Apparatus for holding a substrate, method for forming an electronic module and device

Abstract

This application provides an apparatus for holding a substrate. The apparatus includes: a lower clamp including a clamp substrate, wherein the substrate has at least one electronic component mounted thereon via solder paste, and the clamp substrate is transmissive to laser radiation; and an upper clamp operably mounted on the lower clamp and, together with the lower clamp, defining a cavity for receiving the substrate, wherein the upper clamp includes a frame and ribs to form a grid pattern defining a plurality of openings for exposing the at least one electronic component from the upper clamp, and wherein, when the upper clamp is mounted on the lower clamp to receive the substrate within the cavity and the solder paste is reflowed by the laser radiation, the grid pattern contacts the substrate to apply pressure to press the substrate against the lower clamp.

Description

Technical Field

[0001] This application generally relates to semiconductor technology, and more specifically, to an apparatus for holding a substrate, a method for forming an electronic module with improved warp control, and an apparatus for forming the electronic module. Background Technology

[0002] When a semiconductor die is packaged into a semiconductor package, the die can be attached and bonded to the package substrate via solder bumps or a similar structure. A reflow process may be required to melt the solder bumps that interconnect the semiconductor die with the package substrate. However, when heat is applied to the package substrate during the reflow process, the package substrate may warp and thus bulge from the carrier on which it is placed. Warping of the package substrate can lead to irregular connections and bump cracks, resulting in low yield.

[0003] Fixtures can be used to address warpage of package substrates. For example, a lower and upper fixture can clamp the package substrate between them, especially compressing it in locations where significant warpage is likely. However, conventional fixtures are not satisfactory at reducing severe warpage, particularly for thinner package substrates. Furthermore, conventional fixtures may not be suitable for some advanced reflow processes that re-solder solder bumps, such as laser-assisted bonding or reflow processes.

[0004] Therefore, there is a need for a device for holding a substrate and a method for forming an electronic module with improved warp control. Summary of the Invention

[0005] The objective of this application is to provide an apparatus for holding a substrate and a method for forming an electronic module with improved warp control.

[0006] According to an aspect of this application, a device for holding a packaged substrate is disclosed. The device includes: a lower clamp including a clamp base for placing a substrate, wherein the substrate has at least one electronic component, each electronic component being mounted on the substrate via solder paste, and the clamp base being transmissive to laser radiation; and an upper clamp operably mounted on the lower clamp and defining, together with the lower clamp, a cavity for receiving the substrate, wherein the upper clamp includes a frame and ribs within the frame, and the frame and the ribs form a grid pattern defining a plurality of openings for exposing the at least one electronic component from the upper clamp, wherein when the upper clamp is mounted on the lower clamp to receive the substrate within the cavity and the solder paste is reflowed by the laser radiation, the grid pattern contacts the substrate, thereby applying pressure to press the substrate against the lower clamp.

[0007] According to another aspect of this application, a method for forming an electronic module is disclosed. The method includes: placing a substrate between a lower clamp and an upper clamp, wherein the lower clamp includes a clamp base that is permeable to laser radiation and for holding the substrate, the upper clamp includes a frame and ribs within the frame to form a grid pattern defining a plurality of openings exposing a portion of the substrate; passing at least one electronic component through at least one of the plurality of openings to mount each of the at least one electronic component onto the substrate via solder paste; and applying laser radiation through the clamp base to the substrate to reflow the solder paste to form the electronic module, wherein the grid pattern contacts the substrate to apply pressure to press the substrate against the lower clamp during solder paste reflow.

[0008] According to another aspect of this application, an apparatus for forming an electronic module is disclosed. The apparatus includes: a platform for placing a lower clamp and an upper clamp, the lower clamp and the upper clamp defining a cavity therebetween for receiving a substrate having at least one electronic component mounted thereon via solder paste, wherein the lower clamp includes a clamp base that is transmissive to laser radiation and for holding the substrate, and the upper clamp includes a frame and ribs within the frame to form a grid pattern defining a plurality of openings for exposing the at least one electronic component when the substrate is received in the cavity; and a laser source for applying laser radiation through the clamp base to the substrate to reflow the solder paste, wherein the grid pattern contacts the substrate to apply pressure to press the substrate against the lower clamp during solder paste reflow.

[0009] It should be understood that both the above general description and the following detailed description are exemplary and explanatory only, and do not limit the invention. Furthermore, the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Attached Figure Description

[0010] The accompanying drawings, which are incorporated herein by reference, form part of this specification. Unless expressly indicated otherwise in the detailed description, the features shown in the drawings illustrate only some embodiments of this application, and not all embodiments thereof, and should not be construed as implying to the reader of this specification that all embodiments are possible.

[0011] Figures 1A to 1D A device for holding a substrate according to a first embodiment of this application is shown.

[0012] Figure 2A device for holding a substrate according to a second embodiment of this application is shown.

[0013] Figures 3A to 3D The various steps of a method for forming an electronic module according to a third embodiment of this application are shown.

[0014] Figure 4 The reflow process in a method for forming an electronic module according to a fourth embodiment of this application is illustrated.

[0015] Figure 5 An apparatus for forming an electronic module according to a fifth embodiment of this application is shown.

[0016] Throughout the diagram, the same reference numerals will be used to refer to the same or similar parts. Detailed Implementation

[0017] The following detailed description of exemplary embodiments of this application takes into account the accompanying drawings, which form a part of the description. The drawings illustrate specific exemplary embodiments in which this application may be practiced. The detailed description, including the drawings, describes these embodiments in sufficient detail to enable those skilled in the art to practice this application. Those skilled in the art may further utilize other embodiments of this application and make logical, mechanical, and other changes without departing from the spirit or scope of this application. Therefore, the reader of the following detailed description should not interpret the description in a limiting sense, and the scope of the embodiments of this application is defined only by the appended claims.

