US3634930A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods for bonding leads and testing bond strength
Assignee: AT&T Inc
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Filing: 1969-06-12
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Granted: 1972-01-18
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Expires: 1989-06-12
Abstract
Abstract Bond strengths between bonded leads of electrical devices and conductive elements of circuit patterns are evaluated by preengaging a flexible member such as a wire or strip of metal with the electrical device prior to the making of the bond to be evaluated. The flexible member is engaged with the electrical device with a predetermined releasability so that, when the flexible member is pulled, the member releases from the device if the bonds are of satisfactory strength but the bonds rupture if they are of unsatisfactory strength and, in this instance, the flexible member remains intact. Particular utility resides in employing this system to evaluate bond strengths of leads of beam-lead integrated circuits or transistors when such devices are bonded to thin-film circuits. 52 253 54 3 55 59 260 63 65 266 72 2* 73 74 75 83 85 89 91 95 97 101 105 107 111 113 117 119 121 123 127 131 133 137 139 143 141 147 149 156 159 149 158 162 154 164 168 170 172 174 178 182 184 188 190 W
Inventors
- 👤 Benjamin H Cranston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:07
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49004; Y10T29/49117; Y10T29/49121
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
116 words
A method of bonding a first workpiece to a second workpiece with a bond strength having a specified lower limit, which comprises the steps of: engaging a flexible member with the first workpiece with a predetermined releasibility equivalent to the specified lower limit of bond strength between the workpieces; bonding the first workpiece to the second workpiece; and applying a force to the flexible member sufficient to either release the flexible member from the first workpiece in the event that the bond strength exceeds the specified lower limit or rupture the bond formed between the first and the second workpieces in the event that the bond strength is equal to or below the specified lower limit.
Claim 2
Independent Claim
116 words
A method of bonding a first workpiece to a second workpiece with a bond strength having a specified lower limit, which comprises the steps of: engaging a flexible member with the first workpiece with a predetermined releasibility equivalent to the specified lower limit of bond strength between the workpieces; bonding the first workpiece to the second workpiece; and applying a force to the flexible member sufficient to either release the flexible member from the first workpiece in the event that the bond strength exceeds the specified lower limit or rupture the bond formed between the first and the second workpieces in the event that the bond strength is equal to or below the specified lower limit.
Claim 3
Independent Claim
118 words
A method of making bonds with a bond strength having a specified lower limit between beam leads of a chip and conductive elements formed on a substrate, which comprises the steps of: placing at least one filament having a predetermined breaking strength between a body portion of the chip and the substrate so that portions of the filament are accessible on opposite sides of the body portion; bonding the beam leads to the conductive elements; and pulling the accessible portions of filament away from the substrate to either tear the beam leads from the conductive elements or break the filament if the strength of the bonds between the leads and the elements is below the specified lower limit.
Claim 4
Independent Claim
118 words
A method of making bonds with a bond strength having a specified lower limit between beam leads of a chip and conductive elements formed on a substrate, which comprises the steps of: placing at least one filament having a predetermined breaking strength between a body portion of the chip and the substrate so that portions of the filament are accessible on opposite sides of the body portion; bonding the beam leads to the conductive elements; and pulling the accessible portions of filament away from the substrate to either tear the beam leads from the conductive elements or break the filament if the strength of the bonds between the leads and the elements is below the specified lower limit.
Claim 5
Independent Claim
89 words
A method of making bonds between beam leads of a chip and conductive elements formed on a substrate which comprises the steps of: bonding a back side of the beam leads to a flexible strip with a predetermined releasibility; bonding a front side opposite the back side of the beam leads to the conductive elements; and peeling away the strip so that the beam leads bonded with unsatisfactorily low bond strengths are peeled away from the substrate and beam leads bonded with satisfactory bond strengths are left in place.
Claim 6
Independent Claim
89 words
A method of making bonds between beam leads of a chip and conductive elements formed on a substrate which comprises the steps of: bonding a back side of the beam leads to a flexible strip with a predetermined releasibility; bonding a front side opposite the back side of the beam leads to the conductive elements; and peeling away the strip so that the beam leads bonded with unsatisfactorily low bond strengths are peeled away from the substrate and beam leads bonded with satisfactory bond strengths are left in place.
Claim 7
Dependent Claim
35 words
The method of claim 3 wherein the flexible strip is a compliant bonding medium and the step of bonding the front side of the leads to the conductive elements is performed by compliant bonding techniques.
Claim 8
Dependent Claim
11 words
The method of claim 4 wherein the chips are integrated circuits.
Claim 9
Dependent Claim
66 words
The method of bonding beam leads of a chip of claim 3 wherein the step of bonding a back side of the beam leads to a flexible strip comprises: bonding a compliant bonding medium to the back side of the beam leads with a bond strength equivalent to the specified lower limit of bond strength between the beam leads and the conductive elements on the substrate.
Claim 10
Dependent Claim
18 words
The method of bonding of claim 6, wherein the step of bonding the compliant medium is performed ultrasonically.
Claim 11
Dependent Claim
42 words
The method of bonding of claim 7, wherein the step of bonding the compliant medium is performed with the chips supported on a nonmetallic surface so that the beam leads are bonded only to the compliant medium and not the supporting surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |