JP2021503186A - Improved electronic component interconnection systems and methods - Google Patents

Abstract

Improved interconnection systems and methods for electronic components using ACA are provided. The method is specific to each component to be connected and involves the use of magnets that are optimized in size, strength, and position with respect to the substrate and component. Also provided are ovens adapted for use with methods and systems, as well as kits that provide a portion of the system for use with existing ovens.

Description

Cross-reference of related applications

This application claims priority under US Patent Provisional Application Nos. 62/586, 815, filed November 15, 2017. The contents of this application are incorporated herein by reference in their entirety.

The present application generally relates to the creation of electrical connections for components in electronic circuits. More specifically, the present application relates to an improved method of connecting components to a substrate using an anisotropic conductive adhesive.

As the demand for modern technology continues to grow, the number of electronic devices continues to grow, the use and adoption of such devices continues to grow, the size of such devices continues to shrink, and the electronics required to manufacture such devices. The number of component interconnects has increased enormously. Moreover, in many areas, former analog devices have been replaced by electronic devices and have almost disappeared, and despite the rapid expansion of the power of electronic devices, their size has shrunk dramatically. did.

As modern components shrink and improve performance, more wiring is present in those components in smaller and smaller spaces (ie, increased wiring density), eg different sides of a given chip or component. The tolerance between them is much tighter (ie, the pitch is smaller, as it is called the "minimal pitch").

Therefore, modern components are more sensitive to temperature and pressure, both of which can result in problems or failure of the component or the entire device, including the component. Unfortunately, all current means of creating interconnects, for example between components and their subsystems, have limitations and drawbacks in certain applications.

It is clear to skilled technicians that there are many means of interconnection, such as conventional soldering, anisotropic conductive films (ACF), and anisotropic conductive adhesives (ACA). Both have advantages and disadvantages, and they all provide options that can meet the requirements that arise for a particular interconnect with respect to a particular usage, component, or device.

Traditional soldering involves the local exposure of components to large amounts of heat and pressure. Exposure of such components to these unfavorable or unacceptable conditions can result in complete failure, poor or unstable performance, or significantly shorter service life.

ACF was developed as an effort to improve the interconnection of various applications. These conductive films can reduce the local heat required for soldering connections, but still require significant heat. In addition, generally both heat and pressure are applied to the component, which can be a significant limitation for sensitive components. ACF is also limited in terms of the pitch of the interconnect it is appropriate or compatible with.

ACA has also been developed to provide alternatives for creating difficult interconnects in certain applications. As with the ACF, these adhesives provide conductivity only on the Z axis. ACA, such as those manufactured by SunRay Scientific, include magnetically alignable particles that form interconnects between components when they are aligned along the Z axis upon exposure to a magnetic field. The adhesive matrix is cured, for example by exposure to heat, to complete and secure the interconnect. Since it does not require pressure, ACA is an excellent choice for pressure sensitive components. In addition, for temperature sensitive components, curing can be achieved with low heat. And ACA can be applied to finer pitches than can be achieved using ACF.

The prior art application of ACA has generally adopted a magnetic field applied over the entire substrate using an electromagnet. Such a magnetic field also covers all components mounted on the substrate, but can be disadvantageous if one or more components on the substrate are sensitive to the magnetic field. In addition, the magnetic field applied to a large area includes the entire magnetic field, including magnetic flux lines that are generally not very perpendicular to the XY plane.

Making interconnects with ACA is simple and easy, but in order to make and optimize interconnects with the use of ACA in certain applications, systems and methods need to be improved.

The inventor has discovered a method that provides an unexpected improvement in ACA-based electronic interconnection for a particular application and has developed a system that implements that method. The method selects the appropriate characteristics of the ACA, uses a separate magnet placed for each interconnected component, and uses a magnet for aligning the ACA for each particular component mounted on the substrate. It offers many advantages based on choosing the characteristics to optimize the generation of Z-axis connections (in terms of Z-axis column height, quantity, and orientation). The method provides homogeneous and optimal alignment and curing of ACA-based interconnects, allowing the construction of what the inventor calls a "magnetic palette". The method can provide improved interconnection homogeneity, reduced defects, improved lifespan, and improved functional connection yield, as compared to existing forming methods.

In a first aspect, the present disclosure provides a novel method of aligning and curing ACA-based interconnects in digital devices, electronic devices, and the like. The method of creating the interconnection between the substrate and the components mounted on it using a magnetically alignable anisotropic conductive adhesive (ACA) is generally known.
a) Steps to establish the dimensions and position on the substrate of the first electronic component placed and connected to the substrate,
b) The step of determining the placement position of the first magnet corresponding to the size and position of the component established in step a), and
c) The step of determining the size and strength of the magnet required in step b), and
d) Includes a step of mapping the magnetic flux lines of the magnetic field of the magnet.

Steps a) -d) are repeated for each additional component placed and connected to the substrate to determine the characteristics and placement position of each additional magnet required.

