Planarization of Circuit Board Assemblies Using Vacuum Pressure

Abstract

An example of a method for planarizing a circuit board assembly includes attaching the circuit board assembly to a structure having dimensions that partially surround a space, attaching the circuit board assembly to the structure providing an airtight seal across the space, the structure having at least one port in fluid communication with the space. The method also includes applying a vacuum pressure to the space via the at least one port, the vacuum pressure pushing at least a portion of the circuit board assembly toward the space, and selectively applying a thermal interface material onto a portion of the circuit board assembly while the vacuum pressure is being applied.

Description

Technical Field

[0001] This specification describes an example of a system for planarizing a circuit board assembly using a vacuum pressure.

Background Art

[0002] A circuit board assembly can be curved or bent during the manufacturing process. For example, the center or central part of the circuit board assembly can be higher than all or part of the four sides of the circuit board assembly. Such curvature or bending can have an adverse effect on the operations performed during the manufacturing process involving the circuit board assembly.

Summary of the Invention

Means for Solving the Problems

[0003] An example of a method for planarizing a circuit board assembly includes attaching the circuit board assembly to a structure having dimensions that partially surround a space, attaching the circuit board assembly to the structure resulting in an airtight seal across the space, and the structure having at least one port in fluid communication with the space. The method also includes applying a vacuum pressure to the space via the at least one port, the vacuum pressure pushing at least a portion of the circuit board assembly towards the space, and selectively applying a thermal interface material on a portion of the circuit board assembly while the vacuum pressure is being applied. The method can include one or more of the following features alone or in combination.

[0004] The portion of the circuit board assembly can include components on the surface of the circuit board assembly. The thermal interface material can be applied on the surface of the components. Applying the vacuum pressure can reduce the height deviation of a stack including the circuit board assembly and the structure in the vertical dimension. In some examples, the thermal interface material may not be applied on all or some regions of the circuit board assembly that do not include components.

[0005] In the absence of a vacuum, the circuit board assembly is at least partially curved with respect to the structure. A vacuum pressure can be applied at a magnitude and for a duration sufficient to reduce or eliminate the curvature of the circuit board assembly with respect to the structure. The vacuum pressure can be applied at a magnitude and for a duration sufficient to flatten the circuit board assembly.

[0006] The structure can include a gasket that provides an airtight seal across the space between the circuit board assembly and the structure. The structure can include ribs within the space. The position of the ribs can correspond to the position of the circuit board assembly that does not include components. The ribs can be configured to enable fluid communication with at least one port across the entire space.

[0007] The structure can include alignment pins. Attaching the circuit board assembly to the structure can include aligning the alignment pins of the structure with corresponding holes in the circuit board assembly. Aligning the alignment pins can reduce the mechanical tolerances of the stack including the circuit board assembly and the structure in the horizontal dimension. The mechanical tolerances can be related to the position of the circuit board assembly within the system used to perform the method.

[0008] The method can be performed using a machine that supplies a vacuum pressure. The structure and the circuit board assembly can be at an oblique angle with respect to the substantially rectangular surface of the machine. The method can include contacting a portion of the circuit board assembly to which a thermal interface material is applied with a thermal plate. The method can also include removing the structure from the circuit board assembly. The thermal plate can be or can include a cooling plate.

[0009] An example of a system for flattening a circuit board assembly includes a structure having dimensions that surround a space such that attaching the circuit board assembly to the structure provides an airtight seal over the space. The structure has at least one port in fluid communication with the space. The system includes a vacuum source for applying a vacuum pressure to the space via the at least one port. The vacuum pressure is of a magnitude and duration sufficient to push at least a portion of the circuit board assembly toward the space. The system also includes a robot for selectively applying a thermal interface material onto a portion of the circuit board assembly while the vacuum pressure is being applied. The system may include one or more of the following features, either alone or in combination.

[0010] The portion of the circuit board assembly may include components on the surface of the circuit board assembly. The robot may be controlled to apply the thermal interface material onto the surface of the components. The robot may be controlled not to apply the thermal interface material onto regions of the circuit board assembly that do not include components.

