JP2003506873A - Interconnect assembly and method - Google Patents

Abstract

(57) [Summary] An interconnect assembly and a method for creating and using the interconnect assembly. An exemplary embodiment of an aspect of the invention includes a contact element, the contact element including a base portion adapted to be attached to a substrate, a beam portion connected to and extending from the base portion. The beam portion is designed to have a geometry (eg, a triangular shape) that substantially optimizes stress over the beam portion when bent, and is adapted to be freestanding. An exemplary embodiment of another aspect of the invention includes a method for forming a contact element. The method includes forming a base portion for attaching the electrical assembly to a substrate, and forming a beam portion connected to the base portion. The beam portion is designed to have a geometry that extends from the base portion and, when bent, distributes stress approximately uniformly over the beam portion and is adapted to be freestanding. As will be appreciated, in some embodiments of the present invention, multiple contact elements are used together to form an interconnect assembly. Interconnect assemblies having resilient contact elements, and methods for making these assemblies. In one aspect, an interconnect assembly includes a substrate and a resilient electrical contact element disposed on the substrate. A first portion of the resilient contact structure is disposed on the substrate and a second portion extends away from the substrate and is movable from a first position to a second position under the application of a force. The stop structure is disposed on a surface of the substrate and on a surface of the first portion of the resilient contact structure. According to another aspect of the invention, the beam portion of the resilient contact structure has a substantially triangular shape.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION

The present invention relates to interconnect assemblies and methods for making and using interconnects, and methods for making these interconnect assemblies.

[0002]

BACKGROUND OF THE INVENTION

In the prior art, there are numerous methods for making and using interconnect assemblies, and interconnect assemblies. An interconnect assembly for making electrical interconnections with semiconductor integrated circuits is sometimes referred to as the pitch of interconnect elements.
Close spacing between interconnecting elements must be maintained. Some interconnect assemblies perform these functions throughout the life of the test and integrated circuit. One type of interconnect assembly in the prior art uses resilient contact elements, such as springs, to make temporary or permanent connections to contact pads on semiconductor integrated circuits. Examples of such elastic contact elements were filed in US Pat. No. 5,476,211 and February 26, 1998, entitled "Lithographically Defined Microelectron."
US Continuing Application No. 09 / 032,473 entitled "ic Contact Structures"
Issue and filed July 13, 1998, entitled "Interconnect Assemblies and Me.
U.S. co-pending application 09 / 114,586 entitled "thods". These interconnect assemblies use elastic contact elements that are capable of elastically bending from a first position to a second position, where the elastic contact elements exert a force against another contact terminal. . The force helps ensure good electrical contact, and the elastic contact element thus contributes to provide good electrical contact.

These resilient contact elements are generally elongated metal structures in one embodiment formed according to the process described in US Pat. No. 5,476,211. In another embodiment, the elastic contact elements are lithographically (eg, Lithograph
formed in the manner described in the aforementioned patent application entitled “Mically Defined Microelectronic Contact Structures”. FIG. 1A shows an example of a resilient contact element formed using the technique described in US Pat. No. 5,476,211. Figure 1B shows "Lithogra
3 illustrates an example of elastic contact elements formed using lithographic techniques as described in the aforementioned US patent application entitled "Physically Defined Microelectronic Contact Structures". In general, elastic contact elements are useful on any number of substrates such as semiconductor integrated circuits, probe cards, interposers, and other electrical assemblies. For example, the base of the elastic contact element can be attached to the contact terminals on the integrated circuit, or onto the contact terminals of the interposer substrate, or onto the probe card substrate, or on other substrates with electrical contact terminals or pads. Can be attached to. If one substrate with elastic contact elements is pressed towards and against the other substrate with contact elements contacting the free ends of the elastic contact elements, the free end of each elastic contact element is Positioned relative to the contact pads on the substrate, electrical contact can be made through the compression connection.

As will be appreciated in some instances, it may be desirable to secure the free end to a corresponding contact element by a task such as soldering. However, in many instances it is appropriate to be able to make contact by compression between two substrates such that the contact ends of the elastic contact elements remain free.

Elastic contact elements are useful for making electrical contact. The reason is that the elastic contacts maintain the pressure for good electrical contact, and so that they can make contact even if the height of all contact elements changes slightly. This is because the element deals with tolerances in the vertical or Z directions. However, this pressure sometimes leads to deformation or deterioration of the elastic contact element if the elastic contact element is compressed more than necessary in the vertical direction. One approach to prevent such deformation or degradation of elastic contact elements is to stop on one of the two substrates.
) Is to use a structure. In order to prevent each elastic contact element from over-bending (excessive flexing) or being destroyed as a result of the two substrates being pressed towards each other, the stop structure provides a maximum of elastic contact elements. Effectively limit the deflection. FIG. 1A shows an example of an integrated circuit having contact pads 103 and elastic contact elements 110 attached to each of the contact pads. A plurality of hit stop structures 104 and 105 are disposed on the surface of the integrated circuit 102. These stop structures prevent excessive deflection and can engage another substrate that is pressed towards the surface of semiconductor integrated circuit 102.

FIG. 1B shows an example of a lithographically defined elastic contact element on a substrate such as a semiconductor integrated circuit 120. The integrated circuit has a stop structure 150 on its surface.
including.

The lithographically-defined elastic contact structure of FIG. 1B includes an intermediate layer 123 that makes electrical interconnection with a bonding pad 122 through an opening in a passivation layer 121 on a surface of a substrate of integrated circuit 120. Then, the first metal layer 125
And a second metal layer 126 is formed to create a beam having a step 128 and a beam portion 127. In this example, the beam portion is substantially parallel to the surface of substrate 120. Then the components 181, 182, 18
A tip structure including 3, 184 and 185 is attached to the end of beam 127 to create a resilient contact structure. Further details regarding methods for making and using such lithographically defined resilient contact structures are provided in
"Lithographically Defined Microelectronic Contact Struc referenced above.
described in the US co-pending application entitled "tures" and incorporated herein by reference. While this lithographically defined elastic contact element offers the advantage that it can be formed lithographically using today's photolithographic techniques prevailing in the semiconductor industry, this type of elastic contact element has several drawbacks. Exists. For example, when a force F as shown in FIG. 1B is applied downwardly against tip 185, the action of a torsional moment occurs at the base of the elastic contact element. The action of this torsional moment occurs as a result of the compressive contact that occurs when a contact element on another substrate is pressed towards the tip 185. This torsional moment at the base tends to stress the base and along the beam portion. If the beam portion 127 is rectangular in shape, this will result in localized stress in the portion of the beam near the base of the resilient contact element. Although the stop structure 150 provides some assurance that some level of stress will not be exceeded, there are still some areas of concentrated stress as a result of the rectangular shape that must be considered when designing the elastic contact elements. Exists. In general, it is necessary to increase the amount of material used at a particular location of a resilient contact element by considering these areas of concentrated stress. This consequently limits the ability to design the elastic contact element to be smaller. This is particularly undesirable because the size of the structures on the semiconductor integrated circuit is gradually decreasing.

[0008]   Therefore, it is desirable to provide an improved elastic contact element.

[0009]

[Outline of the Invention]

The present invention provides an interconnect assembly, and methods for making and using the interconnect assembly. An exemplary embodiment of aspects of the present invention includes a contact element that includes a base portion adapted to be attached to a substrate, a beam portion connected to and extending from the base portion. The beam portion has a beam geometry selected to optimize stress. In one embodiment, the shape of the beam portion is substantially triangular and adapted to be self-supporting.

Exemplary embodiments for another aspect of the invention include a method for forming a contact element. The method includes forming a base portion for attaching to a substrate of an electrical assembly and forming a beam portion connected to the base portion. The beam portion has a beam geometry selected to optimize stress. The beam portion extends from the base portion, and in one embodiment its shape is generally triangular and adapted to be self-supporting.

In another example of the invention, the resilient contact element comprises a base portion attached to the substrate,
And a beam portion connected to and extending from the base portion thereof. The beam portion is adapted to be self-supporting to yield any desired size constraints on the beam portion and stress parameters that are substantially optimized for the desired spring constant (eg, spring ratio) for the elastic contact element. With the selected beam geometry. In one embodiment of this example, the geometry is selected to improve the performance of the resilient contact element over a cantilever beam having a substantially constant cross-sectional area. For example, performance may be improved by distributing the stress substantially evenly throughout the beam as it flexes.

As will be appreciated, in some embodiments of the invention, multiple contact elements are used together to form an interconnect assembly.

Also, various other assemblies and methods are described below in conjunction with the following drawings.

