US-12628682-B2 - Bonding systems for bonding a semiconductor element to a substrate, and related methods

Abstract

A bonding system for bonding a semiconductor element to a substrate is provided. The bonding system includes a manifold configured to provide a reducing gas to a bonding area of the bonding system. At least a portion of the manifold is heated.

Inventors

• Adeel Ahmad Bajwa
• Thomas J. Colosimo, JR.
• Matthew B. Wasserman
• Robert N. Chylak

Assignees

• KULICKE AND SOFFA INDUSTRIES, INC.

Dates

Publication Date

20260512

Application Date

20240402

Claims (20)

1. 1 . A bonding system for bonding a semiconductor element to a substrate, the bonding system comprising: a manifold configured to provide a reducing gas to a bonding area of the bonding system; and a heating element for heating at least a portion of the manifold, according to a heat profile, wherein the heat profile includes a time-based heating process having a first temperature setpoint prior to bonding and a second temperature setpoint during bonding.
2. 2 . The bonding system of claim 1 further comprising a gas delivery line configured to transport the reducing gas from a reducing gas source of the bonding system to the manifold, at least a portion of the gas delivery line being heated.
3. 3 . The bonding system of claim 2 wherein the heating element is configured to heat (i) the manifold and (ii) at least the portion of the gas delivery line.
4. 4 . The bonding system of claim 2 further comprising another heating element, the another heating element being configured to heat at least the portion of the gas delivery line.
5. 5 . The bonding system of claim 1 wherein the heat profile is at least partially determined using a temperature of a reducing gas source, wherein the heat profile includes a temperature greater than a temperature of the reducing gas source.
6. 6 . The bonding system of claim 1 further comprising a bonding tool configured to carry the semiconductor element and to bond the semiconductor element to the substrate in connection with a bonding operation.
7. 7 . The bonding system of claim 2 wherein the reducing gas source is a bubbler type system.
8. 8 . The bonding system of claim 1 further comprising a substrate oxide prevention chamber configured to receive a substrate prior to bonding a semiconductor element to a substrate, the substrate oxide prevention chamber having an inert environment when receiving the substrate.
9. 9 . The bonding system of claim 1 further comprising a gas delivery line configured to transport the reducing gas from a reducing gas source of the bonding system to the manifold, wherein the heating element is configured for heating an entire length of the gas delivery line from the reducing gas source to the manifold.
10. 10 . The bonding system of claim 1 wherein the heating element is configured for heating the at least a portion of the manifold above a dew point of the reducing gas to reduce a potential for condensation of the reducing gas.
11. 11 . The bonding system of claim 1 wherein the reducing gas is a formic acid vapor.
12. 12 . The bonding system of claim 1 further comprising a bond head assembly carrying a bonding tool for bonding the semiconductor element to the substrate, the manifold being carried by the bond head assembly.
13. 13 . A method of bonding a semiconductor element to a substrate, the method comprising the steps of: (a) directing a reducing gas from a reducing gas source to a manifold of a bonding system, the manifold distributing the reducing gas to a bonding area of the bonding system; (b) heating the manifold according to a heat profile with a heating element, wherein the heat profile includes a time-based heating process having a first temperature setpoint prior to bonding and a second temperature setpoint during bonding; and (c) bonding a semiconductor element to a substrate at the bonding area.
14. 14 . The method of claim 13 wherein step (a) includes delivering the reducing gas from the reducing gas source to the manifold via a gas delivery line, and step (b) includes heating at least a portion of the gas delivery line.
15. 15 . The method of claim 14 wherein step (b) includes heating the manifold and at least the portion of the gas delivery line with the heating element.
16. 16 . The method of claim 14 wherein step (b) includes heating the manifold with the heating element, and heating at least the portion of the gas delivery line with another heating element.
17. 17 . The bonding system of claim 13 wherein step (c) includes bonding the semiconductor element to the substrate at the bonding area with a bonding tool configured to carry the semiconductor element and to bond the semiconductor element to the substrate in connection with a bonding operation.
18. 18 . The bonding system of claim 13 wherein step (b) includes heating an entire length of the gas delivery line from the reducing gas source to the manifold.
19. 19 . The bonding system of claim 13 wherein step (b) includes heating the manifold above a dew point of the reducing gas to reduce a potential for condensation of the reducing gas.
