Systems and methods for the removal of integrated circuits from populated circuit boards using thermal fluid

Abstract

Some aspects of the present disclosure are generally related to systems for removing integrated circuits (ICs) designated for reuse from populated circuit boards (PCBs). In some embodiments, the ICs are designated for reuse, and the selective removal of the ICs from the PCBs is desirable. The systems described herein, in some embodiments, facilitate relatively precise temperature control of a thermal fluid into which the PCB is submersed. In some embodiments, the systems are configured to modulate a depth at which the PCBs are submersed into a thermal fluid, thereby allowing for selective heating of some or all of the PCB. Still other aspects are related to methods of using the systems described herein.

Description

[0001] SYSTEMS AND METHODS FOR THE REMOVAL OF INTEGRATED

[0002] CIRCUITS FROM POPULATED CIRCUIT BOARDS USING THERMAL FLUID

[0003] RELATED APPLICATIONS

[0004] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 622,044, filed January 17, 2024, and entitled “SYSTEMS AND METHODS FOR THE REMOVAL OF INTEGRATED CIRCUITS FROM POPULATED CIRCUIT BOARDS USING THERMAL FLUID,” which is incorporated herein by reference in its entirety for all purposes.

[0005] TECHNICAL FIELD

[0006] Systems and methods for the removal of integrated circuits designated for reuse from populated circuit boards are generally described.

[0007] BACKGROUND

[0008] Conventionally, integrated circuits (ICs) designated for reuse are recovered from the surface of populated circuit boards (PCBs). However, typical systems and methods for IC removal directly heat the surface of the PCBs via either infrared rays or hot gas until the solder adhering the ICs to the PCBs reaches the temperature liquidus. Infrared rays and hot gas each lack substantial thermal mass, and consequently the temperature applied to the surface of the PCBs during conventional methods substantially exceeds the temperature liquidus of the solder to effectively heat and completely melt the solder. Additionally, the surface temperature to which the PCB is heated cannot be precisely and / or constantly controlled, which results in the methods being inefficient and / or may overheat the ICs and cause subsequent damage to the ICs. Accordingly, improved methods and systems are needed.

[0009] SUMMARY

[0010] Systems and methods for the removal of integrated circuits designated for reuse from populated circuit boards are generally described. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0011] ICs designated for reuse are removed from PCBs by immersing the PCBs in a thermal bath where the thermal fluid is maintained at a constant temperature no hotter than 10 degrees Celsius above temperature liquidus of the solder securing the ICs to the PCBs, and preferably no hotter than about 1 degree Celsius above temperature liquidus, or in other embodiments, depending on factors such as the sensitivity of the ICs to thermal damage no hotter than about 2 degrees Celsius above temperature liquidus. Temperature liquidus for “lead-free” solder is typically 217-221 degrees Celsius, so the thermal fluid is preferably maintained at about 222 degrees Celsius, or in other embodiments at about 223 degrees Celsius, or in yet other embodiments between 222 and 223 degrees Celsius for these solders. Examples of solders that can be melted and / or removed from PCBs include those solders comprising Sn, Pb, Ag, Cu, Zn, Bi, Sb, Au, Si, and / or In. PCBs comprising leaded or lead-free solder can be treated. In certain embodiments, the solder contains Sn, optionally in combination with one or more of Pb, Ag, Cu, Zn, Bi, Sb, Au, Si, and / or In. In some embodiments, the solder contains Au and / or Si.

[0012] The PCBs can, in some embodiments, have a residence time in the thermal bath just long enough for the solder adhering the ICs to the PCBs to reach temperature liquidus, typically 4-6 minutes. The thermal bath may be a shallow trough only deep enough so that the thermal fluid only partially or barely covers all the designated ICs and, in some cases only wide enough to accommodate ICs of maximum anticipated widths. The PCBs can be conveyed through the bath until the solder reaches temperature liquidus. When the solder has reached temperature liquidus, the ICs designated for reuse can be identified by visual inspection or by optical scanning and removed manually or robotically with one or more vacuum wands, mechanical grabbers, and / or other removal tools. The PCBs with their remaining components can then be conveyed to another, second area for bulk removal of components, e.g., into a barrel that is immersed in a separate tank with the same or different type of thermal fluid and that rotates in that tank, with or without agitation of the fluid, until the residual components fall off and can be collected from the barrel when it is removed from the tank, e.g., in a system as described in US Pat. No. 10,362,720, which is herein incorporated by reference in its entirety). Altematively, in some embodiments, the second area in which the remaining components of the PCB may be removed may be a section of the same thermal bath in which the initial ICs designated for reuse are removed downstream of the section in which the initial ICs designated for reuse are removed. In some embodiments, the thermal fluid in the second area may be heated to a different temperature (e.g., higher) than the temperature of the thermal fluid in the thermal bath or thermal bath section in which the initial ICs designated for reuse are removed.