[0011] In the absence of a vacuum, the circuit board assembly is at least partially curved with respect to the structure. The vacuum source may be controlled to apply the vacuum pressure at a magnitude and for a duration sufficient to reduce or eliminate the curvature of the circuit board assembly with respect to the structure. The vacuum source may be controlled to apply the vacuum pressure at a magnitude and for a duration sufficient to flatten the circuit board assembly.

[0012] The structure may include a gasket that provides an airtight seal over the space between the circuit board assembly and the structure. The structure may include ribs within the space. The position of the ribs may correspond to the position of the circuit board assembly that does not include components. The ribs may be configured to enable fluid communication with the at least one port across the entirety of the space. The structure may include alignment pins at positions corresponding to the positions of holes in the circuit board assembly.

[0013] The system may include a machine having a substantially rectangular surface for holding a structure. The machine may include a vacuum source. The structure and the circuit board assembly may be at an oblique angle to the substantially rectangular surface of the machine.

[0014] Any two or more of the features described in this specification, including this summary section, can be combined to form implementations not specifically described herein.

[0015] The system or a part thereof described herein may be at least partially controlled via a computer program product stored in one or more non-transitory machine-readable storage media and including instructions executable by one or more processing devices (e.g., programmed logic such as a microprocessor, application specific integrated circuit, field programmable gate array, etc.). The system or a part thereof described herein may be implemented as one or more apparatuses or methods and may include a computer memory storing executable instructions for implementing control of one or more processing devices and various functions. The apparatuses, systems, methods, and / or components described herein may be configured, for example, through design, structure, arrangement, placement, programming, operation, activation, deactivation, and / or control.

[0016] Details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings and from the claims.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

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[0018] Like reference numerals in the various figures indicate like elements.

[0019] This specification describes example implementations of systems and processes for planarizing a circuit board assembly using vacuum pressure. An example of such a system includes a structure having dimensions that partially surround a space / volume. Attaching the circuit board assembly to the structure results in an airtight seal across the space. The structure includes at least one port in fluid communication with the space. A vacuum source is connected to the port to apply a vacuum pressure to the space. The vacuum pressure is of a magnitude and duration sufficient to push the curved or bent portions of the circuit board assembly toward the space, thereby planarizing the circuit board assembly such that all portions of the circuit board assembly are substantially in the same plane. A robot is configured to selectively apply a thermal interface material (TIM) onto portions of the circuit board assembly while the vacuum pressure is being applied. The robot is controlled to deposit the TIM assuming that the circuit board assembly is flat. If the circuit board assembly is curved or bent, the robot may deposit the TIM in an incorrect location on the circuit board assembly. However, because the circuit board assembly is being planarized by the vacuum pressure, the robot is more likely to deposit the TIM in the intended location on the circuit board assembly, thereby potentially reducing manufacturing errors.

[0020] FIG. 1 shows an example of a top view of an example of the structure 10 of the type described above, and FIG. 2 shows a side perspective view thereof. The shape of the structure 10 is rectangular, but any suitable shape can be used. For example, the structure 10 can be square, trapezoidal or irregular in shape. The structure 10 includes a bottom surface 12 and side walls 14, 15, 16 and 17. The surface 12 and the side walls 14-17 together partially surround a volume or space 20. In the example described herein, as shown in the figure, the space 20 is surrounded by five surfaces and its upper part is open. As will be described below, the structure 10 is configured such that, for example, a circuit board assembly such as a printed circuit board assembly (PCBA) is fitted at the upper part 21 and thereby surrounds the space 20, and is sized or shaped accordingly. In some implementations, the opening at the upper part 21 of the structure 10 has the same size (e.g., area) and shape as the circuit board assembly that is fitted to cover the upper part of the structure.

