Patent Description:
Solder ball mount machines typically have a process flow wherein a wafer is picked up by a robot arm and placed onto a flux station. A mask would be aligned for bump pads on the wafer through alignment marks at that station. Flux would be applied through the template or mask. Flux is opaque and hence ball mount alignment marks would be covered by a flux alignment template to prevent flux from coating the ball mount alignment mark. The mask would be aligned to the wafer by ball mount alignment marks using an optical vision arrangement at the solder ball mount station. The wafer, after inspection would be placed into the processing chamber. Contamination is common. The flux, being opaque thus requires several sets of templates and masks. Multiple sets of alignment mechanisms are needed.

Patent document <CIT> discloses a semiconductor manufacturing apparatus having a semiconductor substrate treating module that has a reflow treating unit with a process chamber for performing a reflow treating process on a semiconductor wafer. The process chamber is formed by a lower housing and an upper housing between. A wafer resting on a rotation plate is transported into the process chamber through a gap between the lower and upper housings when these housings are separated vertically with respect to each other to open up the gap between the housings. Inside the process chamber, the semiconductor is supported on a vacuum chuck of a support member. The support member is supported on the lower housing which is itself moved vertically towards and away from the upper housing by an elevation driving mechanism in order to open and close the gap between the upper and lower housings.

It is an object of the present invention to overcome the contamination, the wasted material and the excessive time disadvantages of the prior art.

It is a further object of the present invention to shorten the process steps, and expense of the prior art systems.

It is yet a further object of the present invention to provide a wafer processing chamber which utilizes optics to insure deposition of solder balls at their proper location and which also utilizes optics to identify and locate any solder ball misplacement.

It is still yet a further object of the present invention to provide a sweeping mechanism to eliminate and reclaim any oversupply of binder upon a wafer arrangement.

According to the invention, there is provided a system for the flux free processing of a plurality of solder balls on a wafer in a wafer treatment process containment chamber, as set forth in claim <NUM> of the appended set of claims.

Also according to the invention, there is provided a method of treating a plurality of solder balls on a wafer in a wafer treatment processing containment chamber, as set forth in claim <NUM> of the appended set of claims.

Described herein is an initial assembly module arranged to process to enable the flux free attachment of a plurality of solder balls to a wafer for use in the electronics industry, the process comprising: depositing a flux free binder on a wafer; blowing compressed dry air over the flux free binder on the wafer to control the depth of the flux free binder thereon; depositing an array of solder balls onto the flux free binder on the wafer through an array of holes in a stencil arranged over the wafer; lowering an array of looped wires attached to a bottom side of the ball mount head into the array of solder balls on the stencil above the wafer; vibrating the array of looped wires in the array of solder balls on the stencil above the wafer; blowing compressed dry air over the array of solder balls on the stencil to displace any stray excess solder balls on the stencil above the wafer; and vacuuming up and collecting any stray excess solder balls displaced by the blown compressed dry air thereover. The process includes: depositing the array of solder balls onto a stencil above the wafer by dropping a number of solder balls from the ball mount head onto the stencil; supporting the wafer on a three zone vacuum chuck to hold the wafer securely thereon; arranging an array of vertically displaceable support pins within the three zone vacuum chuck so as to enable the lowering of the wafer onto the vacuum chuck in a controlled manner by a pneumatic pin control process. The initial assembly module is followed by further treatment, as for example, heat treatment in a further wafer/pad treatment module.

Also described herein is a system for the flux free processing of a plurality of solder balls on a wafer in a wafer treatment process containment chamber, the system comprising: an articulable vacuum support chuck for maintaining support of a wafer containing a plurality of solder balls as the wafer is being processed within the process containment chamber; an articulable flux free binder applicator arranged in binder depositing relationship above the wafer within the process containment chamber; and an articulable curtain-of-fluid dispenser arranged in binder-applied minimization treatment relationship with respect to any flux free binder applied to the wafer within the process containment chamber for applying a curtain of fluid onto the wafer, wherein the curtain of fluid is compressed air. The term "wafer" used herein may also be called a wafer chip, substrate or panel as would be utilized in the electronics industry.