The present invention provides an interconnect assembly and methods for making and using the interconnect assembly. In one example of the present invention, an interconnect assembly includes a substrate and a contact element disposed on the substrate. The first portion of the contact element is adapted to be self-supporting and further adapted to be movable from a first position to a second position when a force is applied to the first portion of the contact element. ing. The interconnect assembly further includes a stop structure disposed on the second portion of the contact element. The stop structure partially defines a second position of the contact element. In one particularly exemplary embodiment of the invention, the substrate comprises a semiconductor integrated circuit. A force is applied when another contact element is mechanically and electrically contacted with the contact element. The stop structure defines a second position that defines the maximum bending of the contact element.

According to another example of the present invention, an interconnect assembly is formed by a method of placing a contact element on a substrate, wherein the first portion of the contact element is self-supporting and the force contact is When applied to the first portion of the element, it can move from the first position to the second position. The method also includes disposing an abutment structure on the second portion of the contact element, the abutment structure defining a second position.

As will be appreciated, multiple contact elements of the present invention can be used to form an interconnect assembly.

An example of a method according to another aspect of the invention includes forming a self-supporting elongate resilient contact element with a mold. In this way, the mold is pushed down into the deformable material, i.e. the mold determines the shape of at least part of the self-supporting elongate elastic contact element. This portion of the self-supporting elongate elastic contact element is then formed on the deformable material.

[0018]   Various other assemblies and methods are described below in conjunction with the figures below.

The invention is illustrated by way of example and not limitation in the accompanying figures. In the attached drawings,
Like reference numbers indicate like elements.

[0020]

[Detailed description]

The present invention relates to interconnect assemblies and methods, and more particularly to interconnect assemblies and methods for making mechanical and electrical contacts to contact elements on an integrated circuit. The following description and drawings are illustrative of the invention and are not to be construed as limiting the invention. Numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, in other instances, well-known or conventional details have not been described in order not to unnecessarily obscure the details of the invention.

FIG. 2A shows a cross-sectional view of an elastic contact element that is an example of an embodiment of the present invention. Figure 2
The elastic contact element 201 of A includes a first metal layer 209 and a second metal layer 210 formed at an oblique angle with respect to the surface of the substrate 202. The first metal layer 209 is selected for its elastic properties in order to impart elasticity to the elastic contact element, and the second metal layer 210 is selected for its conductive property in order to provide good conductivity for the elastic contact element. Can be done. Substrate 202 is generally a semiconductor substrate that includes an integrated circuit, the integrated circuit including various terminals, one of which terminals is contact pad 207 of FIG. 2A.
Indicated as. Typical terminals carry input / output signals, power or ground. The contact pad 207 is coupled to the internal circuit element in the integrated circuit via the wiring layer 206. The wiring layer 206 is disposed in the insulating layer 204, and the wiring layer 206 and / or
Alternatively, the insulating layer 204 is covered by the passivation layer 205 on the upper surface of the substrate 202. Layer 203 can be an insulating layer, or a polysilicon layer, or any other layer known and used in integrated circuits. The contact pad 207 is electrically and mechanically coupled to the shorting layer 208 disposed on the contact pad 207.
Metal layers 209 and 210 are formed on contact pad 207 and on shorting layer 208 with the respective bases of metal layers 209 and 210 electrically connected thereto. Conductivity between the contact pads 207 occurs through the shorting layer 208 and the metal layer 209 and finally to the metal layer 210. As will be appreciated, the elastic contact element 201 of FIG. 2A.
Can also be used in other types of interconnect assemblies, such as probe card assemblies or interposers or other connection systems, where the elastic contact elements are self-supporting from the conductors of the substrate 202 to the elastic contact elements 201. Conductivity can be provided up to the tip, which is the mold. As can be seen from FIG. 2A, this elastic contact element is self-supporting and elongated. Also, in the embodiment shown in FIG. 2A, the elastic contact elements are inclined with respect to the surface of the substrate 202. In the preferred embodiment, this tilt is generally at an oblique angle to the surface of the substrate 202.

In a particular embodiment of the invention, the elastic contact element 201 may be formed such that the beam portion extending from the base is substantially triangular in shape. This is shown in Figure 3A.
Is shown in a plan view of the elastic contact structure 301 shown in FIG. That is, the beam portion 215 of the elastic contact element 201 may be formed to have a substantially triangular shape, such as the beam portion 303 of the elastic contact element 301 shown in FIG. 3A. Resilient contact element 301 includes a base 302 attached to the beam portion and a tip 304 for making electrical contact with another interconnect terminal / pad. FIG. 3B shows in plan view a resilient contact element 301A with a beam portion 303A having a substantially triangular shape.
Another example of The beam portion 303A is attached to the base 302A and the tip 3
Including 04A.

FIG. 2B illustrates another embodiment of the present invention, in this case a stop structure 211.
Are arranged on the upper surface of the substrate 202 and on the part of the base 214 of the elastic contact element 212. In this embodiment shown in FIG. 2B, the substrate 202 includes similar components 203, 204, 205, 206, 207, 208, 209, and 210, as in the interconnect assembly shown in FIG. 2A. . The elastic contact element 212 comprises two metal layers 209 and 210, with the base portion 214 of both metal layers resting on the top surface of the shorting layer 208 and the beam portion 215 of the substrate 202. It is formed to extend from the end of the base portion 214 at an oblique angle with respect to the surface. The beam portion of the elastic contact element 212 can have other shapes, such as a triangular shape, or a rectangular shape or any other known shape that can be used for elastic contact elements. However, in one embodiment,
Beam 215 preferably has a triangular shape, such as beam 303 of FIG. 3A or beam 303A of FIG. 3B. A stop structure 211 is formed on the base portion 214 of the resilient contact element 212. The stop structure 211 determines the maximum amount of deflection of the elastic contact element 212 when the elastic contact element 212 is pressed toward the surface of the substrate 202 by the force F, thereby causing excessive bending of the elastic contact element (eg, , Excessive deflection). If another contact element, such as a contact pad on another substrate, is pressed towards and against the tip 216 of the resilient contact element 212, the upper surface of the stop structure 211 will correspond to the other substrate. To prevent the other substrate from being pressed further toward the surface of the substrate 202. That is, the amount of movement between the two substrates is limited by the stop structure 211, so that the stop structure 211 defines or determines the minimum distance between the substrates and thus the maximum bending of the elastic contact element 212. To do. Further details relating to the advantages of stop structure and its use are described in co-pending application Serial No. 09 / 032,473 filed July 13, 1998 and entitled "Interconnect Assemblies and Methods". `` Interconnect Assemblies and Method
This co-pending application entitled "s" is incorporated herein by reference.

FIG. 2C illustrates a simplified example of an elastic contact structure having a stop structure, according to an example embodiment of the present invention. The interconnect assembly 231 includes a substrate 232 having a wiring layer 237 embedded therein. The wiring layer 237 is electrically coupled to the base portion 235 of the elastic contact element 234. The base portion 235 is the beam portion 2
36. Generally, the beam portion 236 and the base portion 235 are integrally formed in one step, as described below. Both the base portion 235 and the beam portion 236 include multiple conductive layers such as layers 208, 209, and 210 as shown in FIGS. 2A and 2B. As in the embodiment shown in FIGS. 2A and 2B, the beam portion 236 of the resilient contact element 234 extends from the end of the base portion 235 at an oblique angle to the surface of the substrate 232. . The hit stop structure 233 is
Located on and attached to the surface of the substrate 232, and the base portion 2
Located on and attached to the upper surface of 35. As shown in FIG. 2C, the ends of the wiring layer 237 are mechanically attached to and electrically coupled to the base portion 235. The hit stop structure 233 is provided on the upper surface of the substrate 232.
In addition, since it is mechanically attached to the upper surface of the base portion 235, the base portion 2
At 35 (eg, contact pads such as contact pad 411 shown in FIG.
Any torsional moment produced (as a result of the force acting against the tip of the beam portion 236 when pressed towards the surface of 32) is not limited to the base portion 235 and the beam portion 236 but to the stop structure. Balance through various parts of the overall structure, including 233. As will be appreciated, in an alternative embodiment, the stop structure is located only on the base portion 235 and not on the substrate 232, and the stop structure prevents any torsional moments created on the base portion. Helps to balance.

