CA2372551C - Improved structure and method for testing bond strength and/or removing integrated circuit devices bonded to substrates - Google Patents
Improved structure and method for testing bond strength and/or removing integrated circuit devices bonded to substrates Download PDFInfo
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- CA2372551C CA2372551C CA 2372551 CA2372551A CA2372551C CA 2372551 C CA2372551 C CA 2372551C CA 2372551 CA2372551 CA 2372551 CA 2372551 A CA2372551 A CA 2372551A CA 2372551 C CA2372551 C CA 2372551C
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
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Abstract
The present invention relates to methods and structures for facilitating the removal of integrated circuit devices, microelectronic devices or die from substrates and/or for testing the integrity of the bonding between such devices and the substrate, and preferably where the integrated circuit device is a flip chip. The invention provides. in one embodiment a microelectronic device or die having a ball and stud connector attached to a surface of the device opposite to the surface which is intended to be connected to a substrate. In other embodiments, the invention provides for methods and apparatus for removing one or more die attached to a substrate, or assessing the integrity of the bond between each die and the substrate. Each die having a ball and stud connector attached thereto is positioned or secured in a holder. A mechanism clamped to the ball and stud connector applies a tensile force to the die such that the tensile force is exerted essentially perpendicular to the surface of the substrate to which the die is attached and this results from the interaction of the mechanism and the ball and stud connector.
This results in removal of the die from the substrate without significant damage to the die or the substrate or for assessing the integrity of the bond between the die and the substrate by attaching a ball and stud connector to the die. No application of heat is required.
This results in removal of the die from the substrate without significant damage to the die or the substrate or for assessing the integrity of the bond between the die and the substrate by attaching a ball and stud connector to the die. No application of heat is required.
Description
IMPROVED STRUCTURE AND METHOD FOR TESTING BOND
STRENGTH ANDIOR REMOVING INTEGRATED CIRCUIT DEVICES
BONDED TO SUBSTRATES
Field of the Invention The present invention generally relates to packages of integrated circuit devices attached to substrates. More particularly, the invention relates to methods and structures for facilitating the removal of integrated circuit devices, microelectronic devices or die from substrates and for testing the integrity of the bonding between such devices and the substrate, and preferably where the integrated circuit device is a flip chip.
Background of the Invention The use of flip chips and their connections to substrates is one of numerous ways that microelectronic devices may be connected to substrates. A flip chip is an integrated circuit device wherein the chip face providing interconnecting circuit contacts is mounted face down.
The contacts are formed of a lead/tin alloy which when melted, will reflow and maintain their locations on the chip. These are commonly known as controlled collapse chip connection (C4) joints. When attaching flip chips to a module or substrate the chips are positioned on corresponding contact pads on the module and the module carrying the chips are passed through a furnace at a temperature sufficient to melt the lead/tin alloy of each C4 joint and reflow it to the respective contact pads on the module. Upon cooling, the chips will be physically and electrically connected to the module. Because the flip chips with C4 joints permit area connection or contacts across the face area of the chip to the module, and not simply around the periphery of the chip, the chips can be spaced so closely together on the module that they resemble a brick wall arrangement in appearance. The spacing between chips could be in the order of 0.4mm spacing or less. The chip and module structure is typically packaged by introducing adhesive encapsulating material in the space between the chip and the module. This results in enhanced physical protection for the contact structure as well as sealing the structure to prevent damage from moisture. This adhesive encapsulant in effect underfills the space between the chip and the substrate. The substrates or modules are typically comprised of appropriate organic or ceramic materials.
Situations arise where it may become important to test and verify the quality of the bonding between the chip and the substrate. In addition, there are situations where it may be that a particular chip has been determined to be defective and there is a requirement to remove that particular identified chip from the substrate and replace it with an alternative chip. U.5. Patent No. 6,117,695, which issued September 12, 2000 to Adrian S: Murphy et al, is directed to An Apparatus and Method for Testing a Flip Chip Integrated Circuit Package Adhesive Layer. The description provides for tension testing and assessing the integrity of the bond formed by an adhesive layer between the integrated circuit device and a plate, where the plate may be a substrate or a heat spreader. A lower portion of the apparatus for pulling the integrated circuit device is adhesively attached to a surface of the integrated circuit device opposite the plate. The further described apparatus is attached or connected to this lower portion such that a force is applied and the adhesive layer between the integrated circuit and the plate is subjected to a force.
The apparatus provides for a variety of forces to be applied to the adhesive layer which forces include tension, a peel testing of the adhesive, or a shear testing of the adhesive layer.
There is a need, however, for improved methods and apparatus for applying forces to the adhesive bonding between an integrated circuit device and a substrate which are in essentially pure tension in order to remove the chip from the substrate so as to minimize damage to the module and overcome damage to the base metal or inter-metallic and planar layers of the module.
Summary of the Invention The present invention provides in one embodiment a microelectronic device or die having a ball and stud connector attached to a surface of the device opposite to the surface which is intended to be connected to a substrate. In other embodiments, the invention provides for apparatus for removing one or more die attached to a substrate, or assessing the integrity of the bond between each die and the substrate. Each die having a ball and stud connector attached thereto is positioned or secured in a holder. A mechanism clamped to the ball and stud connector applies a tensile force to the die such that the tensile force is exerted essentially perpendicular to the surface of the substrate to which the die is attached and this results from the interaction of the mechanism and the ball and stud connector. Without limiting the above or the specification in any manner, additional embodiments of the invention also provide for methods of removing a die from a substrate without significant damage to the die or the substrate or for assessing the integrity of the bond between a die and a substrate by attaching a ball and stud connector to the die. No application of heat is required. A mechanism is clamped to the ball and stud connector and upon activation the mechanism applies a tensile force to the die such that the force is caused to be essentially perpendicular to the surface of the substrate to which the die is attached.
The perpendicular direction of the force results from the interaction of the mechanism and the ball. and stud connector. The combination of the die, substrate and connector is held in such a manner as to be moveable in the X and/or Y direction resulting from the interaction of the mechanism and the ball and stud connection.
The invention addresses the above identified and other problems associated with the prior art by providing in one aspect, a method for determining the integrity of the bond between an assembled integrated circuit device and a substrate. The method includes attaching a connector to a surface of the integrated circuit device, chip or die wherein said connector includes a ball and stud, and attaching a mechanism, for applying a tensile force to the bond, to the ball of the connector. The mechanism is caused to apply the force to the connector such that the stud limits the angle at which the force is exerted on the integrated circuit device and substrate such that the force is essentially perpendicular to the substrate. The tensile strength of the bond is then observed.