The articulable curtain-of-fluid dispenser preferably comprises an array of air-ejecting-nozzles movably arranged over the wafer being treated. The air ejecting nozzles and the articulable flux free binder applicator are both preferably supported on a common gantry frame arrangement. The system includes a vacuum utilizing excess-solder-ball collecting vessel arranged adjacent the wafer being treated to collect any excess solder balls not properly arranged on the wafer via transfer through holes in the stencil. The system also includes a camera arrangement insertable within the process containment chamber or module, to inspect and analyze the treated wafer for solder ball placement accuracy subsequent to the removal of excess solder balls by the excess-solder-ball collecting vessel.

Also described herein is an optical control system for solder ball attachment to a wafer during its processing in a wafer processing chamber, the system comprising: an overhead frame member supporting an arrangement of overhead sensors in an upper end of a wafer processing chamber; a lower articulable solder ball and wafer vacuum support chuck; and an articulable stencil mask arranged between the chuck and the arrangement of overhead sensors, wherein the overhead sensors monitor the alignment of solder balls on the wafer through the articulable stencil mask during ball alignment processing thereof. The overhead sensors are mounted on overhead gantry frame arrangement, wherein the overhead sensors are movable in the X and Y directions. Each of the overhead sensors comprises a camera with a lens assembly, a light sensor and artificial light source. The wafer vacuum support chuck is first positioned at a vertical distance below the cameras so that the wafer is in focus and wherein the cameras take multiple images of the wafer for transmission to a control computer. Also described herein is a pad alignment arrangement to reorient any nonaligned pads with respect to the articulable stencil mask arranged thereabove.

Also described herein is a method of treating a plurality of solder balls on a wafer in a wafer treatment processing containment chamber, the method comprising: lifting a pad loaded wafer by a robotic arm into the wafer treatment processing containment chamber or module; supporting the pad loaded wafer within the wafer treatment processing containment chamber by a plurality of vertically movable support pins extending from an articulable vacuum chuck arranged within the wafer treatment processing containment chamber; securing the pad loaded wafer onto a plurality of vacuum cups each arranged on the uppermost end of the vertically movable support pins, by a vacuum therethrough; retracting the movable support pins into the articulable vacuum chuck; applying a further vacuum from a plurality of vacuum channels in the articulable vacuum chuck, to a bottom side of the pad loaded wafer to secure the pad loaded wafer thereto; depositing a flux free binder across an upper surface of the pad loaded wafer supported on the articulable vacuum chuck; blowing a curtain of compressed dry air across the binder laden upper surface of the pad loaded wafer; arranging a hole-laden stencil above the surface of the pad loaded wafer; dropping a plurality of solder balls from a ball mount head supported above the pad loaded wafer and onto the pad loaded wafer; blowing a further curtain of compressed dry air over the solder balls on the wafer to eliminate excess solder balls on the wafer; and vacuuming and collecting excess solder balls from the pad loaded wafer which are unaligned and not received within holes in the hole-laden stencil; and removing the pad loaded wafer from the pad loaded wafer treatment containment chamber for processing in a further treatment chamber. The method includes the steps of: lowering a vibratory sweep arrangement to a location above the pad loaded wafer and hole-laden stencil within the wafer treatment containment chamber; vibrating the sweep arrangement over the pad loaded wafer with its solder balls thereon to insure placement of solder balls within a hole in the hole-laden stencil; applying a vacuum along an edge of the stencil to enable collection of excess solder balls from the pad loaded wafer.

Also described herein is a process for the assembly of solder balls on a pad loaded wafer chip or substrate or panel in a wafer chip treatment application chamber, the process comprising the steps of: moving the wafer chip robotically into a wafer chip treatment application chamber; lowering the wafer chip onto an arrangement of pneumatically controlled support pins extending vertically upwardly from an articulable vacuum chuck; securing the wafer chip onto the articulable vacuum chuck by a plurality of vacuum channels therebetween; introducing a gantry frame supported binder spray nozzle and compressed air delivery nozzle arrangement into the wafer chip treatment application chamber; spraying a binder fluid from the binder spray nozzle across an upper surface of the wafer chip therebeneath; spraying a curtain of compressed dry air from the compressed air delivery nozzle onto the upper surface of the wafer chip to remove excess binder fluid therefrom; coarsely aligning the wafer chip on the articulable vacuum chuck; introducing a hole-laden stencil into the wafer chip treatment application chamber above the wafer chip; precisely aligning the wafer with respect to the stencil by an array of cameras supported on a gantry frame within the wafer chip treatment application chamber; verifying the alignment of the stencil with respect to the wafer chip by a verification camera supported on a gantry frame within the wafer chip treatment application chamber; introducing an X, Y and Z direction displaceable ball mount head into the wafer chip treatment application chamber; dropping a plurality of solder balls onto the hole-laden stencil above the wafer chip; and vibrating the arrangement of looped wires onto the plurality of solder balls so as to induce the solder balls into the holes of the hole-laden stencil on the surface of the wafer chip; blowing a curtain of compressed dry air across the hole-laden stencil to move excess solder balls to the edge of the stencil; vacuuming up excess solder balls and storing them for later use. The process includes the steps of: blowing a curtain of compressed dry air across the binder to remove excess binder from the wafer; and aligning solder balls on the minimized binder on the wafer.