The method is also
f) The step of creating a magnetic tray and fixing each magnet to its respective placement position on the tray,
g) With the steps of creating an alignment tray and adapting the alignment tray to hold the substrate during alignment and curing.
h) Steps to place the subsystem on the alignment tray,
i) The step of applying ACA to the substrate in the proper position for the interconnection of each component to be mounted, and
j) The step of placing the first component and each additional component at the position where the ACA of the substrate is applied, and
k) Steps to assemble the alignment tray and magnetic tray,
l) Steps that allow the formation of columns in the Z-axis in the ACA,
m) With the step of curing the ACA, thereby creating an interconnection between the substrate and the first component and each additional component.
including.

Alignment trays and magnetic trays are made of non-magnetic material. The magnetic tray is adapted to accept and hold the first and additional components at each placement position on the tray. The assembled magnet tray (with magnets placed) and the alignment tray (with components and ACA placed on the substrate) can be placed directly in the curing oven as an assembly.

In the second aspect, what is provided here is the use of an anisotropic conductive adhesive (ACA) that can magnetically align the interconnection between the substrate and the electronic components attached to it. It is a system for making. The system is generally a non-magnetic tray adapted to accept and hold each of one or more magnets in a position corresponding to the position of one or more electronic components on the substrate to which the components are connected. Includes a magnet tray that contains.

The system also includes an alignment tray adapted to hold the ACA and the substrate on which one or more components connected to the substrate are placed during ACA alignment and curing.

The system also includes an ACA containing magnetically aligned particles capable of forming conductive interconnects along the Z axis.

Both the alignment tray and the magnetic tray are preferably made of non-magnetic material. In various embodiments, the substrate can only be placed in the alignment tray in one direction.

In a preferred embodiment, the magnet is a permanent magnet. Generally, for each magnet in the magnet tray, the magnetic flux lines are substantially parallel to each other and substantially perpendicular to the XY plane in the area on the substrate corresponding to the area where the components and ACA are located. In a preferred embodiment, the magnetic flux lines are essentially parallel to each other and consist of lines perpendicular to the area on the substrate corresponding to the area where the components and ACA are located.

In a third aspect, the present disclosure provides a kit for making an interconnect between a substrate and an electronic component attached to the substrate using a magnetically alignable anisotropic conductive adhesive. This kit is generally
At least one containing a non-magnetic tray adapted to hold one or more magnets in a position corresponding to the desired placement of the electronic component on the substrate and the desired connection of the component to the substrate using ACA. With two magnetic trays
Includes enough magnets to complete the magnet tray,
Each magnet has the desired size and strength to make an interconnect between the component and the substrate using ACA.
The kit also
With at least one alignment tray adapted to accept and hold the substrate and the components placed on the substrate during the alignment and curing of the ACA to make the interconnect.
Optionally includes an ACA suitable for use with the kit used to make at least one interconnect between the component and the substrate.

In the kit provided, the magnet tray and the alignment tray are configured to be oriented perpendicular to each other. They align the magnet tray and the electronic components (attached to it with ACA) on the substrate on the alignment tray perpendicular to the magnets on the magnet tray when the alignment tray is so assembled. Assembled to do. Each component that requires a connection (interconnection) has a corresponding magnet that aligns with it when the tray is assembled.

In a preferred embodiment of the kit, the magnet comprises a rare earth magnet or other permanent magnet.

In yet another aspect, the present disclosure provides an oven system designed to create an interconnect between a substrate and an electronic component placed on the substrate and connected to the substrate using an ACA. Oven systems generally have a curing oven and one or more shelves or racks, each shelf or rack.
A magnetic tray with one or more magnets, each placed on a substrate and in a position corresponding to the position of an electronic component connected to the substrate using ACA.
Includes an alignment tray in which one or more components placed on the substrate and connected via the ACA are adapted to receive and hold the placed substrate.

These and / or additional aspects, features, and advantages of the present invention will be apparent to those skilled in the art by the present disclosure.

FIG. 1 is a schematic cross-sectional view of an embodiment of a system that magnetically aligns and cures ACA interconnects, with magnet trays, alignment trays, substrates, and components placed therein. Shown. FIG. 2 is a flowchart showing the steps of a method of magnetically aligning and curing components on a substrate using an ACA for making an electrical connection. FIG. 3 is a diagram showing an embodiment of the alignment tray used here. Each tray contains multiple subsystems on which the components connected to the subsystem are located. FIG. 4 is a diagram showing an embodiment of an oven that employs a magnetic pallet system. A. The assembly of multiple magnet trays and alignment trays is shown in the batch oven. Each magnet tray or each alignment tray does not have to be the same, except that the alignment and the outer dimensions of the magnet trays are determined by the dimensions of the oven. Thus, a single oven can be utilized to align and cure a large number of interconnects of multiple electronic components on different substrates or devices. B. FIG. 5 is an enlarged view of an assembly including an alignment tray including orientation means (alignment holes) and a magnet tray. C. It is a plan view of the magnet tray which functions as a rack in an oven.

Provided here are methods and systems that use ACA to provide improved and more homogeneous interconnection of electronic components.

Definitions and Abbreviations Unless expressly defined separately, all technical and scientific terms, industry terms, and acronyms used herein are those commonly understood by those skilled in the art of the present invention or in the field in which the terms are used. Have. In this description, the following abbreviations and definitions apply.

Abbreviations The following abbreviations apply unless otherwise indicated.
AC: AC ACA: Anisotropic conductive adhesive ACF: Anisotropic conductive film DC: Direct current
Gs: Gauss, unit of magnetic field NIB: Neodim-iron-boron PCB: Printed circuit board T: Tesla, unit of SI magnetic field.

Definitions As used herein, "substantially" may mean an amount greater than or less than a reference. Preferably, substantially larger or smaller means that it differs from the reference by at least about 10% to about 100% or more. More preferably, "substantially" in such a case means at least about 20% to about 100% or more larger or smaller than the reference. As will be apparent to those skilled in the art, the term "substantially" can also be used in the expression "substantially all", which is preferably at least 51% of the reference, number of references, or reference amount. Means 60%, 67%, 70%, 75%, 80%, 85%, 90% or more. "Substantially all" also means 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more of a reference, number of references, or reference amount. It can mean 90% or more including%.

As used herein, the singular form of a word contains multiple things and vice versa, unless explicitly denied by the context. Therefore, the use of singular articles generally includes more than one. For example, references to "electrodes" and "diodes" include "electrode groups" and "diodes".

The expressions "including" and "consisting of" should be construed inclusively rather than exclusionally, unless explicitly denied by the context. The expression "contains" is intended to include embodiments that include the phrases "consisting of" and "consisting of". Similarly, the phrase "consisting of" is intended to include embodiments contained by the phrase "consisting of".

When used here, the range is omitted and it is avoided to list and describe each and every value in the range. Where appropriate, all suitable values within the range can be selected as the upper, lower, and end of the range.

Formulations, compositions, methods, and / or other advances disclosed herein are subject to change as will be appreciated by those skilled in the art and are therefore limited to the particular methodologies, protocols, and / or components described herein. Not done. Furthermore, the terms used herein are for the purpose of describing a particular embodiment only and are not intended or intended to limit the scope of the invention disclosed or claimed.

Any formulation, composition, method, or other means or material similar to or equivalent to that described herein can be used in the practice of the present invention, but is preferred formulation, composition, method, or other means or The material is described here.

All patents, patent applications, or other literature, technology and / or scholarly articles cited or referenced herein are hereby referenced and incorporated in their entirety to the extent permitted by applicable law. The description of those references is intended to merely summarize the claims in it. We do not admit that any such patent, patent application, document, or reference is prior art, or any part of them is relevant or important with respect to the patentability of what is claimed here. It does not admit to having. Applicant has the right to question the accuracy and appropriateness of any claim that such a patent, patent application, document, or reference is prior art or has relevance and / or materiality. To hold.

As used herein, the term "alignment" means aligning a composition comprising a magnetic material or magnetic particles. In general, alignment involves arranging magnetic particles in the Z-axis direction under the influence of a magnetic field. Alignment is the process of forming columns in the Z-axis direction. Also, as the context makes clear, the term "alignment" here occasionally ensures the proper orientation (alignment) of two objects with each other, such as alignment trays and magnetic trays, or substrate and alignment trays. It can also be used for making.

As used herein, the term "column" refers to a structure formed by magnetic particles in a composition in the Z-axis direction under the influence of a magnetic field. The column forming process is sometimes referred to as "alignment". The properties of the column (eg, height, diameter, etc.) depend on the strength of the magnet and the properties of the ACA, including the size and amount of magnetic particles in the ACA, and the viscosity and other physical properties of the ACA matrix. Columns can and form within seconds when exposed to a suitable magnetic field.

A "magnet" is capable of generating a "magnetic field", which, as used herein, includes any magnetic field generated by either an electromagnet or a permanent magnet. The "strength" of a magnet can be measured in Gs (or Ts). Those skilled in the art will know how to determine the strength of any given magnet, or how to determine the desired magnetic strength for a given magnet. As used herein, the term "magnetic field mapping" means meticulously determining the shape of the path of a particular magnetic field and magnetic field lines. One of ordinary skill in the art can map the magnetic field of any magnet using a variety of means.

As used herein, "permanent magnet" means a magnet that does not require a current flow to form a sustained magnetic field. The permanent magnets used here may consist of iron, nickel, cobalt, and rare earth metals. A particular preferred embodiment here utilizes a rare earth magnet, such as one containing a lanthanoid element. Magnets containing neodymium or salts thereof may be useful here due to its magnetic strength. In one embodiment, the magnet consists of neodymium, iron, and boron (“NIB magnet”). Samarium, gadolinium, and even dysprosium, and salts thereof may also be used for specific applications. Other types of permanent magnets, such as ceramic magnets and other composite magnets, as well as flexible magnets, may also be suitable here for use in other specific applications.

As used herein, "interconnection" is generally the connection between any two parts of the system. Interconnection here generally refers to, for example, electrical and physical connections between two components or between a component and a substrate. A "substraight" is any material used in an electronic system or device, such as a printed wiring board ("PCB"), to hold or hold other electronic components connected to it. The substrate may be flexible or inflexible. Preferred non-flexible substrates include, for example, PCBs, composites, and rigid polymers, and preferred flexible supports include, for example, flexible polymers.