The invention also addresses these and other problems associated with the prior art by providing a method for removing an integrated circuit device, chip or die bonded to a substrate which includes attaching a connector to a surface of the integrated circuit device, wherein said connector includes a ball and stud, and attaching a mechanism, for applying a tensile force to the bond; to the ball of the connector. The mechanism is caused to apply the force to the connector such that the stud limits the angle at which the force is exerted on the integrated circuit device and substrate such that the force is essentially perpendicular to the substrate. The integrated circuit device is then separated from the substrate with minimal damage to the substrate.
The invention also. addresses these and other problems associated with the prior art by providing an integrated circuit package which includes a die having an array of contacts and a substrate having an array of contacts such that the contacts of said die array are interconnected to said contacts on said substrate by a solder ball grid array and a ball and stud device is attached to a surface of the die opposite to said substrate.
The invention also addresses these and other problems associated with the prior art by providing an apparatus for removing an integrated circuit device interconnected to a substrate by means of a ball grid array of solder balls bonded to respective pads on the device and substrate. The apparatus comprises a ball and stud connector attached to a surface of the integrated circuit device and a holder positioning the substrate. A mechanism is clamped to the ball of the connector for providing a tensile pulling force. The mechanism and the associated connector and holder apply a tensile force to the integrated circuit device in a direction which is essentially perpendicular to the substrate sufficient to separate the integrated circuit device from the substrate with minimal damage to the substrate.
For a better understanding of the invention and of the advantages and objectives obtained through its use, reference should be made to the drawings and to the accompanying descriptive matter wherein there is described exemplary embodiments of the invention.
Brief Description of the Drawings Figure 1 is an illustration of side and perspective views of a ball and stud connecting device shown bonded to a chip which in turn is bonded to a substrate, in accordance with a preferred embodiment of the invention;
Figure 2 shows the stud and ball connecting device of Figure 1 clamped in the adjustable jaws of a chuck assembly;
Figure 3 shows details of a holding fixture and a ball stud connecting device connected to a chip and a holding fixture for a mufti-chip array; and Figure 4 is an illustration of one arrangement for permitting movement of the holding fixture as illustrated in Figure 3 in the X and Y directions.
Detailed Description of the Invention Embodiments of the invention will be subsequently described which are considered to provide new and useful methods and apparatus for testing the integrity of the bond between an integrated circuit device, die or chip and a substrate as well as providing the capability of removing the chip from the substrate with minimal damage to the substrate. The invention results in forces being applied to the chip device which are essentially pure tension forces perpendicular to the substrate and whereby shear forces, or bending moment forces which could result in damages to the chip and/or the substrate, are avoided. This is achieved by the unique use of a ball and stud or ball and stem connector element. The unique ball and stud connector, when clamped by the mating jaws of a chuck assembly and pulled by a load cell and traction apparatus, allows the chip package to move slightly in the X and Y directions so as to result in essentially a pure tensile force being applied when the traction apparatus is activated. In effect, the novel ball stud connector arrangement allows the chip package to be self centred so that the tensile force is essentially in the Z direction perpendicular to the surface of the substrate to which the chip is attached. This results in minimal physical damage to the chip, the substrate, the surface of the substrate; and its various layers in the vicinity of the location where the chip is attached to the substrate so that, for example, another chip can be subsequently attached to replace the removed chip. Where the integrity or strength of the bond is merely being tested; the novel connector resulting in the tensile force on the chip, would ensure valid test results and minimize any forces pulling on the chip at a substantial angle from the vertical. It is noted that the usefulness of the subject invention does not require application of heat or the raising of the temperature of the bond between the chip and substrate:
Although particular details of the inventive concepts will be provided in the description which S follows, these details are considered to be those of preferred embodiments of the invention and thus, it is understood that the invention is not limited to these details. In particular, in addition to use of the invention involving flip chip technology, the invention could as well be used with any known arrangement where integrated circuit chips or die are attached to substrates including thin lead attachments. The particular substrate or module material need not be limited in the sense that organic, ceramic, plastic or any other material that is typically used for such devices would also provide useful results for the described inventive concepts: Within the description of the drawings, like reference numerals are used throughout the description and drawings to illustrate similar elements and components.
The novel ball stud connector used to cold pull and separate an integrated circuit chip attached to a substrate without the application of heat, will be described with reference to Figure 1. The ball stud connector is generally shown by reference 10 in association with an assembled chip substrate package. Chip device 15 is shown bonded to substrate 20 in any well known manner including, for example, an array of contact balls between the respective mating contacts of chip device 15 and substrate 20 and appropriate adhesive underfill between these surfaces. Ball stud connector 10 consists of a spherical portion 11, which will be clamped by jaws of a chuck assembly which is part of a load or traction mechanism or apparatus for creating a pulling or tensile force, as will be subsequently described, and an upstanding stud or stem portion shown by reference 12. Connector 10 includes element 13 and base element 14 of any appropriate configuration for positioning connector 10 on the upper surface of chip device 15 as shown. Ball stud connector 10 is attached to the top surface of chip device 15 by applying glue or adhesive between the lower surface of base element 14 and the upper surface of chip device 15. The adhesive quality and strength of the glue that is used should in general be stronger than the strength of the attachment or bond between chip device 15 and substrate 20: In actual use there is minimal need for precise positioning of ball stud connector 10 on the surface of chip 15. As will be subsequently described, the invention provides for some variation in the X
and Y directions in the positioning of the chip and substrate assembly so as to allow the ball stud connector 10, chip 15 and substrate 20 to be properly positioned with respect to the traction equipment or apparatus and result in essentially tensile forces being applied. The shape of the connector 10 will also tend to compensate for any lack of precision. The area of contact of base 14 on the upper surface of chip 15 should be smaller than the surface area of chip 15, thereby preventing the glue or adhesive which is applied between base 14 and chip 15 from overflowing down the sides of chip 15. Having the dimension of base l4 of connector 10 smaller than the surface area of the chip 15 prevents adhesive from overflowing and further cementing chip 15 to substrate 20 which are already interconnected. If this additional cementing was not prevented, the force resulting from the traction apparatus, for the cold pulling of chip 10 would be greater than the force needed to test the integrity of the bond or remove chip 1 S from substrate 20 as the case may be, for a chip/substrate assembly without the added cement and would in all likelihood, cause mechanical and physical damage to the surface of substrate 20, the contact bumps and/or chip 15.
Connector 10 and all of its various portions and features as described can be made integrally in any known manner as by machining. The material for connector 10 could be any suitable material as would be apparent to one having ordinary skill in the material science. Material selected from brassy steel or plastic would be the preferred material.