Also described herein is a wafer chip assembly arrangement for use in the semiconductor industry, wherein a portion of the wafer chip assembly includes an alignment process in a production module, including the steps of: supporting a pad laden chip on an articulable chuck; moving the articulable chuck and pad laden chip underneath a hole- laden stencil; holding the hole-laden stencil in a fixed position on a base plate, wherein the holes define a unique hole pattern; supporting a pair of imaging cameras within the module and over the stencil; capturing at least two images of at least some of the holes of the unique hole pattern in the hole-laden stencil; and transmitting the images of the unique hole patterns to a control computer for storage and analysis. The wafer chip assembly process may include: identifying a subset of holes from the images as a composite feature; memorizing the precise position of the composite features on the stencil by the control computer in terms of a global coordinate system, wherein the coordinate system is fixed with respect to a base plate stationary element; positioning a pair of alignment cameras over an alignment window; capturing an image of a pad laden wafer by each of the alignment cameras; analyzing the image captured by the alignment cameras by the control computer; comparing the images captured by the imaging cameras and the alignment cameras to determine relative orientation between the holes in the stencil and the pad laden wafer on the articulable chuck; and moving the articulable chuck supporting the pad laden wafer into proper positioning beneath the hole laden stencil, to await solder ball deployment thereon.

The objects and advantages of the present invention will become more apparent when viewed in conjunction with the following drawings, in which:.

Referring now to the drawings in detail, and particularly to <FIG>, there is shown a schematic representation of the present invention as it relates to a fluxless solder ball mount assembly process module with a shortened assembly procedure which procedure will subsequently require a vertically configured heat treatment arrangement, as described in a sister application. The process as generally recited in <FIG> is more specifically described as follows: a FOUP (front operating unified pod container) having a robotic arrangement which loads a pad-loaded wafer into a treatment chamber; a liquid binder is applied to the upper surface of the wafer; excess binder is driven off the chip by a curtain of compressed dry air leaving only a thin film thereon; the wafer is coarsely adjusted with a pre-aligner robotic arm and loaded onto a vacuum support chuck; an optomechanical system aligns the wafer precisely to one aligned fixed stencil; solder balls are applied through holes in the stencil and onto binder coated pads on the wafer; excess balls are removed with a further sweeping application of compressed dry air, the excess balls being retrieved by a vacuum suction system there adjacent; and the wafer is then optically inspected to confirm or if needed, correct ball placement. The properly loaded wafer would then be withdrawn by the robotic arm for subsequent treatment in a further module.

The above-recited process is more specifically depicted in the following figures, beginning with the side elevational view shown in <FIG>, wherein a robotic arm <NUM> is shown delivering a wafer <NUM> into a temperature and humidity controlled application chamber <NUM>. The wafer <NUM> is preloaded with a plurality of solder ball receiving pads <NUM>. A <NUM>-independent-zone vacuum chuck <NUM> is also arranged within the application chamber (module) <NUM>. A plurality of support pins <NUM> extends from the upper surface of the support chuck <NUM>. The support pins <NUM> are vertically displaceable and have a vacuum cup <NUM> arranged on their uppermost or distal end, as may be seen in <FIG>. The robotic arm <NUM> deposits the wafer <NUM> onto the upper ends of the support pins <NUM>, as represented in <FIG>. The support pins <NUM>, carrying the wafer <NUM> are preferably pneumatically withdrawn fully into the vacuum chuck <NUM> and become recessed pins <NUM>, as represented in <FIG>. Once the wafer <NUM> touches the chuck <NUM> a plurality of vacuum channels <NUM> arranged within the chuck <NUM> are actuated to hold the wafer <NUM> firmly in place. The vacuum channels <NUM> are grouped into three zones across the surface of the chuck <NUM> each of which zone may be controlled independently of one another, by a proper computer controlled circuit <NUM>.