As used herein, "parallel" means that two straight lines, such as a line representing magnetic flux, are always separated by the same distance and exist on the same plane without contacting each other, that is, zero degrees to each other. It means that it is at the angle of. Here the parallel lines generally refer to the magnetic flux lines in the Z-axis direction, which are generally perpendicular to the XY plane of the substrate (ie 90 degrees). Since it is difficult to have perfectly parallel flux lines throughout an application involving multiple magnets, the parallel lines in various embodiments are "substantially parallel" to each other and / or the XY plane. Can include cases of substantially right angles to. Such lines may be arranged with each other, for example from about -30 degrees to about 30 degrees and / or about 60 degrees to about 120 degrees with respect to the ZY plane. More preferably, such lines are arranged with each other, for example, from about -15 degrees to about 15 degrees and / or from about 75 degrees to about 105 degrees with respect to the ZY plane. Even more preferably, such lines are arranged with each other, for example, from about -5 degrees to about 5 degrees and / or from about 85 degrees to about 95 degrees with respect to the XY plane. Even more preferably, such lines are arranged, for example, from about 0 degrees to about 2 degrees with each other and / or from about 0 degrees to about 2 degrees perpendicular to the XY plane. The closer the flux lines are parallel to each other and at right angles to the XY plane, the more the ACA will form more parallel columns during the alignment underlying the interconnection, making the interconnection functional or durable. It will be apparent to those skilled in the art that there will be fewer adverse short circuits and other defects.

As used herein, the "Z-axis direction" means the direction perpendicular to the main plane on which the substrate lies, that is, the XY plane.

Detailed Description of Illustrated Embodiments An improved and more homogeneous electronic interconnect with ACA is provided herein in an electronic circuit. Such systems generally include individual magnets located in positions corresponding to each connected component. The size and strength of each magnet is based on the component, substrate, ACA used, and application. Only the components connected by the ACA are exposed to the magnetic field, so sensitive components are not unnecessarily exposed to the magnetic field. Preferably, the optimized interconnection results in higher yields, defects such as less short circuits, and longer service life or longer cycle life. The inventor has made the surprising finding that devising the choice of magnet size, strength, and placement significantly improves the homogeneity and quality of the interconnect. Therefore, disclosed herein are methods and systems that improve the generation of interconnects using ACA.

In a first aspect, the present disclosure provides a novel method of aligning and curing ACA-based interconnects in digital devices, wiring boards, electronic devices and the like. The method of creating the interconnection between the substrate and the components mounted on it using a magnetically alignable anisotropic conductive adhesive (ACA) is generally known.
a) Steps to establish the dimensions and position on the substrate of the first electronic component placed and connected to the substrate,
b) The step of determining the placement position of the first magnet corresponding to the size and position of the component established in step a), and
c) The step of determining the size and strength of the magnet required in step b), and
d) Includes a step of mapping the magnetic flux lines of the magnetic field of the magnet.

Steps a) -d) are repeated for each additional component placed and connected to the substrate to determine the required additional magnet characteristics and placement position. It will be apparent to those skilled in the art that various methods and steps are presented throughout the specification. Unless those steps must be performed strictly in the order as described, the method can be performed in a different order as well, changing the overall purpose and outcome. It should be understood that no interconnection can facilitate the correct achievement.

The method further creates a magnetic tray and secures each magnet to its respective placement position on the tray, and creates an alignment tray, subs during Z-axis alignment (ie column formation) and curing of the ACA. Includes a step of adapting the alignment tray to hold the straight.

The substrate is then placed on the alignment tray. ACA is applied where the components are placed on the substrate. The substrate is then placed with the first and additional components.

Alignment trays (substraights, components to be attached, and coated ACA) and magnetic trays are assembled and the ACA is exposed to magnets. The column is exposed in the ACA for a sufficient amount of time to form a column in the Z-axis direction, then the ACA is cured, thereby creating an interconnection between the substrate and the first and additional components.

Generally, alignment trays and magnetic trays are made of non-magnetic materials such as aluminum or heat resistant materials such as plastics and composites. Magnetic trays are generally adapted to accept primary and additional components at each placement position on the tray. The completed assembly, which includes a magnet tray with magnets and an alignment tray with components and substrates with ACA, can be placed in a curing oven.

In various embodiments, the magnet comprises a permanent magnet. In certain preferred embodiments, the magnet comprises a rare earth magnet. In one embodiment, rare earth magnets, including neodymium or NIB magnets, are used.

The inventor has found that the size and strength of the magnets that generate the interconnects can be determined experimentally in order to optimize the homogeneity and quality of the interconnects formed for the individual application. .. For those skilled in the art, the choice of a particular magnet size and strength is relevant to the column forming process, and the choice of magnet is influenced by column characteristics such as column height, diameter, and strength. Is clear. In addition, the connection of the column to both the component and the substrate is also affected by the properties of the magnet.

Therefore, in certain embodiments, the size and strength of the magnet is determined for optimization or coping with the properties of the columns or the properties of the final interconnect. Such characteristics include column height, interconnect strength, number of resulting short circuits, expected life of the finished device or substrate, yield of usable products, or defect rate or the result of the interconnect generation process. The number of defective products may be included.

The inventor is also apparent due to the use of magnetic flux lines that are substantially parallel to each other and / or substantially perpendicular to the XY plane of the area corresponding to the portion of the substrate on which the component and ACA are located. I found that there are many advantages. In various embodiments, the magnetic flux lines essentially consist of such parallel and / or right angle lines.

