Buckling beam probe arrays and methods for making such arrays including forming probes with lateral positions matching guide plate hole positions

Abstract

Forming buckling beam probe arrays having MEMS probes engaged with guide plates during formation or after formation of the probes while the probes are held in the array configuration in which they were formed is disclosed. Probes can be formed in, or laterally aligned with, guide plate through holes. Guide plate engagement can occur by longitudinally locating guide plates on probes that are partially formed or fully formed with exposed ends, by forming probes within guide plate through holes, by forming guide plates around probes, or forming guide plates in lateral alignment with arrayed probes and then longitudinally engaging the probes and the through holes of the guide plates. Arrays can include probes and a substrate to which the probes are bonded with one or more guide plates. Final arrays can include probes held by guide plates with aligned or laterally shifted hole patterns.

I/We claim: 
     
         1 . A method of forming a probe array, the method comprising:
 (A) forming a plurality of probes on a substrate with each probe having two ends, and at least one intermediate elastically compliant portion, wherein at least one of the ends is configured as a contact end for making electric contact to a second electrical circuit element while an other end is selected from a group consisting of: (1) a contact end for making pressure based contact to a first electric element, and (2) an attachment end for making a fixed contact to the first circuit element, wherein the plurality of probes are formed with probe-to-probe spacings corresponding to contact elements on the second circuit element, wherein the formation of the plurality of probes, comprises:
 forming a plurality of multi-material layers, with each multi-material layer comprising at least two materials, wherein at least one of the at least two materials is at least one structural material and at least one other of the at least two materials is at least one sacrificial material, wherein each multi-material layer defines a cross-section of the plurality of probes; 
   (B) providing at least one guide plate having a plurality of openings to engage the plurality of probes; and   (C) after formation of all multi-material layers of the probes and after providing and engaging the at least one guide plate, separating the probes from unremoved sacrificial material;   wherein (B) providing at least one guide plate is selected from a group consisting of:
 (i) after forming the probes but prior to the removal of all sacrificial material from the plurality of multi-material layers, positioning the at least one guide plate laterally and longitudinally over and around end portions of the probes with the end portions of the probes extending from unremoved sacrificial material; 
 (ii) prior to forming a first layer of the plurality of multi-material layers of the probes forming the at least one guide plate over the substrate, in direct or indirect contact therewith, and then forming the probes through the openings in the at least one guide plate, wherein an end portion of the probes extends from unremoved sacrificial material; 
 (iii) after forming the probes to have only a partial length, positioning the at least one guide plate laterally and longitudinally over and around the end portions of the partial length probes, then completing formation of the length of the probes, wherein at the time of positioning of the at least one guide plate, an end portion of the partially formed probes extends from unremoved sacrificial material; 
 (iv) after forming the probes to have a full length, forming the at least one guide plate with the openings aligned laterally with the probes and positioned longitudinally with the openings at least partially surrounding portions of the probes while other portions of the probes remain covered with unremoved sacrificial material; and 
 (v) after forming the probes to at least partial length, forming at least one guide plate with the openings aligned laterally with the probes but longitudinally above end portions of the probes, and thereafter exposing the end portions of the probes by removing a portion of the sacrificial material, and lowering the at least one guide plate longitudinally over and around the end portions of the probes. 
   
     
     
         2 . The method of  claim 1  wherein forming of each multi-material layer comprises:
 (a) depositing at least a first of the at least two materials; 
 (b) depositing at least a second of the at least two materials; 
 (c) planarizing at least two of the at least two deposited materials, including planarizing at least one structural material and at least one sacrificial material and wherein each successively formed multi-material layer of the plurality of multi-material layers is adhered to a previously formed multi-material layer or a non-multi-material layer that in turn was adhered directly or indirectly to a previously formed multi-material layer. 
 
     
     
         3 . The method of  claim 1  wherein the probes with a full length are formed with an end portion extending from unremoved sacrificial material by an amount selected from a group consisting of:
 (a) less than a lateral dimension of an individual probe; 
 (b) less than a lateral dimension of a spacing between adjacent probes; 
 (c) less than a fraction of a height of a probe where the fraction is selected from a group consisting of (1) ½, (2) ⅓, (3) ¼, (4) ⅕, (5) 1/10, and (6) 1/20; 
 (d) less than N thicknesses of the guide plate, wherein N is selected from a group consisting of (1) 4, (2) 3, (3) 2, (4) 1, (5) ½, (6) ⅓, and (7) ¼; 
 (e) less than an amount selected from a group consisting of 500 microns, 200 microns, 100 microns, 50, microns, 20 microns, 10 microns, and 5 microns. 
 