The next step in the process as recited in <FIG>, is represented initially in <FIG> wherein a side elevational view shows the application chamber <NUM> having a lower end whether the vacuum support chuck <NUM> residing thereat. A gantry frame <NUM> extends into and within the chamber <NUM>, above the wafer <NUM>, which is pre-loaded with its pads <NUM>, the gantry frame <NUM> being movable controllably thereacross (either transversely or longitudinally, or both ways) thereacross by computer controlled servomotors. An array of binder spray nozzles <NUM> are arranged on the lower end of the gantry frame <NUM>, enabled to spray a liquid binder "b" therethrough, via a conduit in the gantry frame <NUM> and onto the wafer <NUM> therebelow. An "air knife" <NUM> is also arranged on the lower end of the gantry frame <NUM>, so as to also apply a computer controlled curtain of compressed dry air across the width of the wafer <NUM> thereinbelow, as necessary, by computer controlled movement of the gantry frame <NUM>. Actuation of the gantry frame <NUM> scans the nozzles <NUM> and the air knife <NUM> over the wafer <NUM>.

<FIG> shows the binder "b", being sprayed upon the pad loaded wafer <NUM>, meaning both the wafer <NUM> and the pads <NUM>, as the gantry frame <NUM> traverses the breath of the wafer <NUM> therebeneath. It is to be noted that the binder "b" is shown having an excessive accumulation on the wafer <NUM> and possibly on the pads <NUM>, as viewed on the right hand side of <FIG>. <FIG> represents the traversal of the gantry frame <NUM> above the binder coated wafer <NUM> therebeneath.

The gantry frame <NUM> in <FIG> depicts the air knife <NUM>, preferably comprised of an array of nozzles <NUM>, (described further hereinbelow), sweeping a curtain of humidity and temperature controlled compressed dry air across the surface of the binder laden wafer <NUM> supported on the vacuum chuck <NUM>. The compressed dry air may be blown perpendicular to or angled with respect to the horizontal surface of the wafer <NUM>. The mechanical and/or evaporative action of the compressed dry air blown curtain or stream drives excess binder off of the wafer <NUM>, as shown in the left hand side of the application chamber <NUM> and into a collection vessel (not shown) through a lower drain port <NUM> therewithin. A thin film of binder <NUM> shown on the wafer <NUM> on the right hand side of the wafer <NUM>, is represented in <FIG>. The thickness of that thinned binder film <NUM> may be controlled by controlling the flow rate of the compressed dry air, the scan speed of the gantry frame <NUM>, the position of the air knives <NUM> or their nozzle shapes.

A side elevational view of the alignment process of the wafer <NUM>, held by the vacuum support chuck <NUM>, the wafer <NUM> and its respective pads <NUM> are all being represented in <FIG>, the pads <NUM> having received their thin film of binder "b". An alignment camera arrangement <NUM> is arranged within the application chamber <NUM>, on a gantry frame arrangement <NUM>, the camera arrangement <NUM> being movably controlled in the X and Y directions on that gantry frame arrangement <NUM>, by servomotors <NUM> and <NUM>. Each alignment camera <NUM> is comprised of a lens assembly, a light sensor or and an artificial light source. The vacuum support chuck <NUM> also shown in <FIG> is supported, and may be actuated by a multi-axis stage <NUM> in the X, Y, and Z directions and may be rotated in the theta direction (about the z-axis) through interaction by the control computer <NUM>. The chuck <NUM> is <NUM>st positioned a vertical distance below the cameras <NUM> such that the wafer <NUM> is in focus as is shown in <FIG>. The cameras observe the wafer <NUM> through the alignment window, an opening <NUM> in the base plate <NUM>. An alignment beam "I" represents the camera's "field of view" in <FIG> emanating from one of the pair of alignment cameras <NUM> directed downwardly onto the array of pads <NUM> therebeneath. A separately supported and controlled verification camera <NUM> is also shown in <FIG> to be described further hereinbelow.

