Texas Instruments Corporation

Rafael C Alfaro

Thomas H Ramsey

Katherine G Heinen

Michael A Mignardi

Paul Joseph Hundt

Gonzalo Amador

James R Peterson

David B Blair

Robert A Davis

Lau B Howe

An apparatus for breaking a wafer into individual devices. An anvil 100 is pressed against a flexible membrane 304 on which a wafer 300 is attached. A vacuum is applied to the anvil 100 which allows the flexible membrane 304 and the wafer 300 to be pressed against the face of the anvil 100. As the flexible membrane 304 is deformed against the anvil 100, the wafer 300 breaks into individual devices 302. Dicing debris that is created when the wafer 300 is broken falls into a base fixture 408 so that the debris does not contact and damage the devices 302.

Apparatus for breaking and separating dies from a wafer

An apparatus for breaking a wafer into individual devices, and a method of using the same. An anvil 100 is pressed against a flexible membrane 304 on which a wafer 300 is attached. A vacuum is applied to the anvil 100 which allows the flexible membrane 304 and the wafer 300 to be pressed against the face of the anvil 100. As the flexible membrane 304 is deformed against the anvil 100, the wafer 300 breaks into individual devices 302. Dicing debris that is created when the wafer 300 is broken falls into a base fixture 408 so that the debris does not contact and damage the devices 302.

Method and apparatus for breaking and separating dies from a wafer

The present invention provides a thermally enhanced molded cavity package (10) having a package body (12) with upper (40) and lower (42) sections. The package body (12) has a cavity (22) with the cavity opening (32) in the upper section (40) of the package body (12). The present package (10) includes a lead frame (14) with a plurality of individual leads (16) that are external to the cavity (22) and a plurality of lead fingers (28) that are internal to the cavity (22). The present package (10) also includes a heat spreader (34) for increasing heat dissipation from the package (10) in the lower section (42) of the package body (12) and coupled to the lead frame (14). The heat spreader (34) has a first surface (26) forming a floor of the cavity upon which a microcircuit chip (24) may be mounted and a second surface forming a base (36) of the package body (12). The upper section (40) of the package body (12) includes a lid seat (33) for supporting a lid (30) and for maintaining the lid (30) parallel to the floor (26) of the cavity when the lid (30) is placed in the cavity opening (32).

Thermally enhanced molded cavity package having a parallel lid

A process for partially sawing the streets on semiconductor wafers. After sawing the streets can be covered by a protective material, and then the wafer continues its processing as before. After the wafer is broken, the protective material may or may not be removed. Additionally, the wafer may be broken into individual chips using a wedge piece that has a number of individual wedges on it, where the individual wedges press against the partially sawn streets, causing the wafer to break.

Wafer method for breaking a semiconductor

A method is provided for forming a thermally enhanced molded cavity package of a type which includes a lid and which is for housing a microcircuit chip. The molded package includes a heat spreader and a lead frame. The method includes the steps of attaching the lead frame to one surface of the heat spreader. A mold press is secured or clamped to-the lead frame and to the opposite surface of the heat spreader. Molding compound is injected into the press to form the package body having an upper and a lower section. During molding, a cavity is provided in the package body having the first surface of the heat spreader as a cavity floor and a lid seat is constructed in the upper section of the package body for maintaining a lid received thereon substantially parallel with respect to the cavity floor. The heat spreader is bonded to at least one of the package body sections and to at least one of the leads of the lead frame.

Methods for manufacturing a thermally enhanced molded cavity package

A method for electrically connecting integrated circuit copper-gold ball bond that connect a bond wire (18) with a bond pad (14) forms a palladium layer (16) in the electrical connection between the bond wire (18) and the bond pad (14). The connection avoids excessive stresses that arise from intermetallic formations between the bond wire (18) and the bond pad (14).

Method for obtaining metallurgical stability in integrated circuit

Active sites (18) on a semiconductor wafer (14) are protected from particulate and fluid contaminants (40,42)while the wafer (14) is sawed into chips (16) by a tape (62) carrying a pattern of adhesive (64) which is congruent and registerable with saw paths (15) between the active sites (18). Adhering the tape (62) to the wafer (14) encapsulates each active site (18) beneath a non-adherent protective envelope which if formed by adhesive-free portions (68) of the tape (62) as sawing occurs along the saw paths (15) and the congruent adhesive pattern (64). After sawing, the adhesive (64) is treated, as by directing UV through the tape (62), to release the tape (62) from the chips (16).

Grid array masking tape process

Integrated partial sawing process

An (10) and method is provided for bonding wire (12) to the bond sites (28) of integrated circuits (14). In preferred embodiments gold wire (12) is bonded to aluminum bond pad (28). Apparatus (10) includes a high frequency ultrasonic energy source (20) designed to provide ultrasonic energy at frequencies above about 125 kHz. The ultrasonic energy is imparted to the bonding interface (32) via transducer (18) and capillary (16). The transducer is modified in length and tool clamp point (40) is sited on transducer (18) so that the wavelength of the high frequency ultrasonic energy is at the antinodal point in its application to interface (32) and thus is optimized. In the preferred embodiments of the process the ultrasonic energy is applied at about 350 kHz at ambient temperature. In this fashion, the bond formed between bond end (30) and bond pad (28) is optimized in terms of shear strength, bonding time and processing temperatures. Particularly beneficial results are noticed with respect to aluminum alloy bond pads such as Al, 2% copper, which were particularly troublesome in terms of intermetallic formation and bond strength in the prior art. Thus according to the invention, the use of high frequency ultrasonic energy in the aforementioned range, superior strength bonds are formed with greater processing parameter flexibility.

