JP3262531B2 - Bent flying lead wire bonding process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for bonding a wire to a surface, for example, to form a probe for an electronic device or to form an electrical connection on an electronic circuit device. To the process of bonding to the surface. More specifically, it relates to a wire bonded at one end and free at the other end.

[0002]

2. Description of the Related Art Wire bonding techniques are used to connect germanium transistors to other electronic devices.
It was first developed in the 950s. Wire bonding techniques continue to be used for connecting most integrated circuit devices. Thermal energy, mechanical forces, and ultrasonic vibrations have been used to bond small wires to the terminals of the device.

[0003]

SUMMARY OF THE INVENTION The Angled Flying Lead, disclosed herein,
(AFL) The wire bonding process uses the same basic process used for standard thermosonic ball bonding, which involves an array of diverse areas and peripheral interconnects, such as high density lands. It was developed to make grid arrays and high density IC probes.

In the conventional wire bonding shown in FIG. 1, the free end of the wire is ball-bonded to a contact pad on the surface. The wire is bent and bonded to another pad with a wedge. The wire connecting the two pads is curved. The shape of this curvature depends on the distance between the two connected pads. When the wire connecting the two pads is cut, two wires of different shapes are created. Using the wire bonded to the surface as a probe in an electronic device (described below), or connecting the array of contact pads on a first surface to an array of contact pads on a second surface facing the first surface. Where interconnects are desired, conventional wire bonding processes are useless for making such structures. To make a probe for an electronic device using a wire bonded to the surface (probe wire), one end of the wire is bonded to a contact pad on the support substrate of the probe wire. The other end of the probe wire must be placed in contact with the contact pad on the device under test. When the probe of the electronic device is moved to engage the contact pad of the device to be tested, it is desirable that the free end (probe tip) of the wire bend to slide over the surface of the contact pad being probed. . This sliding action causes the tip of the probe to make good electrical contact with the contact pad. Since the probe is used many times, the tip of the probe wire may be touched several thousand times (preferably more than 1,000 times, more preferably more than 10,000 times, most preferably more than 100 times) against the contact pads on the device being tested. , 0
(00 times or more), and is disengaged and is repeatedly bent. The probe tip must also have the desired degree of sliding, be flexible enough to withstand multiple engagements without distortion, and be sufficiently pressable without distortion. . The present invention provides a reliable process and technique for forming many probe wires into a desired shape to satisfy all these requirements.

[0005]

SUMMARY OF THE INVENTION It is desirable to have a technique for forming a wire bonded to a surface such that the wire can be formed in any desired shape that provides the desired properties. It is. The wires can be bonded to electrical contact pads on the surface, pulled away from the surface, and cut to have free ends. The wire is bent so that its free end has a predetermined shape that provides advantageous properties, such as desired flexibility.

It is an object of the present invention to provide a process for bonding wires to an electronic circuit device, one end of which is attached to the surface of the device and the other end extending away from the surface of the device.

It is another object of the present invention to provide a process for bonding a wire to an electronic circuit device such that the wire is formed at an angle to the surface of the electronic circuit device.

It is yet another object of the present invention to provide a process for bonding a wire to an electronic circuit device such that the wire has a bent shape.

[0009]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a standard wire bonding process, which includes a gold wire (preferably a wire) passed through a hollow pointed ceramic tool called a capillary 115. Begin by forming a ball at the end of 110). The ball is pressed against the first bonding surface 116 of the substrate 118 while the substrate 118 is heated from below, and ultrasonic energy is applied via the capillary 115 as shown in step 1 of FIG. Metallurgy on the substrate surface is critical for the wire bonding process. After ball bonding the wire to the first substrate surface 116, the capillary 115 (indicated by arrow 120) is lifted while the substrate is moved (FIG. 1, step 2) to create a loop shape in the wire. . Next, the capillary 115 is lowered and the side 124 of the wire is
It is pressed against the surface 128 of 26, thereby forming a second bonding or wedge bonding 130 (FIG. 1, step 3). Capillary 115
Is lifted slightly, as indicated by arrow 132, and a mechanical clamp is actuated to hold the wire in place while the capillary is lifted again and cuts the wire at the end of wedge bonding 134 (FIG. 1,
Step 4). The ball is formed at the end of the gold bonding by placing the electrode under the tip 136 of the wire and melting the end of the wire using a high voltage discharge (FIG. 1,
Step 5).