<FIG> shows a pair of alignment cameras <NUM> mounted on a transverse beam <NUM> as part of the gantry frame <NUM>, and are computer controlled so as to move independently on that transverse beam <NUM> in the X direction. The beam <NUM> itself is actuated in the Y direction, but is parallel to the X direction. Each camera <NUM> is preferably comprised of a lens assembly, a light sensor and artificial light source for this process of component alignment, the vacuum chuck <NUM> being initially positioned at a vertical distance below the cameras <NUM>, such that the surface of the wafer <NUM> is in focus. Each camera <NUM> then is programmed to capture an image of a different position on the wafer <NUM> and sends these images to the control computer <NUM> via a proper circuit <NUM>. This visual information is processed through the control computer <NUM>, to indicate the precise position of the wafer <NUM> on the vacuum chuck <NUM>. Upon determination of the precise position of the wafer <NUM>, the stage <NUM>, through circuit <NUM>, actuates the chuck <NUM> as instructed to align the wafer <NUM> in the proper X, Y and Theta orientation, as represented in <FIG> such that only a single additional translation step is needed to align the pads <NUM> of the wafer <NUM> directly below corresponding holes <NUM> on a ball stencil <NUM>, represented in <FIG> in <FIG> described hereinbelow.

There is a hole-laden or holed-ball stencil <NUM>, mentioned hereinabove, shown in a side elevational view in <FIG>, arranged within the chamber <NUM> above a vacuum support chuck <NUM>. The vacuum support chuck <NUM> shown movably controlled by a stage <NUM> thereunder. A downward looking verification camera <NUM> is shown mounted above the ball stencil <NUM>. The verification camera <NUM> may be movable vertically by proper computer control in the "Z" direction with the pneumatic support arrangement <NUM>. The wafer <NUM> is first translated in the "Y" direction from its position below the alignment camera arrangement <NUM> to a position directly below the ball stencil <NUM> and the verification camera <NUM>. The wafer <NUM> on the chuck <NUM> is then translated in the "Z" direction such that it contacts or nearly contacts the bottom of the ball stencil <NUM>. Once the wafer <NUM> is raised up to the ball stencil <NUM> and the verification camera <NUM> is in its down position, the ball stencil <NUM> and the wafer <NUM> are within the focal plane of the verification camera <NUM>. The computer controlled verification camera <NUM> is instructed to take an image of a single location on the wafer <NUM>. The control computer <NUM> uses this information to confirm the final alignment between the wafer <NUM> and the ball stencil <NUM>. Once confirmed, the verification camera <NUM> is lifted up by controlled lift pneumatic driver <NUM> and out of the way of the ball mount head <NUM>, shown hereinbelow in <FIG> and described therewith.

Each of these pads <NUM> should end up centered in the X and Y directions under one of the holes <NUM> in the ball stencil <NUM>. Arrangement between the wafer <NUM>, its pads <NUM> and the holed-stencil <NUM> shown in <FIG> in plan view. The figure on the left, <FIG> shows the wafer <NUM> itself with a plurality of pads <NUM> neatly aligned thereon. <FIG> on the right shows the wafer <NUM> itself with its plurality of pads <NUM>. The stencil <NUM> represented in <FIG> has a similar neatly aligned array of holes <NUM> thereon. When the wafer <NUM> is in proper alignment, each of these pads <NUM> should end up centered in the X and Y directions under one of the holes <NUM> in the ball stencil <NUM>. The verification camera <NUM> is then instructed by the control computer to take a picture of a subset of these aligned pad <NUM> and holes <NUM>. If all of the pads <NUM> and holes <NUM> within the camera's field of view are determined by the control computer <NUM> to be in proper alignment, then the entire wafer <NUM> is presumed to be properly aligned.