[0018] In this application, unless otherwise expressly stated, the use of the singular includes the plural form. In this application, unless otherwise stated, the use of “or” means “and / or”. Furthermore, the use of the term “comprising” is not restrictive. Additionally, unless otherwise expressly stated, terms such as “element” or “assembly” cover both elements and assemblies comprising one unit and elements and assemblies comprising more than one sub-unit. Furthermore, the section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0019] As used herein, for ease of description, spatial relative terms such as “below,” “under,” “above,” “upper,” “upper,” “lower,” “left,” “right,” “vertical,” “horizontal,” and “side” may be used to describe the relationship between an element or feature and another element (or feature) or feature (or feature), as shown in the diagrams. In addition to the orientations depicted in the diagrams, the spatial relative terms are intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein shall be interpreted accordingly. It should be understood that when an element is referred to as “connected to” or “coupled to” another element, the element may be directly connected to or coupled to the other element, or there may be intermediate elements present.

[0020] As mentioned above, a reflow process can be implemented to melt the solder bumps that interconnect semiconductor dies with a substrate. During the reflow process, a lower and upper jig clamps the substrate between them, especially pressing the substrate in locations where significant warpage may occur. However, conventional jigs cannot satisfactorily reduce severe warpage. Specifically, in laser-assisted bonding or reflow processes, the solder bumps are reflowed by laser radiation emitted from a laser source beneath the substrate. Conventional jigs may not be suitable for this type of reflow process with reverse laser radiation.

[0021] To address this problem, a device for holding a substrate is provided, which can be used in packaging processes such as solder reflow processes. The device includes a lower clamp and an upper clamp, the lower clamp having a clamp substrate that is transmissible to laser radiation, and the upper clamp being operatively mounted on the lower clamp. A substrate is housed between the lower and upper clamps and has at least one electronic component, each of which can be mounted on the substrate via solder paste. The upper clamp includes a grid pattern defining a plurality of openings for exposing at least one electronic component from the upper clamp. During the solder reflow process, laser radiation passes through the clamp substrate and reaches the substrate to reflow the solder paste. Simultaneously, the grid pattern contacts the substrate to apply pressure to press the substrate against the lower clamp. More specifically, the grid pattern can compress the substrate at peripheral and central regions. Thus, a larger area of ​​the substrate can be pressed against the lower clamp, thereby mitigating substrate warpage with greater force and in a more uniform manner.

[0022] Figures 1A to 1D A device for holding a substrate according to a first embodiment of this application is shown. Figure 1A It is a top view of the device, and Figure 1B This is a bottom view of the device. Figure 1C The device is along Figure 1A The cross-sectional view of line AA' in the middle, and Figure 1D Showing Figure 1C A magnified view of region V in the image.

[0023] like Figures 1A to 1C As shown, a means for holding a substrate 101 is provided. Specifically, the means includes a lower clamp 102 and an upper clamp 104 to receive the substrate 101 between them. The substrate 101 has at least one electronic component 120, and each of the at least one electronic component 120 is mounted on the substrate 101 via solder paste. The means is used to hold the substrate 101 during a solder paste reflow process, such that the solder paste melts to interconnect the at least one electronic component 120 with the substrate 101.

[0024] In some embodiments, the substrate 101 may be attached to various electronic components 120. The electronic components 120 may be attached to different regions on the top surface of the substrate 101, such as... Figure 1A and 1C As shown in the illustration. Electronic component 120 may comprise any of a variety of types of semiconductor dies, semiconductor packages, or discrete devices. For example, electronic component 120 may comprise one or more digital chips, analog chips, or mixed-signal chips, such as application-specific integrated circuit (“ASIC”) chips, sensor chips, wireless and radio frequency (RF) chips, memory chips, logic chips, or voltage regulator chips. Electronic component 120 may also comprise one or more passive electrical components, such as resistors, capacitors, inductors, etc. In some embodiments, electronic component 120 may comprise an integrated circuit chip for wireless communication and / or signal processing, which may require an antenna for transmitting and receiving wireless signals. In some embodiments, electronic component 120 may further comprise output and / or input circuitry for an antenna structure for wireless communication.

[0025] Depending on the dimensions of the electronic components 120 and the substrate 101, multiple electronic components 120 can be specifically arranged and attached to the substrate 101. For example, in Figure 1CIn the embodiments shown, the plurality of electronic components 120 may have different sizes and heights. Furthermore, the plurality of electronic components 120 may be classified into several subgroups. Each subgroup may occupy a corresponding portion of the substrate 101, and portions of the substrate 101 between two adjacent subgroups may be exposed for mounting the fixture 104. The portion of the substrate 101 in which the subgroups of electronic components 120 are disposed may be referred to as the active region, while the exposed portion of the substrate 101 may be referred to as the non-active region. It is understood that, due to the mechanical and material properties of the electronic components 120 and the substrate 101, it is suitable to apply pressure to the non-active region rather than to the active region of the substrate 101. Furthermore, the number of electronic components 120 included in the several subgroups may be the same or different. Furthermore, the size, height, structure, and layout of the electronic components 120 in the several subgroups may be the same or different. In some embodiments, the different subgroups of the plurality of electronic components 120 may be attached to the substrate 101 in a generally linear manner. In some other embodiments, subgroups of multiple electronic components may be arranged in an alternating manner on substrate 101, for example, near different corners or edges of substrate 101.

[0026] As mentioned above, multiple electronic components 120 may be attached to the substrate 101 via corresponding solder paste, and therefore, when the substrate 101 is held by the device, a reflow process or other similar heating or curing process may be required on the substrate 101. It is understood that the substrate 101 may further comprise conductive patterns on which solder paste may be deposited or applied. In some embodiments, the substrate 101 may comprise one or more dielectric layers, wherein conductive layers and vias (not shown) are formed in the dielectric layers. For example, the dielectric layers may be laminates laminated to each other. Due to the combined composition of the substrate 101 and the various electronic components 120 attached thereto, the substrate 101 may warp, for example, when heat is applied during the reflow process.