As a result of utilizing the provided methods in various embodiments, the ACA forms columns that are substantially uniform in height and diameter. In a preferred embodiment, the ACA forms a column that is substantially perpendicular to the XY planes of the components and substrates and is substantially uniform.

In order to further optimize the method, further improve homogeneity, and make the method more error-free, in one embodiment, the substrate unidirectionally shapes the alignment tray shape of the portion that houses and / or holds the substrate. It is configured so that it can be placed in the alignment tray only with. According to this, in manufacturing, the technician can arrange the substrate in the alignment tray with good reproducibility.

In other embodiments, the alignment tray includes alignment means such as positioning pins, complementary structures, or the like, and the magnetic tray and alignment tray can only be assembled in the proper orientation with each other. Make sure that. Instead, the alignment and the shape of the magnetic trays allow assembly in only one direction. It will be apparent to those skilled in the art that there are many simple ways to provide proper orientation. Such features further improve homogeneity, allowing any engineer to use this method in manufacturing.

As mentioned above, this method generally allows the assembly containing the aligned magnetic trays and alignment trays to be placed directly in the curing oven. Preferably, the alignment tray and the magnet tray contain a material that can withstand the curing conditions for curing the ACA. In one embodiment, the tray is made of aluminum or a heat resistant, non-magnetic material that can withstand temperatures of, for example, 50-70 ° C, 68-80 ° C, 70-100 ° C, 75-120 ° C, 100-140 ° C, or higher. is there. The development of curing methods at lower temperatures is expected to continue, and the materials used for alignment and magnet trays may change accordingly.

The method can be more fully understood with reference to the figures. FIG. 2 shows a flowchart of embodiment 200 of one of the methods described herein. As illustrated, as described in step 210, the method generally begins with an understanding of the substrate and the components placed therein and connected using the ACA. By mapping the dimensions and positions of each component, it is possible to design a magnet tray and determine the required placement position of each magnet 220.

The size and strength of each magnet can be determined 225 based on the specifications of the application. The characteristics of the magnetic field, for example the magnetic flux lines of each magnet, can be determined or mapped 230. Those skilled in the art will understand how to determine the size, strength, and magnetic flux lines of each magnet required. Those skilled in the art will also understand that it may be preferable to change the order of the steps described above depending on a given application.

Those skilled in the art will further understand that the properties of the magnet affect the development and formation of Z-axis columns within the ACA. Stronger magnets allow for higher columns to form faster, but magnets that are too strong are not desirable. In various embodiments, the ideal properties of the magnet are determined experimentally for a given application.

A magnet tray is made 235 and magnets selected for work are fixed 240 in their respective positions. It is clear that the magnet tray is designed to accommodate each magnet in its respective position by any useful means that does not change the position or magnetic field of the magnet with respect to the component and substrate. In one embodiment, the magnetic tray is made of aluminum with holes at the locations where each magnet is located. The magnet is fixed in position by some means that does not change the strength of the magnet or the magnetic flux lines 240. In certain embodiments, it may be convenient to use an adhesive to secure the magnet to the magnet tray.

An alignment tray is created to act as a carrier for the substrate and components and to ensure that the position of the substrate and each component placed therein is aligned with the position of the corresponding magnet in the magnet tray. The alignment tray is adapted to accept and hold the substrate during ACA alignment and subsequent curing 250. The tray may be adapted to secure the substrate by some means during the process of making the interconnect. In one embodiment, a recess is created that is complementary to the shape of the substrate and passively accepts and constrains the substrate during processing. In a preferred embodiment, the substrate can be accepted in the alignment tray in only one direction, reducing the risk of misalignment with the magnets in the magnet tray.

At the position where the component is placed 265, ACA is applied to the substrate 260. In some embodiments considered herein, the steps may vary, for example, the components may be placed and the ACA may be applied at the same time. Those skilled in the art will also appreciate that the process sequence here can be substituted as long as each component is correctly placed in the desired position on the substrate with the desired amount of ACA between the two as a final result.

The alignment tray and the magnet tray are then brought closer to each other. In a preferred embodiment, the trays must be aligned while being positioned perpendicular to each other. This is enforced by a structure that prevents the alignment tray with the substrate from sliding across the magnetic field of the magnet in the magnet tray and initiating improper column formation. By requiring the magnet trays and alignment trays to be brought closer in this way, column formation is optimized and substantially limited to the Z-axis direction. Thus, the assembled tray 270 (“assembly” or magnet pallet assembly) can then be placed in the oven for curing under appropriate conditions. The oven is an assembly because the assembled trays fit each other in an optimized manner for Z-axis (ie, perpendicular) column formation parallel to each other, and because the assembly is movable without substantially interfering with the columns. It may be a batch oven in which is manually taken in and out, or it may be a semi-continuous oven, or a continuous oven such as a reflow oven in which the assembly moves through the oven on a conveyor. After curing the ACA, there is little risk of affecting the column structure, i.e. the columns within the cured ACA are stable.