<FIG> displays the alignment process, wherein during the setup of the tool, before processing begins, the gantry frame <NUM> positions the two alignment cameras <NUM> over the stencil <NUM>. The stencil <NUM> is held in a fixed position on the base plate <NUM> and remains fixed throughout its setup and processing. The stencil <NUM> contains a plurality of holes <NUM> and a unique hole pattern corresponding to the particular wafer <NUM> which will be processed. While each camera <NUM> (both of them) is over the stencil <NUM>, each captures an image of the part of the stencil <NUM>, which image is a section of the overall pattern of holes <NUM>. These image sections are identified in <FIG> as stencil image # <NUM> (<NUM>) and stencil image #<NUM> (<NUM>). These image sections <NUM> and <NUM> are sent to the control computer <NUM> for storage and analysis. Each image captures a number of stencil holes <NUM> as shown in <FIG>. In actuality, the number of holes <NUM> may be in the hundreds. Once the control computer <NUM> receives an image, this and software identifies a subset of holes <NUM> within the image <NUM> or <NUM> which form a unique pattern which will be referred to as a "composite feature". After this composite feature is identified, the vision software determines the precise position and orientation of the composite feature. The result is that during training, software identifies and memorizes the precise position of the two composite features on the stencil <NUM> in terms of a global coordinate system. This "global coordinate" is fixed with respect to stationary elements of the tool such as the base plate <NUM>.

The gantry frame <NUM> then positions the alignment cameras <NUM> and <NUM> over the alignment window <NUM> as shown in <FIG>. The camera positions are then locked in place and remain fixed all during processing and production of the wafer <NUM>. When a wafer <NUM> is processed, it is loaded onto the support chuck <NUM> as represented in <FIG> and positioned under the alignment cameras <NUM> and <NUM>. The wafer <NUM> contains a plurality of pads <NUM>. Each camera <NUM> and <NUM> captures an image of part of the wafer <NUM>, a section of the overall pad pattern. These image sections identified in <FIG> is wafer image # <NUM> (<NUM>) and wafer image # <NUM> (<NUM>). These images are then sent to the control computer <NUM> for analysis. Each image <NUM> and <NUM> may capture as many or more pads <NUM> as shown in <FIG>. Once the control computer <NUM> receives an image <NUM> and/or <NUM>, the vision software identifies a subset of pads <NUM> within the image <NUM> and/or <NUM> which form a unique pattern, a "composite feature' like that on the stencil <NUM>. After the composite features are identified, the vision software now compares stencil image #<NUM> (<NUM>) to wafer image # <NUM> (<NUM>) and stencil image # <NUM> (<NUM>) to wafer image #<NUM> (<NUM>), this comparison being represented in <FIG>. The software calculates the X, Y, Z and Theta motions that the support chuck <NUM> must make such of the final positions and orientations of each pair of the wafer stencil composite features will match as shown in <FIG>, the control computer <NUM> through the proper circuit <NUM>, then commands the support chuck <NUM> to execute these calculated motions. The wafer <NUM> is thus aligned and brought upwardly near or into contact with the bottom of the stencil <NUM>.

After the support chuck <NUM> finishes its motion and the wafer <NUM> is in position underneath the stencil <NUM>, the wafer - stencil alignment must be confirmed. To do this, the verification camera <NUM> captures a single image of the stencil <NUM> and the wafer <NUM>. This image is labeled "verification image" and <NUM> as represented in <FIG>. As with the alignment cameras <NUM> and <NUM>, the verification camera <NUM> captures a subset of the overall hole - pad pattern. The verification camera <NUM> sends this image to the control computer <NUM> where the vision software identifies the holes <NUM> and the pads <NUM> in that image. The vision software calculates the center of each pad <NUM> and of each hole <NUM>, and compares them. Based on the relative position of the centers of the pads <NUM> and the centers of the holes <NUM>, the software program determines whether the final alignment of the wafer <NUM> and stencil <NUM> is good as the verification image shown in <FIG> or as bad as he verification image shown in <FIG>. If the wafer <NUM> and the stencil <NUM> are perfectly aligned, the center of each pad <NUM> will match the center of a hole <NUM> as shown by the verification image shown in <FIG>.