FIG. 2 shows a cross-section of an electronic circuit component 11 and several bent flying leads 10 mounted on a first surface 12 of the component 11 according to the invention. The bent flying leads 10 can be attached to a variety of different electronic circuit components 11. The bent flying lead 10 is connected to the first surface 12 of the electronic circuit component 11.
The upper metallized circuit pads 13 are bonded. Electronic circuit component 11 must provide a rigid substrate for the thermosonic wire bonding process to be successful. FIGS. 1, 2 and 3 for the bent flying lead wire bonding process are essentially the same as the standard thermosonic wire bonding process. A discharge 22 from an electronic flame off (EFO) device 21 is used to melt the end of the bonding wire 16 extending through the tip of the ceramic capillary tool 15. This discharge 22 is controlled to provide a uniform sized ball 14 at the end of the bonding wire 16.

FIG. 3 shows the ball-shaped end of the bonding wire 16 with the metallized pad 1 on the surface of the electronic circuit component 11.
3 shows a ceramic capillary tool 15 used to press on 3; Ultrasonic energy 30 applied through the ceramic capillary tool 15 and thermal energy applied through the substrate holding the electronic circuit component 11 causes the bonding between the bonding wire 16 and the metallized pad 13 on the surface of the electronic circuit component 11. Used to form ball bonding 19.

FIG. 4 shows the movement 40 of the electronic circuit components and the movement 41 of the ceramic capillary tool. The movement 40 of the electronic component is determined by the free end of the bent flying lead 10 and the ball attached to the electronic component 11.
It is used to determine the offset between the bondings 19. The movement of the ceramic capillary tool 15 provides sufficient slack in the bonding wire to minimize the stress on the ball bonding 19 during subsequent steps.

FIG. 5 shows a bent flying lead 10.
Additional movement 5 of the ceramic capillary tool used to create the angled curved shape 17 of FIG.
Indicates 0. The movement 50 of the capillary tool must be controlled so as not to deform the adjacent bent flying lead 10.

FIG. 6 shows a cutting blade 60 used to cut the bonding wire 62 to form the free end 18 of the bent flying lead 10. The cutting blade 60 must be accurately positioned to correctly position the free end 18 of the bent flying lead 10 (61). Ceramic capillary tool 15
Is lifted (62) and a clamp is used to hold the bonding wire while the bonding wire is cut at the tip of the cutting blade 60.

FIG. 7 shows retraction of the cutting blade (70) and upward movement of the ceramic capillary tool (71).
Is shown. The end 72 of the bonding wire extending from the tip of the ceramic capillary tool is the next ball
This process is repeated to form the desired number of bent flying leads 10 on the electronic circuit component 11 used for bonding.

FIG. 8 shows an alternative embodiment of the wire cutting process shown in FIG. The alternative wire cutting process shown in FIG. 7 uses two blades 8 instead of one.
0 and 83 are used. The movement and positioning of each blade 80, 83 cuts on both sides of the wire so that the wire breaks at this point. This dual blade configuration can be used to cut high tensile strength wires.

FIG. 9 shows a second alternative embodiment of a wire cutting process similar to the two-blade process of FIG. A second alternative embodiment of the wire cutting process shown in FIG. 9 is used to make a straight wire 100 attached to an electronic component 11. The movement and positioning 91,94 of the two blades 90,93 are controlled to cut both sides of the wire and break the wire at this point.

FIG. 10 shows a bent flying lead.
A configuration is shown in which three wires 120, 121, and 122 are attached to the electronic circuit component 11 using a wire bonding process. All three wires 120, 121, 122 are made at a height 124 above the surface of the electronic circuit component 11. The configuration of the three wires is a straight wire 12
0, angled wire 121, and electronic circuit component 1
1 includes a wire 122 having a portion parallel to the surface. Variations of these three wire configurations can also be made, such as different angles 123 of different dimensions and different wire offsets 125 as shown for angled wire 121.
Includes wires with

FIG. 11 shows a bent flying lead.
A configuration is shown in which four wires 130, 131, 133, and 134 are attached to the electronic circuit component 11 using a wire bonding process. This four wire configuration comprises two straight wires 130 of different heights 132, 136,
131, including two angled wires 133, 134 of different heights 135, 137.

FIGS. 12 and 13 show various wire shapes 141, 142, 143, 144, which can be implemented in accordance with the present invention.
145, 146, 147, 148 are shown conceptually. These different wire geometries are created by controlling both the capillary tip descent and the offset movement of the wire bonding stage. The wire shape can be continuously curved, a portion of the wire curved, a portion of the wire straight, and combinations thereof.