[0021] The structure 10 also includes one or more ribs 22a-22e within the space. The ribs include walls having the same or substantially the same height as the height of the side walls 14-17. In this context, "substantially the same" includes manufacturing variations or minor irregularities in the height of the ribs and / or the side walls. The ribs provide stability and support the circuit board assembly. The ribs are arranged within the space based on the position of the structure on the circuit board assembly that is fitted at the upper part of the structure 10. In one example, the ribs are at positions corresponding to positions on the circuit board assembly that do not contain components.

[0022] Referring to FIGS. 3 and 4, a circuit board assembly, such as circuit board assembly 25 (FIG. 4 omits the components of the circuit board assembly), can be composed of components and a substrate that holds conductive traces and / or conductive layers. The circuit board assembly includes two surfaces, namely a mounting surface 27 and a bottom 28. The mounting surface 27 is a place where components 26, such as active and passive electronic devices (e.g., programmable logic 26a, memory 26b, resistor 26c, and other types of components), can be mounted and electrically connected to the circuit board assembly. The bottom 28 usually does not include components, but in some mounting forms, the bottom of the circuit board assembly may include components. The bottom can be a place where the circuit board assembly is connected to another structure electrically, mechanically, or both electrically and mechanically. In the example of FIGS. 3 and 4, there are no components along positions 30 to 30e on the mounting surface or the bottom surface of the circuit board assembly 25. These positions correspond to ribs 22a to 22e of the structure 10. Thereby, when the circuit board assembly 25 is attached to the structure 10 and a vacuum source is applied, the chance of the ribs damaging the components is reduced.

[0023] Referring again to FIGS. 1 and 2, the ribs are arranged to allow fluid communication throughout the space 20. That is, the ribs can include holes, openings, or paths through which air can travel to and from all positions within the space 20. In this example, there is an opening 32 between ribs 22c and 22d, through which air can be sent to the sub-compartment 33. There is also an opening 34 between ribs 22a and 22b, through which air can pass. In this context, a sub-compartment includes one or more regions of a space, such as space 20, and this region is partially surrounded by one or more of the ribs.

[0024] FIG. 5 shows an example of another structure 40, which has the same function as structure 10 but has a different rib configuration. Here, ribs 42a and 42b include an opening 41, through which air travels between sub-compartments 40a and 40b.

[0025] Referring again to FIG. 1, the structure 10 includes at least one / one or more air ports 35a, 35b that are in fluid communication with the space 20. Air can travel between the ports and all regions of the space 20. These ports are configured to connect to their own components, such as a vacuum source 37, e.g., a compressor, an air pump, etc., or to create a vacuum to suck air from or optionally introduce air into the space 20, and are, for example, sized, shaped, and airtight in such a manner. In one example, the vacuum source 37 can include or be connected to one or more hoses 37a, 37b. The ports 35a, 35b are also configured to connect to their respective hoses 37a, 37b such that a pressure, including a vacuum pressure, is applied to the space 20 through those hoses.

[0026] In some implementations, the hoses can be in a position that makes it difficult or inconvenient to connect to the ports. For this reason, as shown in FIG. 6, using the techniques described herein, a structure 50, which is a deformed form of the structures 10 and 40, can be provided on a machine 51 having a substantially rectangular surface for holding the structure during a process. The machine 51 is connected to or includes a vacuum source (not shown). The machine 51 holds the structure (and the circuit board assembly on the structure) at an angle 52 that is oblique (e.g., an angle that is not 90 degrees or a multiple of 90 degrees) with respect to the substantially rectangular surface of the machine. Holding the structure at an oblique angle facilitates and enables the connection between the hoses 53a, 53b and the respective ports 54a, 54b of the structure 50. That is, in this example, there is no need to bend or stretch the hoses to connect to the ports of the structure.