[0013] Some aspects are related to systems. In some embodiments, the system is for removing components designated for reuse from a populated circuit board. In some embodiments, the system comprises a container defining an interior volume, fluid in the interior volume of the container, and a temperature controller associated with the fluid, wherein the temperature controller is configured to maintain a temperature of the fluid to within 10 degrees C from a target temperature. In some embodiments, the temperature controller of the system is configured to maintain a temperature of the fluid to within 2 degrees C from a target temperature. In some embodiments, the temperature controller of the system is configured to maintain a temperature of the fluid to within 1 degree C from a target temperature. In some embodiments, a target temperature of the fluid of the system is at or just above the temperature liquidus of a solder present on the populated circuit board, for example, approximately 222 degrees C for a solder with a temperature liquidus of 221 degrees C (e.g., a 96.5% / 3.5% Tin / Silver solder). In some embodiments, the system comprises a container or bath defining an interior volume, fluid in the interior volume of the container or bath, and a depth controller associated with the container or bath and configured to adjust a depth to which the populated circuit board is submerged in the fluid in the container or bath. In some embodiments, the system comprises a container or bath defining an interior volume, fluid in the interior volume of the container or bath, a temperature controller associated with the container or bath, and a depth controller associated with the container, wherein the temperature controller is configured to maintain a temperature of the fluid to within 1 degree, or alternatively within 2 degrees C from a target temperature and wherein the depth controller unit is configured to adjust a depth to which the populated circuit board is submerged into the fluid in the container. Some aspects are related to methods. In some embodiments, the method comprises heating and controlling a temperature of a thermal liquid in contact with a populated circuit board to within 10 degrees C of a liquidus temperature of a solder adhering one or more integrated circuits to the populated circuit board and selectively removing one or more of the integrated circuits from the populated circuit board. In some embodiments, the method comprises heating and controlling the temperature of the thermal liquid in contact with the populated circuit board to within 1 degree or alternatively within 2 degrees C of the liquidus temperature of the solder adhering one or more integrated circuits to the populated circuit board. In some embodiments, the method comprises selectively removing one or more of the integrated circuits from the populated circuit board comprises using a first method. In some embodiments, the method further comprises removing the remaining integrated circuits of the plurality of integrated circuits using a second method. In some embodiments, the method further comprises at least partially submerging a populated circuit board into the fluid.

[0014] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:

[0017] FIGS. 1A and IB show schematic diagrams of portions of thermal fluid IC removal systems, according to some embodiments; FIGS. 2A-2C show schematic diagrams of a PCB being conveyed along a thermal fluid bath of a system, according to some embodiments;

[0018] FIGS. 3 A and 3B are schematic diagrams depicting the removal of components from a PCB, according to some embodiments; and

[0019] FIG. 4 is a method flow diagram detailing methods of IC removal from PCBs as described herein, according to some embodiments.

[0020] DETAILED DESCRIPTION

[0021] Some aspects of the present disclosure are generally related to systems for removing components (e.g., integrated circuits (ICs)) designated for reuse from populated circuit boards (PCBs). In some embodiments, the ICs are designated for reuse, and the selective removal of the ICs from the PCBs in a functional state is desirable. The systems described herein, in some embodiments, facilitate relatively precise temperature control of a thermal fluid into which the PCB is submerged. In some embodiments, the systems are configured to modulate a depth at which the PCBs are submerged into a thermal fluid, thereby allowing for selective heating and / or removal of some or all of components of the PCB. Still other aspects are related to methods of using the systems described herein.