FIG. 13 shows some shapes and forms of wire tips, including straight line 167, straight line 166 with sharp contacts, straight line 165 with sharp contacts coated with a suitable contact alloy, One with a sharp pointed needle
64, to which a suitable contact alloy is attached 163;
Examples include a ball-shaped member 162, a ball-shaped member 161 to which a suitable contact alloy is attached, and a member having a pointed needle attached to a contact end.

FIG. 14 schematically illustrates a frame structure that can be adapted to match the coefficients of thermal expansion of silicon and other materials. The tip of the wire needs to be kept in a precise position before and after engaging the pads of the electronic device at temperatures up to 180 ° C. The various contact configurations shown are made at the ends of the wire to facilitate various contact and test applications.

FIG. 15 is a schematic diagram showing the structure of a test apparatus according to the present invention. The test device 208 is a means 20 for keeping the probe tip 210 in contact with a contact position 212 on the device under test 204 placed on the support 206.
0, 202.

The minimum spacing between bent flying leads depends on the diameter of the wire used and the size and configuration of the capillary used to bond the wire. Smaller diameter wires can be bonded closer. The shape of the tip of the capillary can be modified to be in the shape of a bottle neck, or to create recesses in the sides to allow closer bonding of the bent flying leads. The maximum height of the bent flying lead also depends on the diameter and material properties of the bonding wire and the offset distance between the ball bonding and the free end of the wire. Smaller diameter wires (about 25 to 50 microns) better fit shorter leads, and larger diameter wires (about 50 to 75 microns) better fit longer leads. Important material properties of the wire include stiffness and tensile strength. The properties of the wire can be controlled by the alloy used for the wire material and the elongation for forming the wire.

US Patent Application 09 filed June 1, 1989
No. 088,394 and US Pat. No. 5,371,654 are incorporated by reference.

Although a preferred embodiment of the present invention has been described, it will be appreciated that various modifications and improvements that fall within the scope of the claims herein may be made by those skilled in the art. This claim is to be construed to cover the protection of the first disclosed invention.