[0027] Referring back to FIGS. 1 and 2, the circuit board assembly is fitted on top of the structure 10 to surround the space 20. When surrounded, the space 20 is airtight and prevents air from entering or leaving. The space 20 can still be considered airtight even if a small amount of air enters or exits the space, provided that the small amount of air that enters or exits does not prevent or significantly impair the planarization of the circuit board assembly using the vacuum pressure described herein. Referring also to FIG. 7, in some implementations, a gasket 56 can be disposed along all or a portion of the outer periphery on top of the structure 10 to improve or facilitate the airtight seal between the circuit board assembly 25 and the structure 10. The gasket 56 can be made of rubber, plastic, or other bendable or soft materials capable of providing an airtight seal between the circuit board assembly, the gasket, and the structure when the circuit board assembly is on the gasket. In some implementations, the gasket can be part of the structure. For the purposes described herein, a circuit board assembly "on" a structure can include a circuit board assembly placed directly on the structure without a gasket or a circuit board assembly placed on a gasket that is on or part of the structure.

[0028] Referring again to FIGS. 1 and 2, the structure 10 can also include two or more alignment pins 58 and 59. The alignment pins 58 and 59 are aligned with corresponding holes 61 and 62 (FIG. 3) through the circuit board assembly 25. Thus, when the circuit board assembly 25 is fitted onto the structure 10, the alignment pins 58, 59 are fitted into their respective holes 61, 60, thereby ensuring that the circuit board assembly 25 is in the correct or intended placement on the structure 10.

[0029] Referring to FIG. 8, the structure 10 is part of a system 65 for manufacturing devices such as test equipment, includes a circuit board assembly 25 on the structure 10 / gasket 56, and is at least temporarily planarized using the techniques described herein. The system 65 includes a vacuum source 37 such as the vacuum source described above, and applies a vacuum pressure to the hermetic space 20 surrounded by the structure 10 and the circuit board assembly 25 via ports 35a, 35b (FIG. 1). The vacuum pressure is of a magnitude and duration sufficient to push the curved or bent portions of the circuit board towards the space, thereby planarizing the circuit board assembly. In one example, the vacuum pressure is greater than 20 inches of mercury, for example 20 - 24 inches of mercury. However, the vacuum pressure is not limited to these values.

[0030] The system 65 also includes a robot 66 mounted on a gantry 67, which is configured to move in the X - dimension direction 68, Y - dimension direction 69, and Z - dimension direction 70 with respect to the circuit board assembly 25. For example, the robot 66 can be mounted on a rail 70 and moved along the rail 70 in the X - dimension direction 68. The rail 70 can be mounted on a rail 71 and moved in the Y - dimension direction 69 to move the robot in the Y - dimension direction. The robot 66 can include an actuator, etc., that moves in the Z - dimension direction to bring the TIM dispenser 72 close to the component 26a. Alternatively, the robot 66 can be mounted close enough to the components of the mounting surface 27 so that movement in the Z - dimension direction is not required. The robot 66 is configured to selectively apply TIM on the surface portions of the components and / or the circuit board assembly without components while the vacuum pressure is being applied. Although one robot is shown, the system 65 can include multiple robots for depositing TIM.

[0031] As described above, the mounting surface 27 of the circuit board assembly 25 includes components. Some of those components generate heat. Examples of heat-generating components include, but are not limited to, programmable logic such as a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), memory such as random access memory (RAM), and resistors. When heat accumulates, it can adversely affect the operation of the circuit board assembly. For this reason, a thermal plate such as a cooling plate 75 (FIG. 9) can be used to conduct heat away from the components of the circuit board assembly. The cooling plate 75 can be made of metal or other thermally conductive material and can be temperature controlled, for example, by the control system described herein, using a refrigerant or other cooling mechanism to maintain it at a specific temperature such as 70 degrees Fahrenheit (°F) or less, 60°F or less, 50°F or less, or lower. The components on the circuit board assembly and / or portions of the circuit board assembly that do not include components (e.g., the substrate base material) can be brought into thermal contact with the cooling plate, thereby transferring heat from the components and / or the circuit board assembly to the cooling plate.