Ultrasonic bonding process beyond 125 kHz

A linear, direct-drive microelectronic bonding apparatus (10) provides a bondhead mounting plate (20), a stationary magnetic circuit (21), a moving coil (22), a primary wire clamp housing (23), a transducer mount (24), and a high frequency ultrasonic transducer (25) (above 100 kHz), and a capillary (26). Bondhead assembly (16) is configured to present a collective axial wire path bore (27) along which wire (12) is fed to bond site (28) for forming microelectronic bond interconnections at bond site (28). In accordance with the invention, collective wire path bore (27) provides a protected method of feeding wire (12) to bonding site (28), while magnetic circuit (21) and moving coil (22) provide actuation in a substantially linear downward direction towards the bonding site. In contradistinction, prior art bonding strokes, rather than being substantially linear, are arc-like due to the capillary and transducer being perpendicular to one another. In the present invention, transducer (25) and capillary (26) are substantially axially aligned. The substantially vertical downward bonding stroke allows bondhead assembly (16) to be used for 'deep access' packages and other hard-to-reach sizes, shapes and designs of packages. In addition, ultrasonic transducer (25) has a reduced mass in comparison to the prior art which, in conjunction with the high frequency ultrasonic energy provides a low amplitude oscillation weld with greater precision and positioning.

Linear, direct-drive microelectronic bonding apparatus and method

An apparatus (10) and method is provided for bonding wire (12) to the bond sites (28) of integrated circuits (14). In preferred embodiments a bond end (30) on gold wire (12) is bonded to aluminum bond pad (28). Apparatus (10) includes a high frequency ultrasonic energy source (20) designed to provide ultrasonic energy at frequencies from about 100 kHz to about 125 kHz. The ultrasonic energy is imparted to the bonding interface (32) via transducer (18) and capillary (16). The transducer (18) is modified in length and tool clamp point (40) is sited on transducer (18) so that the high frequency ultrasonic energy is at the antinodal point in its application to interface (32) and thus is optimized. In preferred embodiments of the process, the ultrasonic energy is applied at about 114 kHz. In this fashion, the bond formed between bond end (30) and bond pad (28) is optimized in terms of shear strength, bonding time and processing temperatures. Particularly beneficial results are noticed with respect to aluminum alloy bond pads such as Al, 2% Cu, which have been particularly troublesome in terms of intermetallic formation and bond strength in the prior art. Thus according to the invention, the use of high frequency ultrasonic energy in the aforementioned range, results in superior strength bonds formed with greater processing parameter flexibility.

Process for enhanced intermetallic growth in IC interconnections

An apparatus (10) and method is provided for bonding wire (12) to the bond sites (28) of integrated circuits. In preferred embodiments gold wire (12) is bonded to aluminum bond pad (28). Apparatus (10) includes a high frequency ultrasonic energy source (20) designed to provide ultrasonic energy at frequencies above about 100 kHz causing the interface temperature required for adequate bonding to be greatly reduced. Heating element (19) applies thermal energy to interface (32) via capillary (16) and transducer (18). Therefore, according to the invention, less thermal energy is required from heater block (22) which is heating interface (32) via IC (14) and leadframe (15). In this fashion, leadframe (15) is maintained at a lesser temperature than in the prior art. Since leadframe (15) is at a lesser temperature, it can be plated with a material having a lower melting point (e.g. tin or solder). In preferred embodiments, leadframe (15) is substantially plated with tin (melting point 185.degree. C.) and maintained at about 165.degree. C. Interface (32) is maintained at about 180.degree. C. by thermal energy from heating element (19) (during the bonding process). In preferred embodiments capillary (16) is substantially made of beryllium oxide for adequate thermal conductivity.

Method and apparatus for transducer heating in low temperature bonding

The disclosure relates to a wire bonding capillary having a body with a cylindrical upper portion and a contiguous lower tip portion, the tip portion having an exterior inward taper and an internal bore extending through the body, the bore having a first substantially constant cross sectional region extending through the cylindrical portion, a second inwardly tapering region contiguous to the first region, a third substantially constant cross sectional region contiguous to the second region, a fourth outwardly tapering region contiguous to the third region and a fifth outwardly tapered region contiguous to the fourth region having greater outward taper than the fourth region. The fourth region has a taper from about forty-five degrees to about ninety degrees and preferably seventy degrees and is substantially bisected by the axis of the bore and the taper in the fifth region is from about one hundred degrees to about one hundred seventy degrees and preferably one hundred ten degrees and is substantially bisected by the axis of the bore.

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Carrollton, TX, United States of America

Rafael C Alfaro