In summary, the following matters are disclosed regarding the configuration of the present invention. (1) A process for making a bent flying lead wire structure to be attached to an electronic circuit component, wherein the process is used to bond the bent flying lead wire to a first surface of the electronic circuit component. A first process step, a second process step in which the movement of the wire capillary tool and the XY stage is controlled to form a desired shape in the bent flying lead wire, A third process step in which a mechanism having a cutting blade is positioned to contact the flying lead wire; and the capillary tool to tension the wire against the cutting blade to cut the wire. A fourth process step in which is lifted. (2) The process of (1) above, further comprising forming a plurality of angles on the flying lead wire with respect to a surface of the electronic circuit component. (3) The process of (2) above, further comprising forming the flying lead wires at a plurality of heights with respect to a surface of the electronic circuit component. (4) The method further comprising forming the lead wire such that the flying lead wire has any shape of straight, partially straight, continuously curved, and a combination thereof. The process of (3). (5) A process for making a bent flying lead wire structure to be attached to an electronic circuit component, the method comprising bonding the bent flying lead wire to a first surface of the electronic circuit component; Controlling the movement of the wire capillary tool and the XY stage to form a desired shape on the bent flying lead wire; and positioning small movements on both sides of the wire, positioned on both sides of the flying lead wire. Cutting the flying lead wire with a mechanism having a double cutting blade for making a notch, and raising the capillary tool to cut the wire at the point where the notch was made by the cutting blade; The bent flying lead wire has a wire tip Process, including that and, the. (6) The process of (5) above, further comprising forming a plurality of angles on the flying lead wire with respect to a surface of the electronic circuit component. (7) The process of (6) above, further comprising forming the flying lead wires at a plurality of heights with respect to a surface of the electronic circuit component. (8) The above (1) to (1) further comprising maintaining the flying lead wire in a predetermined position by arranging a sheet of material having a plurality of openings so that the flying lead wire passes through the opening. Structure according to 5). (9) The structure according to (8) above, wherein a compliant frame structure is used to support the sheet of material. (10) The structure according to (8), wherein the sheet is separated from the surface by electronic components to provide flexible support. (11) the sheet is separated from the surface of the electronic component by a rigid support, and the rigid support acts as an isolation or stop to limit the degree of movement of the wire tip in a direction perpendicular to the surface. Working structure according to (8) above. (12) The structure according to (8), wherein the sheet is separated from the surface of the electronic component by a support having a composite structure of a rigid layer and a conformable layer. (13) The structure according to (10), wherein a space between the surface of the electronic component and the sheet is filled with a compliant medium. (14) The structure according to (13), wherein the compliant medium is an elastic material. (15) The compliant medium is a foamed polymer material (1).
Structure according to 3). (16) The structure according to the above (10), wherein the flexible support is selected from a spring or an elastic material. (17) The above-mentioned (8), wherein the wire tip has a shape selected from any of a nodule, a ball contact shape, a straight contact end, a sharp needle, a plurality of sharp needles, a sharp nodule, and a combination thereof. Structure according to. (18) The tip of the wire is Ir, Pd, Pt, Ni, A
u, Rh, Re, Co, Cu and a structure according to (8) selected from any of these alloys. (19) The bent flying lead wires are Ir, Pd, Pt, Ni, Au, Rh, Re, Co, C
u and a structure according to (8), coated with a material selected from any of these alloys. (20) The sheet is laminated with Invar, Cu / Invar / C
The structure according to the above (8), which is made of a material selected from a u-layer and a molybdenum layer. (21) The structure according to (8), wherein the sheet is made of a material selected from the group consisting of metal, polymer, semiconductor and dielectric. (22) The structure according to the above (20), wherein the sheet is covered with a polymer layer. (23) The sheet (2), wherein the sheet is covered with an insulating layer.
Structure according to 0). (24) The structure according to (20) above, wherein said sheet is coated with a thin layer of a compliant polymer. (25) The structure according to (20), wherein the sheet is laminated between two insulating layers. (26) An apparatus using the structure of (8) for testing an electronic device, wherein the means for retaining the structure of (1) is provided, and the structure of (1) is transferred to the electronic device. And means for retractably moving away from the wire tip so that the wire tip contacts an electrical contact location on the electronic device, and means for providing an electrical signal to the elongated electrical conductor. (27) The process according to the above (1), wherein the electronic circuit component is a substrate having an electric conductor pattern. (28) providing a substrate surface having a plurality of wire bondable locations; wire bonding wires to each of the wire bondable locations using a wire capillary tool; and After controlling the position of the capillary tool and forming a wire bond to the wire bondable location of the wire, moving the capillary tool relative to the surface when the capillary tool leaves the surface. Forming a wire having a predetermined shape.

[Brief description of the drawings]

FIG. 1 shows the steps of a standard wire bonding process.

FIG. 2 illustrates a preferred embodiment of a bent flying lead wire bonding process.

FIG. 3 illustrates a preferred embodiment of a bent flying lead wire bonding process.

FIG. 4 illustrates a preferred embodiment of a bent flying lead wire bonding process.

FIG. 5 illustrates a preferred embodiment of a bent flying lead wire bonding process.

FIG. 6 illustrates a preferred embodiment of a bent flying lead wire bonding process.

FIG. 7 illustrates another embodiment of a bent flying lead wire bonding process.

FIG. 8 illustrates another embodiment of a bent flying lead wire bonding process.

FIG. 9 illustrates various configurations of bent flying lead wire shapes.

FIG. 10 illustrates various configurations of bent flying lead wire shapes.

FIG. 11 illustrates various configurations of bent flying lead wire shapes.

FIG. 12 illustrates various forms of bent flying lead wire shapes.

FIG. 13 illustrates various shapes of a wire tip made to facilitate engaging the wire tip with a pad of an electronic device.

FIG. 14 shows a schematic of a frame structure used to control the accuracy of wire positioning and to provide a coefficient of thermal expansion that matches the coefficient of thermal expansion of silicon at elevated temperatures for wafer testing.

FIG. 15 is a schematic diagram showing a structure according to the present invention in a test apparatus.

