INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

Field

The present disclosure is directed to a moisture barrier for use between bond pads and other components in an integrated circuit, and more particularly to a moisture barrier for use between bond pads and other components in integrated circuits that use a polyimide interlayer insulator.

Description of the Related Art

Some semiconductor integrated circuits (ICs) use polyimide as an interlayer insulator. However, during operation under ambient conditions, as well as during high accelerated stress testing (HAST) test conditions (high temperature, high pressure, high moisture conditions), polyimide acts as a wick to draw moisture from outside and transport it to sensitive elements on the ICs, such as bond pads that are used for high voltage and are near die edges or close to other components that are low voltage. In the presence of moisture, metal migration between bond pads and other components (e.g., other bond pads, capacitors) has been seen to cause a short circuit (e.g., in products that use gold-based metallization and polyimide based isolation between metal layers). Such moisture primarily travels along an interface between adjacent polyimide layers.

SUMMARY

Accordingly, there is a need for an improved manner to avoid moisture exposure to bond pads that can cause metal migration between the bond pads or between a bond pad and another component (e.g., a capacitor), that can lead to a short circuit, such as in semiconductor integrated circuits that use polyimide as an interlayer insulator.

In accordance with one aspect of the invention, a packaged module is provided with a moat (e.g., a no polyimide zone) proximate that provides a moisture barrier. In one implementation, the moat is provided around one or more bond pads (e.g., provided around each bond pad).

In accordance with one aspect of the disclosure, a semiconductor die is provided. The semiconductor die comprises a substrate layer and one or more metal layers disposed over the substrate layer. The semiconductor die also comprises a first polymer interlevel dielectric layer and a second polymer interlevel dielectric layer disposed over the substrate, at least one of the first and second polymer interlevel dielectric layers spaced from (e.g., laterally spaced from) the one or more metal layers by a trench so that an interface between the first and second polymer interlevel dielectric layers is spaced apart from the one or more metal layers. The semiconductor die also comprises a topcoat insulation layer disposed over the one or more metal layers and one or more polymer interlevel dielectric layers. The top coat insulation layer is impervious to moisture and the trench inhibits migration of moisture along the interface to the one or more metal layers, thereby preventing metal migration from the one or more metal layers along the interface.

In accordance with another aspect of the disclosure, a radiofrequency module is provided. The radiofrequency module comprises a printed circuit board. The radiofrequency module also comprises a semiconductor die mounted on the printed circuit board. The semiconductor die comprises a substrate layer and one or more metal layers disposed over the substrate layer. The semiconductor die also comprises a first polymer interlevel dielectric layer and a second polymer interlevel dielectric layer disposed over the substrate, at least one of the first and second polymer interlevel dielectric layers spaced from (e.g., laterally spaced from) the one or more metal layers by a trench so that an interface between the first and second polymer interlevel dielectric layers is spaced apart from the one or more metal layers. The semiconductor die also comprises a topcoat insulation layer disposed over the one or more metal layers and one or more polymer interlevel dielectric layers. The top coat insulation layer is impervious to moisture and the trench inhibits migration of moisture along the interface to the one or more metal layers, thereby preventing metal migration from the one or more metal layers along the interface.

In accordance with another aspect of the disclosure, a wireless mobile device is provided. The wireless mobile device comprises one or more antennas, a front end system that communicates with the one or more antennas, and a semiconductor die. The semiconductor die comprises a substrate layer and one or more metal layers disposed over the substrate layer. The semiconductor die also comprises a first polymer interlevel dielectric layer and a second polymer interlevel dielectric layer disposed over the substrate, at least one of the first and second polymer interlevel dielectric layers spaced from (e.g., laterally spaced from) the one or more metal layers by a trench so that an interface between the first and second polymer interlevel dielectric layers is spaced apart from the one or more metal layers. The semiconductor die also comprises a topcoat insulation layer disposed over the one or more metal layers and one or more polymer interlevel dielectric layers. The top coat insulation layer is impervious to moisture and the trench inhibits migration of moisture along the interface to the one or more metal layers, thereby preventing metal migration from the one or more metal layers along the interface.

In accordance with another aspect of the disclosure, a method of making a semiconductor die is provided. The method comprises forming or providing a substrate layer, and forming or applying one or more metal layers over the substrate layer. The method also comprises forming or applying a first polymer interlevel dielectric layer over the substrate layer and forming or applying a second polymer interlevel dielectric layer over the first polymer interlevel dielectric layer to define an interface therebetween. At least a portion of the first and second polymer interlevel dielectric layers are adjacent at least one of the one or more metal layers. The method also comprises forming a trench in the one or both of the first and second polymer interlevel dielectric layers and filling the trench such that the interface between the first and second polymer interlevel dielectric layers is separated from (e.g., laterally separated from) the one or more metal layers. The method also comprises forming or applying a topcoat insulation layer over the one or more metal layers and first and second polymer interlevel dielectric layers, the topcoat insulation layer being impervious to moisture. The trench inhibits migration of moisture along the interface to the one or more metal layers, thereby preventing metal migration from the one or more metal layers along the interface.

In accordance with another aspect of the disclosure, a method of making a radiofrequency module is provided. The method comprises forming or providing a printed circuit board that includes a substrate layer. The method also comprises forming or providing a semiconductor die. Forming or providing the semiconductor die comprises forming or providing a substrate layer, and forming or applying one or more metal layers over the substrate layer. Forming or providing the semiconductor die also comprises forming or applying a first polymer interlevel dielectric layer over the substrate layer and forming or applying a second polymer interlevel dielectric layer over the first polymer interlevel dielectric layer to define an interface therebetween. At least a portion of the first and second polymer interlevel dielectric layers are adjacent at least one of the one or more metal layers. Forming or providing the semiconductor die also comprises forming a trench in the one or both of the first and second polymer interlevel dielectric layers and filling the trench such that the interface between the first and second polymer interlevel dielectric layers is separated from (e.g., laterally separated from) the one or more metal layers. Forming or providing the semiconductor die also comprises forming or applying a topcoat insulation layer over the one or more metal layers and first and second polymer interlevel dielectric layers, the topcoat insulation layer being impervious to moisture. The trench inhibits migration of moisture along the interface to the one or more metal layers, thereby preventing metal migration from the one or more metal layers along the interface. The method also comprises mounting the semiconductor die on the printed circuit board.