20. 20 . A bonding system for bonding a semiconductor element to a substrate, the bonding system comprising: a manifold configured to provide a reducing gas to a bonding area of the bonding system during a bonding operation; a heating element for heating at least a portion of the manifold; and a bonding tool configured to carry the semiconductor element and to bond the semiconductor element to the substrate in connection with the bonding operation.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 18/227,202 filed on Jul. 27, 2023, which claims the benefit of U.S. Provisional Application No. 63/398,328, filed on Aug. 16, 2022, the content of both of which is incorporated herein by reference. FIELD The invention relates to bonding systems (such as flip chip and/or thermocompression bonding systems) and related bonding processes, and more particularly, to improved systems and methods for bonding a semiconductor element to a substrate including the use of a reducing gas. BACKGROUND Traditional semiconductor packaging typically involves die attach processes and wire bonding processes. Advanced semiconductor packaging technologies (e.g., flip chip bonding, thermocompression bonding, etc.) technologies continue to gain traction in the industry. For example, in thermocompression bonding (i.e., TCB), heat and/or pressure (and sometimes ultrasonic energy) are used to form a plurality of interconnections between (i) electrically conductive structures on a semiconductor element and (ii) electrically conductive structures on a substrate. In certain flip chip bonding or thermocompression bonding applications, the electrically conductive structures of the semiconductor element and/or the substrate may include copper structures (e.g., copper pillars) or other material(s) that is subject to oxidation and/or other contamination. In such applications, it is desirable to provide an environment suitable for bonding. Conventionally, such an environment may be provided by using a reducing gas at the bonding area to reduce potential oxidation and/or contamination of the electrically conductive structures of the semiconductor element or the substrate to which it will be bonded. It would be desirable to provide improved bonding systems for bonding such semiconductor elements to a substrate, and related methods. SUMMARY According to an exemplary embodiment of the invention, a bonding system for bonding a semiconductor element to a substrate is provided. The bonding system includes a reducing gas delivery system configured to provide a reducing gas to a bonding area of a bonding system. The bonding system also includes a gas delivery line configured to transport the reducing gas from a reducing gas source to the reducing gas delivery system. At least a portion of the gas delivery line is heated. According to various exemplary embodiments of the invention, the bonding system of the immediately preceding paragraph may include any one or more of the following features: a portion of a manifold for distributing the reducing gas may also be heated with a heating element; the reducing gas is a formic acid vapor; the formic acid vapor has a concentration of 4-15% formic acid; a heating element for heating the gas delivery line; the gas delivery line is heated according to a heat profile; the heat profile is at least partially determined using a temperature of the reducing gas source; the heat profile includes a temperature greater than the temperature of the reducing gas source; the temperature of the reducing gas source is 20° C.-70° C.; the reducing gas source is a bubbler type system; a substrate oxide prevention chamber configured to receive a substrate prior to bonding a semiconductor element to a substrate, the substrate oxide prevention chamber having an inert environment when receiving the substrate; a substrate oxide reduction chamber configured to receive the substrate prior to receipt of the substrate by the substrate oxide prevention chamber and configured to receive the reducing gas, and further comprising another reducing gas delivery system configured to provide the reducing gas to the substrate oxide reduction chamber; and an additional gas delivery line configured to transport the reducing gas from the reducing gas source to the substrate oxide reduction chamber, wherein at least a portion of the additional gas delivery line is heated. According to another exemplary embodiment of the invention, a method of bonding a semiconductor element to a substrate is provided. The method includes: directing a reducing gas from a reducing gas source to a bonding area of a bonding system using a gas delivery line; heating at least a portion of the gas delivery line; and bonding a semiconductor element to a substrate at the bonding area. According to various exemplary embodiments of the invention, the method of the immediately preceding paragraph may include any one or more of the following features: a portion of a manifold for distributing the reducing gas may also be heated with a heating element; the directing step includes delivering the reducing gas to the bonding area via a reducing gas delivery system; the reducing gas is a formic acid vapor; the formic acid vapor has a concentration of 4-15% formic acid; the heating step includes heating the gas delivery line (e.g., using a heating element) according to a heat profi