[0032] Thermal contact between the cooling plate and a component and / or a portion of the circuit board assembly without components can be implemented by the TIM. That is, all or part of the component and / or the portion of the circuit board assembly without components can be physically contacted with the TIM, and the TIM can be physically contacted with the cooling plate. In some implementations, the TIM can be made of any material that complies with standards, has thermal conductivity, and has electrical insulation. For example, the TIM can be or include paraffin wax and / or silicone-based materials. The TIM can be deposited on the component and / or on the portion of the circuit board assembly without components by the robot 66 in a semi-solid or gel-like form. Next, the cooling plate contacts the TIM, thereby providing a heat path through the TIM between the cooling plate and the component including the TIM and / or the portion of the substrate surface. In some implementations, the TIM can be cured or solidified before contacting the cooling plate, resulting in a deformable, soft TIM that is flexible enough to provide a thermal interface between the cooling plate and the component including the TIM and / or the portion of the circuit board assembly.

[0033] The robot 66 is controlled by a control system to move over the mounting surface 27 of the circuit board assembly 25 to a pre-programmed position, and at each pre-programmed position, a pre-programmed amount of TIM can be deposited. The pre-programmed positions may correspond to the positions of components such as 26a, 26f that generate heat as described above and / or the positions of the circuit board assembly itself that require thermal control (e.g., cooling). That is, the TIM is applied to the surfaces of such components. The pre-programmed amount may be based on the area to be coated. For example, components with a larger surface area may require a larger amount of TIM. On the other hand, components with a smaller surface area may require a smaller amount of TIM. The thickness of the deposited TIM layer may be based on the type of material, the heat in question, the position where the TIM is deposited, and / or the vulnerability of the circuit board assembly and / or components. For example, a thicker TIM layer can be used for more vulnerable components to reduce the possibility of damage to those components when the circuit board assembly contacts the cooling plate. For example, the TIM layer used for the portion of the substrate without components can be made thicker to enable contact between those TIM layers and the cooling plate. This is because the components have a height and such contact can be hindered. The example of FIG. 8 shows the robot 66 moving to another component 26a after depositing the TIM 29 on the component 26f. Note that only two components of the circuit board assembly 25 are shown for simplicity. As shown in FIG. 3, for example, the circuit board assembly 25 includes three or more components.

[0034] As shown in FIG. 8, the control system 76 may include one or more processing devices 77, an example of which will be described here. The control system 76 also includes a memory 78 that stores computer code or instructions 79 executable by one or more processing devices to perform at least a portion of the processes described herein for controlling the operation of the vacuum source 37, the operation of the robot 66, and any other applicable automated functions described herein.

[0035] As described above, the robot 66 is controlled to move to a position on the mounting surface and deposit TIM at a pre-programmed position on the surface of the component and / or the circuit board assembly itself. However, the pre-programmed position is defined for a flat circuit board assembly, i.e., a substrate having a shape that is flat or substantially flat (e.g., the change in flatness / surface height is 5%, 4%, 3%, 2% or less). However, the substrate, and thus the circuit board assembly, can be curved or bent as described above. This can be the result of heat, humidity or other environmental factors. The curvature or bending causes portions of the circuit board assembly to be raised, which can affect the position of the components depositing TIM and / or portions of the circuit board assembly without components. This can lead to errors in depositing TIM. Therefore, the techniques described herein and the process 80 described below with respect to FIG. 9 are used to flatten the circuit board assembly before applying TIM so that all portions of the circuit board assembly are substantially in the same plane when TIM is applied by the robot. This flattening can reduce the chance of the robot depositing TIM at an incorrect position.

[0036] In accordance with process 80, the circuit board assembly 25 is placed on the structure 10 in contact with the gasket 56 on the structure 10 (80a). This configuration is shown in FIG. 8. The placement can be done manually or automatically (e.g., using robotics not shown) and the holes in the circuit board assembly 25 can be aligned with the corresponding alignment pins on the structure 10. The circuit board assembly 25 is placed in contact with the gasket 56 with the mounting side up using sufficient force to provide an airtight or substantially airtight seal between the circuit board assembly 25 and the gasket / structure 10.