[0027] An upper clamp 104 is operably mounted on a lower clamp 102 such that the two clamps 102, 104 are operable to hold a substrate 101 between them. The lower clamp 102 has a clamp base 105 for holding the substrate 101. For example, the lower clamp 102 may be a plate on which the substrate 101 can be placed flat. In some embodiments, the lower clamp 102 may be slightly recessed in its central region to receive the substrate 101 and, for example, to prevent the substrate 101 from sliding off the lower clamp 102 when the lower clamp 102 is slightly tilted. In some alternative embodiments, the lower clamp 102 may have a flat top surface. Furthermore, the clamp base 105 may include a plurality of device placement areas X and an assembly area Y. When the substrate 101 is placed on the lower clamp 102, each of the plurality of device placement areas X is aligned with one of the active regions of the substrate 101, and the assembly area Y is aligned with the non-active region of the substrate 101.

[0028] In addition, such as Figure 1B and 1C As shown, the fixture base 105 of the lower fixture 102 is formed of a material that is transmissible to laser radiation. In some embodiments, the fixture base 105 may comprise glass (e.g., soda lime glass) or quartz. During the solder paste reflow process, laser radiation, such as infrared radiation, may be emitted from a laser source disposed beneath the fixture base 105. The laser radiation may penetrate the fixture base 105 to reach the substrate 101 and subsequently heat the solder paste and reflow it. In some preferred embodiments, more than 90% of the laser energy entering the fixture base 105 may be transferred to the substrate 101 and used for the solder paste reflow process.

[0029] like Figure 1A and 1B As shown, the lower clamp 102 may have a rectangular layout. Therefore, the upper clamp 104 may have substantially the same shape and size as the lower clamp 102, allowing the two clamps 102 and 104 to be aligned and attached to each other. Specifically, the upper clamp 104 may have a frame 106 in its peripheral area and at least one rib 108 inside the frame 106 (i.e., in the central region of the upper clamp 104). The frame 106 may have the shape of a rectangular ring comprising two parallel vertical portions and two parallel horizontal portions, each parallel horizontal portion connected to one of the two vertical portions. Figures 1A to 1C In the embodiment shown, the upper clamp 104 includes two ribs 108 extending parallel to each other between two vertical portions of the frame 106. The two ribs 108 are spaced apart by a specific distance, and each of the two ribs 108 is parallel to the two vertical portions of the frame 106 and perpendicular to the two horizontal portions of the frame 106. Additionally, each of the ribs 108 traverses an internal opening of the frame 106 and connects to the two horizontal portions of the frame 106. In this way, the frame 106 and the ribs 108 form a grid pattern that defines a plurality of openings 110 within the upper clamp 104. The openings 110 may be large enough to allow electronic components 120 to be exposed through the grid pattern 108. In this case, pressure can be applied to the electronic components 120 without passing through the upper clamp 104, thereby avoiding damage to the electronic components 120. Figure 1A and 1BIn the embodiment shown, ribs 108 and frame 106 define three openings 110 that expose three subgroups of electronic components 120, respectively. It will be understood that the grid pattern 108 may have more or fewer ribs 108, or may have other arrangements. For example, only one rib 108 may be arranged at the center of an inner opening in frame 106, such that the inner opening can be separated by the rib 108 into two identical or similar openings 110, which expose two subgroups of electronic components 120, respectively. In some alternative embodiments, another rib 108 may be formed in the grid pattern and above the exposed portion of the substrate 101 located between two adjacent subgroups of electronic components 120, thereby providing a grid pattern with more openings 110. Ribs 108 in the grid pattern can generate and apply greater and more uniform pressure to the substrate 101, which is beneficial in mitigating warpage of the substrate 101, as will be described in detail later.

[0030] In some embodiments, at least one rib 108 and frame 106 may be formed as a single piece. In some other embodiments, each of the at least one rib 108 and frame 106 may be provided separately and assembled together prior to the reflow process. In this case, a specific number of ribs 108 may be selected and placed at the desired location on frame 106 according to the layout of electronic components 120 on substrate 101. In some embodiments, upper clamp 104 may further include securing elements, such as fasteners, for securing the ribs 108 at the desired location on frame 106. In some other embodiments, the horizontal portion of frame 106 may include a pair of slots, each slot formed on the inner surface of one of the horizontal portions, and the two ends of rib 108 may be inserted into the pair of slots respectively to secure rib 108 in place with frame 106. In some cases, the number of slot pairs is greater than the number of ribs 108. In this way, by simply changing the number of ribs 108 connected to the frame 106 and / or the position of the ribs 108 on the frame 106, the grid pattern can have various layouts in a single kit with the frame 106 and ribs 108, thereby enhancing the flexibility of using the clamp 104. In some other embodiments, the ribs 108 and the frame 106 may be formed of a ferromagnetic material such as steel. The ribs 108 can be attracted by the frame 106 and are held in place when the ribs are placed on the frame 106, which provides further convenience for the assembly process.

[0031] like Figure 1CAs shown, the upper clamp 104 further includes a skirt portion 112 at the periphery of the bottom surface of the frame 106. When the upper clamp 104 is mounted on the lower clamp 102, the skirt portion 112 contacts the lower clamp 102 such that a cavity is defined between the clamp base 105 and the grid pattern to accommodate the substrate 101. The thickness of the skirt portion 112 may be substantially equal to or slightly less than the thickness of the substrate 101 (excluding the electronic components 120 mounted thereon). In embodiments where the lower clamp 102 may be recessed in its central region, the sum of the thickness of the skirt portion 112 and the depth of the recess in the lower clamp 102 may be substantially equal to or slightly less than the thickness of the substrate 101. In this way, a clamping force can be applied to the substrate 101 at its periphery by the lower clamp 102 and the upper clamp 104 without damaging the electronic components 120, and the substrate 101 can be securely positioned between the lower clamp 102 and the upper clamp 104.