     
     
         4 . The method of  claim 1  wherein the at least one guide plate is positioned with the openings at least partially surrounding the probes with a full length wherein only a end portion of a longitudinal length of the probes extend from unremoved sacrificial material at the time of guide plate formation, wherein the end portion is selected from a group consisting of:
 (a) less than a lateral dimension of an individual probe; 
 (b) less than a lateral dimension of a closest spacing between adjacent probes; 
 (c) less than a fraction of a height of a probe where the fraction is selected from a group consisting of (1) ½, (2) ⅓, (3) ¼, (4) ⅕, (5) 1/10, and (6) 1/20; 
 (d) less than N thicknesses of the guide plate, wherein N is selected from a group consisting of (1) 4, (2) 3, (3) 2, (4) 1, (5) ½, (6) ⅓, and (7) ¼; 
 (e) less than an amount selected from a group consisting of (1) 500 microns, (2) 200 microns (3) 100 microns, (4) 50, microns, (5) 20 microns, (6) 10 microns, and (7) 5 microns. 
 
     
     
         5 . The method of  claim 1  wherein the probes formed to at least partial length have an end portion extending from unremoved sacrificial material by an amount selected from a group consisting of:
 (a) less than a lateral dimension of an individual probe; 
 (b) less than a lateral dimension of a spacing between adjacent probes; 
 (c) less than a fraction of a height of a probe where the fraction is selected from a group consisting of (1) ½, (2) ⅓, (3) ¼, (4) ⅕, (5) 1/10, and (6) 1/20; 
 (d) less than N thicknesses of the guide plate, wherein N is selected from a group consisting of (1) 4, (2) 3, (3) 2, (4) 1, (5) ½, (6) ⅓, and (7) ¼; 
 (e) less than an amount selected from a group consisting of (1) 500 microns, (2) 200 microns (3) 100 microns, (4) 50, microns, (5) 20 microns, (6) 10 microns, and (7) 5 microns. 
 
     
     
         6 . The method of  claim 1 , further comprising, after separating the probes from unremoved sacrificial material:
 relative lateral shifting of the at least one guide plate with respect to the substrate to provide the probes with a desired placement, shape, and/or configuration due to lateral offsetting.   
     
     
         7 . The method of  claim 1 , further comprising, before separating the probes from unremoved sacrificial material:
 remove the substrate and a portion of the sacrificial material exposing further end portions of the probes; and   positioning a further guide plate with further openings at least partially surrounding the further end portions of the probes extending from unremoved sacrificial material.   
     
     
         8 . The method of  claim 7 , further comprising, after separating the probes from unremoved sacrificial material:
 relative lateral shifting of the at least one guide plate with respect to the further guide plate to provide the probes with a desired placement, shape, and/or configuration due to lateral offsetting.   
     
     
         9 . The method of  claim 1 , wherein forming the at least one guide plate over the substrate prior to forming a first layer of the plurality of multi-material layers of the probes comprises:
 forming a masking material with openings at the desired probe locations for the probes with a required probe-to-probe spacing;   positioning the at least one guide plate with openings coated by a coating material aligned with the openings of masking material;   forming a patterned masking material over the at least one guide plate; and   depositing structural material into the openings of the masking materials and of the at least one guide plate to partially form the probes.   
     
     
         10 . The method of  claim 9 , further comprising:
 after partial formation of the probes, removing the masking material and exposing respective end portions of the probes;   depositing a sacrificial material to surround the respective end portions and fill in at least part of the gaps around the probes and the at least one guide plate; and   planarizing the sacrificial material and the structural material forming the probes to set a planar surface for a subsequent layer formation.   
     
     
         11 . The method of  claim 10 , further comprising:
 after planarizing the sacrificial material and the structural material forming the probes, forming additional layers on the planar surface, each additional layer comprising the structural material forming the probes and the sacrificial material;   forming a last layer of masking material;   removing the masking material to expose further end portions of the probes; and   positioning a further guide plate with further openings at least partially surrounding the exposed further end portions of the probes.   
     
     
         12 . The method of  claim 11 , further comprising, after positioning the further guide plate and before separating the probes from unremoved sacrificial material:
 forming one or more additional probe layers which include structural material and sacrificial material to complete the probes.   
     
     
         13 . The method of  claim 11 , further comprising, after separating the probes from unremoved sacrificial material:
 relative lateral shifting of the at least one guide plate with respect to the further guide plate to provide the probes with a desired placement, shape, and/or configuration due to lateral offsetting.   
     
     
         14 . The method of  claim 11 , further comprising, before positioning the further guide plate:
 coating the exposed further end portions of the probes with a coating material to provide a spacing between the probes and side walls of the openings of the further guide plate.   
     
     
         15 . The method of  claim 1 , wherein the probe array is a two-dimensional probe array.