[0037] Before, during, or after placing the circuit board assembly (80a), the vacuum source 37 is connected to the ports 35a, 35b (FIG. 1) of the structure 10 via hoses 37a, 37b. The hoses can be part of the structure, the vacuum source, or another machine. In any case, the control system 76 controls the vacuum source to apply a vacuum pressure to the space 20 enclosed by the airtight circuit board assembly 25 (80b). The vacuum pressure pushes or pulls the curved or bent portions of the circuit board assembly 25 towards the space, thereby flattening the circuit board assembly and being of a magnitude and duration sufficient to substantially planarize the substrate of the circuit board assembly. Applying the vacuum pressure can reduce the height deviation of the stack / assembly 81 including the circuit board assembly 25, the gasket 56, and the structure 10 in the vertical dimension. The magnitude and duration of the vacuum pressure required to push or pull the curved or bent portions of the circuit board assembly towards the space can depend, for example, on the size of the space, the size of the circuit board assembly, and / or the amount of curvature or bending. In one example, the magnitude of the vacuum pressure is greater than 20 inches of mercury or between 20 and 24 inches of mercury. The duration of the vacuum pressure can span the entire time until the robot applies the TIM and the cooling plate 75 contacts the TIM.

[0038] In this regard, after applying the vacuum pressure (80b) to flatten the circuit board assembly and while the vacuum pressure is being continuously applied, the robot 66 is controlled by the control system 76 to selectively deposit TIM on the surface of the components and / or on portions of the circuit board assembly that do not include the components (80c). The robot selectively applies TIM in the sense that the robot applies TIM to pre-programmed positions, but the substrate, conductive traces, and / or portions of one or more components can remain without TIM, i.e., without TIM being present on top. However, optionally, the entire mounting surface 27 of all components and the circuit board assembly can be covered with TIM.

[0039] After all of the TIM has been applied, the resulting assembly, namely the structure 10, gasket 56, circuit board assembly 25, and TIM 29, is partially disassembled (80d) at the point where the structure 10 is removed. For example, air can be introduced into the space 20 by, for example, operating the vacuum source 37 in reverse to pull apart or loosen the connection between the structure 10 and the circuit board assembly 25. The structure 10 can then be removed from the assembly manually or using robotics (not shown). The remainder, namely the circuit board assembly 25 and TIM 29, is then moved to a compression system either manually or using robotics (not shown), where it is combined with the structure, which can be the structure 10, the gasket 56, and the cooling plate 75 (80f). This combination is implemented without using a vacuum pressure or other fixing mechanism. For example, referring to FIG. 10, the structure 10, gasket 56, circuit board assembly 25 including TIM 29, and cooling plate 75 can be combined by arranging them in a stack. The resulting stacked assembly 81 shown in FIG. 11 is inserted into a compression mechanism (not shown). The compression mechanism applies forces in the directions of arrows 90a, 90b to bring the cooling plate into thermal contact with the TIM.

[0040] Specifically, the cold plate contacts the TIM on and / or over a portion of the circuit board assembly that does not include components, thereby providing a thermal path through the TIM between the cold plate and the components and / or the portion of the circuit board assembly that does not include components. The cold plate, circuit board assembly, and structure can be brought into contact manually or automatically using robotics (not shown). In some implementations, the cold plate 76 may also include holes 83, 84 for aligning with the alignment pins 58, 59 of the structure 10 so that the cold plate is properly positioned. That is, the alignment pins 58, 59 can protrude through the holes 61, 60 of the circuit board assembly 25 and thereby engage the corresponding holes 83, 84 of the cold plate. The amount of pressure applied to bring the cold plate, circuit board assembly, and structure into contact is sufficient to allow heat conduction between the cold plate and all or part of the circuit board assembly through the TIM, but not so great as to damage the circuit board assembly including the components mounted thereon.

[0041] After the assembly and cold plate have been compressed, the combined assembly 81 is removed (80g) either manually or using robotics (not shown) from the compression system. The circuit board assembly and cold plate can be secured together using screws or other types of fasteners (80h). Thereafter, the structure 10 including the gasket 56 can be removed from the remainder of the combined assembly (80i). For example, the structure 10 including the gasket 56 can then be removed manually or using robotics (not shown) from the cold plate / TIM / circuit board assembly. The resulting combination of the circuit board assembly and cold plate, excluding the structure 10 and gasket 56, can be used in a system such as a test system. For example, the resulting assembly can be a test fixture or part thereof for a test system.