[0032] In some embodiments, when the substrate 101 is inserted between the lower clamp 102 and the upper clamp 104, each of the plurality of ribs 108 of the mesh pattern 108 may contact the substrate 101 to apply pressure to the substrate 101 in a non-active region. Furthermore, the clamp base 105 includes a plurality of device placement areas X and an assembly area Y. When the upper clamp 104 is mounted on the lower clamp 102, each of the plurality of device placement areas X is aligned with one of the plurality of openings 110, and the assembly area Y is aligned with the frame 106 or ribs 108 of the mesh pattern. In some other cases, the substrate 101 may have a thickness slightly smaller than the gap between the lower clamp 102 and the upper clamp 104, and the mesh pattern 108, or particularly its ribs 108, may not contact the top surface of the substrate 101 prior to the solder paste reflow process. However, when the solder paste is reflowed by laser radiation, the mesh pattern can come into contact with the substrate 101 to apply pressure so as to press the substrate 101 against the lower fixture 102.

[0033] In addition, such as Figure 1B and 1C As shown, one or more magnets 114 can be embedded within the clamp base 105. Additionally, the grid pattern is at least partially formed of a ferromagnetic material. Thus, when the upper clamp 104 is mounted on the lower clamp 102, the grid pattern of the upper clamp 104 is attracted by the plurality of magnets 114. Due to the magnetic attraction between the grid pattern and the magnets 114, the grid pattern can be brought closer to the clamp base 105, thereby increasing the pressure applied to the substrate 101 through the ribs 108 and frame 106 of the grid pattern. Figure 1D Showing Figure 1CAn enlarged view of region V shows the pressure applied to the substrate 101 by the ribs 108 and the frame 106 to overcome the protrusion of the substrate 101. More specifically, the grid-patterned frame 106 can compress the peripheral region of the substrate 101, and the grid-patterned ribs 108 can compress the exposed portion of the central region of the substrate 101. In this way, pressure can be applied to a larger area of ​​the substrate 101, and can also be applied in a more uniform and controlled manner to reduce warpage of the substrate 101 during solder paste reflow. It should be noted that in Figure 1D The diagram shows rib 108, substrate 101, and magnet 114, and for simplicity, details are omitted. Figure 1C Other elements in region V.

[0034] exist Figure 1A and 1B In the embodiment shown, the magnet 114 comprises two columns of magnets 114 aligned with two vertical portions of the frame 106, and another two columns of magnets 114 aligned with corresponding two ribs 108 of the grid pattern. In some embodiments, each column of magnets 114 comprises three magnets 114, the three magnets being evenly distributed across the corresponding vertical portion or corresponding rib 108 of the frame 106, such as... Figure 1B As shown in the diagram. In some other embodiments, the magnets 114 may be unevenly distributed, and more magnets 114 may be concentrated in the portion of the assembly area Y closer to the electronic component 120 to apply greater pressure to the portion of the substrate 101 where more severe warping may occur. It is understood that more or fewer magnets 114 may be embedded in the jig base 105 depending on the layout of the grid pattern. In some examples, each magnet 114 may have a circular shape, or a rectangular, square, or any other suitable shape. The distance from each magnet 114 to the top surface of the lower jig 102 may be, for example, 0.2 mm to 20 mm to allow appropriate magnetic interaction between the magnet 114 and the upper jig 104. In some embodiments, the magnet 114 may be a permanent magnet, while in some alternative embodiments, the magnet 114 may be an electromagnet that can be activated or deactivated by control circuitry. Additionally, in embodiments where the magnet 114 may be an electromagnet, the strength of the magnetic field generated by the magnet 114 may be adjusted by control circuitry, for example, by adjusting the power supply level to the electromagnet. In this way, the strength of the magnetic field can be adjusted to be smaller to reduce minor warping, or the strength of the magnetic field can be adjusted to be larger to reduce major warping. Optionally, the warping detection device can be used to detect warping of the substrate 101 at different locations to adjust the magnetic field.

[0035] although Figure 1AThe image shows that magnet 114 can be positioned below both frame 106 and rib 108, but in some alternative embodiments, magnet 114 may be positioned only below rib 108. In this case, other fasteners, such as clamps, pins, or clips, may be arranged at or around frame 106 of lower clamp 102 to secure lower clamp 102 to upper clamp 104 and hold substrate 101 between them.

[0036] In some other embodiments, a portion, rather than the entirety, of the upper clamp 104 may be formed of a ferromagnetic material. For example, the upper clamp 104 may have a base material and a bottom material, the base material being a dielectric material such as rubber or plastic or a metal such as copper, and the bottom material being a ferromagnetic material attached to the base material, with the bottom material closer to the lower clamp 102 when the upper clamp 104 is placed on the lower clamp 102. In some preferred embodiments, a coating of silicone or other similar elastic material may be disposed beneath the bottom material to buffer between the substrate 101 on the lower clamp 102 and the upper clamp 104. In some alternative embodiments, the upper clamp 104 may also include one or more magnets 114, which may be embedded within a grid pattern, particularly within the ribs 108 and / or the frame 106. These magnets 114 may further improve magnetic interaction with the magnets 114 in the lower clamp 102.

[0037] In addition, such as Figure 1B and 1C As shown, the lower clamp 102 further includes a plurality of passages 103 extending through the clamp base 105. The passages 103 are fluidly coupled to a vacuum source to apply vacuum pressure to the substrate 101 when it is placed on the lower clamp 102. In some examples, each passage 103 may have a circular shape, or a rectangular, square, or any other suitable shape. In some embodiments, the passages 103 may be interconnected with each other via additional channels within the clamp base 105. The vacuum attraction force generated by the vacuum pressure applied to the substrate 101 can further reduce warpage of the substrate 101 during reflow processes. In some preferred embodiments, the plurality of passages 103 are uniformly distributed within a plurality of device placement areas X of the clamp base 105 to apply vacuum attraction force to the active regions of the substrate 101. In this way, the warpage of the active region of substrate 101 can be reduced by the vacuum attraction applied to the active region through passage 103, and the warpage of the non-active region of substrate 101 can also be reduced by the magnetic attraction applied to the non-active region through the magnetic attraction between the grid pattern and magnet 114. Therefore, a larger area of ​​substrate 101 can be pressed against lower clamp 102, thereby further mitigating the warpage of almost the entire substrate 101 in a more sufficient and uniform manner.