[0022] Electronics including PCBs may be utilized until the electronics cease to function properly and / or new generations of the electronics are released. At such times, the electronics may be recycled, where various components (e.g., ICs) may be designated for reuse. Conventionally, ICs designated for reuse are recovered from the surface of PCBs by directly heating the surface of the PCBs using either infrared rays or hot gas until the solder adhering the ICs to the PCBs reaches the temperature liquidus. Infrared rays and hot gas each lack substantial heat capacity and thermal mass, and consequently the maximum temperature typically used to facilitate desired removal times can be quite high, such that the temperature experienced by an IC on the surface of the PCBs during such conventional methods may substantially exceed the temperature liquidus of the solder and may cause thermal damage to sensitive ICs. Additionally, using conventional methods, the surface temperature to which the PCB is heated cannot be precisely and / or consistently controlled, which may introduce inefficiencies and / or may overheat the ICs and result in damaged ICs. Accordingly, some aspects of the present disclosure are generally related to systems and methods related to precisely heating PCBs to facilitate removal of ICs designated for reuse from the PCBs.

[0023] FIG. 1A is an example of a portion of a system 100 first disclosed herein. System 100 includes a container 110 having an interior volume 115 that is partially filled with fluid 120. A temperature sensor 130 is present in container 110 and may be in communication with control unit 140. As shown in FIG. IB and as described elsewhere herein, the system 100 may be configured to receive one or more populated circuit boards 150 within the fluid 120 of the container 110.

[0024] The system may include a container or bath. The container or bath may be sized and adapted to receive one or more populated circuit boards. For example, as shown in FIGS. 1A-1B, the container 110 is sized and adapted to receive the populated circuit board 150. The container or bath may be any of a variety of shapes, for example, cylindrical, a rectangular prism, or other regular or irregular shapes. Depending on the PCBs to be inserted into the container or bath, and / or the desired throughput related to the number of PCBs being inserted into the container, the size of the container or bath may be adjusted.

[0025] In some embodiments, the container or bath may contain a fluid. The fluid may be a thermal fluid having a high heat capacity and may be a liquid up to at least a temperature exceeding a liquidus temperature of a solder present on a populated circuit board. In some embodiments, the fluid may be a thermal fluid able to maintain a temperature when transferring heat to and / or from a populated circuit board. In some embodiments, the fluid may be or include any of a variety of fluids. Non-limiting examples of thermal fluids which can be used according to the present invention (e.g., to melt solder) are: synthetic and natural oils, mineral oils, petroleum oils (e.g., those comprising paraffinic and / or naphthenic hydrocarbons), aromatics (e.g., those compounds comprising benzene-based structures and including the diphenyl oxide / biphenyl fluids, the diphenylethanes, dibenzyltoluenes, and terphenyls), vegetable oils, animal oils, polymeric organosilicon compounds and silicon oils, hybrid glycol fluids, natural and synthetic waxes and paraffins, molten salts, ionic liquids and mixtures thereof, as well as thermal fluids marketed under trademarked names like Dowtherm™, Syltherm™, Therminol™, Duratherm™, Calflo™, Petro-Therm™, Paratherm™, Xcelpherm™, Dynalene™, and the like. Other fluids are also possible. The amount of fluid in the container or bath may be any of a variety of suitable amounts, in accordance with some embodiments. In some embodiments, the amount of fluid may be selected to achieve certain depths of fluids. For example, as described elsewhere herein, in some embodiments, a PCB having ICs may be partially submerged in the fluid such that the board may be within the fluid but the ICs may be substantially out of the fluid. In some embodiments, the entire PCB and the ICs may be submerged in the fluid. Accordingly, the amount of fluid in the container or bath may be selected such that a maximum depth of the fluid (e.g., into which the PCB may be inserted) is greater than or equal to 0.1 inches, greater than or equal to 0.2 inches, greater than or equal to 0.25 inches, greater than or equal to 0.3 inches, greater than or equal to 0.4 inches, greater than or equal to 0.5 inches, greater than or equal to 0.6 inches, greater than or equal to 0.7 inches, greater than or equal to 0.8 inches, greater than or equal to 0.9 inches, greater than or equal to 1 inch, greater than or equal to 1.25 inches, greater than or equal to 1.5 inches, greater than or equal to 1.75 inches, greater than or equal to 2 inches, or greater than or equal to 2.25 inches. In some embodiments, the amount of fluid in the container or bath may be selected such that a maximum depth of the fluid (e.g., into which the PCB may be inserted) is less than or equal to 2.5 inches, less than or equal to 2.25 inches, less than or equal to 2 inches, less than or equal to 1.75 inches, less than or equal to 1.5 inches, less than or equal to 1.25 inches, less than or equal to 1 inch, less than or equal to 0.9 inches, less than or equal to 0.8 inches, less than or equal to 0.7 inches, less than or equal to 0.6 inches, less than or equal to 0.5 inches, less than or equal to 0.4 inches, less than or equal to 0.3 inches, less than or equal to 0.25 inches, or less than or equal to 0.2 inches. Combinations of the foregoing ranges are possible (e.g., greater than or equal to 0.1 inches and less than or equal to 2.5 inches). Other ranges are also possible.

