EP-4739078-A1 - A METHOD OF MANUFACTURING A SEMICONDUCTOR DEVICE

Abstract

The present disclosure relates to a method of manufacturing a semiconductor device, specifically of the connection of a bonding wire to a semiconductor die. In a first aspect of the disclosure, there is provided a method of manufacturing a semiconductor device, comprising the steps of: - providing a semiconductor die onto a substrate; - applying a paste to said semiconductor die; - connecting a bonding wire to said paste by means of ultrasonic motion.

Inventors

• LIU, XU
• Wang, Ruitong
• Ti, Ching Shian

Assignees

• Nexperia B.V.

Dates

Publication Date

20260506

Application Date

20251029

Claims (16)

1. A method of manufacturing a semiconductor device, comprising the steps of: - providing a semiconductor die onto a substrate; - applying a paste to said semiconductor die; - connecting a bonding wire to said paste by means of ultrasonic motion.
2. The method according to claim 1, wherein the ultrasonic motion of the step of connecting has a duration of in between 1 µs and 1000 µs.
3. The method according to any of the previous claims, wherein prior to the step of connecting and after the step of applying a paste, the method comprises the step of drying the paste.
4. The method according to any of the previous claims, wherein the paste comprises a metal sintering paste, preferably comprising copper particles.
5. The method according to any of the previous claims, wherein the bonding wire comprises a metal, preferably copper.
6. The method according to any of the previous claims, wherein the step of applying the paste comprises any of: - printing; - dispensing; - injecting; - spraying; - pick-and-place.
7. The method according to any of the previous claims, wherein the paste comprises a thickness of in between 10 µm and 500 µm preferably in between 30 µm and 100 µm and even more preferably in between 50 µm and 70 µm.
8. The method according to claim 3, wherein the step of drying comprises pre-baking the semiconductor device.
9. The method according to any of the previous claims, wherein the step of connecting comprises applying a localized increase in temperature and/or pressure.
10. The method according to claim 9, wherein the localized increased temperature is in between 100 and 300 degrees Celsius.
11. The method according to any of the claims 9-10, wherein the localized increased pressure is in between 1 MPa and 200 MPa.
12. The method according to any of the previous claims, wherein the ultrasonic motion of the step of connecting comprises any of: - a lateral motion; - a vertical motion, in a direction away from and towards the semiconductor die.
13. The method according to any of the previous claims, wherein the step of connecting by means of ultrasonic motion comprises sintering the entire paste.
14. The method according to any of the claims 1-12, wherein the step of connecting by means of ultrasonic motion comprises sintering a connection part of the paste connected to the bonding wire.
15. The method according to claim 14, wherein the method comprises an additional step of sintering a remaining part of the paste.
16. The method according to any of the previous claims, wherein during the step of connecting, external heating is applied to the semiconductor device, thereby increasing the temperature of the paste.

Description

Technical field The present disclosure relates to a method of manufacturing a semiconductor device, specifically of the connection of a bonding wire to a semiconductor die. Background Wire bonding is a process used in semiconductor device packaging to create electrical connections between the semiconductor die (the chip) and the external leads or substrate. This may be done using thin metal wires, most commonly made from gold, aluminum, or copper. Using copper (Cu) wire in wire bonding may offer advantages, including lower cost compared to gold, better electrical conductivity, and higher current-carrying capacity. Copper also provides superior thermal conductivity, which helps in dissipating heat more efficiently, making it ideal for high-power applications. Additionally, its mechanical strength enhances durability and reliability, especially in environments prone to mechanical stress. Copper's ability to be used in thinner wires without compromising performance supports further miniaturization of electronic components. However, bonding process for thicker wires, especially copper, can introduce more mechanical stress on the bond pads and underlying structures of the die. The added mechanical load can cause delamination, pad lifting, or even damage to the underlying circuitry. One approach to solve this issue is to apply a copper metallization layer during the wafer process. However, the cost may be high due to the front-end process steps including lithography, sputtering, electroplating, and etching, and the thickness of the metallization layer will be limited. Another approach is to bond an additional buffer bulk metal layer on the top surface of the chip by soldering or sintering. However, the manufacturing of such metal buffer components may require special care and this introduces an additional joining step in the method of manufacturing, which increases the process complexity. Summary A summary of aspects of certain examples disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects and/or a combination of aspects that may not be set forth. The present disclosure aims to overcome the drawbacks identified in the background section. In a first aspect of the disclosure, there is provided a method of manufacturing a semiconductor device, comprising the steps of: providing a semiconductor die onto a substrate;applying a paste to said semiconductor die;connecting a bonding wire to said paste by means of ultrasonic motion. The inventors have found that it may be beneficial to provide a method of manufacturing a semiconductor device, in particular the process of connecting a bonding wire to a semiconductor device, wherein the method is more streamlined than the prior art. Herein, as the background suggests, there is a need for a simplified connection step. The inventors have found that it may be beneficial to provide a paste on the semiconductor die. In specific, this paste is applied to the top surface of the chip. The paste may comprise separated particles, which may form a dense and complete layer after the step of connecting by means of ultrasonic motion.The paste is simple to be applied to the semiconductor die as it is a malleable substance. The paste may comprise a film, preform, ink or other paste like forms. The step of connecting comprises providing a bonding wire in the paste, after which the bonding wire is vibrated or ultrasonically moved. This results in the forming of a dense layer on top of the semiconductor die, wherein the dense layer comprises the attached bonding wire. This therefore allows for a method of manufacturing having low constraints on the bonding process. This results in a faster process and a more streamlined process, resulting in a strong bond between the bonding wire and the semiconductor die. This may result in a structure having no die cracking issues as well as no delamination, pad lifting or damage to underlying circuitry. In an example of the disclosure, the ultrasonic motion of the step of connecting has a duration of in between 1 µs and 1000 µs. Due to the localized high temperature and high pressure, which may be partly due to a pressure being exerted on the paste by the bonding wire during the step of connecting, the paste may fully sinter in a short time. This is beneficial as it allows for a fast connection process. In an example of the disclosure, prior to the step of connecting and after the step of applying a paste, the method comprises the step of drying the paste. Drying the paste prior to the step of connecting allows the bonding process to sinter fully. Compared with the wet paste, the as-dried pad contains features: The solvent is evaporated and only the solid content remaining. If you do WB directly on the we