Tape automated bonding leads having a stiffener and a method of bonding with same

Claim 2

A tape automated bonding (TAB) method, comprising the steps of: providing a substrate having an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; bonding the leads to a semiconductor device; and removing the stiffener from the leads by irradiating each lead with a laser beam having a spot diameter which is less than one third of the distance between the focal point of the laser beam and the semiconductor device.

Claim 3

A TAB method according to claim 1, wherein said removing step is performed after bonding step.

Claim 4

A TAB method according to claim 1, wherein said removing step is performed before said bonding step.

Claim 5

A TAB method according to claim 1, wherein said removing step comprises irradiating the leads with a laser beam having a wavelength which is more readily absorbed by the leads than by the semiconductor device.

Claim 6

A TAB method according to claim 1, further comprising the step of providing a coating on the semiconductor device which is reflective to the laser beam prior to said removing step.

Claim 7

A tape automated bonding (TAB) method, comprising the steps of: providing a substrate having an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; bonding the leads to a semiconductor device; and removing the stiffener from the leads by focussing a laser beam on the leads so that the depth of field of the laser beam is less than the distance between the focal point and the semiconductor device.

Claim 8

A tape automated bonding (TAB) method, comprising the steps of: providing a substrate having an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; bonding the leads to a semiconductor device; and removing the stiffener from the leads by focussing a laser beam on the leads so that the depth of field of the laser beam is less than the distance between the focal point and the semiconductor device.

Claim 9

A TAB method according to claim 6, wherein said removing step is performed after bonding step.

Claim 10

A TAB method according to claim 6, wherein said removing step is performed before said bonding step.

Claim 11

A TAB method according to claim 6, wherein said removing step comprises irradiating the leads with a laser beam having a wavelength which is more readily absorbed by the leads than the semiconductor device.

Claim 12

A TAB method according to claim 6, further comprising the step of providing a coating on the semiconductor device which is reflective to the laser beam prior to said removing step.

Claim 13

A process for tape automated bonding (TAB) bonding of leads to bonding pads of a semiconductor device, the bonding pads having a thickness x above the surface of the semiconductor device, comprising the steps of: providing a tape having a first surface facing the semiconductor device, a second surface facing away from the semiconductor device, a thickness y between the first and second surfaces, an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; bonding the leads to the bonding pads of a semiconductor device; and cutting the stiffener from the leads by focussing a laser beam on the first surface of the leads, the laser beam having a spot diameter which is less than approximately (x+y)/3 and having a depth of field less than approximately y.

Claim 14

A process for tape automated bonding (TAB) bonding of leads to bonding pads of a semiconductor device, the bonding pads having a thickness x above the surface of the semiconductor device, comprising the steps of: providing a tape having a first surface facing the semiconductor device, a second surface facing away from the semiconductor device, a thickness y between the first and second surfaces, an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; bonding the leads to the bonding pads of a semiconductor device; and cutting the stiffener from the leads by focussing a laser beam on the first surface of the leads, the laser beam having a spot diameter which is less than approximately (x+y)/3 and having a depth of field less than approximately y.

Claim 15

A method according to claim 11, wherein said cutting step comprises focussing a laser beam having a wavelength of less than approximately 0.5 microns on the leads.

Claim 16

A method according to claim 11, wherein said cutting step comprises focussing a laser beam having a wavelength of approximately 0.19 microns to approximately 0.51 microns on the leads.

Claim 17

A method according to claim 11, wherein said cutting step comprises focussing an excimer laser beam on the leads.

Claim 18

A process for tape automated bonding (TAB) bonding of leads to bonding pads of a semiconductor device, the bonding pads extending a distance x above the surface of the semiconductor device, comprising the steps of: (a) providing a tape having a first surface facing the semiconductor device, a second surface facing away from the semiconductor device, a thickness y between the first and second surfaces, an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; (b) aligning the leads with the bonding pads of the semiconductor device; (c) soldering the leads to the bonding pads after said step (b); (d) providing a beam of laser light having a wavelength of approximately 0.19 microns to approximately 0.51 microns, a power of approximately 10-20 joules per square centimeter and a pulse frequency of approximately 75-100 Hz; (e) passing the beam of laser light through a collimating aperture; (f) focussing the beam of laser light on the first surface of a lead over the surface of the semiconductor device so that the laser beam has a spot diameter which is less than approximately 15 microns and has a depth of field less than approximately y; and (h) pulsing the laser beam until the lead is severed.

Claim 19

A process for tape automated bonding (TAB) bonding of leads to bonding pads of a semiconductor device, the bonding pads extending a distance x above the surface of the semiconductor device, comprising the steps of: (a) providing a tape having a first surface facing the semiconductor device, a second surface facing away from the semiconductor device, a thickness y between the first and second surfaces, an aperture, a plurality of leads extending into the aperture, and a stiffener attached to the portion of the leads extending into the aperture; (b) aligning the leads with the bonding pads of the semiconductor device; (c) soldering the leads to the bonding pads after said step (b); (d) providing a beam of laser light having a wavelength of approximately 0.19 microns to approximately 0.51 microns, a power of approximately 10-20 joules per square centimeter and a pulse frequency of approximately 75-100 Hz; (e) passing the beam of laser light through a collimating aperture; (f) focussing the beam of laser light on the first surface of a lead over the surface of the semiconductor device so that the laser beam has a spot diameter which is less than approximately 15 microns and has a depth of field less than approximately y; and (h) pulsing the laser beam until the lead is severed.