Once connector 10 has been appropriately attached to chip 15 and the adhesive cured, as is well known, the jaws of an adjustable chuck assembly are clamped to connector 10 in order to est the integrity of the bond between chip 15 and substrate 20 or to remove chip 15 from substrate 20 as the case may be, as is generally depicted in Figure 2. Figure 2 shows connector 10, including spherical portion or ball 11, base 14 and stud or stem 12, glued to the top surface of chip 15 by adhesive 16 and where chip 15 is bonded, as shown by reference 17 in a well known manner as by solder ball contacts and adhesive underfill, to substrate 20. The chuck assembly is shown generally by reference 25. Such chuck assembly 25 and load or traction apparatus (not shown in Figure 2) attached thereto for creating a pulling or tensile force is well known and other than particular details which will be subsequently described, need not be further elaborated. Suitable traction apparatus for applying a tensile force has been obtained from Instron Corporation, Canton, Massachusetts.
Adhesive material 16 need not be uniformly applied to the area between base 14 of connector 10 and chip 15 and in addition connector 10 need not be initially perpendicular to substrate 15 as some variation can be accommodated by the invention to result in essentially tensile forces being applied as will be subsequently described.
A commercially available adhesive that has been successfully used as adhesive 16 as part of this invention is known by the trade name Loctite 495 or Superbonder 49950 available from Loctite Corporation, Cleveland, Ohio. Other suitable adhesives may also be available from Loctite Corporation or other suppliers of adhesives such as 3M Company of London, Canada.
The use of various materials for the ball and stud connector may require the use of alternative adhesives as would be readily apparent to those having ordinary skill in the relevant materials art. The adhesive per se is not considered to be an inventive aspect of the present inventions.
Chuck assembly 25 includes a pair of jaws 26 adjustably positioned to clamp upon ball 11 of connector 10 . The shape of the inner surfaces of jaws 26 provides clamping surfaces which are complementary to and match the shape of the spherical ball 11. Once jaws 26 are physically positioned around ball 11 of connector 10, a sleeve lock 27 of chuck assembly 25 is manually slid downwardly into place by the operator. Sleeve 27 is designed with a tapered surface which force jaws 26 to close gradually around ball 11 of connector 10 when sleeve 27 is moved downward, until sleeve 27 is completely in contact with jaws 26. When sleeve 27 is properly positioned, jaws 26 are clamped onto ball 11 and cannot be opened.
Subsequently, after the pulling operation has been completed by the traction apparatus and the chuck assembly on ball stud connector 10, jaws 26 can be manually opened by the operator by sliding sleeve 27 upwards out of engagement with the jaws 26. Stud connector 10 can then be disengaged from jaws 26.
The significance of stud or stem element 12 of connector 10 will now be described. As can be seen from Figure 2, if connector 10 is not positioned in essentially a vertical orientation with respect to chip 15 or substrate 20 as a result of non-uniform application of adhesive 16 for example, stud 12 abuts against an inside surface of jaws 26 of the chuck assembly 25. Thus, when jaws 26 are properly assembled and clamped to ball stud connector 10 around ball 11, the force exerted by chuck assembly 25 on connector IO and subsequently chip 15 which is attached thereto is essentially in the vertical direction. If; during assembly of jaws 26 around ball 11 of connector 10, connector 10 is at too great an angle to the vertical of the horizontal plane of chip or substrate 20; by virtue of stud 12 abutting the inside surface of jaws 26 the arrangement will force ball 11 to slightly rotate within jaws 26 causing the attached chip 15 and substrate 20 to be similarly displaced in the X and Y plane. If there is too much inclination of the connector 10 10 to the vertical when jaws 26 are attempted to be clamped on to ball 11, sleeve lock 27 as previously described will be prevented from sliding downwards over jaws 26 and locking them in place around ball 11. If jaws 26 are not appropriately locked in place, they may slip on ball 11 of connector 10 or ball may actually slip out of jaws 26 and prevent proper execution of the pull test. Thus the interaction of the complementary shape of the inner surface of jaws 26 to the ball 1 S 1 l and the physical abutting of stem 12 against an inner surface of j aws 26, will result in essentially tension forces being exerted on chip 15 by the chuck assembly 25 combined with attached load cell and traction apparatus. This will result in proper testing of the joint integrity between chip 15 and substrate 20 or, if desired, will result in chip 15 being ultimately removed from substrate 20 with minimal damage to chip 15 and substrate 20.
The description so far, with reference to Figures 1 and 2, has described the assembly and theory of implementation of the invention. In practice, however, the substrate with one or more chips attached thereto should be retained in a holding fixture in order to perform the integrity test or removal of the chip. Figure 3 illustrates the positioning of substrate 20 with chip device 15 attached thereto and along with ball stud connector 10 mounted thereon in a substrate holder 30.
Holder 30 is designed to have an appropriate shallow depression on the upper surface thereof as shown in order to accommodate the shape of substrate 20. Cover 31 having an opening to accommodate the shape of chip device 15 is placed to overlay substrate 20 as shown and in particular the portions of substrate 20 extending past chip 15 and maintains substrate 20 within the depression of holder 30. Cover 31 and substrate holder 30 are appropriately clamped such that the substrate 20 is held in place when a chuck assembly and associated traction apparatus is clamped to connector 10 by means of jaws 26 as previously described and a tensile force is applied to connector 10 and chip 15 so as to measure the integrity of the bond between chip 15 and substrate 20 or to remove chip 15 from substrate 20 as the case may be.
Previously, the description has only pertained to testing or removing a single chip from a substrate. Where a substrate having multiple chips attached thereto is involved, it may very well be desirable to provide the capability of testing or removing any one or more of the chips in such a mufti-chip array. To accommodate this, holder 30 and cover 31 are designed to have a number of openings corresponding to the number of chips as shown by reference 32 in Figure 3. In Figure 3, only one connector 10 is illustrated as connected to a chip but it could very well be that each one of the other openings 33 in cover 31 for the chips, could accommodate a similar connector 10 attached thereto. Holder 32 would function in a comparable manner to the holder previously described for a single chip such that corresponding depressions would exist in substrate holder 30 to the openings 33. In operation, cover 31 is clamped to the substrate holder 30 in a similar manner as had been previously described so that when a chuck assembly is attached to one or more of the connectors 10 positioned in openings 33 and associated 'traction apparatus is activated; the integrity of the joints between the respective chips 15 and substrates could be tested or alternatively the chips 15 could be removed from the substrate 20 as a result 20 of the applied tensile forces. Chuck assembly 25 could be either moved over the respective openings 33 or the holder 32 could be moved under the chuck assembly 25 such that the jaws 26 of the chuck assembly would in turn be clamped on to the respective connectors 10 in a similar manner as had been previously described.