Some dimensions are also noted in FIGS. 2C and 3A to provide an example of the present invention. As will be appreciated, the following examples are merely illustrative of the invention and are not intended to limit the invention, but are exhaustive examples of possible structures within the scope of the invention. Nor was it intended to provide the set. One case(
In FIG. 4, for example), the distance c represents the maximum displacement or deflection of the elastic contact element. In one example, this is about 3 μm. This distance c
Is generally less than the element compliance, which is the total amount of deflection or bending available before the elastic contact element "breaks." This distance in one example (see, eg, FIG. 4) is from the point where there is no force being pressed against the tip to the point where the tip is pressed and flush with the top surface of the stop structure 233. Indicates the amount of movement of the tip. Examples of these two states are shown in FIG. 2C where no tip force is applied, and force is applied to the tip so that the surface of one substrate 410 contacts the top surfaces of the stop structures 406 and 407 vertically. Shown in FIG.

As shown in FIG. 2C, the thickness t represents the overall thickness of the elastic contact element in a vertical cross section of the elastic contact element. Generally, this thickness is about the same across any particular cross-section, but, as will be appreciated, in alternative embodiments, this thickness can be different for a particular cross-section. Also, as will be appreciated, FIG. 2C depicts a simplified example of resilient contact element 234, the base portion and beam portion of which may be made of one or more conductive layers. In an exemplary embodiment, the thickness is about 25 μm and the total height h of the resilient contact element 234 is about 150 μm (about 6 mils).

For some embodiments, the spring rate of the resilient contact element is about 0.4-0.8 g /
μm (about 1-2 g / mil), where the spring ratio “k” represents the spring force divided by the spring displacement (k = F / x). As will be appreciated, if the geometry and material are selected for a particular elastic contact element, the spring thickness generally determines the spring ratio. Thickness is a major factor in determining stress at maximum deflection, and thickness depends on the material of the elastic contact element. As will be appreciated, some design points or goals are established for the resilient contact element such that the maximum stress on the resilient contact element is less than the desired amount. The use of a stop structure 233 helps control the maximum amount of stress and also helps reduce stress at maximum deflection by suppressing torsional moments at the base portion of the resilient contact element. This can be seen from FIG. 4, which is described in more detail below.

The resilient contact element can have a curved shape that provides some of the advantages described herein in connection with FIGS. 2D, 2E, 2F, 2G, and 2H.
FIG. 2D shows a cross-sectional view of a curved elastic contact element 234A, which elastic contact element 2
34A includes a base portion 235A, a tip 239A, and a curved beam portion 236A. The base portion 235A is electrically coupled to the wiring layer 237. The bend of the beam section can be used to compensate for bending of the beam section during deflection of the elastic contact element. This compensation is shown in the comparisons shown in Figures 2E, 2F, 2G, and 2H.

The stop structure 233 includes a base portion 235A and a substrate 23 (if desired).
Placed on top of two.

2E and 2F respectively show a resilient contact element which is initially straight, before and after deflection of the resilient contact element. When force F is applied to the tip of beam portion 236, the beam portion bends as shown in FIG. 2F, which causes the tip to tilt away from the surface of the contact point on another substrate, resulting in a shallow angle θ ₁ . It occurs between the line representing the surface of the contact point and the line passing through the end of the beam section. These lines are shown in FIG.
Shown in. This shallow angle tends to be undesirable for making good electrical connections.

2G and 2H respectively show an elastic contact element that is curved from the beginning, before and after the elastic contact element is deflected. When force F is applied to the tip of beam portion 236A, this beam portion tends to be straight, as shown in FIG. 2H. As a result of this straightening, the angle θ ₂ (the angle between the line representing the surface of the contact point and the line passing through the end of the beam section) is not as shallow as the angle θ ₁ and thus a better electrical contact. Is realized by using curved elastic contact elements.

3A and 3B show another aspect of the invention, in which the beam portion of the resilient contact element has a substantially triangular shape. The elastic contact element 301 includes a base 302 that corresponds to the base 235 of FIG. 2C. Beam portion 30 shown in plan view in FIG. 3A
3 corresponds to the beam portion 236 of FIG. 2C. Beam portion 303 includes a tip 304 that corresponds to tip 239 of resilient contact element 234 of FIG. 2C. Beam part 303
The triangular shape of helps to more evenly distribute the stresses created when the tip 304 is pressed towards the surface on which the base 302 rests, across the entire beam (eg, tip to base). This allows the use of less material in the beam 303 and further obtains good performance with respect to the elastic contact element, such as the ability to withstand continuous stresses throughout the service life of the elastic contact element. Will be possible. FIG. 3B shows an elastic contact element having an alternative triangular shape.

FIG. 3C shows a resilient contact element 31 having a substantially triangular shape in plan view.
Another example of 0 is shown. In this case, the triangle is modified at the electrical contact end 312 to include a rectangular portion. The beam portion of the resilient contact element 310 is generally self-supporting, is flexible when depressed and includes a triangular portion 314 and a rectangular portion 312. The triangular portion is attached to the base portion 316. The beam portion may be attached to the base portion 316 at an oblique angle and lithographically formed with the base portion 316. It can be seen that the cross-sectional areas taken at the different cross sections 318 and 320 are different, which also applies to the contact elements 301 and 301A.

The beam portion geometry of these substantially triangular shaped resilient contact elements provides improved performance over cantilever beam springs having a substantially constant cross-sectional area. Other shapes may be selected to provide improved performance over cantilever beam springs having a substantially constant cross-sectional area. The substantially triangular shape gives good behavior of the spring under stress, allowing the spring to be more tightly packed (small pitch). FIG. 3D is shown in FIG. 3C on a substrate 322 (which may be an integrated circuit or an electrical connection substrate that may be used to test or make a permanent connection to the integrated circuit). Closely packed (eg, 1
3 shows an array of 0 μm pitch) elastic contact elements 310A, 310B, 310C, 310D. The geometry of the beam portion depends on the given size constraints (eg size as determined by packing the contact elements) and the given spring ratios and any / desired compliance with the contact elements. With respect to quantity, it is chosen to give the optimum stress behavior. Smaller sizes, as determined by size constraints for a given spring rate and a given compliance, tend to place more stress on certain points of the cantilever beam with constant cross-sectional area. On the other hand, a substantially triangular shaped elastic contact element allows for tighter packing (see eg FIG. 3D) and smaller size, under stress for the same spring ratio and given compliance. Allows good behavior of.

In an exemplary embodiment, dimensions l ₁ and l ₂ are about 225 μm (about 9 mils) and dimension l ₃ is about 675 μm (about 27 mils). An array of these elastic contact elements is formed on a substrate, such as an integrated circuit or a contactor for contacting the integrated circuit, resulting in a densely packed array of such elastic contact elements. . FIG. 8B shows an example of the layout of the array on the substrate 803. In one embodiment, these elastic contact elements can be packed very densely so that the distance between corresponding points (eg, bases) on adjacent contact elements is 750μ.
m (30 mils) and even as small as about 2.5 μm (0.1 mils). FIG. 3D shows another example of an array of densely packed (close pitch) elastic contact elements.

Practical use of the interconnect assembly according to one embodiment of the invention will now be described with reference to FIG. The substrate 402 includes a resilient contact element 403 having a beam portion 405 and a base portion 404. In this particular implementation, the beam portion 405 may have a triangular shape or may have another shape, such as a rectangular shape. Two hit stop structures 406 and 407 are attached to the top surface of substrate 402, and hit stop structures 406 are also attached to the top of base 404. The base 404 makes mechanical and electrical contact with the wiring layer 415 in the substrate 402. As will be appreciated, the substrate 402 can be a semiconductor integrated circuit, or it can be a passive wiring layer such as a probe card or interposer structure. As shown in FIG. 4, another interconnect assembly 410 having contact pads 411 makes electrical and mechanical contact with the tip of beam portion 405. The entire assembly 401, including substrates 410 and 402, are pressed together to ensure a good compression connection between the tip of beam portion 405 and the surface of contact pad 411. The contact pads 411 make electrical contact with other components via the wiring layer 412 of the substrate 410. As the substrate 410 is pressed toward the substrate 402, the tip of the beam portion 405 performs a wiping action that occurs laterally along the direction of arrow 413 as shown in FIG. This improves the electrical contact between the beam portion 405 and the pad 411, and thus improves the electrical contact between the wiring layers 415 and 412. As will be appreciated, FIG. 4 illustrates a situation in which the substrate 410 is fully pressed against the substrate 402, and thus there is no possibility of further “movement” (they cannot come closer). This represents the maximum deflection of the elastic contact element 403. However, during use of the assembly 401, the elastic contact element 403
The two substrates may not be in contact because they are curved with less than the maximum deflection while still achieving an acceptable conductivity between the beam 405 and the pad 411. The final assembly of substrates 402 and 410 may be accomplished by mechanical force (eg, F _M shown in FIG. 4) and / or by an adhesive (not shown) applied between the surfaces of substrates 402 and 410. Can be held in place by a variety of techniques, including with maximum deflection of the elastic contact element, or less than maximum deflection.