[0026] The use of a thermal fluid that is a liquid, when contrasted to the use of a gas or IR rays as may be conventionally used to heat PCBs, may be beneficial for any number of a variety of reasons. For example, the thermal fluid may have a high heat capacity, and thus may be able to maintain a desired temperature with little fluctuation when transferring heat to or from a PCB. For example, in some such embodiments, a temperature of the thermal fluid may change, but the change may be relatively small due to the high heat capacity of the thermal fluid. In some embodiments, a temperature change of the thermal fluid may be mitigated by counteracting a loss of heat of the thermal fluid by inputting heat via a temperature controller. Additionally, and as described in more detail elsewhere herein, a temperature controller thermally coupled to the thermal fluid may facilitate the precise control of the temperature of the thermal fluid. In some such embodiments, the temperature of the thermal fluid may be maintained to within precise range of a target temperature, which may be selected to minimize and / or avoid damaging ICs present on a PCB when heating the PCB to remove the ICs. In some embodiments, the temperature controller is configured to heat a PCB contained within an associated container or bath to a temperature within 10 degrees C (e.g., or within 5 degrees C, within 2 degrees C, within 1 degree C, within 0.5 degree C, within 0.25 degree C, or within 0.1 degree C) of a target temperature.

[0027] In some embodiments, the fluid may be selected so that it may be heated to a relatively high temperature without a substantial quantity (less than 5 vol. %) evaporating over the course of time required to remove the ICs from a PCB being processed, e.g., a temperature corresponding to and / or if higher than a liquidus temperature of a solder used to adhere electronic components onto a circuit board.

[0028] Referring again to FIG. 1A, the system 100 may include a control unit 140. In some embodiments, the control unit may be a temperature controller. The temperature controller may be in thermal contact with the thermal fluid 120 in the container 110. In some embodiments, the temperature controller may be configured to control a temperature of the fluid in the container as measured with temperature sensor 130. In some such embodiments, the temperature controller may be configured to change a temperature of the fluid, where the temperature sensor may monitor the temperature of the fluid. The communication between the temperature controller and the temperature sensor may facilitate a feedback loop between the temperature sensor and the temperature controller to more precisely control the temperature of the fluid. While not pictured in FIG. 1A, the temperature controller may further include a feature (e.g., a stir bar, electronic mixers, circulating pump, etc.) to provide agitation and / or convection within fluid 120 to facilitate a relatively uniform temperature of fluid 120 throughout its entirety.

[0029] To change the temperature of the fluid, the temperature controller may include a component for heating the fluid. In some embodiments, the temperature is controlled via a heating component of the temperature controller that is controlled by a control circuit and / or computer of the temperature controller. Example heating components include a heat exchanger, and / or an electrically resistive heater element, an infrared radiant heater, or the like. Other heating components for heating the fluid are also possible.

[0030] In some embodiments, the temperature controller is configured to controllably heat the PCB. As mentioned above, the temperature controller may be configured to heat and / or control a temperature of the fluid, in some embodiments. According to some embodiments, the fluid is liquid and may remain a liquid to relatively high temperatures, e.g., at least up to 10 degrees Celsius over a liquidus temperature of a solder on a PCB. In some embodiments, the temperature controller may be configured to heat the fluid of the system to a temperature corresponding above a liquidus temperature of the solder. In some embodiments, the temperature controller may be configured to heat the fluid of the system to a temperature above the liquidus temperature of a solder present on a PCB. In some embodiments, the temperature controller may be configured to control a temperature of the fluid so as to control the temperature of a PCB submerged therein.