Reference had previously been made to the slight movement which may result in the X andlor Y
directions of the chip/substrate package when connector 10 is not preferably properly vertically aligned and such movement results from the abutment of stem 12 against the inner portion of jaws 26. This resulting adjusting action can be accommodated by mounting holder 30 on a carriage that is movable in the X and Y directions. With reference to Figure 4, one exemplary embodiment for accommodating this movement will be described. As shown, chuck assembly 25 is clamped to connector 10 in a manner as previously described. Connector 10 is adhesivley attached to a chip as previously described. Cover 31, having multiple windows with one connector 10 shown protruding from each window thereof, is shown clamped to holder 30 and thereby restraining the substrate upon which the chips are mounted as previously described and illustrated. Typical clamping means are as generally illustrated in Figure 4 but the details of such are considered to be within the knowledge of one having ordinary skill in this technology. Holder 30 and cover 31 are shown positioned on a holding plate 4U which in turn is mounted on two carriages 41 and 42 which permit movement of the substrate and connector assembly in the X
and Y directions respectively. As a result, when ball 11 of connector 10 is improperly oriented within jaws 26, the resulting force of stud 12 on the inner surface of jaws 26 as previously described, causes the package to move in either the X or Y directions or both, in order to properly orient ball 11 of connector 10 within jaws 26. This results in a self centering movement of connector 10 within jaws 26. When jaws 26 are properly clamped onto ball 11 of connector 10, thus resulting in connector 10 being essentially vertically aligned with respect to the substrate and essentially perpendicular thereto; all of the pulling forces from chuck assembly 25 and traction apparatus are essentially in the vertical direction and are communicated through connector 10 to the interface between chip 15 and substrate 20 without any resulting shear forces or forces in an inclined direction. As needed, for a mufti-chip array the above process is repeated for each chip and connector shown in Figure 4.
It is apparent in the above description that Garners 41 and 42 shauld be freely moveable in the X
and Y directions respectively. When connector 10 and chuck assembly 25 are initially manually pre-aligned, chuck assembly 25 and stud 12 on connector 10 may not be essentially perpendicular to the surfaces of substrate 20 and chip 15. Jaws 26 of chuck assembly 25 axe clamped to ball 11 of connector 10 but since no pressure or forces are being applied there is no resulting movement: When the traction mechanism is activated and chuck assembly 25 is caused to move upward, jaws 26 clamped to ball 11 will start applying a force to stud 12, as had been previously described, and this will cause carriers 41 and 42 to move in the X
and Y directions respectively until the essentially perpendicular orientation of connector 10 is obtained.
Carriages 41 and 42 are intended to be freely moveable. If this is not the case and a carriage is prevented from being moved in response to the forces on stud 12, chuck assembly 25 may apply an undesirable non-uniform force which is not essentially perpendicular resulting in a prying action on chip 15. This could result, for example, in a corner of chip 15 being separated from substrate 20 and exposing chip 15 to failure as by fracture or other physical and mechanical damage.
As is well known, the integrity of the chip-to-substrate bond can be determined by a measurement of the pull strength per contact point of the connection resulting from a meter provided on the load cell. If desired, a microscopic verification and examination may also be conducted of the bond as it reaches the fracture point.
In order to facilitate the subsequent testing of the chip-to-substrate bond or removing the chip from the substrate altogether, as the case may be, during assembly and packaging of the chip on the substrate, a ball stud connector 10 as previously described, could be attached to and form part of the microelectronic device package. Similarly, in the fabrication of mufti-chip substrate packages, each one of the chips could be assembled with a ball stud connector so that each chip can be subsequently tested or removed as may be desirable without having to add one or more additional connectors.
Preferred embodiments of the present invention have been described hereinabove by way of example only and not of limitation such that those of ordinary skill in the art of he exemplary embodiments would readily appreciate that numerous modifications of detail may be made to the present invention, all coming within its spirit and scope. Various alternatives and modifications may be devised without departing from the invention. Accordingly, the present invention is intended to embrace all alternatives, modifications and variations which fall within the scope of the appended claims:
STRENGTH ANDIOR REMOVING INTEGRATED CIRCUIT DEVICES
BONDED TO SUBSTRATES
Field of the Invention The present invention generally relates to packages of integrated circuit devices attached to substrates. More particularly, the invention relates to methods and structures for facilitating the removal of integrated circuit devices, microelectronic devices or die from substrates and for testing the integrity of the bonding between such devices and the substrate, and preferably where the integrated circuit device is a flip chip.
Background of the Invention The use of flip chips and their connections to substrates is one of numerous ways that microelectronic devices may be connected to substrates. A flip chip is an integrated circuit device wherein the chip face providing interconnecting circuit contacts is mounted face down.
The contacts are formed of a lead/tin alloy which when melted, will reflow and maintain their locations on the chip. These are commonly known as controlled collapse chip connection (C4) joints. When attaching flip chips to a module or substrate the chips are positioned on corresponding contact pads on the module and the module carrying the chips are passed through a furnace at a temperature sufficient to melt the lead/tin alloy of each C4 joint and reflow it to the respective contact pads on the module. Upon cooling, the chips will be physically and electrically connected to the module. Because the flip chips with C4 joints permit area connection or contacts across the face area of the chip to the module, and not simply around the periphery of the chip, the chips can be spaced so closely together on the module that they resemble a brick wall arrangement in appearance. The spacing between chips could be in the order of 0.4mm spacing or less. The chip and module structure is typically packaged by introducing adhesive encapsulating material in the space between the chip and the module. This results in enhanced physical protection for the contact structure as well as sealing the structure to prevent damage from moisture. This adhesive encapsulant in effect underfills the space between the chip and the substrate. The substrates or modules are typically comprised of appropriate organic or ceramic materials.
Situations arise where it may become important to test and verify the quality of the bonding between the chip and the substrate. In addition, there are situations where it may be that a particular chip has been determined to be defective and there is a requirement to remove that particular identified chip from the substrate and replace it with an alternative chip. U.5. Patent No. 6,117,695, which issued September 12, 2000 to Adrian S: Murphy et al, is directed to An Apparatus and Method for Testing a Flip Chip Integrated Circuit Package Adhesive Layer. The description provides for tension testing and assessing the integrity of the bond formed by an adhesive layer between the integrated circuit device and a plate, where the plate may be a substrate or a heat spreader. A lower portion of the apparatus for pulling the integrated circuit device is adhesively attached to a surface of the integrated circuit device opposite the plate. The further described apparatus is attached or connected to this lower portion such that a force is applied and the adhesive layer between the integrated circuit and the plate is subjected to a force.