[0038] Additionally, the lower clamp 102 further includes a plurality of retaining posts 131 protruding from its top surface. In some embodiments, the retaining posts 131 may extend from the interior to the exterior of the clamp base 105. The retaining posts 131 may be distributed within the assembly area Y of the clamp base 105, for example, at the periphery of the clamp base 105 and in the central area of ​​the clamp base 105, such as... Figure 1C As shown in the illustration. In some embodiments, the retaining post 131 may be accessible to the magnet 114. It is also understood that the retaining post 131 may penetrate the embedded magnet 114. Thus, the grid pattern further includes, for example, a plurality of through holes 130 extending through the frame 106 and the plurality of ribs 108. When the upper clamp 104 is mounted on the lower clamp 102 to receive the substrate 101, the plurality of retaining posts 131 are respectively received within the through holes 130. Thus, the upper clamp 104 can be fixed in place with the lower clamp 102 without lateral movement, thereby securing the substrate 101 between them.

[0039] In some other embodiments, fasteners such as clamps, pins, or clips may be arranged at the frame 106 of the upper clamp 104 to secure the upper clamp 104 to the lower clamp 102 and hold the substrate 101 between them. In some alternative embodiments, the clamp base 105 may include a passage 103 within both the device placement area X and the assembly area Y to apply vacuum pressure to the entire substrate 101. Therefore, at least some of the retaining posts 131 may be omitted.

[0040] Figure 2 A device for holding a substrate 101 according to a second embodiment of this application is shown. Figure 2 The device shown in the image, in addition to further including a heating block 240 placed below the lower clamp 102, has the same... Figures 1A to 1D The device shown in the article has the same structure and materials.

[0041] like Figure 2As shown, the heating block 240 can directly contact the bottom surface of the lower fixture 102. When the solder paste is heated by laser radiation and reflowed, the heating block 240 can apply additional heat to the lower fixture 102. Additionally, the heating block 240 is permeable to laser radiation, allowing the laser radiation to successfully pass through the heating block 240 and the lower fixture 102 and reach the substrate 101 and the solder paste thereon. The heating block 240 may contain the same material as the lower fixture 102, such as quartz or glass. In this way, in addition to the laser radiation energy applied to the solder paste, the additional heat energy can raise the ambient temperature of the atmosphere surrounding the substrate 101 during the laser radiation process, mitigating heat dissipation. Furthermore, since the heating block 240 is in direct contact with the lower fixture 102, the additional heat energy can be convectively transferred to the lower fixture 102, and thus to the substrate 101 and the solder paste. This allows the solder paste to be heated via a hybrid heating mechanism, which includes both laser radiation heating and convection heating, resulting in higher reflow efficiency and lower energy requirements for the laser source. Furthermore, by applying lower laser radiation energy from the laser source, the overall heat generated within the formed device can be reduced, preventing or mitigating burn-off effects caused by excessive laser radiation energy. In some embodiments, the heating block 240 may include a heater for generating additional heat. In some other embodiments, the heating block 240 may be preheated to a high temperature to transfer heat to the lower clamp 102. Additionally, the heating block 240 may include a passage 103 connecting the lower clamp 102 and a vacuum source, such that vacuum pressure can be applied to the substrate 101 through the passage of the heating block 240 and the passage 103 of the lower clamp 102.

[0042] In some embodiments, the heating block 240 may have a base portion and sidewalls surrounding the base portion. Thus, the sidewalls define a cavity above the base portion to accommodate the lower clamp 102, and the top surface of the base portion and the inner surface of the sidewalls are respectively attached to the bottom surface and lateral surface of the lower clamp 102. In this way, the heat energy generated by the heating block 240 can be transferred to the lower clamp 102 through the larger contact area between the heating block 240 and the lower clamp 102, thereby improving heating efficiency. Additionally, a channel in the heating block 240 may pass through the base portion to connect the passage 103 to a vacuum source. It is understood that the channel may also pass through the sidewalls, which shortens the distance from the passage 103 of the lower clamp 102 to the vacuum source.

[0043] Figures 3A to 3D The illustration shows various steps of a method for forming an electronic module according to a third embodiment of this application. At least a portion of each step of the method may be performed by… Figures 1A to 1C The device shown in the article is implemented.

[0044] like Figure 3AAs shown, an apparatus for holding a substrate 301 is provided. The apparatus includes a lower clamp 302 and an upper clamp 304. More specifically, the lower clamp 302 includes a clamp base 305 that is transmissible to laser radiation. The substrate 301 is placed on the top surface of the clamp base 305. The upper clamp 304 includes a frame 306 and at least one rib 308 within the frame 306 to form a grid pattern. The upper clamp 304 is mounted on the top surface of the lower clamp 302 to receive the substrate 301 between the lower clamp 302 and the upper clamp 304. The grid pattern of the upper clamp 304 defines a plurality of openings 310 exposing a portion of the substrate 301. Furthermore, the frame 306 of the grid pattern and each of the plurality of ribs 308 are contactable with the substrate 301. The ribs 308 in the grid pattern can generate greater and more uniform pressure on the substrate 301, which helps to mitigate potential warping of the substrate 301 that may occur during reflow processes or other similar heating processes.

[0045] In some embodiments, the upper clamp 304 further includes a skirt portion 312 at the periphery of the bottom surface of the frame 306. When the upper clamp 304 is mounted on the lower clamp 302, the skirt portion 312 contacts the lower clamp 302. Clamping force can be applied to the substrate 301 at its periphery by the lower clamp 302 and the upper clamp 304. Furthermore, one or more magnets 314 may be embedded within the clamp base 305. Additionally, the grid pattern is at least partially formed of a ferromagnetic material. Furthermore, the lower clamp 302 further includes a plurality of retaining posts 331 protruding from its top surface. Correspondingly, the grid pattern further includes a plurality of through holes, for example, through the frame 306 and the ribs 308. When the upper clamp 304 is mounted on the lower clamp 302 to receive the substrate 301, the plurality of retaining posts 331 are respectively inserted into the through holes 330. Furthermore, the lower clamp 302 further includes a plurality of passages 303 extending through the clamp base 305, the plurality of passages 303 being fluidly coupled to a vacuum source to apply vacuum pressure to the substrate 301.

[0046] Next, as Figure 3B As shown, at least one electronic component 320 may pass through at least one of a plurality of openings 310, and each of the at least one electronic component 320 may have solder paste applied to its bottom surface. In this manner, each of the at least one electronic component 320 is mounted on the substrate 301 via solder paste. In some other embodiments, solder paste may be applied to an exposed portion of the substrate 301 before mounting the at least one electronic component 320 onto the substrate 301. In some embodiments, the solder paste may comprise a metallic solder material, such as tin, and a flux material.

[0047] Next, as Figure 3CAs shown, laser radiation is emitted from a laser source 330 positioned below the lower fixture 302. The laser radiation can penetrate the fixture substrate 305 to reach the substrate 301 and solder paste. In this way, sufficient laser radiation energy can then be transferred to the substrate 301 and solder paste, allowing the solder paste to be heated and reflowed to form solder bumps. This results in the formation of an electronic module with reduced substrate warpage. The laser radiation provides more uniform and rapid heating of the solder paste during the reflow process, which contributes to the formation of high-quality electrical connections. Furthermore, since the laser radiation is applied to the substrate 301 from its bottom surface, undesirable effects on the electronic components 320 during laser radiation transmission are avoided. During the reflow process, the non-active areas of the substrate 301, i.e., the exposed portions of the substrate 301 not occupied by at least one electronic component 320, are pressed against the lower fixture 302 by a grid pattern. More specifically, the grid pattern frame 306 can compress the peripheral area of ​​the substrate 301, and the grid pattern ribs 308 can compress the exposed portion of the central area of ​​the substrate 301. Additionally, due to the vacuum attraction caused by the vacuum pressure applied through the passage 303 of the lower clamp 302, the active area of ​​the substrate 301, i.e., the remaining portion of the substrate 301 occupied by at least one electronic component 320, can be attracted to the lower clamp 302. In this way, a larger area of ​​the substrate 301 can be pressed against the lower clamp 302, thereby further mitigating warping of almost the entire substrate 301 in a more thorough and uniform manner.

[0048] In some preferred embodiments, laser radiation can be applied for a duration ranging from 2 to 5 seconds. Additionally, the temperature of the lower fixture 302 can be maintained between 80°C and 100°C. Therefore, the temperature of the lower fixture 302 can be raised and maintained at a relatively moderate level, which avoids thermal shock to the solder paste caused by sudden temperature increases.

[0049] Next, after forming an electrical connection between at least one electronic component 320 and the substrate 301, the laser source 330 can be turned off. Subsequently, the solder paste reflow process ends, and the formed electronic module can be cooled. For example, the temperature of the substrate 301 and the solder paste can begin to decrease to a lower temperature, such as room temperature. In some preferred embodiments, the cooling step of the electronic module can last for 5 seconds or longer, thereby allowing sufficient solidification of the solder paste, i.e., allowing the formation of solid solder bumps.

[0050] Next, flux residue can be removed from the electronic module using a cleaning process. The electronic module can then be detached from the upper clamp 304 and lower clamp 302, and can proceed with testing or subsequent manufacturing processes.

[0051] Figure 4 The reflow process in a method for forming an electronic module according to a fourth embodiment of this application is illustrated. This process can be performed... Figure 3A and 3B The steps shown are implemented afterward. Figure 4 The steps shown are not performed. Figure 3C The steps are shown in the diagram. Therefore, details of the other steps can be found in [reference needed]. Figure 3A and 3B The embodiments described herein will not be described in detail below.

[0052] like Figure 4 As shown, a heating block 440 is attached to a lower fixture 302. The heating block 440 can directly contact the bottom surface of the lower fixture 302. When the solder paste is heated and reflowed by laser radiation, the heating block 440 can apply additional heat to the lower fixture 302. Additionally, the heating block 440 is permeable to laser radiation, allowing the laser radiation to pass through the heating block 440 and the lower fixture 302 and reach the substrate 301 and the solder paste. The heating block 440 may contain the same material as the lower fixture 302, such as quartz or glass. Because the heating block 440 is in direct contact with the lower fixture 302, additional heat energy can be convectively transferred to the lower fixture 302, and thus to the substrate 301 and the solder paste. This allows the solder paste to be heated via a hybrid heating mechanism that includes direct laser radiation heating and convective heat transferred from the heating block 440, resulting in higher reflow efficiency and lower energy requirements for the laser source 330. Details of the heating block 440 can be found in [reference needed]. Figure 2 The heating block 240 in the described embodiment will not be described in detail below.

[0053] In some embodiments, the heating block 440 may be placed on the lower fixture 302 prior to the reflow process of the solder paste on the substrate 301 to preheat the lower fixture 302. For example, the heating block 440 may be placed on the lower fixture 302 after at least one electronic component 320 has been mounted on the substrate 301 and before the solder paste is reflowed by laser radiation. It is also understood that the heating block 440 may be attached to the lower fixture 302 during the reflow process. In some other embodiments, the heating block 440 may be attached to the lower fixture 302 before the substrate 301 is placed on the lower fixture 302. In this case, the heating block 440 may be turned on shortly before or during the reflow process of the solder paste.

[0054] Figure 5 An apparatus for forming an electronic module according to a fifth embodiment of this application is shown. Details of the process for forming the electronic module may be similar to... Figures 3A to 3D ,or Figure 4 The method for forming an electronic module is shown.

[0055] like Figure 5As shown, the device may include five sequentially arranged areas: a loading area A, a mounting area B, a reflow area C, a cooling area D, and an unloading area E. The device further includes a platform 500 for placing a substrate 501 and means for holding the substrate 501. The means for holding the substrate 501 includes an upper clamp 504 and a lower clamp 502, which receive the substrate 501 between them. Details of the holding means may be similar to... Figures 1A to 1D The holding device is shown. Furthermore, the platform 500 may be in the form of an integrated component spanning from loading region A to unloading region E. In some embodiments, a main cavity may be provided to include all five regions or even more additional regions as needed, which prevents contaminants from entering the device, thereby protecting the substrate 501 and the structures thereon during the electronic module fabrication process.