A method of making an interconnect assembly will now be described. This method represents a particular example of the invention, and as will be appreciated various other methods may be employed using alternative techniques and procedures. The method 500 shown in FIG. 5 begins at step 502.
This particular method involves redistribution of contact pads having a particular configuration and geometry with respect to another set of contact pads where the redistribution layer has a different configuration and / or geometry. Assumed to be applied for distribution. As will be appreciated, in other situations a redistribution layer may not be needed and the contact element of the present invention may be terminated directly to the wiring layer of the substrate without the redistribution layer (see Figure 6E).
At step 502, a passivation layer, such as a polyimide layer, is added to the top surface of the substrate with the contact pads disposed on the top surface. In one embodiment, the polyimide layer can be spun onto the top surface to evenly cover the surface. The passivation layer is then patterned using conventional photolithography to form openings in the passivation layer above the contact pads on the surface of the substrate. These contact pads can be the input / output interconnects of a semiconductor integrated circuit, or they can be passive or active substrates, or substrates such as probe cards or interposers or other interconnect assemblies. It can be the upper contact terminal.

FIG. 6A illustrates an interconnect assembly 60 having contacts 604 on the top surface of a substrate 602.
1 is shown. The wiring layer 603 is disposed in the substrate 602 and provides electrical conductivity between the pad 604 and another component such as a circuit in the substrate 602 or a contact terminal in another position on the substrate 602. As will be appreciated, wiring layer 60 is generally
3 is placed in the insulating layer of the substrate 602. Also, as will be appreciated, the portion shown in FIG. 6A is the top of the substrate 602 and other wiring layers and / or circuit elements are
It is located below this part shown in FIG. 6A. Step 502 for passivation layer
, And is shown as passivation layer 605 in FIG. 6A.
This passivation layer is patterned to create openings 606 above contact pads 604.

In step 504 of FIG. 5, a shorting layer is applied over the surface of passivation layer 605 and over the surface of contact pad 604. A conventional photoresist is then applied over the entire surface of the shorting layer, and the photoresist is patterned using conventional photolithography to form an opening above the shorting layer. The shorting layer can be formed from copper, titanium, or titanium / tungsten, or other suitable metallization, and can be sputtered onto the surface of layer 605.
An example of the resulting interconnect assembly is shown in FIG. 6B after step 504.
The interconnect assembly 608 of FIG. 6B includes a passivation layer 605 and a shorting layer 609 disposed over the contact pads 604. The contact pad and the shorting layer 609 are conductive. The patterned photoresist layer 610 includes an opening 611 over a portion of the shorting layer. This opening is used to form a redistribution layer where the layout of contact pad 604 will be redistributed to another location. This may help relax the interconnect pitch achieved at the end of the process in which the elastic contact elements are formed on the substrate 602. FIG. 6C shows a plan view of the redistribution wiring layer. 6C shows a pattern of photoresist 610 with holes formed in patterned photoresist 610, among others. This hole exposes a portion of the shorting layer 609, as shown in FIG. 6C.

In step 506 of FIG. 5, a redistribution layer is added over the shorting layer. The redistribution layer can be applied by electroplating (or electroless plating) a metal layer (eg, copper or gold) onto the exposed portion of the shorting layer, in which case
The short circuit layer is used as a cathode in the electroplating process. As will be appreciated, on a typical substrate there will be many such redistribution traces formed on the surface of the substrate in each of the patterned openings of patterned photoresist 610. Exists.

After the redistribution layer is applied, the patterned photoresist layer 610 is removed, and the shorting layer exposed after removing the patterned photoresist layer is also removed. The redistribution layer can be used as a mask to remove the shorting layer. Thus, in this case, one metal (eg, Ti / W) can generally be used to form the short-circuit layer, and another metal (eg, Cu) can be used to form the redistribution layer. , So that the redistribution layer remains intact while the shorting layer is removed by etching or under the action of a solvent or etchant resisted by the metal of the redistribution layer. The result of step 506 is shown in FIG. 6D. It can be seen that the patterned photoresist layer 610 has been removed, and the unprotected portions of the shorting layer 609 have also been removed, leaving the structure of the interconnect assembly 614 shown in FIG. 6D. The shorting layer 609 requires subsequent electroplating (eg,
In an alternative embodiment (since layer 642 has electrically isolated regions due to layer openings), shorting layer 609 is not removed in step 506, but step 514.
Is removed at.

As will be appreciated, steps 502, 504, and 506 are used to form a plurality of redistribution traces, such as redistribution layers, on the surface of substrate 602. This is required in some cases where the contact pad is designed to be connected to an interconnection mechanism in addition to the elastic contact element, or is desirable for other reasons. Also, as will be appreciated, in some instances, such a redistribution layer is not necessary and thus elastic contact elements may be fabricated on the vias or other contact elements on the surface of the substrate. An example of a via is shown in FIG. 6E, where posts 623 of conductive material are on top surface 6 of substrate 621.
Exposed at 22. The conductive post 623 is formed on the wiring layer 6 in the substrate 621.
Electrically coupled to 23. In general, the material surrounding the wiring layer 624 and the posts 623 is an insulating layer. The substrate 621 is typically part of a semiconductor integrated circuit, but other interconnect assemblies such as printed wiring boards, interposers, etc. can be used. The processing from structure 620 shown in FIG. 6E is similar to the processing of structure 614 shown in FIG. 6D of steps 508-516 of FIG. That is, the structure 620 is processed in step 50.
It need not be processed at 2, 504, and 506, but may be processed at steps 508, 510, 512, 514, and 516, such as structure 614 shown in FIG. 6D.

The next step in method 500 is step 508, where photoresist is applied and patterned to include beveled openings on the photoresist. The resulting interconnect assembly structure is shown as structure 631 in FIG. 6F. Photoresist 633 is applied and patterned to form an opening 632 having a slope 634 over a portion of the opening. The opening is at least partially disposed over a portion of conductive layer 615. As will be appreciated, generally the flat portion of this opening is utilized to assemble the base for the resilient contact element and the beveled portion 634 is used to assemble the beam portion of the resilient contact element.

There are a number of known techniques in the art for forming openings in photoresist that include slopes on the photoresist. For example, a gradient can be formed on the photoresist using a grayscale mask with a relatively continuous opacity gradient from transparent to black. Other methods can be used to provide tapered sidewalls, such as gently reflowing the masking material to taper the sides of the opening, the intensity of the exposure, or the exposure time for the masking material. Controlling, changing the distance of the mask from the masking layer during exposure, once through the mask with small transparent areas and twice separately with a mask with larger transparent areas. This includes exposing the masking layer, or a combination of these methods. A method for forming an opening having tapered sidewalls is:
"Lithographically Defined Microelectronic Contact Struc referenced above.
Further described in the United States co-pending application entitled "tures", which co-pending application is incorporated herein by reference. Also, a method of stamping a deformable material with a die to form an elastic contact element using the deformable material is described below.

After step 508, step 510 adds a seed layer and applies photoresist and patterns to form triangular openings (in one example embodiment) for the resilient contact elements. Including that. The seed layer 642 shown in FIG.
It can be applied over the surface of photoresist 633 by conventional sputtering of a suitable metal layer (eg Cu or Ti or Ti / W). If the shorting layer 609 is removed in step 506, the seed layer 642 provides a continuous conductive surface except for the sidewalls 645, but if the shorting layer 609 is retained in step 506, the seed layer 642 has its entire surface. Can be electrically discontinuous across.

In one preferred embodiment, care is taken during the sputtering process to avoid or prevent the sputtered material from remaining on the vertical sidewalls 645,
As such, the openings in photoresist 633 do not receive a continuous layer of seed material. In another example, the sputtering covers some or all of the vertical sidewalls 645. In this embodiment, subsequent masking and patterning steps cover some or all of the sputtered sidewalls so as to minimize or prevent subsequent deposition of additional conductive material on the vertical sidewalls. Is generally preferred.

After the seed layer 642 is applied, a photoresist layer is applied over the surface of the seed layer 642, as shown in FIG. 6G. Then, as shown in FIG. 6G,
The photoresist layer is patterned to form openings 643 in the patterned photoresist layer 646. The opening is used to deposit at least one conductive layer, such as a metal layer, on top of the exposed portion of seed layer 642. This includes depositing the beam portion of the elastic element on the sloped portion 644 of the exposed portion of the seed layer 642. Subsequent plating or other deposition steps are generally desired to fill the contours of the final shape in the usual manner. In a preferred embodiment, the seed layer is predominantly deposited at the bottom of the openings in the photoresist, especially the photoresist from the masking and patterning steps of step 510.

