphery of the lower top plate32, depending on purposes.

For example, when the upper plate511of the hollow pressuring section501is desired to be expanded to increase the pressure of the central portion of the lower top plate32compared to that of the periphery, the targeted difference in pressure setting (Pd) can be set to a certain positive value, so as to enable control the pressure (P1) detected by the first pressure detecting section419to be larger than the pressure (P2) detected by the second pressure detecting section432. On the contrary, when the upper plate511of the hollow pressuring section501is desired to be depressed to increase the pressure of the periphery of the lower top plate32compared to that of its central portion, the targeted difference in pressure setting (Pd) can be set to a certain negative value, so as to enable control the pressure (P1) detected by the first pressure detecting section419to be smaller than the pressure (P2) detected by the second pressure detecting section432.

Also, as shown as the broken line inFIG. 20, instead of feeding back the measured value (P2) of the second pressure detecting section432, the pressure controller724may feed back the pressure (P3) of the main cylinder613detected by the pressure sensor632, thereby adjusting the main valve616by the PI operation based on the deviation (Pt−P3) to control the fluid of the main EV section610, in an attempt to raise the elevation module60. Likewise, the pressure controller742can feed back the pressure (P4) of the hollow pressuring section501detected by the pressure sensor436, thereby adjusting the valve502of the hollow pressuring section501based on the deviation (Pd−P4+P2) or deviation (Pd−P4+P3) to adjust the amount of the fluid flowing in the hollow pressuring section501or the pressure of the hollow pressuring section501, instead of feeding back the pressure (P1) detected by the first pressure detecting section419.

The pressuring apparatus840as shown inFIG. 12throughFIG. 20adjusts the pressure of the hollow pressuring section501, based on the difference between the pressure detected by the first pressure detecting section419and the pressure detected by the second pressure detecting section432. However, the embodiment of adjusting a pressure is not limited to such a configuration. In another possible example, the pressure of the hollow pressuring section501may be adjusted based on the pressure detected from at least two of the plurality of first pressure detecting sections419. For example, the aforementioned pressure adjustment may be pursued by setting, to be P1, the pressure detected by the first pressure detecting section419nearest to the center between the two first pressure detecting sections419whose distance from the center of the lower top plate32is different from each other, and setting, to be P2, the pressure detected by the other of the first pressuring detecting sections419that is farther from the center. In this case, the averaged values of the pressures detected by the plurality of first pressure detecting sections419being at a constant distance from the center can be set to P1and P2respectively.

The pressuring apparatuses240,840as shown inFIG. 1throughFIG. 20convey the pressure of the hollow pressuring section501to the lower top plate32via the first supporting column418. However, the embodiment of conveying the pressure is not limited to this example. In an another possible example, the pressure of the hollow pressuring section501can be conveyed to the lower top plate32, by bringing the upper surface of the hollow pressuring section501into contact with the lower top plate32, or by interposing a plate-shaped member therebetween. In such cases, the second supporting column431may be omitted.

The operations, the processes, the steps, or the like in the apparatus, the system, the program, and the method described in the claims, the specification, and the drawings are not necessarily performed in the described order. The operations, the processes, the steps, or the like can be performed in an arbitrary order, unless the output of the former-described processing is used in the later processing. Even when expressions such as “First,” or “Next,” or the like are used to explain the operational flow in the claims, the specification, or the drawings, they are intended to facilitate the understanding of the invention, and are never intended to show that the described order is mandatory.