[0056] exist Figure 5 In the embodiments shown, the lower clamp 502, upper clamp 504, and substrate 501 housed between them can be transferred from loading area A to unloading area E to complete the electronic module fabrication process. In some embodiments, a transport mechanism may be arranged on platform 500 and extend from loading area A to unloading area E. During the manufacturing process, the transport mechanism is used to transport substrate 501 from loading area A through mounting area B, reflow area C, and cooling area D, and finally to unloading area E. The transport mechanism may include a conveyor belt or carrier on a track to transport substrate 501, lower clamp 502, and upper clamp 504 at a controlled speed. It should also be understood that the device may not include a transport mechanism, and substrate 501 may be transported manually.

[0057] More specifically, in loading region A, substrate 501 is placed between lower clamp 502 and upper clamp 504. Further details of this step are similar to... Figure 3A The details shown will not be repeated hereafter. In some embodiments, the lower clamp 502 further includes a plurality of passages extending through the clamp base of the lower clamp 502 and fluidly coupled to a vacuum source to apply vacuum pressure to the substrate 501. Thus, the platform 500 may include channels or conduits therein to connect the passages of the lower clamp 502 to the vacuum source as the means of holding the substrate 501 is transported from loading region A to a subsequent region.

[0058] Next, the lower clamp 502 and upper clamp 504 holding the substrate 501 are transferred to the mounting area B. In the mounting area B, at least one electronic component 520 passes through at least one of a plurality of openings 510, each having solder paste attached to its bottom surface. In this manner, each of the at least one electronic component 520 is mounted on the substrate 501 via solder paste. In some embodiments, the solder paste may first be printed or otherwise applied to the substrate 501, and at least one electronic component 520 is mounted on the substrate 501 via the solder paste. In some embodiments, the solder paste may comprise a metallic solder material and a flux material. The details of the mounting steps may be similar to those described above. Figure 3B The details shown will not be repeated here.

[0059] Next, the lower clamp 502, upper clamp 504, and substrate 501 are transferred to the reflow area C. In the reflow area C, a laser source 530 is positioned below the lower clamp 502 to emit laser radiation to reflow the solder paste. A reflow chamber 521 is arranged on the platform 500 of the reflow area C to accommodate the substrate 501, lower clamp 502, and upper clamp 504 during the solder paste reflow process. In some other embodiments, the platform 500 may extend through the reflow chamber 521. When the substrate 501 is accommodated within the reflow chamber 521, the laser source 530 is activated, and laser radiation is emitted from the laser source 530. In some embodiments, the laser source 530 may be positioned below the top surface of the platform 500 within the reflow area C. It is also understood that the laser source 530 may alternatively be positioned below the platform 500. The platform 500 may include a recess or opening above the laser source 530 to allow laser radiation to enter the lower clamp 502. Since the lower fixture 502 is permeable to laser radiation, the laser radiation can penetrate the fixture substrate and reach the substrate 501 and the solder paste. In this way, sufficient laser radiation energy can then be transferred to the substrate 501 and the solder paste, allowing the solder paste to be heated and reflowed to form solder bumps. This forms the electronic module. During the reflow process, the mesh pattern contacts the substrate 501 due to the magnetic attraction of the magnet 514 within the lower fixture 502, thus pressing the substrate 501 against the lower fixture 502. Additionally, a portion of the substrate 501 can also be attracted to the lower fixture 502 due to the vacuum attraction caused by the vacuum pressure applied through the passage in the lower fixture 502. Further details of the solder paste reflow process are similar to... Figure 3C The details shown will not be repeated here.

[0060] In some other embodiments, the reflow area C further includes a heating block disposed on the platform 500. The heating block may be in direct contact with the bottom surface of the lower fixture 502. When the solder paste is heated by laser radiation and reflowed, the heating block can apply additional heat to the lower fixture 502. Additionally, the heating block is permeable to laser radiation, allowing the laser radiation to successfully pass through the heating block and the lower fixture 502 and reach the substrate 501 and the solder paste. Therefore, the solder paste can be heated by a hybrid heating mechanism. In some other embodiments, the heating block may be attached to the lower fixture 502 when the lower fixture 502 is in the loading area A. The heating block may be turned off when the substrate 501, the lower fixture 502, and the upper fixture 504 are accommodated in the loading area A and the mounting area B, and may be turned on when the substrate 501, the lower fixture 502, and the upper fixture 504 are accommodated in the reflow area C.

[0061] In some other embodiments, the heating block may be preheated to a temperature higher than that of the lower fixture 502. In this case, after at least one electronic component 520 is mounted on the substrate 501, the heating block may be attached to the lower fixture 502 to provide additional heat to the lower fixture 502 during the reflow process. Further details of the heating block may be similar to those described above. Figure 2 or Figure 4 The details shown will not be repeated here.

[0062] Next, after establishing an electrical connection between at least one electronic component 520 and the substrate 501 via solder bumps, the laser source 530 can be turned off. The substrate 501, lower jig 502, and upper jig 504 are transported to cooling region D. In cooling region D, the formed electronic module can be cooled, thereby allowing sufficient solidification of the formed solder bumps. During the cooling step, the upper jig 504 holds the substrate 501 against the lower jig 502, which prevents warping during the cooling step. Flux material can then be removed from the electronic module. In some other embodiments, cooling region D can be omitted, and the electronic module can be cooled directly in reflow region C.

[0063] Next, the electronic module, lower clamp 502, and upper clamp 504 are transported to unloading area E. In unloading area E, substrate 501 is separated from upper clamp 504 and lower clamp 502, and the electronic module can continue with testing or subsequent manufacturing processes.

[0064] Although the apparatus for holding a substrate, the method for forming an electronic module, and the device for forming an electronic module of this application have been described in conjunction with the corresponding figures, those skilled in the art will understand that modifications and adaptations can be made to the apparatus, the method, or the device without departing from the scope of the invention.