The apparatus provides for a variety of forces to be applied to the adhesive layer which forces include tension, a peel testing of the adhesive, or a shear testing of the adhesive layer.
There is a need, however, for improved methods and apparatus for applying forces to the adhesive bonding between an integrated circuit device and a substrate which are in essentially pure tension in order to remove the chip from the substrate so as to minimize damage to the module and overcome damage to the base metal or inter-metallic and planar layers of the module.
Summary of the Invention The present invention provides in one embodiment a microelectronic device or die having a ball and stud connector attached to a surface of the device opposite to the surface which is intended to be connected to a substrate. In other embodiments, the invention provides for apparatus for removing one or more die attached to a substrate, or assessing the integrity of the bond between each die and the substrate. Each die having a ball and stud connector attached thereto is positioned or secured in a holder. A mechanism clamped to the ball and stud connector applies a tensile force to the die such that the tensile force is exerted essentially perpendicular to the surface of the substrate to which the die is attached and this results from the interaction of the mechanism and the ball and stud connector. Without limiting the above or the specification in any manner, additional embodiments of the invention also provide for methods of removing a die from a substrate without significant damage to the die or the substrate or for assessing the integrity of the bond between a die and a substrate by attaching a ball and stud connector to the die. No application of heat is required. A mechanism is clamped to the ball and stud connector and upon activation the mechanism applies a tensile force to the die such that the force is caused to be essentially perpendicular to the surface of the substrate to which the die is attached.
The perpendicular direction of the force results from the interaction of the mechanism and the ball. and stud connector. The combination of the die, substrate and connector is held in such a manner as to be moveable in the X and/or Y direction resulting from the interaction of the mechanism and the ball and stud connection.
The invention addresses the above identified and other problems associated with the prior art by providing in one aspect, a method for determining the integrity of the bond between an assembled integrated circuit device and a substrate. The method includes attaching a connector to a surface of the integrated circuit device, chip or die wherein said connector includes a ball and stud, and attaching a mechanism, for applying a tensile force to the bond, to the ball of the connector. The mechanism is caused to apply the force to the connector such that the stud limits the angle at which the force is exerted on the integrated circuit device and substrate such that the force is essentially perpendicular to the substrate. The tensile strength of the bond is then observed.
The invention also addresses these and other problems associated with the prior art by providing a method for removing an integrated circuit device, chip or die bonded to a substrate which includes attaching a connector to a surface of the integrated circuit device, wherein said connector includes a ball and stud, and attaching a mechanism, for applying a tensile force to the bond; to the ball of the connector. The mechanism is caused to apply the force to the connector such that the stud limits the angle at which the force is exerted on the integrated circuit device and substrate such that the force is essentially perpendicular to the substrate. The integrated circuit device is then separated from the substrate with minimal damage to the substrate.
The invention also. addresses these and other problems associated with the prior art by providing an integrated circuit package which includes a die having an array of contacts and a substrate having an array of contacts such that the contacts of said die array are interconnected to said contacts on said substrate by a solder ball grid array and a ball and stud device is attached to a surface of the die opposite to said substrate.
The invention also addresses these and other problems associated with the prior art by providing an apparatus for removing an integrated circuit device interconnected to a substrate by means of a ball grid array of solder balls bonded to respective pads on the device and substrate. The apparatus comprises a ball and stud connector attached to a surface of the integrated circuit device and a holder positioning the substrate. A mechanism is clamped to the ball of the connector for providing a tensile pulling force. The mechanism and the associated connector and holder apply a tensile force to the integrated circuit device in a direction which is essentially perpendicular to the substrate sufficient to separate the integrated circuit device from the substrate with minimal damage to the substrate.
For a better understanding of the invention and of the advantages and objectives obtained through its use, reference should be made to the drawings and to the accompanying descriptive matter wherein there is described exemplary embodiments of the invention.
Brief Description of the Drawings Figure 1 is an illustration of side and perspective views of a ball and stud connecting device shown bonded to a chip which in turn is bonded to a substrate, in accordance with a preferred embodiment of the invention;
Figure 2 shows the stud and ball connecting device of Figure 1 clamped in the adjustable jaws of a chuck assembly;
Figure 3 shows details of a holding fixture and a ball stud connecting device connected to a chip and a holding fixture for a mufti-chip array; and Figure 4 is an illustration of one arrangement for permitting movement of the holding fixture as illustrated in Figure 3 in the X and Y directions.
Detailed Description of the Invention Embodiments of the invention will be subsequently described which are considered to provide new and useful methods and apparatus for testing the integrity of the bond between an integrated circuit device, die or chip and a substrate as well as providing the capability of removing the chip from the substrate with minimal damage to the substrate. The invention results in forces being applied to the chip device which are essentially pure tension forces perpendicular to the substrate and whereby shear forces, or bending moment forces which could result in damages to the chip and/or the substrate, are avoided. This is achieved by the unique use of a ball and stud or ball and stem connector element. The unique ball and stud connector, when clamped by the mating jaws of a chuck assembly and pulled by a load cell and traction apparatus, allows the chip package to move slightly in the X and Y directions so as to result in essentially a pure tensile force being applied when the traction apparatus is activated. In effect, the novel ball stud connector arrangement allows the chip package to be self centred so that the tensile force is essentially in the Z direction perpendicular to the surface of the substrate to which the chip is attached. This results in minimal physical damage to the chip, the substrate, the surface of the substrate; and its various layers in the vicinity of the location where the chip is attached to the substrate so that, for example, another chip can be subsequently attached to replace the removed chip. Where the integrity or strength of the bond is merely being tested; the novel connector resulting in the tensile force on the chip, would ensure valid test results and minimize any forces pulling on the chip at a substantial angle from the vertical. It is noted that the usefulness of the subject invention does not require application of heat or the raising of the temperature of the bond between the chip and substrate:
Although particular details of the inventive concepts will be provided in the description which S follows, these details are considered to be those of preferred embodiments of the invention and thus, it is understood that the invention is not limited to these details. In particular, in addition to use of the invention involving flip chip technology, the invention could as well be used with any known arrangement where integrated circuit chips or die are attached to substrates including thin lead attachments. The particular substrate or module material need not be limited in the sense that organic, ceramic, plastic or any other material that is typically used for such devices would also provide useful results for the described inventive concepts: Within the description of the drawings, like reference numerals are used throughout the description and drawings to illustrate similar elements and components.