It should be understood that in certain components, a phenomenon referred to herein as "chip flipping" can occur. If the component is magnetically polar, i.e. the component has two separate magnetic poles, for example, and when exposed to the magnetic field of the magnet tray, the component "inverts" to tune in with the magnetic field. When the system is exposed to the magnet tray, the ACA has not yet been aligned or cured, so there is no way to prevent the chip from flipping over. In extreme cases, the component can be completely separated from the substrate. This only happens to certain components, but if it does, it's a problem. The inventor has developed a simple solution to this problem if such a component exists. It is necessary to include an additional "tacking" step before exposing the component or chip to the magnet tray. In general, the component in question is fixed to the substrate. One useful method is to apply a small amount of epoxy in the presence of a magnetic field to retain the sensitive components. This method involves applying a small amount of UV curable epoxy to secure the component, followed by exposure to UV light of sufficient intensity and duration to ensure that the epoxy cures. The substrate, component, and ACA assemblies are then placed in the proper proximity to the magnet tray, allowing the Z-axis column to be formed without worrying about the component or chip flipping over.

In the second of many aspects, the present disclosure provides a system in which the interconnect between the substrate and the electronic components attached therein is made using an anisotropic conductive adhesive (ACA) that can be magnetically aligned. To do. The system includes a non-magnetic tray adapted to accept and hold each of one or more magnets in positions corresponding to the position of one or more electronic components on the substrate to which the components are connected. Includes magnet tray.

The system also includes an alignment tray that is adapted to accept a substrate on which one or more components connected to it using ACA are placed. The alignment tray can hold the substrate during ACA alignment and curing.

The system also includes an ACA containing magnetically alignable particles capable of forming conductive interconnects along the Z axis. The formulation of ACA can vary for a particular application as it can be determined by the characteristics of the electronic components or the devices to which the components are interconnected. ACA may be made of different sizes of electromagnetic or conductive particles, for example for applications with different pitch requirements.

In a preferred embodiment, the alignment tray and the magnetic tray are made of non-magnetic material. In one embodiment, the substrate can be placed on the alignment tray in only one direction to avoid confusion and mistakes, allowing non-technical personnel to assist in manufacturing.

In general, the magnet tray and alignment tray are fitted so that the components on the substrate are vertically aligned together in a removable state so that they are aligned vertically (aligned up and down) with the magnets in the magnet tray. The ACA is exposed to a magnetic field such that the magnetic flux lines are substantially perpendicular to the XY plane defining the substrate. It is preferable that such a configuration is maintained until the curing of ACA is completed.

In various embodiments of the system, the magnet is a permanent magnet. Rare earth magnets are useful for many applications here, including magnets containing neodymium, such as NIB magnets. These magnets can provide a strong magnetic field.

In one embodiment, the assembly including the magnet tray, the alignment tray, and the substrate on which the components are placed can be placed directly in the curing oven. According to this, the aligned ACA is cured with minimal movement and with little risk of being disturbed when the columns formed in the Z-axis direction are exposed to a magnetic field. In another embodiment, the assembly and / or magnet tray functions as a rack that can slide directly into the oven and does not require supporting shelves or additional racks for use. In another embodiment, the assembly can be placed on a conveyor mechanism to use a semi-continuous or continuous processing oven. In such an embodiment, the conveyor has a number of different configurations with the same or different configurations of subsystems and components, each with its own tailored magnetic tray designed according to specifications and interconnected components and subsystems. It may include an assembly.

In various embodiments of each magnet in the magnet tray of the system, the magnetic flux lines are substantially parallel to each other and substantially perpendicular to the XY plane in the area corresponding to the area of the substrate in which the components and ACA are located. Is. Optimal interconnections result from such configurations. In various embodiments, the ACA is substantially uniform and forms columns substantially perpendicular to the XY planes of the components and substrates.

With reference to further figures, FIG. 1 shows embodiment 100 of an ACA interconnected system that magnetically aligns and cures, illustrating certain features of the system. A cross-sectional view of an embodiment of an ACA interconnect that magnetically aligns and cures is shown showing a non-magnetic magnet tray 110 with a plurality of magnets 120 arranged therein. The magnet tray 110 has an opening (not shown) for accommodating the magnet 120, which is fixed in the magnet tray 110 by a fixing means that does not interfere with the magnet 120 by changing an adhesive (not shown) or other magnetic flux lines. Unsigned for convenience and clarity). The alignment tray 130 has a recess that receives the substrate 140 that is held while aligning and curing the ACA to form an interconnect. The substrate 140 has a plurality of electronic components 150 disposed on it. The ACA (not shown) is applied or placed between the component 150 and the substrate 140 (or perhaps already applied). As shown, the arrangement of each magnet 120 corresponds to the position of the component 150 on the substrate 140, and the magnet 120 is vertically aligned (aligned) with the component 150. In this configuration, the magnetic field provides the force to align the electromagnetic particles of ACA (not shown) to form a Z-axis column. As shown, the area covered by each magnet 120 is larger than the area covered by the corresponding component 150, and the system 100 is the same size as the prior art electromagnet or component covering the entire surface of the substrate. Provides a more optimized and homogeneous alignment compared to magnets in.