[0031] For example, in some embodiments, a solder of a PCB may have a liquidus temperature of 220 degrees C. Accordingly, in some embodiments, a temperature controller of the system may be configured to heat the fluid of the system to an average temperature of greater than or equal greater than or equal to 220 degrees C, greater than or equal to 221 degrees C, greater than or equal to 222 degrees C, greater than or equal to 223 degrees C, greater than or equal to 224 degrees C, greater than or equal to 225 degrees C, greater than or equal to 226 degrees C, greater than or equal to 227 degrees C, greater than or equal to 228 degrees C, or greater than or equal to 229 degrees C. In some embodiments, the temperature controller may be configured to heat the fluid of the system to an average temperature of less than or equal to 230 degrees C, less than or equal to 229 degrees C, less than or equal to 228 degrees C, less than or equal to 227 degrees C, less than or equal to 226 degrees C, less than or equal to 225 degrees C, less than or equal to 224 degrees C, less than or equal to 223 degrees C, less than or equal to 222 degrees C, or less than or equal to 221 degrees C,. combinations of the foregoing ranges are possible (e.g., greater than or equal to 220 degrees C and less than or equal to 230 degrees C, greater than or equal to 220.5 degrees C and less than or equal to 221.5 degrees C). Other ranges are also possible. In some embodiments, the temperature controller may be configured to heat a fluid to higher or lower ranges than the foregoing ranges, for example, based on a target liquidus temperature of a solder on a PCB.

[0032] In some embodiments, the temperature controller may be configured to heat the fluid of the system to the ranges described above with relatively high precision. For example, in some embodiments, the temperature of the fluid in the system when heated by the temperature controller, may be heated to within 2 degrees C, 1 degree C, 0.5 degrees C, or 0.1 degrees C of the target temperature. In some embodiments, once an average temperature of the fluid reaches the target temperature, the average temperature of the fluid may be controlled to fluctuate by less than or equal to 1 degrees C, less than or equal to 0.5 degrees C, or less than or equal to 0.1 degrees C, absent short term fluctuations caused by any external stimuli (e.g., upon insertion of a PCB into the fluid).

[0033] Referring again to FIG. 1A, the system 100 may include a control unit 140. As described above, in some embodiments, the control unit may include a temperature control component. In some embodiments, the control unit 140 (or a separate control unit (not shown)) includes sensors and control features for thermal liquid depth control. In some such embodiments, the depth controller may be in communication with one or more depth or pressure sensors 130 and / or weir or skimming / liquid removal device. In some embodiments, the depth controller controls a depth to which a PCB is submerged into the fluid of the system. For example, in some embodiments, the depth controller may be configured to monitor and / or change a position of a PCB within a fluid, e.g., by using sensors 130 as shown in FIG. 1A and / or to control the depth of the thermal fluid to control submersion depth. Such position sensors may be any of a variety of types of devices, e.g., optical sensors. In some embodiments, the depth controller may change a depth to which the PCB is submerged in the fluid, for example, by modulating the amount of fluid in the container and / or changing a position of the PCB in the container.

[0034] In one exemplary embodiment, a system includes a conveyor that transports a PCB through a bath having portions with varying thermal fluid depths to provide depth control in what may be operated as a continuous or semi-continuous process. Consider FIGS. 2A-2C, which show schematic diagrams of such an embodiment including a conveyor 142 in container 110 of system 100 that transports PCB 150 in direction 135. In some embodiments, the conveyor 142 may include a first ramp portion 147 along which a PCB 150 is conveyed in direction 135 to a first, shallow section 146 of fluid bath 120. In some embodiments, as illustrated in FIG. 2B, the first section 146 may be positioned relative to the fluid 120 to only partially submerge the PCB 150 in the fluid. In certain embodiments, the thermal fluid in the first section or in the entire bath during the time in which the PCB is resident in the first section, is maintained at a first, lower temperature, e.g., within 1 degree C or within 2 degrees C of the liquidus temperature of the solder securing the ICs to the PCB. During this phase of the removal, the most thermally sensitive ICs may be removed such that they are exposed to relatively low temperatures while not being submerged or only partially submerged to protect them from thermal damage. Once such ICs have been removed, the conveyor 142 may transport the PCB with any remaining ICs or other components via a second ramp portion 145 to a second, deeper portion 144 of thermal bath 120. The temperature in this second portion in certain embodiments may be maintained at a higher temperature (or a temperature controller associated with the system may be operated to increase the temperature of the entire thermal bath after the PCB 150 has been transported to second section 144) to more quickly remove remaining components and solder from the PCB. In some embodiments, the conveyor of the system, when present, may include any of a number of ramp and flat portions for positioning the PCB at different depths within the fluid of the system. A final ramp portion 143 of conveyor 142 may be configured to convey a PCB (or the now bare board portion thereof) out of fluid bath 120 of system 100.