Continuing on the front page (72) Inventor Kiess Edward Vogel U.S.A. 19,4747, Mohegan Lake, New York, Lux Lane 4 (72) Inventor Paul Alfred Lalo, U.S.A. 10954, Naut, NY, Apartment Day, James Drive 4 (72) Inventor Dahyun Siey 12603 U.S.A., 12603, Vervalen Drive, Poughkeepsie, NY 16 (56) Reference U.S. Pat. Field (Int.Cl. ⁷ , DB name) H01L

Claims (27)

(57) [Claims] 1. A process for making a bent flying lead wire structure to be attached to an electronic circuit component, the process being used to bond the flying lead wire to a surface of the electronic circuit component. A second cutting step in which movement of a wire capillary tool and an XY stage is controlled to form a desired shape in the flying lead wire; A third process step positioned to contact the lead wire; and the flying lead while the capillary tool is lifted to tension the flying lead wire against the cutting blade. The wire is held by a clamp and the single cutting blade A fourth process for cutting said flying lead wires.
And a process comprising: 2. The process of claim 1, further comprising forming a plurality of angles on said flying lead wire with respect to a surface of said electronic circuit component. 3. The process of claim 2, further comprising forming said flying lead wires at a plurality of heights with respect to a surface of said electronic circuit component. 4. The method of claim 1, further comprising forming the lead wire such that the flying lead wire has a shape that is straight, partially straight, continuously curved, and any combination thereof. 4. The process of claim 3 comprising: 5. A process for making a bent flying lead wire structure for attachment to an electronic circuit component, the method comprising: bonding the flying lead wire to a surface of the electronic circuit component; Controlling the movement of the wire capillary tool and the XY stage to form the desired shape on the wire; and a double cut positioned on both sides of the flying lead wire to make small notches on both sides of the wire. Cutting the flying lead wire with a mechanism having a blade; raising the capillary tool to cut the wire at the point where the notch is made by the cutting blade; and bending the flying wire. The lead wire has a wire tip; Process. 6. The process of claim 5, further comprising forming a plurality of angles on said flying lead wire with respect to a surface of said electronic circuit component. 7. The process of claim 6, further comprising forming said flying lead wires at a plurality of heights with respect to a surface of said electronic circuit component. 8. The method of claim 1, further comprising maintaining the flying lead wire in place by arranging a sheet of material having a plurality of openings such that the flying lead wire passes through the opening. Process according to 2, 3, 4 or 5. 9. The process of claim 8, wherein a compliant frame structure is used to support the sheet of material. 10. The process of claim 8, wherein said sheet is separated from said surface by electronic components to provide flexible support. 11. The sheet is separated from the surface of the electronic component by a rigid support, and the rigid support isolates or stops the wire to limit the extent of movement of the wire tip in a direction perpendicular to the surface. Claim 8 to work as a child
The process described in. 12. The process of claim 8, wherein said sheet is separated from said surface of an electronic component by a support having a composite structure of rigid and conformable layers. 13. The process of claim 10, wherein the space between the surface of the electronic component and the sheet is filled with a compliant medium. 14. The compliant medium is an elastic material.
The process described in. 15. The process of claim 13, wherein the compliant medium is a foamed polymer material. 16. The process of claim 10, wherein said flexible support is selected from a spring or a resilient material. 17. The wire tip has a shape selected from any of a nodule, a ball contact shape, a straight contact end, a sharp needle, a plurality of sharp needles, a sharp nodule, and a combination thereof. The process of claim 8. 18. The wire tip is Ir, Pd, Pt, N
9. The process according to claim 8, wherein the process is selected from i, Au, Rh, Re, Co, Cu and alloys thereof. 19. The bent flying lead wire may be formed of Ir, Pd, Pt, Ni, Au, Rh, Re, C
9. The process according to claim 8, wherein the process is coated with a material selected from the group consisting of o, Cu and an alloy thereof. 20. The process according to claim 8, wherein said sheet is made of a material selected from the group consisting of invar laminate, Cu / invar / Cu laminate, and molybdenum laminate. 21. The process of claim 8, wherein said sheet comprises a material selected from the group consisting of metals, polymers, semiconductors and dielectrics. 22. The process according to claim 20, wherein said sheet is coated with a polymer layer. 23. The process according to claim 20, wherein said sheet is coated with an insulating layer. 24. The process according to claim 20, wherein said sheet is coated with a thin layer of a compliant polymer. 25. The process according to claim 20, wherein said sheet is laminated between two insulating layers. 26. Apparatus for testing an electronic device, comprising: means for retaining the structure of claim 1; and a plurality of openings through which said flying lead wires pass. A sheet for maintaining a predetermined position; and a structure for retractably moving the structure toward and away from the electronic device such that the wire tip contacts an electrical contact location on the electronic device. Means for providing an electrical signal to the elongate electrical conductor. 27. The process according to claim 1, wherein said electronic circuit component is a substrate having a pattern of electrical conductors.