FIG. 3 illustrates an embodiment of the alignment tray 300 and shows various aspects thereof. One tray 310 depicted includes a plurality of subsystems (not shown), each having one component 320. In another embodiment (not shown), depending on the size, one alignment tray may hold one substrate with one or more components. In this embodiment, the presence of the alignment (alignment) means 330, which is a hole, allows proper alignment (alignment) with the magnet tray (not shown) using, for example, a pin or rod, and the magnet tray and alignment. The tray is arranged vertically and the magnets in the magnet tray are aligned (aligned) with the corresponding components interconnected to the substrate on the alignment tray. In various embodiments, alignment trays have simple shapes, such as different hole shapes, hole patterns, or offsets, different hole sizes, holes, because proper alignment is important for the correct formation of interconnects. A combination of pins, may be included, with the complementary structure of the magnet tray so that the alignment tray and the magnet tray can be aligned (aligned) with each other in only one direction. It will be apparent to those skilled in the art that many means are recognized within the art to achieve proper alignment (alignment) between two objects.

In another aspect, the present disclosure provides a kit that uses an anisotropic conductive adhesive that is magnetically aligned between a substrate and an electronic component attached thereto to create an interconnect.
Kits are generally
At least one containing a non-magnetic tray adapted to hold one or more magnets in a position corresponding to the desired placement of the electronic component on the substrate and the connection of the component with the desired substrate using ACA. With a magnetic tray
With enough magnets to complete the magnet tray, each magnet has the desired size and strength to make an interconnect between the component and the substrate using ACA.
Includes at least one alignment tray, adapted to accept and hold the substrate and the components placed on the substrate during the alignment and curing of the ACA to make the interconnect.

Optionally, the kit also includes an ACA suitable for use with the kit for making interconnects using the kit between the component and the substrate.

The magnet trays and alignment trays are generally configured to be oriented perpendicular to each other, and when the magnet trays and alignment trays are assembled in such an orientation, the electronic components placed on the substrate on the alignment trays are magnet trays. It can be assembled so that it is aligned vertically with the magnet above. This configuration is used in both the alignment and curing steps in various embodiments.

In a preferred embodiment, the oriented and assembled magnet trays and alignment trays (“assembly”) can be placed in a curing oven. In one embodiment, the magnet tray or assembled tray functions as a rack in the oven or as a rack for transfer into a semi-continuous or continuous oven such as a reflow oven or a curing tunnel.

In various embodiments, when the magnet trays and alignment trays are combined and assembled, for each magnet in the magnet tray, the magnetic flux lines are substantially parallel to each other, corresponding to the area of the substrate in which the components are located. It is substantially perpendicular to the XY plane in the area. In general, the ACA located between the substrate and the component above it is a column that is substantially perpendicular to the XY plane of the component and the substrate and is substantially uniform when the tray is oriented and assembled. To form.

In a further aspect, the present disclosure provides an oven system that creates an interconnect between a substrate and an electronic component that is placed on it and connected using an ACA. The system generally operates according to the method as described above for the other systems described herein. Generally, the oven system includes a curing oven and a magnetic tray with one or more magnets placed on the substrate and in a position corresponding to the position of the electronic components connected via the ACA. Includes one or more shelves or racks and an alignment tray in which one or more components placed therein and connected via ACA are adapted to receive and hold a placed substrate. ..

In one embodiment, the magnet is a permanent magnet. Rare earth magnets are useful for many applications here, including magnets containing neodymium, such as NIB magnets.

In various embodiments of the oven system, for each magnet in the magnet tray of the system, the magnetic flux lines are substantially parallel to each other and substantially in the XY plane in the area corresponding to the area of the substrate in which the components and ACA are located. Is right angle. In various embodiments, the ACA forms a column that is substantially perpendicular to the XY plane of the component and substrate and is substantially uniform.

Embodiment 400 of the oven system is shown in FIG. As shown, each assembly 450 of the magnet tray 410 and the alignment tray 420 can function as a rack 425 in a batch oven 401 generally designed to accommodate a plurality of such racks 425. An enlarged view of the assembly 450 is shown as an inset in FIG. 4B, with the assembled magnet tray 410 and the assembled magnet tray 410 holding the substrate, components, and ACA (generally 430) during the entire Z-axis column alignment and curing process. Alignment tray 420 is included. Alignment holes 435 ensure that the assemblies are combined only in the correct orientation. Insertion FIG. 4C shows another magnet tray 410 in which a plurality of permanent magnets 415 are arranged.

The scope of the present invention is indicated by the claims attached herein, but may be influenced by, for example, the limits of linguistic expression. Specific terms are used to describe the invention, but these terms are used generically and descriptively and are not intended to be limiting. Further, although preferred embodiments of the claimed invention are described herein, it will be apparent to those skilled in the art that such embodiments are provided for illustration purposes only. Given the disclosures provided herein, one of ordinary skill in the art may make certain changes, amendments, and substitutions. Therefore, it is clear that the invention of the present application is feasible in a manner other than that specifically described, and such a method of execution of the invention is within the scope of the claims or equivalent. Therefore, it does not deviate from the scope and spirit of the claims of the present application.