FIG. 6G shows an example of structure 641 after completion of step 510. FIG. 6H shows a plan view of a part of the structure 641. Notably, a portion of the structure 641 over the opening 643 is shown in the plan view of FIG. 6H. It can be seen that the patterned photoresist layer 646 exposes only a portion of the seed layer 642. In the particular example shown in FIG. 6H, the base portion of the resilient contact element has an exposed seed layer 642.
Seed layer 6 formed on the rectangular portion of the substrate, exposing the beam portion of the elastic contact element.
It is formed in a triangular portion of 42. This results in an elastic contact structure having beam portions that are substantially triangular in shape, such as the elastic contact structure shown in FIG. 3A. As will be appreciated, in other embodiments, other shapes, such as rectangular shapes, may be used for the beam portion, and thus a plan view of such a structure may appear different from FIG. 6H. Ah

After structure 641 is formed by completing step 510, step 512 is performed on structure 641 to achieve structure 651 shown in FIG. 6I. Step 51
2 generally includes, in one exemplary embodiment, electroplating a first metal layer, and then electroplating a second metal layer into the triangular opening. In an alternative embodiment,
The openings can have different shapes (eg, rectangular shapes to form rectangular beam portions), and alternative methods can be used to deposit one or more conductive layers into the openings. The seed layer 642 (or the underlying shorting layer that is retained if the seed layer 642 is electrically discontinuous across its surface) is used as the cathode in the electroplating process, as shown in FIG. 6I. Metal layers 652 and 653 are plated over the exposed portions of the shorting layer in openings 643. In one embodiment, the first metal layer 652 is selected to provide sufficient mechanical elasticity so that the final elastic contact element comprises sufficient elasticity for its intended operation.
In a particular embodiment, nickel-cobalt alloys can be used. The alloy can be 70% nickel and 30% cobalt. This alloy may be heat treated as described in co-pending application 08 / 931,923, filed September 17, 1997. The second metal layer 653 is generally selected to provide good conductivity, and can be, for example, gold, or rhodium, or a palladium cobalt alloy. Various other layer configurations and material compositions are described further below. As will be appreciated, numerous types of other materials can be selected for these metal layers, and these materials are described in US Pat. No. 5,476,211.

After one or more conductive layers have been deposited into the openings 643, the structure 651 is complete and step 514 is performed to remove the photoresist layer and the sputtered shorting layer, shown in FIG. 6J. The structure 661 is realized. Remove the photoresist layer,
Alternatively, a conventional solvent or dry etching method for stripping is utilized to remove the shorting layer using a solvent or etchant that selectively removes the sputtered seed layer, such as seed layer 642. Therefore, the patterned photoresist layer 646 and the patterned photoresist layer 636 are removed. Also, substantially all of the seed layer 642 is removed, leaving the portion of the layer underneath the base of the resilient contact element 662, as shown in FIG. 6J. As a result, FIG.
Resulting in a structure that can then be used as an interconnect assembly (if there is no stop structure) or with the stop structure after it has been formed in step 516. .

Step 516 is performed on structure 661 if it is desired to form a stop structure (stop structure) on the interconnect assembly. This process is a commercial SU
Photoimaging materials such as negative photoresist such as 8 (Photo-imageable mat
erial: PIM) over the entire surface of structure 661. This PIM
It is desirable that the is uniformly applied to a uniform thickness and relatively flat, preferably as flat as possible. Therefore, a PIM structure such as a photoresist structure 661
It is preferred to spin coat onto the surface of the. After spin-coating the photoresist, care should be taken to apply sufficient photoresist material such that the photoresist covers the base of the resilient contact element 662. That is, the height of the final structure provided by this spin-coated photoresist should be greater than the height h of the base of the resilient contact element. In general, the height of the final structure should also be less than the height of the free-standing contact points of the elastic contact element. In general, the difference between the height of the free-standing contact point and the height of the final stop structure provided by this photoresist should be made to be the maximum amount of deflection c described above.

After the appropriate amount of photoresist has been applied, the photoresist layer is exposed and developed to achieve the desired height of the photoresist relative to the height h of the base of the elastic contact element (s). To be done. The photoresist layer is exposed through the mask 690 so that the areas around and below the beam portion of the elastic contact element remain unexposed and the adjacent areas are exposed. The PIM in one embodiment is a negative photoresist (which means that the unexposed areas due to the mask 690 are developed to remove the photoresist (and leave a portion of the exposed photoresist)). 6K), an opening 674 is formed as shown in FIG. 6K. In one embodiment, the mask 690 can be a rectangular mask and provides sufficient clearance for the beam portion moving up and down within the aperture 674. In an alternative embodiment, the mask 690 can be a triangular mask designed to fit around the triangular shape of the beam portion of the elastic contact element when the elastic contact element is triangular beam shape. Thus, the structure 671 shown in FIG. 6K results from step 516, resulting in a stop structure 672 attached to the base portions 652A and 653A of the resilient contact structure, the conductive layer 615, and the passivation layer 605. A portion 673 of the stop structure 672 is attached to and on the base portions 653A and 652A.

FIG. 6L shows a plan view of the structure shown in FIG. 6K. FIG. 6L shows a mask 690.
Is considered to have a triangular shape instead of a rectangular shape. Thus, the openings in patterned photoresist 672 that form the stop structure are triangular openings that conform to the shape of the triangular beam section and move up and down within opening 674. Provide ample clearance. In FIG. 6L, the base 653A is shown lying underneath the stop structure 672. In an alternative embodiment, a rectangular mask 690A is used over the beam portion at the exposure step 516 to form the rectangular opening 674A shown in FIG. 7B. This rectangular opening in the stop structure 672 can be used for a triangular beam section as shown in FIG. 7B, or for a beam section that is rectangular.
As will be appreciated, whichever mask shape is selected, the stop structure 67
Sufficient clearance should be provided for the beam sections moving up and down in the two openings.

FIG. 7A illustrates a cross-sectional view of a plurality of resilient contact elements, the resilient contact elements including a perimeter of the base of the resilient contact elements and a stop structure disposed thereon.

FIG. 8A shows an alternative embodiment of forming a resilient contact element that includes three parts: a base portion, a beam portion, and a contact portion. The contact portion serves to contact the second electronic component, as described in detail above. Further, the contact portion is used to mount the tip structure onto the end of the beam. Examples of various tip structures and methods for attaching the tip structures are provided in "Lithographically Defined Microelectr
U.S. co-pending application entitled "onic Contact Structures", and U.S. co-pending application 08 / 819,464 filed March 17, 1997. In particular, FIG. 8A illustrates the structure after step 512 (without steps 502, 504, and 506 because this assembly does not utilize a redistribution layer), after a stage in the fabrication process of the interconnect assembly. . The structure of FIG. 8A includes conductive posts 604A disposed in the insulating layer of substrate 602A. The conductive posts are electrically coupled to seed layer 642A, which corresponds to seed layer 642 in FIG. 6I. Seed layer 642A is sputtered on patterned photoresist layer 633A, which photoresist layer includes openings having sloped sidewalls. The sputtered seed layer 642A is used to electroplate two metal layers to form the structure shown in FIG. 8A. Electroplating is performed through patterned photoresist mask 646A, which corresponds to patterned mask 646 of Figure 6I. After the plating process is performed, each metal layer includes a base portion such as base portion 653A, a beam portion such as beam portion 653B, and a contact portion such as contact portion 653C. After the electroplating step is completed, step 514 is performed to remove the photoresist layers 646A and 633A, then the sputtered seed layer 642A is removed, leaving the portion underneath the base 653A. The resulting structure can be used as a resilient contact element in an interconnect assembly without a stop structure, or as described above, performing step 516 can form a stop structure. .

FIG. 8B shows an array 800 of two elastic contact elements 801 and 802 on the surface of a substrate 803. FIG. 8B is a perspective view and it will be appreciated that generally a majority of resilient contact elements may be disposed on the surface of a substrate such as a semiconductor integrated circuit or other interconnect assembly. The elastic contact element shown in FIG. 8B is similar to the type shown in FIG. 8A. The reason is that they include contact portions at the ends of the beam structure. A beam structure, such as beam portion 653B, is substantially triangular in shape and is attached to base portion 653A. The contact portion 653C has another contact terminal (
For example, it may itself act as a contact tip for contacting a contact terminal 411) as shown in FIG. 4, or attach a tip structure as described above onto a support portion 653C to provide a tip structure. be able to. Also, the structure can be adapted for permanent connection to the contact pads (eg, by use of solder or conductive epoxy).