[0042] An example of a test apparatus is a hardware device configured to send a test signal to a DUT (device under test). The test signal may include a stimulus that induces a response in the DUT, such as a voltage or current. The test apparatus is also configured to receive signals from the DUT, including response signals to the test signal, and analyze those signals from the DUT to determine whether the DUT passed or failed the test, e.g., whether the response to the stimulus was as expected. For example, the test apparatus can compare the response signal to one or more pre-defined thresholds and based on the comparison, determine whether the DUT passed or failed the test. Examples of types of test apparatuses that can use the resulting assembly include, but are not limited to, radio frequency (RF) test apparatuses, digital test apparatuses, and parametric test apparatuses.

[0043] An example of a test system may include a plurality of test apparatuses (e.g., one, two, three, four or more), which may be configured to perform one or more types of tests such as RF tests, digital tests, parametric tests, etc. The test system also includes a control system, which may be part of one or more of the test apparatuses, distributed across one or more of the test apparatuses, or separate from the test apparatuses. The control system may include one or more processing devices, examples of which are described herein. The control system includes memory storing computer code or instructions executable by one or more processing devices to execute one or more test programs and control the tests by sending instructions to one or more of the test apparatuses.

[0044] All or part of the systems and processes described herein, as well as various modified forms thereof, can be at least partially configured or controlled by one or more computers, such as control system 76, using one or more computer programs tangibly embodied on one or more information carriers, such as one or more non-transitory machine-readable storage media. The computer programs can be described in any form of programming language, including compiled languages or interpreted languages, and can be deployed in any form, such as a stand-alone program or as modules, parts, subroutines, or other units suitable for use in a computer environment. The computer programs can be deployed to be executed on one computer or on multiple computers at one site, or can be distributed across multiple sites and interconnected by a network.

[0045] Acts related to configuring or controlling the test systems and processes described herein can be performed by one or more programmable processors executing one or more computer programs to control or perform all or part of the operations described herein. All or part of the test systems and processes can be configured or controlled by special-purpose logic circuit configurations, such as FPGAs (Field Programmable Gate Arrays) and / or ASICs (Application Specific Integrated Circuits) or embedded microprocessors localized in the hardware of the device.

[0046] Processors suitable for the execution of a computer program include, for example, both general-purpose and special-purpose microprocessors, as well as any one or more processors of any kind of digital computer. Generally, a processor receives instructions and data from a read-only memory area, a random access memory area, or both. Elements of a computer include one or more processors for executing instructions and one or more storage area devices for storing instructions and data. Generally, a computer also includes or is operatively coupled to one or more machine-readable storage media, such as magnetic disks, magneto-optical disks, or optical disks, for storing data, from which it receives data, to which it transmits data, or both. Non-transitory machine-readable storage media suitable for embodying computer program instructions and data include all forms of non-volatile storage areas. Examples include semiconductor storage area devices such as EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), and flash memory area devices, magnetic disks such as internal hard disks or removable disks, magneto-optical disks, as well as CD-ROM (compact disk read-only memory) and DVD-ROM (digital versatile disk read-only memory).

[0047] Elements of different described implementations can be combined to form other implementations not specifically described above. Elements can generally be excluded from the system described above without adversely affecting the operation of those elements or the operation of the system. Further, various separate elements can be combined into one or more individual elements to perform the functions described herein.

[0048] Other implementations not specifically described herein are also within the scope of the following claims.

Claims

1. A method comprising: attaching a circuit board assembly to a structure having a dimension that partially surrounds a space, providing an airtight seal across the space, the structure having at least one port in fluid communication with the space; applying a vacuum pressure to the space via the at least one port, the vacuum pressure pushing at least a portion of the circuit board assembly toward the space; selectively applying a thermal interface material onto a portion of the circuit board assembly while the vacuum pressure is being applied; and a method including the above.