The novel ball stud connector used to cold pull and separate an integrated circuit chip attached to a substrate without the application of heat, will be described with reference to Figure 1. The ball stud connector is generally shown by reference 10 in association with an assembled chip substrate package. Chip device 15 is shown bonded to substrate 20 in any well known manner including, for example, an array of contact balls between the respective mating contacts of chip device 15 and substrate 20 and appropriate adhesive underfill between these surfaces. Ball stud connector 10 consists of a spherical portion 11, which will be clamped by jaws of a chuck assembly which is part of a load or traction mechanism or apparatus for creating a pulling or tensile force, as will be subsequently described, and an upstanding stud or stem portion shown by reference 12. Connector 10 includes element 13 and base element 14 of any appropriate configuration for positioning connector 10 on the upper surface of chip device 15 as shown. Ball stud connector 10 is attached to the top surface of chip device 15 by applying glue or adhesive between the lower surface of base element 14 and the upper surface of chip device 15. The adhesive quality and strength of the glue that is used should in general be stronger than the strength of the attachment or bond between chip device 15 and substrate 20: In actual use there is minimal need for precise positioning of ball stud connector 10 on the surface of chip 15. As will be subsequently described, the invention provides for some variation in the X
and Y directions in the positioning of the chip and substrate assembly so as to allow the ball stud connector 10, chip 15 and substrate 20 to be properly positioned with respect to the traction equipment or apparatus and result in essentially tensile forces being applied. The shape of the connector 10 will also tend to compensate for any lack of precision. The area of contact of base 14 on the upper surface of chip 15 should be smaller than the surface area of chip 15, thereby preventing the glue or adhesive which is applied between base 14 and chip 15 from overflowing down the sides of chip 15. Having the dimension of base l4 of connector 10 smaller than the surface area of the chip 15 prevents adhesive from overflowing and further cementing chip 15 to substrate 20 which are already interconnected. If this additional cementing was not prevented, the force resulting from the traction apparatus, for the cold pulling of chip 10 would be greater than the force needed to test the integrity of the bond or remove chip 1 S from substrate 20 as the case may be, for a chip/substrate assembly without the added cement and would in all likelihood, cause mechanical and physical damage to the surface of substrate 20, the contact bumps and/or chip 15.
Connector 10 and all of its various portions and features as described can be made integrally in any known manner as by machining. The material for connector 10 could be any suitable material as would be apparent to one having ordinary skill in the material science. Material selected from brassy steel or plastic would be the preferred material.
Once connector 10 has been appropriately attached to chip 15 and the adhesive cured, as is well known, the jaws of an adjustable chuck assembly are clamped to connector 10 in order to est the integrity of the bond between chip 15 and substrate 20 or to remove chip 15 from substrate 20 as the case may be, as is generally depicted in Figure 2. Figure 2 shows connector 10, including spherical portion or ball 11, base 14 and stud or stem 12, glued to the top surface of chip 15 by adhesive 16 and where chip 15 is bonded, as shown by reference 17 in a well known manner as by solder ball contacts and adhesive underfill, to substrate 20. The chuck assembly is shown generally by reference 25. Such chuck assembly 25 and load or traction apparatus (not shown in Figure 2) attached thereto for creating a pulling or tensile force is well known and other than particular details which will be subsequently described, need not be further elaborated. Suitable traction apparatus for applying a tensile force has been obtained from Instron Corporation, Canton, Massachusetts.
Adhesive material 16 need not be uniformly applied to the area between base 14 of connector 10 and chip 15 and in addition connector 10 need not be initially perpendicular to substrate 15 as some variation can be accommodated by the invention to result in essentially tensile forces being applied as will be subsequently described.
A commercially available adhesive that has been successfully used as adhesive 16 as part of this invention is known by the trade name Loctite 495 or Superbonder 49950 available from Loctite Corporation, Cleveland, Ohio. Other suitable adhesives may also be available from Loctite Corporation or other suppliers of adhesives such as 3M Company of London, Canada.
The use of various materials for the ball and stud connector may require the use of alternative adhesives as would be readily apparent to those having ordinary skill in the relevant materials art. The adhesive per se is not considered to be an inventive aspect of the present inventions.
Chuck assembly 25 includes a pair of jaws 26 adjustably positioned to clamp upon ball 11 of connector 10 . The shape of the inner surfaces of jaws 26 provides clamping surfaces which are complementary to and match the shape of the spherical ball 11. Once jaws 26 are physically positioned around ball 11 of connector 10, a sleeve lock 27 of chuck assembly 25 is manually slid downwardly into place by the operator. Sleeve 27 is designed with a tapered surface which force jaws 26 to close gradually around ball 11 of connector 10 when sleeve 27 is moved downward, until sleeve 27 is completely in contact with jaws 26. When sleeve 27 is properly positioned, jaws 26 are clamped onto ball 11 and cannot be opened.
Subsequently, after the pulling operation has been completed by the traction apparatus and the chuck assembly on ball stud connector 10, jaws 26 can be manually opened by the operator by sliding sleeve 27 upwards out of engagement with the jaws 26. Stud connector 10 can then be disengaged from jaws 26.
The significance of stud or stem element 12 of connector 10 will now be described. As can be seen from Figure 2, if connector 10 is not positioned in essentially a vertical orientation with respect to chip 15 or substrate 20 as a result of non-uniform application of adhesive 16 for example, stud 12 abuts against an inside surface of jaws 26 of the chuck assembly 25. Thus, when jaws 26 are properly assembled and clamped to ball stud connector 10 around ball 11, the force exerted by chuck assembly 25 on connector IO and subsequently chip 15 which is attached thereto is essentially in the vertical direction. If; during assembly of jaws 26 around ball 11 of connector 10, connector 10 is at too great an angle to the vertical of the horizontal plane of chip or substrate 20; by virtue of stud 12 abutting the inside surface of jaws 26 the arrangement will force ball 11 to slightly rotate within jaws 26 causing the attached chip 15 and substrate 20 to be similarly displaced in the X and Y plane. If there is too much inclination of the connector 10 10 to the vertical when jaws 26 are attempted to be clamped on to ball 11, sleeve lock 27 as previously described will be prevented from sliding downwards over jaws 26 and locking them in place around ball 11. If jaws 26 are not appropriately locked in place, they may slip on ball 11 of connector 10 or ball may actually slip out of jaws 26 and prevent proper execution of the pull test. Thus the interaction of the complementary shape of the inner surface of jaws 26 to the ball 1 S 1 l and the physical abutting of stem 12 against an inner surface of j aws 26, will result in essentially tension forces being exerted on chip 15 by the chuck assembly 25 combined with attached load cell and traction apparatus. This will result in proper testing of the joint integrity between chip 15 and substrate 20 or, if desired, will result in chip 15 being ultimately removed from substrate 20 with minimal damage to chip 15 and substrate 20.