[0035] In certain embodiments, the control unit 140 illustrated in FIGS. 1A-1B and 2A- 2C may be a temperature controller and / or a depth controller. In some embodiments, while not pictured, both a temperature controller and a separate depth or pressure controller may be included in the system, so that a depth to which a PCB is submerged in the fluid may be controlled while the temperature of the fluid is simultaneously and / or independently controlled.

[0036] In some embodiments, the system for removing components from PCBs may further include an element for removing ICs from the PCB. Such an element for removing components from a PCB may remove ICs 152 from bare board 154 of PCB 150 as shown in FIG. 3A. In some embodiments, as shown in FIG. 3B, only certain ICs 152 are removed from bare board 154 of PCB 150. In some such embodiments, the ICs that are designated for reuse may be selectively removed before the PCB is introduced (e.g., moved to, conveyed, etc.) to a second section (e.g., section 144 of FIG. 2C) for bulk removal of components 156. In some such embodiments, the ICs that are selectively removed may be designated for reuse before the PCB is introduced to the deeper and / or hotter chip removal portions of the system. In some embodiments, the deeper and / or hotter chip removal portions of the system are the second area for bulk removal of components (e.g., as illustrated in FIGS. 2A-2C).

[0037] The tool for removing components (e.g., ICs) from the PCB may be any of a variety of appropriate tools for such purposes know in the art, in accordance with some embodiments. In some embodiments, the tool for removing components from the PCB may be a ‘pick and place’ machine configured to selectively and physically grab and remove components from the PCB. In some embodiments, the tool for removing components from the PCB may be configured to selectively apply a suction force to components (e.g., ICs) of the PCB designated for reuse to remove such components. Other tools for removing components from the PCB may also be used, as this disclosure is not so limited. In some embodiments, the tool for removing components from the PCB may be coupled to a processor and / or a microcontroller to automate, e.g., via robotics, the removal (e.g., selective removal) of the components from the PCB.

[0038] In some embodiments, the second area for bulk removal of components may be configured to remove the remaining ICs (i.e., after an initial removal of ICs designated for reuse) from the PCBs. As noted above, in some embodiments, the second area of the system may be a deeper and / or hotter chip removal second section of the system. In some embodiments, the second section may be a continuation of the thermal fluid bath in which the initial components are removed (e.g., as shown in FIGS. 2A- 2C). In some other embodiments, the second area may be a second, separate container or separate thermal fluid bath into which the PCBs with remaining components may be placed. The thermal fluid of the second area, in accordance with some embodiments, may be controlled to a different temperature than the thermal fluid in the first (e.g., initial) area in which the initial components are removed from the PCB. In some embodiments, the different temperature may be selected so as to be high enough to remove any remaining components from the PCB relatively quickly and / or completely. In some embodiments, the different temperature may be greater than or equal to 220 degrees C, greater than or equal to 221 degrees C, greater than or equal to 222 degrees C, greater than or equal to 223 degrees C, greater than or equal to 224 degrees C, greater than or equal to 225 degrees C, greater than or equal to 228 degrees C, greater than or equal to 230 degrees C, or greater than or equal to 232 degrees C, and / or less than or equal to 235 degrees C, less than or equal to 238 degrees C, or less than or equal to 240 degrees C.

[0039] In some embodiments, the removal of bulk components within a second area of the system occurs by simple gravity assisted removal of the components when solder or other adhesives are heated and liquified or otherwise thermally compromised. In some embodiments, the removal of bulk components within the second area of the system is assisted by applying a mechanical, pneumatic, and or fluid force to the components, e.g., by scraping and / or brushing the surface of the PCB including the components. In some embodiments, applying a force to the components may be performed using any suitable tool or method, for instance, applying a force by brushing a flexible wire brush across the surface of the PCB. It will be understood that the PCBs may both be heated and have a force applied thereto in order to remove any bulk components remaining on the surface of the PCB.