2. The portion of the circuit board assembly includes components on a surface of the circuit board assembly, The method according to claim 1, wherein the thermal interface material is applied onto a surface of the component.

3. The method according to claim 1, wherein applying the vacuum pressure reduces a height deviation of a stack including the circuit board assembly and the structure in a vertical dimension.

4. The method according to claim 2, wherein the thermal interface material is not applied onto an area of the circuit board assembly that does not include the component.

5. When there is no vacuum, the circuit board assembly is at least partially curved with respect to the structure, The method according to claim 1, wherein the vacuum pressure is applied at a magnitude and for a duration sufficient to reduce or eliminate the curvature of the circuit board assembly with respect to the structure.

6. The method according to claim 5, wherein the vacuum pressure is applied at a magnitude and for a duration sufficient to flatten the circuit board assembly.

7. The method according to claim 1, wherein the structure includes a gasket that provides the airtight seal across the space between the circuit board assembly and the structure.

8. The method according to claim 1, wherein the structure includes ribs within the space, and positions of the ribs correspond to positions of the circuit board assembly that do not include components.

9. The method according to claim 8, wherein the ribs are configured to enable fluid communication with the at least one port across the entire space.

10. The method according to claim 1, wherein the structure includes alignment pins, and attaching the circuit board assembly to the structure includes aligning the alignment pins of the structure with corresponding holes in the circuit board assembly.

11. The method according to claim 10, wherein aligning the alignment pins reduces the mechanical tolerances of a stack including the circuit board assembly and the structure in a horizontal dimension, and the mechanical tolerances are related to the position of the circuit board assembly within the system used to perform the method.

12. The method is performed using a machine that supplies the vacuum pressure, The method according to claim 1, wherein the structure and the circuit board assembly are at an oblique angle to a substantially rectangular surface of the machine.

13. contacting a portion of the circuit board assembly to which the thermal interface material is to be applied with a thermal plate, and removing the structure from the circuit board assembly The method according to claim 1, further comprising.

14. The method according to claim 13, wherein the thermal plate includes a cooling plate.

15. A structure having dimensions surrounding a space such that attaching a circuit board assembly to the structure provides an airtight seal across the space, and having at least one port in fluid communication with the space; A vacuum source for applying a vacuum pressure to the space via the at least one port, the vacuum pressure being of a magnitude and duration sufficient to push at least a portion of the circuit board assembly toward the space; A robot for selectively applying a thermal interface material to a portion of the circuit board assembly while the vacuum pressure is being applied; A system including.

16. The portion of the circuit board assembly includes components on a surface of the circuit board assembly, The system according to claim 15, wherein the robot is controlled to apply the thermal interface material on the surfaces of the components.

17. The system according to claim 15, wherein the robot is controlled not to apply the thermal interface material on regions of the circuit board assembly that do not include the components.

18. In the absence of a vacuum, the circuit board assembly is at least partially curved with respect to the structure. The system of claim 15, wherein the vacuum source is controlled to apply the vacuum pressure at a magnitude and for a duration sufficient to reduce or eliminate the curvature of the circuit board assembly relative to the structure.

19. The system of claim 18, wherein the vacuum source is controlled to apply the vacuum pressure at a magnitude and for a duration sufficient to flatten the circuit board assembly.

20. The system of claim 15, wherein the structure includes a gasket that provides the airtight seal across the space between the circuit board assembly and the structure.

21. The system of claim 15, wherein the structure includes ribs within the space, and the position of the ribs corresponds to the position of the circuit board assembly that does not include components.

22. The system of claim 21, wherein the ribs are configured to enable fluid communication with the at least one port across the entirety of the space.

23. The system of claim 15, wherein the structure includes alignment pins at positions corresponding to the positions of holes in the circuit board assembly.

24. A machine having a substantially rectangular surface for holding the structure, the machine further including the vacuum source, The system of claim 15, wherein the structure and the circuit board assembly are at an oblique angle relative to the substantially rectangular surface of the machine.

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