Today, in a newly published patent application from Apple Inc., we get to see a glimpse behind one of the many processes behind their new powerhouse A4 processor. Apple's patent reveals systems and methods for providing a system-on-a-substrate. In particular, this patent relates to systems and methods for reducing the total size of a system's circuitry by providing all of the components of the system on the same microchip. A microchip that the patent reveals is behind the iPad, iPhone and likely to be used in other future Apple products such as Apple TV.
Systems, such as systems for an electronic device, are often created from multiple components. For example, the components of a system could include one or more of a processor, memory (e.g., RAM, SDRAM, DDR RAM, or ROM), CODEC circuitry, Input/Output ("I/O") circuitry, communication circuitry, accelerometers, capacitors, inductors, or any other suitable components. Traditionally, each of these components is a distinct "entity" and could be created on a separate microchip or could be included in a separate package.
To create the circuitry for the entire system, the separate components (e.g., separate microchips) are typically coupled together through a printed circuit board ("PCB") or other suitable medium. The PCB could be fabricated with the appropriate wiring or routing to suitably connect all of the separate components.
Apple's patent generally relates to systems and methods for providing a system-on-a-substrate (like an SOC). For example, rather than including the components of a system as discrete entities (e.g., as discrete microchips or as discrete parts), the components of a system could be formed together in "bare die" form. In other words, the components could be formed together on a single substrate, such as a silicon die or a die of other suitable material. In this manner, the components of an entire system could be densely and efficiently packed together, thus allowing the system to achieve a smaller size than a system using components that are discrete entities.
The components could include, for example, one or more of a processor, memory (e.g., RAM, SDRAM, DDR RAM, and ROM), CODEC circuitry, Input/Output ("I/O") circuitry, communication circuitry, accelerometers, capacitors, or any other suitable components.
In some embodiments, a die including the components of a system could be coupled to a substrate. The substrate, in turn, could be coupled to a flexible printed circuit board ("flex"). The substrate and the flex could include any suitable wiring and routing to electrically couple the die to other parts of the system such as, for example, a flash memory. In some embodiments, the flex can be coupled to a different surface of the substrate than the die. In some embodiments, the flex can be coupled to the same surface of the substrate as the die.
In some embodiments, the flex could include a ledge to which one or more components could be coupled. In some embodiments, a system could be created which does not include a substrate. In this case, all necessary wiring could be provided through the flex. In some embodiments, test points could be provided for a component of a die. For example, the test points could be included in a portion of the flex located substantially below the component to be tested.
In some embodiments, rather than being included together in a single die, the components of a system could be included as discrete entities. The discrete entities could be coupled to a substrate rather than being coupled to a printed circuit board ("PCB"). As a substrate can have more stringent design rules than a PCB, coupling the discrete entities to the substrate could allow for a system that is smaller and more compact in size. For example, the wiring for the system could be created using fewer layers and could be formed more densely in a substrate than in a PCB.
Apple's patent, in respect to components discussed earlier, states that "A system utilizing these components could be included in any suitable electronic device such as, for example, a cellular telep