[0040] Some aspects of the present disclosure are generally related to IC removal methods as described herein. FIG. 4 shows an example method flow diagram detailing how to practice certain methods and / or use the systems described herein to perform such methods. Method 400 comprises at least partially submerging a PCB into a fluid at step 410. As described above, in some embodiments, the depth in the fluid to which the PCB is submerged may be controlled, e.g., by a depth controller. In some embodiments, the PCB may be only partially submerged in the fluid. In some embodiments, the PCB may be completely submerged in the fluid.

[0041] According to some embodiments, the method 400 comprises heating the PCB to within 10 degrees C over and / or is within a few degrees C of a liquidus temperature of a solder adhering one or more integrated circuits to the PCB 420 (e.g., within 9 degrees C, within 5 degrees C, within 2 degrees C, within 1 degree C, and so forth as described elsewhere herein). In some embodiments, the heating of the PCB may be to a temperature that precisely corresponds to about 2 degrees C or 1 degree C over the liquidus temperature of the solder on the PCB. In some embodiments, heating the PCB to a temperature within a certain range of the liquidus temperature of a solder is advantageous as it may prevent any components of the PCB (e.g., ICs designated for reuse) from being exposed to temperatures substantially higher than the liquidus temperature of the solder, which may prevent the degradation and / or otherwise damaging of the components on the PCB and may facilitate their reuse. The heating of the PCB may be performed using a temperature controller as described in more detail elsewhere herein.

[0042] During heating of the PCB, the solder adhering components to the PCB may be melted sufficiently to remove selected ICs. The method 400 may further comprise selectively removing one or more of such ICs from the PCB - step 430. In some embodiments, removing one or more ICs from the circuit board of the PCB may proceed while the PCB remains submerged in the fluid. In some embodiments, the PCB may be removed from the fluid before removing one or more of the ICs from the circuit board. Still, in some embodiments, the PCB may be partially removed from the fluid before removing one or more of the ICs from the circuit board. For example, referring again to FIGS. 2A-2C, the PCB 150 may be moved to a position as in FIG. 2C where the PCB is only slightly or partially submerged in the fluid of the system. According to some such embodiments, the PCB is positioned such that the circuit board and solder adhering the components (e.g., ICs) remains substantially submerged in the fluid while the components are substantially removed from the fluid. Such positioning of the PCB relative to the fluid, in some embodiments, may facilitate the selective removal of one or more components of the PCB as the solder adhering the components may remain heated by the fluid and thus may remain at its liquidus temperature (e.g., and substantially melted).

[0043] Again, as described above, selectively removing components from the PCB may include removing only a portion of the components on the PCB, as illustrated in FIG. 3B. In some such embodiments, the components that are selectively removed, e.g., by step 430, may be designated for reuse before performing the step 440 to remove additional / remaining components. That is, in some embodiments, method 400 may comprise designating at least some of the components of the PCB for removal by a first method step 430. Still, in some embodiments, all of the components present on the PCB may be removed by the first method step 430. In other embodiments, not all components from the PCB may be removed by the first method step 430. As noted, method 400 may further comprise removing the remaining integrated circuits of the PCB using a second method step 440, e.g., when the selective removal of one or more components of the PCB does not remove all of the components from the PCB. In some embodiments, following removal of some of the ICs from the PCB via the first method, the PCB may remain at least partially submerged in the thermal fluid to remain heated until any remaining components present on the PCB are ready to be removed by a second method. This may be desirable, in some embodiments, to minimize the energy needed during a second method to heat the PCB. Any of a variety of second methods steps 440 may be utilized to remove any remaining components from the PCB. For example, in some embodiments, the PCB with the remaining components may be moved to a second area. In some embodiments, the second area may be a second portion of a contiguous thermal bath in which the initial components designated for reuse are also removed. In some embodiments, the second area may be a separate container or separate thermal fluid bath into which the PCBs are placed. In some embodiments, the thermal fluid in the second area may be heated to a different temperature (e.g., higher) than the temperature of the thermal fluid in the thermal bath. The different temperature, in some embodiments, may be selected so as to be high enough to remove any remaining components, while avoiding any excess energy usage. As another example, methods that may be used to remove remaining components from the PCBs are described in US Pat. No. 10,362,720, which was previously referenced and incorporated by reference.