Claims (20)

A method of creating an interconnect between a substrate and an electronic component placed therein using a magnetically aligned anisotropic conductive adhesive (ACA).
The method is
a) Steps to establish the dimensions of the first component placed and connected to the substrate and its position on the substrate.
b) The step of determining the position of the first magnet with respect to the size and position of the component established in step a), and
c) The step of determining the size and strength of the magnet required in step b), and
d) The step of mapping the magnetic flux line of the magnetic field of the magnet and
e) A step of repeating steps a) -d) for each additional component placed and connected to the substrate to determine the required additional magnet characteristics and placement position.
f) The step of creating a magnetic tray and fixing each magnet to its respective placement position on the tray,
g) With the step of creating an alignment tray and adapting the alignment tray to hold the substrate during alignment and curing.
h) The step of arranging the substrate on the alignment tray and
i) A step of applying ACA to the substrate at one or more positions where the components are placed, and
j) A step of arranging the first component and each additional component on the substrate, and
k) The step of assembling the alignment tray and the magnetic tray, and
l) A step that enables the formation of a column in the Z-axis direction in the ACA,
m) A step of curing the ACA, thereby creating an interconnection between the substrate and the first component and each additional component.
Including
The alignment tray and the magnetic tray are made of non-magnetic material, and the magnet tray is adapted to accept the first and additional components at each placement position on the tray.
The assembly, including the magnet tray with magnets and the substrate on which the components and ACA are located, can be placed in a curing oven.
Method. The method of claim 1, wherein the magnet comprises a permanent magnet. The method of claim 2, wherein the magnet comprises a rare earth magnet. Optimizing the height of the column,
Optimization of the strength of the interconnection,
Reduction of the number of short circuits,
Increased expected life of the finished device or board,
To improve the yield of usable products, or to reduce defects or defective products as a result of making the interconnects.
The method of claim 3, wherein the size and strength of each magnet is independently and experimentally determined. For each magnet in the magnet tray, the magnetic flux line
Virtually parallel to each other
Substantially perpendicular to the XY plane of the area corresponding to the area of the substrate on which the component and ACA are located.
The method according to claim 4. The method of claim 1, wherein the ACA forms columns that are substantially uniform in height and diameter. The method of claim 1, wherein the ACA forms a substantially uniform column, the column being substantially perpendicular to the XY plane of the component and the substrate. The method of claim 1, wherein the substrate can be arranged in only one direction in the alignment tray. The method according to claim 1, wherein the alignment tray includes positioning means, and the magnetic tray and the alignment tray can be assembled only in directions suitable for each other. The method of claim 1, wherein the alignment tray and the magnet tray include a material that can withstand the curing conditions for curing the ACA. A system for making interconnects between a substrate and the electronic components attached to it using a magnetically aligned anisotropic conductive adhesive (ACA).
The system
A magnet containing a non-magnetic tray adapted to accept and hold each of the magnets in a position corresponding to the position of the electronic component on the substrate to which the component is connected. With the tray
An alignment tray adapted to hold the ACA and the substrate on which one or more components connected to the substrate are placed during the alignment and curing of the ACA.
Includes ACA, which contains magnetically aligned particles capable of forming conductive interconnects in the Z-axis direction.
Both the alignment tray and the magnetic tray are made of non-magnetic material.
The magnet tray and the alignment tray are arranged vertically together in a removable state so that the component on the substrate is vertically aligned (aligned) with the magnet in the magnet tray. The ACA is exposed to a magnetic field such that the magnetic flux lines are substantially perpendicular to the XY plane defining the substrate.
The substrate can only be placed in one direction within the alignment tray.
system. The system according to claim 11, wherein the magnet is a permanent magnet. The system according to claim 11, wherein the magnet is a rare earth magnet. For each magnet in the magnet tray, the magnetic flux line
Virtually parallel to each other
13. The system of claim 13, wherein the component and the ACA are substantially perpendicular to the XY plane of the area corresponding to the area of the substrate. 11. The system of claim 11, wherein the ACA forms a substantially uniform column, the column being substantially perpendicular to the XY plane of the component and the substrate. 11. The system of claim 11, wherein the assembly comprising the magnet tray and the substrate on which the components are located can be placed in a curing oven or brought in directly. 16. The assembly or magnet tray acts as a rack that can slide or be carried directly into the oven and does not require support shelves, additional racks, or other support. system. A kit that uses an anisotropic conductive adhesive that is magnetically aligned between the substrate and the electronic components attached to it to create an interconnect.
The kit
At least one containing a non-magnetic tray adapted to hold one or more magnets in a position corresponding to the desired placement of the electronic component on the substrate and the connection of the component with the desired substrate using ACA. With a magnetic tray
With enough magnets to complete the magnet tray, each magnet has the desired size and strength to make an interconnect between the component and the substrate using the ACA.
With at least one alignment tray adapted to accept and hold the substrate and the components placed on the substrate during alignment and curing of the ACA to make the interconnect.
Optionally, includes an ACA suitable for use with the kit to make at least one interconnect using the kit between the component and the substrate, and includes.
The magnet tray and the alignment tray are configured to be vertically aligned with each other, and when the magnet tray and the alignment tray are assembled in such an orientation, the magnet tray and the alignment tray are arranged on a substrate on the alignment tray. A kit in which the electronic components are assembled so that they are aligned perpendicular to the magnets on the magnet tray. The kit of claim 18, wherein the oriented and assembled magnet trays and alignment trays can be placed in a curing oven or brought in directly. 19. The kit of claim 19, wherein the magnet tray or the assembled tray functions as a rack in the oven.

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