9A, 9B, 9C, and 9D illustrate another method for forming a resilient contact element in accordance with the present invention. The mold 901, which may be photolithographically formed, comprises at least a portion of the resilient contact element that is a "negative" profile. Mold 90
1 is shown in FIG. 9A, before being used in the deformable material 903, the deformable material 9
03, the deformable material is disposed on the substrate 905 including the wiring layer 906. The substrate 905 and the wiring layer 906 are similar to the structure shown in FIG. 6E. The deformable material 903 can be any number of materials such as PMMA (polymethylmethacrylate), which is deformable when pressed or stamped with a mold and which also forms a resilient contact element. Can be used to undergo spring metal deposition and then removed. In the embodiment shown in FIG. 9A, the mold 90
1 includes a base portion 901B and an inclined portion 901A. As will be appreciated, other geometric shapes can be used, including a rotated “L” shape (eg, ¬), or the shape that results in the curved beam portion of FIG. 2D.

As shown in FIG. 9B, the mold 901 is pressed into the deformable material. To deform the deformable material to achieve the desired shape, a few pounds (1 pound =
A pressure of about 0.45 kg) is required (depending on the type of deformable material). This causes the base portion 901B to substantially contact the surface of the substrate 905, leaving a thin region of deformable material and separating this surface from the base portion 901B in one exemplary embodiment. The mold 901 is pressed into the deformable material and takes the actual shape from the opposite shape of the mold, as shown in Figure 9B. The mold 901 is then separated from the substrate 905 and the deformable material 903, leaving the structure shown in FIG. 9C. The structure is then "cleaned" to remove the thin areas of deformable material 903A that were beneath the base portion 901B. The structure is cleaned using an isotropic etch to remove all exposed deformable material, but not the substrate 905. This etch is performed for a period of time sufficient to remove all of the thin area 903A, but leaves most of the rest of the deformable material 903, including the beveled portion 903B. The structure may be cleaned using plasma etching or reactive ion etching to remove thin areas 903A, or using laser ablation etching. The structure after removal of thin area 903A is shown in FIG. 9D and the structure is further processed (eg, steps 510, 5 of FIG. 5).
12, 514, and 516) prepared and shaped deformable material is used to form the resilient contact element.

There are many methods for forming the mold. The mold can be formed from a silicon wafer by laser etching the surface of the wafer. Optical imaging material (which can be cured) to define the mold by photolithography
A glass-backed substrate with is used with a mask. To define the mold, the silicon carbide wafer can be machined by using electrical discharge machining techniques on the silicon carbide wafer. A mold is formed by forming the opposite of the mold with a wax (eg, paraffin), sputtering a short-circuit layer on the surface of the opposite, and then electrolytically plating a metal onto the short-circuit layer on the wax. Can be formed.

The above description has provided specific details regarding materials and processing steps.
As will be appreciated, the present invention may be practiced with variations on other types of materials and processes. For example, in just a few of the many preferred embodiments, the sputtered shorting layer can use copper, gold, aluminum, titanium, titanium / tungsten, or other suitable metallization. Further, the redistribution traces 615 can use copper or gold materials in forming the traces. Other materials can be used with similar results, as will be apparent to those skilled in the art.
As another alternative embodiment, as will be appreciated, other methods can be used to form the various layers. For example, electroless plating, chemical vapor deposition (CVD)
Alternatively, a process based on physical vapor deposition (PVD) can be used instead of electroplating.

In the preceding description, the present invention has been described with reference to particular exemplary embodiments thereof. However, it will be apparent that various modifications and changes can be made without departing from the broader scope and spirit of the invention as set forth in the claims.

[Brief description of drawings]

FIG. 1A is a perspective view of a substrate 102 having an abutment structure on a substrate and an example of a plurality of elastic contact elements disposed on the substrate, the substrate 102 having the elastic contact elements and the abutment structure.

FIG. 1B is a cross-sectional view of an elastic contact element and a stop structure, showing an example of a lithographically formed elastic contact element formed on a substrate having a stop structure.

[FIG. 2A]   FIG. 6 is a cross-sectional view of a resilient contact element, according to one embodiment of the invention.

FIG. 2B is a cross-sectional view of another embodiment of an elastic contact structure of the present invention having a stop structure disposed on the base of the elastic contact element.

FIG. 2C shows a cross-sectional view of another example of an embodiment of a resilient contact element according to the present invention, in which the stop structure is located on the base of the resilient contact element.

[Fig. 2D]   Figure 5 shows a cross-sectional view of another example of an elastic contact element of the present invention.

2E, 2F, 2G and 2H compare the flexure of the elastic contact element shown in FIG. 2E, which is the first straight line, with the flexure of the initially curved elastic contact element shown in FIG. 2G. A sectional view is shown.

FIG. 3A   FIG. 3 is a plan view of an example of a resilient contact element according to the present invention.

FIG. 3B   FIG. 6 is a plan view of another example of an elastic contact element according to the present invention.

[Fig. 3C]   FIG. 6 is a plan view of another example of an elastic contact element according to the present invention.

[Fig. 3D]   In plan view, it shows an array of elastic contact elements arranged on a substrate.

FIG. 4 shows, in cross-section, an example of an interconnect assembly of the present invention that includes a resilient contact element having an abutment structure disposed on the base of the contact element, showing the abutment structure and the resilient contact element. Another substrate is also shown in contact with the substrate to be held.

FIG. 5 is a flow chart illustrating an example method for forming resilient contact elements and abutment structures according to one embodiment of the invention.

FIG. 6A illustrates a cross-sectional view of a structure of an interconnect assembly during formation of elastic contact elements according to one method of the present invention.

FIG. 6B shows another cross-sectional view at a later stage in the manufacturing process for making resilient contact elements, according to one embodiment of the invention.

FIG. 6C   6B shows a plan view of a portion of structure 608 shown in FIG. 6B.

FIG. 6D   FIG. 6 shows a cross-sectional view of the structure resulting after some of the processing steps shown in FIG.

FIG. 6E   FIG. 6 shows a cross-sectional view of an alternative substrate on which the elastic contact element of the present invention may be formed.

FIG. 6F   6 shows a cross-sectional view after some processing steps of the method of FIG.

FIG. 6G   FIG. 6 shows another cross-sectional view after further processing steps of the method of FIG.

FIG. 6H   Figure 6G shows a plan view of a portion of the structure shown in Figure 6G.

FIG. 6I   6 shows another cross-sectional view of a structure formed according to the method shown in FIG.

6J shows another cross-sectional view of a resilient contact element, as formed according to the method shown in FIG.

[Figure 6K]   FIG. 6 shows a further cross sectional view after further processing steps according to the method of FIG.

[FIG. 6L]   FIG. 7C shows a plan view according to one embodiment of the structure shown in FIG. 6K.

FIG. 7A illustrates in cross-section an embodiment having a plurality of resilient contact elements and their corresponding abutment structures.

FIG. 7B is a perspective view of one resilient contact element disposed within a well-formed contact structure, according to an illustrative embodiment of the invention.

FIG. 8A   Figure 7 shows an alternative embodiment of a resilient contact element according to the invention in cross section.

FIG. 8B   FIG. 8B is a perspective view of the resilient contact element of FIG. 8A after the elements have been assembled.

9A, 9B, 9C, and 9D show cross-sectional views of a substrate during another method for forming a resilient contact element in accordance with the present invention.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW [Continued Summary] Assembly Is the substrate and the elastic electrical contacts arranged on the substrate. Includes tactile elements. The first portion of the elastic contact structure is the substrate The second portion extends above the substrate and is located above It is possible to move from the first position to the second position under It The stop structure is on the surface of the substrate and Located on the surface of the first portion of the tactile structure. Of the present invention According to another aspect, the beam portion of the resilient contact structure is substantially It has a triangular shape.