[0065] The discussion herein includes numerous illustrative figures illustrating various parts of means for holding a substrate, methods for forming electronic modules, and apparatus for forming electronic modules. For clarity, these figures do not show all aspects of every example means, method, or apparatus. Any example means, method, and / or apparatus provided herein may share any or all characteristics with any or all other means, methods, and / or apparatus provided herein.

[0066] Various embodiments have been described herein with reference to the accompanying drawings. However, it will be apparent that various modifications and changes can be made thereto, and additional embodiments can be implemented, without departing from the broader scope of the invention as set forth in the appended claims. Furthermore, other embodiments will be apparent to those skilled in the art upon consideration of the description and practice of one or more embodiments of the invention disclosed herein. Therefore, it is intended that this application and the examples herein be considered exemplary only, wherein the true scope and spirit of the invention are indicated by the list of exemplary claims appended.

Claims

1. A device for holding a substrate, characterized in that, The device includes: A lower fixture, comprising a fixture base for placing a substrate, wherein the substrate has at least one electronic component, each electronic component being mounted on the substrate via solder paste, and the fixture base being transmissible to laser radiation; and An upper clamp operably mounted on a lower clamp and together with the lower clamp defining a cavity for receiving the substrate, wherein the upper clamp includes a frame and ribs within the frame, and the frame and the ribs form a grid pattern defining a plurality of openings for exposing the at least one electronic component from the upper clamp, wherein when the upper clamp is mounted on the lower clamp to receive the substrate within the cavity and the solder paste is reflowed by the laser radiation, the grid pattern contacts the substrate, thereby applying pressure to press the substrate against the lower clamp.

2. The apparatus according to claim 1, characterized in that, The lower clamp further includes a plurality of magnets embedded in the clamp base, and when the upper clamp is mounted on the lower clamp, the grid pattern of the upper clamp can be attracted by the plurality of magnets.

3. The apparatus according to claim 2, characterized in that, The grid pattern is formed at least in part by a ferromagnetic material.

4. The apparatus according to claim 2, characterized in that, The fixture base includes multiple device placement areas and an assembly area. When the upper fixture is mounted on the lower fixture, each of the multiple device placement areas is aligned with one of the multiple openings located within the grid pattern, and the assembly area is aligned with the grid pattern.

5. The apparatus according to claim 4, characterized in that, The plurality of magnets are embedded in the assembly area.

6. The apparatus according to claim 4, characterized in that, The lower clamp further includes a plurality of passages extending through the clamp substrate and fluidly coupled to a vacuum source to apply vacuum pressure to the substrate via the plurality of passages when the substrate is placed on the lower clamp.

7. The apparatus according to claim 6, characterized in that, The multiple pathways are distributed within the multiple device placement areas.

8. The apparatus according to claim 1, characterized in that, The upper clamp further includes a skirt portion at the periphery of the bottom surface of the frame, such that the cavity is defined between the clamp base and the grid pattern to accommodate the substrate, wherein the skirt portion contacts the lower clamp when the upper clamp is mounted on the lower clamp.

9. The apparatus according to claim 1, characterized in that, The lower clamp further includes a plurality of fixing posts protruding from its top surface, and the grid pattern further includes a plurality of through holes for receiving the plurality of fixing posts respectively when the upper clamp is mounted on the lower clamp to accommodate the substrate.

10. The apparatus according to claim 1, characterized in that, The fixture substrate includes glass or quartz.

11. The apparatus according to claim 1, characterized in that, The device further includes a heating block for placing and heating the lower clamp, and the heating block is permeable to the laser radiation.

12. A method for forming an electronic module, characterized in that, The method includes: A substrate is placed between a lower clamp and an upper clamp, wherein the lower clamp includes a clamp base that is permeable to laser radiation and for holding the substrate, and the upper clamp includes a frame and ribs within the frame to form a grid pattern that defines a plurality of openings exposing a portion of the substrate. At least one electronic component is passed through at least one of the plurality of openings to mount each of the at least one electronic component onto the substrate via solder paste; and Laser radiation is applied to the substrate through the fixture substrate to reflow the solder paste to form the electronic module, wherein the grid pattern contacts the substrate to apply pressure to press the substrate against the lower fixture during solder paste reflow.

13. The method according to claim 12, characterized in that, The step of applying laser radiation through the fixture substrate to the substrate includes: The laser radiation is applied for a duration ranging from 2 to 5 seconds.

14. The method according to claim 12, characterized in that, The lower clamp further includes a plurality of magnets embedded in the clamp base, and when the upper clamp is mounted on the lower clamp, the grid pattern of the upper clamp can be attracted by the plurality of magnets.

15. The method according to claim 12, characterized in that, The step of reflowing the solder paste by applying laser radiation to the substrate further includes: The lower clamp is heated by a heating block attached to the bottom surface of the lower clamp, wherein the heating block is permeable to the laser radiation.

16. The method according to claim 12, characterized in that, The solder paste comprises a metallic solder and a flux material, and after laser radiation is applied to the substrate through the fixture substrate, the method further comprises: Remove the flux material from the electronic module; and Separate the electronic module from the upper clamp and the lower clamp.

17. An apparatus for forming an electronic module, characterized in that, The device includes: A platform for placing a lower clamp and an upper clamp defining a cavity therebetween for receiving a substrate having at least one electronic component mounted thereon via solder paste, wherein the lower clamp includes a clamp base that is laser-radiation-transmissible and for holding the substrate, and the upper clamp includes a frame and ribs within the frame to form a grid pattern defining a plurality of openings for exposing the at least one electronic component when the substrate is received in the cavity; and A laser source is provided to apply laser radiation through the fixture substrate to the substrate to reflow the solder paste, wherein the mesh pattern contacts the substrate to apply pressure to press the substrate against the lower fixture during solder paste reflow.

18. The device according to claim 17, characterized in that, The platform further includes: A loading area for placing the substrate between the lower clamp and the upper clamp; A mounting area for mounting the at least one electronic component on the substrate via the solder paste; A reflow area, the reflow area being associated with the laser source, wherein the laser source is configured to apply laser radiation to the substrate when the substrate is in the reflow area; and An unloading area for separating the substrate from the upper clamp and the lower clamp.

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