The ball mounting process is represented in <FIG>, wherein the wafer <NUM> has been raised up to the bottom of the stencil <NUM>, as represented in <FIG> and <FIG>. The ball mount head <NUM> is robotically brought into the application chamber <NUM> through a side thereof, and is controllably lowered into proximity of the holes <NUM> in the stencil <NUM>, the ball mount head <NUM> being computer controlled by a "coarse" "Y" direction pneumatic control arrangement <NUM> and a "Z" direction pneumatic control arrangement <NUM>. A "fine" "Y" direction pneumatic control arrangement <NUM>, represented in <FIG>, is discussed further hereinbelow. The coarse "Y" direction pneumatic control arrangement <NUM> moves the ball mount head <NUM> out of the way of the verification camera <NUM>. The ball mount head <NUM> in one preferred embodiment is an array of transversely extending sweep members <NUM>, in one preferred embodiment, consisting of thin coils or loops of wire <NUM>, attached onto the underside of the ball mount head <NUM>. In another preferred embodiment, thin flexible brushes (not shown for clarity of the drawings) replace the coils or loops of wire <NUM> on the underside of the ball mount head <NUM>. Those sweep members <NUM> or more specifically, those loops of wires <NUM> underneath the ball mount head <NUM> nearly contact or just barely contact the stencil <NUM>. A reservoir <NUM> within the ball mount head <NUM> is programmed to release a volume of solder balls <NUM> which is thus dispersed across the upper surface of the stencil <NUM>. A wave generator <NUM> is actuated by the control computer <NUM> through the proper circuit <NUM>, to begin vibrating the sweep members <NUM>, preferably loops of wire <NUM>, in brushing contact with the solder balls <NUM> on the surface of the stencil <NUM>. The brushing vibration of the wires <NUM> (or sweep member <NUM> brushes) contact the solder balls <NUM> and the vibration of the wires <NUM> results in movement of the solder balls <NUM>. As the solder balls move over the stencil <NUM>, they drop through the holes <NUM> in the stencil, and stick to the binder "b" coated wafer pads <NUM> properly arrayed therebeneath. Distribution of the solder balls <NUM> and filling of the holes <NUM> in the stencil <NUM> is further encouraged by oscillating the wires back and forth a different dimension, as for example, only several millimeters of oscillation using the fine "Y" pneumatic controlled driver <NUM> mounted on the ball mount head <NUM>, in conjunction with the other separate drivers <NUM> and <NUM>, again, represented in <FIG> mounted on the ball mounted head <NUM>. After the solder balls <NUM> have been distributed amongst the holes <NUM> in the surface of the stencil <NUM>, the ball mount head <NUM> is controllably effected to move up and out of the way of the compressed dry air sweep detailed hereinbelow in <FIG>.

The solder ball sweep and recovery discussed earlier is shown again in <FIG>. Once the solder balls <NUM> filed through the holes <NUM> in the stencil <NUM>, and are stuck onto the binder-laden pads <NUM> situated on the wafer <NUM>, the air knife <NUM> is actuated to sweep over the surface of the solder ball laden stencil <NUM>, thus effecting a curtain of compressed dry air from its nozzles <NUM>, as the air knife <NUM> is caused to move as it is carried by a pneumatically driven arm <NUM>. Excess solder balls <NUM> not properly secured to a binder "b" on a pad <NUM> on the wafer <NUM> are driven before the curtain of compressed dry air sweeping across the solder ball laden stencil <NUM>, effecting loose solder balls <NUM> towards a vacuum and collection vessel <NUM> at the downstream end of the compressed dry air sweep process. Thus, those solder balls <NUM> which did not fall into a receiving hole <NUM> in the stencil <NUM> are swept along before the air knife <NUM> (the compressed dry air nozzle arrangement <NUM>) into capture by that collection vessel <NUM>. Those solder balls <NUM> may be reused in further processing of additional wafers.

Claim 1:
A system for the flux free processing of a plurality of solder balls (<NUM>) on a wafer (<NUM>) in a wafer treatment process containment chamber (<NUM>), the system including the wafer treatment process containment chamber (<NUM>), and comprising:
an articulable vacuum support chuck (<NUM>) for maintaining support of a wafer (<NUM>) containing a plurality of solder balls (<NUM>) as the wafer is being processed within the process containment chamber (<NUM>);
characterized in that the system further comprises:
an articulable flux free binder applicator (<NUM>) arranged in binder depositing relationship above the wafer (<NUM>) within the process containment chamber (<NUM>); and
an articulable curtain-of-fluid dispenser (<NUM>) arranged in binder-applied excess minimization treatment relationship with respect to any flux free binder (<NUM>) applied to the wafer (<NUM>) within the process containment chamber (<NUM>) for applying a curtain of fluid onto the wafer, wherein the curtain of fluid is compressed air.