Claims (108)

[Claims] 1. A contact element of an interconnect assembly, a base portion adapted to be attached to a substrate, and a beam portion connected to and extending from the base portion, the shape of the beam portion. Is a substantially triangular and adapted to be self-supporting, comprising a beam portion and a contact element. 2. The beam portion of the contact element is adapted to be elastic and the thickness of the beam portion is substantially less than a lateral dimension across the upper surface of the beam portion.
The contact element of claim 1. 3.   The contact element is   A first layer that is electrically conductive; and   The contact element of claim 1, further comprising a second layer that is mechanically elastic. 4. The contact element of claim 1, wherein the beam portion extends from the base portion at an oblique angle to the surface of the substrate. 5. The contact element of claim 1, wherein the base portion and the beam portion are lithographically formed. 6. The contact element of claim 1, wherein the beam portion is elongated and elastic and the substrate comprises an integrated circuit in a semiconductor material. 7.   The contact element of claim 1, further comprising a tip portion connected to the beam portion. 8. The contact element of claim 7, wherein the tip portion is integrally formed with the beam portion. 9.   9. The contact element of claim 8, wherein the base portion and the beam portion are integrally formed. 10. The interconnect assembly further comprises a plurality of contact elements, each of the contact elements having a respective base portion adapted to be attached to the substrate and a respective base portion. A plurality of respective beam portions connected to and extending from each, the respective beam portions being substantially triangular in shape and adapted to be self-supporting; Adjacent contact elements of the contact elements are about 2.5 to 20 on the substrate.
The contact element of claim 1, wherein the contact elements are spaced at a pitch in the range of 00 μm. 11.   The contact element of claim 10, wherein the pitch is less than about 500 μm. 12. The method according to claim 12,   The contact element of claim 10, wherein the substrate comprises an integrated circuit in a semiconductor material. 13. The contact element of claim 1, wherein the beam portion extends from an end of the base portion at an oblique angle to the surface of the substrate, the base portion being parallel to the surface. 14. The contact element of claim 1, further comprising a tip structure fabricated separately from the beam portion and mounted on the beam portion. 15. A method of forming a contact element, the method comprising forming a base portion for attachment to a substrate of an electrical assembly, and forming a beam portion connected to the base portion. The beam portion extends from the base portion, is substantially triangular in shape, and is adapted to be self-supporting. 16. 16. The method of claim 15, wherein the beam portion is elastic and elongated. 17. The base portion and the beam portion are lithographically formed.
the method of. 18. The method of claim 17, wherein the base portion and the beam portion are integrally formed in one step. 19. The step of applying a first mask layer by the base portion and the beam portion, and the step of forming a first opening in the first mask layer, wherein the first opening is Formed by a step of having a first region and a second region, the second region having sloped walls; and depositing a conductive material into the first opening,
The method of claim 17. 20. After forming the first opening, applying a second mask layer, and forming a second opening in the second mask layer that defines the substantially triangular shape. 20. The method of claim 19, further comprising: 21. The method of claim 20, wherein depositing the conductive material comprises plating the conductive material into the first opening through the second opening. 22. The conductive material deposited in the first region forms the base portion, and the conductive material deposited in the second region forms the beam portion, and 20. The method of claim 19, wherein a beam portion extends from the end of the base portion at an oblique angle to the surface of the substrate. 23. A contact element of an interconnect assembly, a base portion adapted to be attached to a substrate, and a beam portion connected to and extending from the base portion, the beam portion being self-supporting. A contact element, adapted to be a mold and having a beam geometry that, when bent, has a beam geometry that distributes stress substantially evenly across the beam. 24. The beam portion of the contact element is adapted to be elastic, the thickness of the beam portion being substantially less than a lateral dimension across the upper surface of the beam portion.
The contact element of claim 23. 25.   The contact element is   A first layer that is electrically conductive; and   24. The contact element of claim 23, further comprising a second layer that is mechanically elastic. 26. The contact element of claim 23, wherein the beam portion extends from the base portion at an oblique angle to the surface of the substrate and has a substantially triangular shape. 27. The base portion and the beam portion are lithographically formed.
Contact elements. 28. The contact element of claim 23, wherein the beam portion is elongated and elastic and the substrate comprises an integrated circuit in a semiconductor material. 29.   24. The contact element of claim 23, further comprising a tip portion connected to the beam portion. 30. The contact element of claim 29, wherein the tip portion is integrally formed with the beam portion. 31. The contact element of claim 30, wherein the base portion and the beam portion are integrally formed. 32. The interconnect assembly further comprises a plurality of contact elements, each of the contact elements having a respective base portion adapted to be attached to the substrate and a respective base portion. Respective beam portions connected and extending from each, said respective beam portions having the geometry of said beam and adapted to be self-supporting; Adjacent contact elements of a plurality of contact elements on the substrate are about 2.5 to 20.
24. The contact elements according to claim 23, which are arranged at a pitch in the range of 00 [mu] m. 33.   33. The contact element of claim 32, wherein the pitch is less than about 500 μm. 34.   33. The contact element of claim 32, wherein the substrate comprises an integrated circuit in a semiconductor material. 35. The contact element of claim 23, wherein the beam portion extends from an end of the base portion at an oblique angle to the surface of the substrate, the base portion being parallel to the surface. 36. The contact element of claim 23, further comprising a tip structure fabricated separately from the beam portion and mounted on the beam portion. 37. A method of forming a contact element, the method comprising forming a base portion for attachment to a substrate of an electrical assembly, and forming a beam portion connected to the base portion. The beam portion extends from the base portion, is adapted to be self-supporting, and has a beam geometry that, when bent, distributes stress substantially evenly throughout the beam. 38. The method of claim 37, wherein the beam portion is elastic and has an elongated, substantially triangular shape. 39. The base portion and the beam portion are lithographically formed.
the method of. 40. The method of claim 39, wherein the base portion and the beam portion are integrally formed in one step. 41. A step of applying a first mask layer to the base portion and the beam portion, and a step of forming a first opening in the first mask layer, wherein the first opening is formed. Formed by the steps of: having a first region and a second region, the second region having a sloped wall; and depositing a conductive material into the first opening.
40. The method of claim 39. 42. Applying a second mask layer after forming the first opening, and forming a second opening in the second mask layer that defines the substantially triangular shape. 42. The method of claim 41, further comprising: 43. The method of claim 42, wherein depositing the conductive material comprises plating the conductive material in the first opening through the second opening. 44. The conductive material deposited in the first region forms the base portion, and the conductive material deposited in the second region forms the beam portion, 42. The method of claim 41, wherein a beam portion extends from the end of the base portion at an oblique angle to the surface of the substrate. 45. A contact element of an interconnect assembly, a base portion adapted to be attached to a substrate, and a beam connected to, extending from, the base portion and adapted to be self-supporting. A portion of which the beam geometry is designed to produce any desired size constraints for the beam portion and stress parameters substantially optimized for the desired spring constant for the contact elements. A contact element consisting of a beam part and a beam. 46. The beam portion of the contact element is adapted to be elastic and the thickness of the beam portion is substantially less than a lateral dimension across the upper surface of the beam portion.
The contact element of claim 45. 47.   The contact element is   A first layer that is electrically conductive; and   47. The contact element of claim 45, further comprising a second layer that is mechanically elastic. 48. The contact element of claim 45, wherein the beam portion extends from the base portion at an oblique angle to the surface of the substrate and has a substantially triangular shape. 49. The contact element is elastic, the base portion and the beam portion are lithographically formed separately, and the geometric shape outperforms a cantilever beam having a substantially constant cross-sectional area. 46. is selected to improve
Contact elements. 50. The contact element of claim 45, wherein said beam portion is elongated and elastic and said substrate comprises an integrated circuit in a semiconductor material. 51.   46. The contact element of claim 45, further comprising a tip portion connected to the beam portion. 52. The contact element of claim 51, wherein the tip portion is integrally formed with the beam portion. 53. The contact element of claim 52, wherein the base portion and the beam portion are integrally formed. 54. The interconnect assembly further comprises a plurality of contact elements, each of the contact elements having a respective base portion adapted to be attached to the substrate and a respective base portion. Respective beam portions connected and extending from each, said respective beam portions having the geometry of said beam and adapted to be self-supporting; Adjacent contact elements of a plurality of contact elements on the substrate are about 2.5 to 20.
46. The contact elements of claim 45, spaced apart at a pitch in the range of 00 [mu] m. 55.   55. The contact element of claim 54, wherein the pitch is less than about 500 [mu] m. 56.   55. The contact element of claim 54, wherein the substrate comprises an integrated circuit in a semiconductor material. 57. The contact element of claim 45, wherein the beam portion extends from an end of the base portion at an oblique angle to the surface of the substrate, the base portion being parallel to the surface. 58. The contact element of claim 45, further comprising a tip structure fabricated separately from the beam portion and mounted on the beam portion. 59. A method of forming a contact element, the method comprising: forming a base portion for attachment to a substrate of an electrical assembly; and forming a beam portion connected to the base portion. The beam portion extends from the base portion and is adapted to be self-supporting to provide stress parameters substantially optimized for any desired size constraints on the beam portion and a desired spring constant for the resilient contact element. With the beam geometry designed to occur. 60. The method of claim 59, wherein the beam portion is elastic and has an elongated, substantially triangular shape. 61. The base portion and the beam portion are lithographically formed separately and the beam geometry is selected to improve performance over a cantilever beam having a substantially constant cross-sectional area. 61. The method of claim 60, wherein 62. The method of claim 60, wherein the base portion and the beam portion are integrally formed in one step. 63. The base portion and the beam portion comprising applying a first mask layer, and forming a first opening in the first mask layer, the first opening comprising: Formed by the steps of: having a first region and a second region, the second region having a sloped wall; and depositing a conductive material into the first opening.