The description so far, with reference to Figures 1 and 2, has described the assembly and theory of implementation of the invention. In practice, however, the substrate with one or more chips attached thereto should be retained in a holding fixture in order to perform the integrity test or removal of the chip. Figure 3 illustrates the positioning of substrate 20 with chip device 15 attached thereto and along with ball stud connector 10 mounted thereon in a substrate holder 30.
Holder 30 is designed to have an appropriate shallow depression on the upper surface thereof as shown in order to accommodate the shape of substrate 20. Cover 31 having an opening to accommodate the shape of chip device 15 is placed to overlay substrate 20 as shown and in particular the portions of substrate 20 extending past chip 15 and maintains substrate 20 within the depression of holder 30. Cover 31 and substrate holder 30 are appropriately clamped such that the substrate 20 is held in place when a chuck assembly and associated traction apparatus is clamped to connector 10 by means of jaws 26 as previously described and a tensile force is applied to connector 10 and chip 15 so as to measure the integrity of the bond between chip 15 and substrate 20 or to remove chip 15 from substrate 20 as the case may be.
Previously, the description has only pertained to testing or removing a single chip from a substrate. Where a substrate having multiple chips attached thereto is involved, it may very well be desirable to provide the capability of testing or removing any one or more of the chips in such a mufti-chip array. To accommodate this, holder 30 and cover 31 are designed to have a number of openings corresponding to the number of chips as shown by reference 32 in Figure 3. In Figure 3, only one connector 10 is illustrated as connected to a chip but it could very well be that each one of the other openings 33 in cover 31 for the chips, could accommodate a similar connector 10 attached thereto. Holder 32 would function in a comparable manner to the holder previously described for a single chip such that corresponding depressions would exist in substrate holder 30 to the openings 33. In operation, cover 31 is clamped to the substrate holder 30 in a similar manner as had been previously described so that when a chuck assembly is attached to one or more of the connectors 10 positioned in openings 33 and associated 'traction apparatus is activated; the integrity of the joints between the respective chips 15 and substrates could be tested or alternatively the chips 15 could be removed from the substrate 20 as a result 20 of the applied tensile forces. Chuck assembly 25 could be either moved over the respective openings 33 or the holder 32 could be moved under the chuck assembly 25 such that the jaws 26 of the chuck assembly would in turn be clamped on to the respective connectors 10 in a similar manner as had been previously described.
Reference had previously been made to the slight movement which may result in the X andlor Y
directions of the chip/substrate package when connector 10 is not preferably properly vertically aligned and such movement results from the abutment of stem 12 against the inner portion of jaws 26. This resulting adjusting action can be accommodated by mounting holder 30 on a carriage that is movable in the X and Y directions. With reference to Figure 4, one exemplary embodiment for accommodating this movement will be described. As shown, chuck assembly 25 is clamped to connector 10 in a manner as previously described. Connector 10 is adhesivley attached to a chip as previously described. Cover 31, having multiple windows with one connector 10 shown protruding from each window thereof, is shown clamped to holder 30 and thereby restraining the substrate upon which the chips are mounted as previously described and illustrated. Typical clamping means are as generally illustrated in Figure 4 but the details of such are considered to be within the knowledge of one having ordinary skill in this technology. Holder 30 and cover 31 are shown positioned on a holding plate 4U which in turn is mounted on two carriages 41 and 42 which permit movement of the substrate and connector assembly in the X
and Y directions respectively. As a result, when ball 11 of connector 10 is improperly oriented within jaws 26, the resulting force of stud 12 on the inner surface of jaws 26 as previously described, causes the package to move in either the X or Y directions or both, in order to properly orient ball 11 of connector 10 within jaws 26. This results in a self centering movement of connector 10 within jaws 26. When jaws 26 are properly clamped onto ball 11 of connector 10, thus resulting in connector 10 being essentially vertically aligned with respect to the substrate and essentially perpendicular thereto; all of the pulling forces from chuck assembly 25 and traction apparatus are essentially in the vertical direction and are communicated through connector 10 to the interface between chip 15 and substrate 20 without any resulting shear forces or forces in an inclined direction. As needed, for a mufti-chip array the above process is repeated for each chip and connector shown in Figure 4.
It is apparent in the above description that Garners 41 and 42 shauld be freely moveable in the X
and Y directions respectively. When connector 10 and chuck assembly 25 are initially manually pre-aligned, chuck assembly 25 and stud 12 on connector 10 may not be essentially perpendicular to the surfaces of substrate 20 and chip 15. Jaws 26 of chuck assembly 25 axe clamped to ball 11 of connector 10 but since no pressure or forces are being applied there is no resulting movement: When the traction mechanism is activated and chuck assembly 25 is caused to move upward, jaws 26 clamped to ball 11 will start applying a force to stud 12, as had been previously described, and this will cause carriers 41 and 42 to move in the X
and Y directions respectively until the essentially perpendicular orientation of connector 10 is obtained.
Carriages 41 and 42 are intended to be freely moveable. If this is not the case and a carriage is prevented from being moved in response to the forces on stud 12, chuck assembly 25 may apply an undesirable non-uniform force which is not essentially perpendicular resulting in a prying action on chip 15. This could result, for example, in a corner of chip 15 being separated from substrate 20 and exposing chip 15 to failure as by fracture or other physical and mechanical damage.
As is well known, the integrity of the chip-to-substrate bond can be determined by a measurement of the pull strength per contact point of the connection resulting from a meter provided on the load cell. If desired, a microscopic verification and examination may also be conducted of the bond as it reaches the fracture point.
In order to facilitate the subsequent testing of the chip-to-substrate bond or removing the chip from the substrate altogether, as the case may be, during assembly and packaging of the chip on the substrate, a ball stud connector 10 as previously described, could be attached to and form part of the microelectronic device package. Similarly, in the fabrication of mufti-chip substrate packages, each one of the chips could be assembled with a ball stud connector so that each chip can be subsequently tested or removed as may be desirable without having to add one or more additional connectors.