[0044] While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teaching of the present invention is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present invention.

[0045] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0046] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0047] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law. As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0048] Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

[0049] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0050] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMSWhat is claimed is:

1. A system for removing components designated for reuse from a populated circuit board, comprising: a container or bath; fluid in the container or bath; and a temperature controller associated with the fluid, wherein the temperature controller is configured to maintain a temperature of the fluid to within 10 degrees C from a target temperature.

2. The system as in claim 1, wherein the temperature controller is configured to maintain the temperature of the fluid to within 2 degrees C from the target temperature.

3. The system as in claim 1, wherein the temperature controller is configured to maintain the temperature of the fluid to within 1 degree C from the target temperature4. The system as in any one of the preceding claims, wherein the target temperature is the temperature liquidus of a solder present on the populated circuit board, optionally, 220 degrees C.

5. The system of claim 1, wherein the fluid is a thermal liquid.

6. The system of claim 1, wherein the container or bath contains the populated circuit board.

7. A system for removing components designated for reuse from a populated circuit board, comprising: a container or bath; fluid in the container or bath; and a depth controller associated with the container or bath and configured to adjust a depth to which the populated circuit board is submerged in the fluid in the container or bath.

8. The system of claim 7, wherein the fluid is a thermal liquid.

9. The system of claim 8, wherein the container or bath contains the populated circuit board partially submerged in the thermal liquid.

10. A system for removing components designated for reuse from a populated circuit board, comprising: a container or bath; fluid in the container or bath; a temperature controller associated with the container or bath; and a fluid depth controller associated with the container or bath, wherein the temperature controller is configured to maintain a temperature of the fluid to within 10 degree C from a target temperature and wherein the depth controller unit is configured to adjust a depth of the fluid in which the populated circuit board is submerged in the container.

11. The system of claim 10, wherein the fluid is a thermal liquid.

12. The system of claim 11, wherein the container or bath contains the populated circuit board partially submerged in the thermal liquid.

13. The system of claim 10, wherein the target temperature is a temperature liquidus of solder affixing the components to the populated circuit board.

14. The system as in claim 10, wherein the temperature controller is configured to maintain the temperature of the fluid to within 2 degrees C from the target temperature.

15. The system as in claim 10, wherein the temperature controller is configured to maintain the temperature of the fluid to within 1 degree C from the target temperature16. A method, comprising:heating and controlling a temperature of a thermal liquid in contact with a populated circuit board to within 10 degrees C of a liquidus temperature of a solder adhering one or more integrated circuits to the populated circuit board; and selectively removing one or more of the integrated circuits from the populated circuit board.

17. A method as in claim 16, comprising heating and controlling the temperature of the thermal liquid in contact with the populated circuit board to within 2 degrees C of the liquidus temperature of the solder adhering one or more integrated circuits to the populated circuit board.

18. A method as in claim 16, comprising heating and controlling the temperature of the thermal liquid in contact with the populated circuit board to within 1 degree C of the liquidus temperature of the solder adhering one or more integrated circuits to the populated circuit board.

19. A method as in any one of claims 16-18, wherein selectively removing one or more of the integrated circuits from the populated circuit board comprises using a first method.

20. A method as in any one of claims 16-19, further comprising removing the remaining integrated circuits of the plurality of integrated circuits using a second method.

21. A method as in any one of claims 16-20, further comprising at least partially submerging a populated circuit board into the fluid.

22. A system for removing components designated for reuse from a populated circuit board, comprising: a container or bath; and a temperature controller associated with the container or bath, wherein the temperature controller is configured to heat the populated circuit board to a temperature within 10 degrees C of a target temperature.

23. The system as in claim 22, wherein the temperature controller is configured to heat the populated circuit board to within 2 degrees C of a target temperature.

24. The system as in claim 22, wherein the temperature controller is configured to heat the populated circuit board to within 1 degree C of a target temperature.

25. The system as in any one of claims 22-24, wherein the target temperature is the temperature liquidus of a solder present on the populated circuit board, optionally, 220 degrees C.

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