62. The method of claim 61. 64. After forming the first opening, applying a second mask layer, and forming a second opening in the second mask layer that defines the substantially triangular shape. 64. The method of claim 63, further comprising: 65. The method of claim 64, wherein depositing the conductive material comprises plating the conductive material into the first opening through the second opening. 66. The conductive material deposited in the first region forms the base portion, and the conductive material deposited in the second region forms the beam portion, 64. The method of claim 63, wherein the beam portion extends from the end of the base portion at an oblique angle to the surface of the substrate. 67. An interconnect assembly comprising: a substrate and a contact element disposed thereon, the first portion of the contact element being adapted to be self-supporting and the force being the contact element. When applied to the first portion of
A contact element that is further adapted to be movable from the position of to the second position,
And an abutment structure disposed on the second portion of the contact element and defining the second position. 68. The interconnect assembly of claim 67, wherein a plurality of said contact elements are disposed on said substrate and the pitch of said disposed contact elements is in the range of about 2.5 μm to 2000 μm. 69. The interconnect assembly of claim 67, wherein the substrate has bonding pads connected to microelectronic elements and the contact elements are located on the bonding pads. 70. The interconnect assembly of claim 67, wherein the substrate has redistributed conductors connected to microelectronic elements and the contact elements are disposed on the redistributed conductors. 71. The interconnect assembly of claim 67, wherein the substrate has bond pads connected to test equipment and the contact elements are located on the bond pads. 72. The contact element is elastic and the stop structure is urged against the second portion by the force when the force is applied to the first portion.
The interconnect assembly of claim 67. 73. The interconnect assembly of claim 67, wherein the contact element comprises at least one metal layer. 74. The contact element comprises a first metal layer and a second metal layer, the first metal layer providing elasticity to the contact element, and the second metal layer being conductive. 68. The interconnect assembly of claim 67, which provides to said contact element. 75. The interconnect assembly of claim 67, wherein said contact element is an elongated resilient contact element. 76. The first portion of the contact element is angled with respect to the surface of the substrate, such that one end of the first portion of the contact element is above the surface of the substrate. 68. The interconnect assembly of claim 67, at the height of. 77. The interconnect assembly of claim 67, wherein a portion of the first portion of the contact element projects at a height above the surface of the stop structure. 78. The interconnect assembly of claim 77, wherein the height at which the contact element projects from the surface of the stop structure is a predetermined height. 79. The force is applied when the substrate comprises an integrated circuit in a semiconductor material and another contact element is mechanically and electrically contacted with the contact element. Interconnect assembly. 80. The force is applied when the contact element is an elastic contact element and another contact element is mechanically and electrically contacted with the contact element, and the elastic contact is caused by the force. 68. The interconnect assembly of claim 67, wherein an element bends from the first position to the second position and the stop structure defines the second position defining a maximum bend of the resilient contact element. . 81. The interconnect assembly of claim 67, wherein the first portion of the contact element has a substantially triangular shape and the third portion of the contact element is the apex of the triangle. 82. The interconnect assembly of claim 67, wherein the stop structure has a vertical height that is less than the vertical height of the shortest contact element that is statistically likely to be present. 83. A method of forming an interconnect assembly, the method comprising disposing a contact element on a substrate, the first portion of the contact element being self-supporting. A step of moving from a first position to a second position when applied to the first portion of the contact element, and a stop structure defining the second position, the contact element And placing on a second portion of the. 84. The method of claim 83, wherein disposing the contact element on the substrate comprises disposing another contact element on the substrate at a fine pitch. 85.   84. The method of claim 83, wherein the contact elements are self-supporting and elastic. 86. Placing the contact element includes applying a first mask layer on the substrate, wherein the first mask layer has sloped walls and the first mask layer. 84. The method of claim 83, further comprising: forming an opening extending into the layer; and depositing a metal layer on the sloped wall of the opening of the first mask layer. 87. The sloped wall tapers by using a gradual scale, tapering by reflow, tapering by controlled exposure, and tapering by varying the mask distance. 87. The method of claim 86, wherein the method is tilted using at least one technique of applying or tapering with multiple exposures. 88. After forming the sloping walls, the method comprises: disposing a mask pattern having a pattern of substantially triangular shape on the first mask layer; According to said substantially triangular shape, said first
87. The method of claim 86, further comprising: depositing the metal layer in the opening of the mask layer of. 89. The method of claim 86, wherein the step of depositing the metal layer comprises using one of a sputtering deposition process, an electroplating process, a chemical vapor deposition process, and an electroless plating process. 90. Depositing the metal layer includes depositing a first metal layer selected for elastic properties, and depositing a second metal layer selected for conductive properties. 87. The method of claim 86. 91. Removing a portion of the first mask layer to allow the contact element to be self-supporting; and adding to cover the second portion of the contact element. 87. The method of claim 86, further comprising the step of adding a layer of. 92. A step of planarizing the first mask layer to form the hit stop structure, wherein the hit stop structure is less than a vertical height of the shortest contact element present. 92. The method of claim 91, further comprising the step of having a vertical height. 93. Removing the first masking layer, and adding a second layer over the second portion of the contact element such that the first portion of the contact element is self-supporting. 87. further comprising the step of enabling
the method of. 94. A step of planarizing the second layer to form the hit stop structure, wherein the hit stop structure is less than the vertical height of the shortest contact element. 94. The method of claim 93, further comprising the step of having a height. 95. The contact element is an elastic contact element that is self-supporting, and a force is applied when another contact element is mechanically and electrically contacted with the contact element, the force causing 84. The elastic contact element bends from the first position to the second position and the stop structure defines the second position defining a maximum bend of the elastic contact element. Method. 96. The contact element is a resilient contact element that is self-supporting, and the stop structure is
The force is urged against the second part when the force is applied to the first part such that another contact element mechanically and electrically contacts the contact element. 84. The method of claim 83, wherein the method is applied when done. 97. An electrical system comprising: a first substrate having a first contact element, a second substrate, and at least one second contact element disposed on the second substrate. And the first portion of the second contact element is adapted to be self-supporting and the force is
At least one second contact element that is further adapted to be movable from a first position to a second position when applied to the first portion of the second contact element by a second contact element of And and disposed on a second portion of the second contact element to define the second position,
An electrical system consisting of a hit stop structure. 98. The second substrate has a bonding pad connected to a microelectronic element,
The second portion of the second contact element is disposed on the bond pad,
The first substrate is (1) a test probe assembly having the first contact element for contacting the second contact element; and (2) the microelectronic during use of the microelectronic element. 98. The method of claim 97, wherein the package has one of the first contact elements for housing an element. 99. A method for forming a self-supporting and elongate resilient contact element, the method comprising the step of pushing the mold down into a deformable material, the mold comprising: And determining the shape of at least a portion of the elongate elastic contact element, and forming at least the portion of the free-standing and elongate elastic contact element on the deformable material. Method. 100. The forming step comprises the steps of: after the deformable material is deformed by the mold;
100. The method of claim 99, comprising depositing a conductive material on the deformable material. 101. The method of claim 100, wherein the mold is self-supporting and includes a plurality of shapes to accommodate a plurality of elongated resilient contact element portions. 102. The method of claim 101, further comprising removing the deformable material after depositing the conductive material. 103. The method of claim 102, wherein the self-supporting and elongated resilient contact elements are disposed on corresponding electrical interconnect pads on a substrate. 104.   104. The method of claim 103, wherein the substrate comprises a semiconductor integrated circuit. 105. A lithographically formed resilient contact element extending upwardly from the substrate and having a lithographically defined curved beam portion. 106. A base portion mechanically attached to the substrate and electrically coupled to electrical interconnection terminals on the substrate, the resilient contact elements being released after being initially formed. 106. The lithographically formed resilient contact element of claim 105, further comprising a base portion that is self-supporting. 107. The curved portion of the curved beam portion extends upwardly away from the substrate,
107. The lithographically-formed elastic contact element of claim 106, wherein the bend is lithographically defined by a curved bevel of a sacrificial layer that is removed to release the elastic contact element. 108. The method of claim 1, further comprising a sacrificial layer that defines a bend of the curved beam portion.
06 lithographically formed resilient contact elements.