Preferred embodiments of the present invention have been described hereinabove by way of example only and not of limitation such that those of ordinary skill in the art of he exemplary embodiments would readily appreciate that numerous modifications of detail may be made to the present invention, all coming within its spirit and scope. Various alternatives and modifications may be devised without departing from the invention. Accordingly, the present invention is intended to embrace all alternatives, modifications and variations which fall within the scope of the appended claims:
Claims (17)
1. ~A method for determining the integrity of solder bonds between an assembled integrated circuit device and a substrate wherein the integrated circuit device is interconnected to the substrate by solder interconnections between respective contact pads on the integrated circuit device and the substrate, comprising:
attaching a connector to a surface of the integrated circuit device wherein said connector includes a ball and stud;~
attaching a mechanism to the ball of the connector for applying a tensile force to said bonds at a particular angle to the substrate wherein the mechanism is attached to the ball of the connector by means of a pair of adjustable jaws;
causing said mechanism to apply a tensile force to said connector whereby the stud and connector limit the angle at which the mechanism exerts said force on the solder bonds between the integrated circuit device and substrate such that the angle is essentially perpendicular to the surface of the substrate; and observing the tensile strength of said bonds.
attaching a connector to a surface of the integrated circuit device wherein said connector includes a ball and stud;~
attaching a mechanism to the ball of the connector for applying a tensile force to said bonds at a particular angle to the substrate wherein the mechanism is attached to the ball of the connector by means of a pair of adjustable jaws;
causing said mechanism to apply a tensile force to said connector whereby the stud and connector limit the angle at which the mechanism exerts said force on the solder bonds between the integrated circuit device and substrate such that the angle is essentially perpendicular to the surface of the substrate; and observing the tensile strength of said bonds.
2. ~The method according to claim 1 wherein said integrated circuit device is a flip chip connected to said substrate.
3. ~The method according to claim 2 wherein said pair of jaws has a shape which is complementary to the shape of the ball of the connector and said jaws clamp the ball.
4. ~The method according to claim 3 wherein said mechanism is comprised of a load cell and traction apparatus.
5. ~The method according to claim 4 wherein said connector is adhesively attached to the surface of the integrated circuit device.
6. ~The method according to claim 5 wherein adhesive underfill attaches the integrated circuit device to the substrate.
7. ~A method for removing an integrated circuit device bonded to a substrate wherein the integrated circuit device is interconnected to the substrate by solder interconnection bonds between respective contact pads on the integrated circuit device and the substrate comprising:
attaching a connector to a surface of the integrated circuit device, wherein said connector includes a ball and stud;
attaching a mechanism to the ball of the connector for applying a tensile force to said bonds at a particular angle to the substrate wherein the mechanism is attached to the ball of the connector by means of a pair of adjustable jaws;
causing said mechanism to apply a tensile force to said connector whereby the stud and connector limit the angle at which the mechanism exerts said force on the bonds between the integrated circuit device and substrate such that the angle is essentially perpendicular to the surface of the substrate; and separating the integrated circuit device from the substrate with minimal damage to the substrate.
attaching a connector to a surface of the integrated circuit device, wherein said connector includes a ball and stud;
attaching a mechanism to the ball of the connector for applying a tensile force to said bonds at a particular angle to the substrate wherein the mechanism is attached to the ball of the connector by means of a pair of adjustable jaws;
causing said mechanism to apply a tensile force to said connector whereby the stud and connector limit the angle at which the mechanism exerts said force on the bonds between the integrated circuit device and substrate such that the angle is essentially perpendicular to the surface of the substrate; and separating the integrated circuit device from the substrate with minimal damage to the substrate.
8. ~The method according to claim 7 wherein said integrated circuit device is a flip chip attached to said substrate.
9. ~The method according to claim 8 wherein said pair of jaws have a shape which is complementary to the shape of the ball of the connector and said jaws clamp the ball.
10. ~The method according to claim 9 wherein said mechanism is comprised of a load cell and traction apparatus.
11. ~The method according to claim 10 wherein said connector is adhesively attached to the surface of the integrated circuit device.
12. The method according to claim 11 wherein adhesive underfill attaches the integrated circuit device to the substrate.
13. Apparatus for removing an integrated circuit device interconnected to a substrate by means of a ball grid array of solder balls bonded to respective contact pads on the device and substrate comprising:
a ball and stud connector attached to a surface of the integrated circuit device;
a holder positioning the substrate;
a mechanism for applying a tensile force wherein said mechanism includes a pair of jaws adjustably clamped to the ball of said connector whereby said jaws and said stud of the connector limit the angle at which the tensile force is exerted on the integrated circuit device and substrate such that the tensile force is essentially perpendicular to the surface of the substrate; and means including said connector, said holder and said mechanism for applying a tensile force to the integrated circuit device in a direction which is essentially perpendicular to the surface of the substrate sufficient to separate the integrated circuit device from the substrate with minimal damage to the substrate.
a ball and stud connector attached to a surface of the integrated circuit device;
a holder positioning the substrate;
a mechanism for applying a tensile force wherein said mechanism includes a pair of jaws adjustably clamped to the ball of said connector whereby said jaws and said stud of the connector limit the angle at which the tensile force is exerted on the integrated circuit device and substrate such that the tensile force is essentially perpendicular to the surface of the substrate; and means including said connector, said holder and said mechanism for applying a tensile force to the integrated circuit device in a direction which is essentially perpendicular to the surface of the substrate sufficient to separate the integrated circuit device from the substrate with minimal damage to the substrate.
14. The apparatus of claim 13 wherein said integrated circuit device is a flip chip attached to said substrate.
15. The apparatus of claim 14 wherein adhesive underfill is present between the flip chip and the substrate.
16. The apparatus of claim 15 wherein said mechanism includes a load cell and a traction apparatus.
17. The apparatus of claim 16 wherein said integrated circuit device, substrate and holder are positioned in a movable means such that said movable means is caused to move in the X and Y
directions as a result of interaction of said jaws and said stud of the connector.
directions as a result of interaction of said jaws and said stud of the connector.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2372551 CA2372551C (en) | 2002-02-18 | 2002-02-18 | Improved structure and method for testing bond strength and/or removing integrated circuit devices bonded to substrates |
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| Application Number | Priority Date | Filing Date | Title |
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| CA 2372551 CA2372551C (en) | 2002-02-18 | 2002-02-18 | Improved structure and method for testing bond strength and/or removing integrated circuit devices bonded to substrates |
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| CN111323293B (en) * | 2020-03-23 | 2022-12-06 | 天津大学 | Microelectronic device lead bonding strength test fixture under temperature environment |
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