The invention relates to semiconductor components, and more particularly, to scribe seal architectures for use in semiconductor components.
In semiconductor electronics, the general trend toward smaller form factors is continuous. In order to reduce form factors, more circuitry must be placed on less wafer real estate. Placing a system containing different types of circuitry on a single chip can reduce form factor and enhance performance. Frequently, system-on-a-chip (SOC) semiconductor devices are used for various applications such as high-speed data transmission and signal processing in wireless and wired systems. As spacing for functional circuit blocks shrinks, however, adjacent circuit blocks may begin to interfere with one another, reducing their performance. Each of the SOC functional blocks may have its own range of power supply conditions and performance requirements. Different power domains may co-exist for digital and analog and RF functional blocks on an integrated chip, for example.
The sharing of a common substrate for different circuit blocks can introduce noise problems. Various efforts to address noise concerns have been used in the arts. For example, it is known to spatially separate circuits in an effort to reduce noise. Other approaches include separating the ground and power supply connections of functional circuit blocks, or placing structures between circuit blocks in order to reduce unwanted current flow.
Generally, numerous semiconductor devices are manufactured using a single semiconductor wafer substrate. The wafer is typically partitioned into individual rectangular dice or chips using scribe streets or lanes. After the layers of circuitry and associated metallic interconnects have been applied to the active regions of the chips, the wafers are sawn along scribe lines to singulate the chips. The chips then undergo further packaging and testing for shipment to customers for inclusion in electronic systems. The sawing process inevitably causes chipping and cracking along the scribe streets. In order to prevent or reduce the propagation of cracks, it is known to design the scribe streets to ensure that the remaining material surrounds the active region of a chip with a scribe seal structure. Multiple layers of metallic and dielectric material are applied laterally adjacent to, or extending across the scribe street for a distance greater than the saw kerf. Alternating metal layers are typically coupled vertically with metal-filled vias and trenches. When the wafer is sawn along the scribe line, a seal structure remains around the edge of each individual chip. It is also known to use a second, inner scribe seal structure around the periphery of each chip, substantially parallel to the outer seal, in order to further isolate the active area from potential physical damage, noise, and ESD events.
In SOC designs, it is known to use an inner guard ring scribe seal structure between functional circuit blocks, such as analog and digital circuit blocks, to segregate the blocks and reduce noise. This approach to noise reduction between the blocks is highly desirable from a manufacturing viewpoint, since no new techniques or process steps are required. The intra-chip scribe seal is prepared as for an inner peripheral seal. However, since the SOC blocks continue to share the same substrate, in some instances noise propagation between the circuit blocks can be a problem.
Due to these and other problems, improved edge and intra-chip scribe seal structures for sealing and separating functional circuit blocks in SOC devices would be useful and advantageous in the arts. Preferably, the technological innovations providing improved scribe seals and circuit block separation would be flexible enough to be applied to various semiconductor product families and would be accomplished using established manufacturing techniques so that substantial investment in new manufacturing processes is not required.
In carrying out the principles of the present invention, in accordance with preferred embodiments thereof, scribe lane structures form edge and intra-chip seals for use in protecting semiconductor integrated circuitry.
According to a preferred embodiment, an integrated circuit chip includes two substantially parallel scribe seal structures around the periphery of the chip, the two scribe seal structures having a separation gap.
According to another aspect of the invention, an embodiment of the invention also includes two or more distinctive circuitry blocks such as analog and digital circuitry, separated by an intra-chip seal. The intra-chip seal preferably also includes two substantially parallel scribe seal structures separating the circuit blocks, the two scribe seal structures have a separation gap.
According to yet another aspect of the invention, an integrated circuit having two or more distinctive circuit blocks separated by a scribe seal structure with a separation gap also includes a routing channel for use in passing signals among the circuit blocks.
According to another aspect of the invention, an integrated circuit chip embodiment includes an analog circuitry block and digital circuitry block with an intra-chip scribe seal separating the analog block from the digital block. The intra-chip seal has two substantially parallel scribe seal structures between the circuit blocks with a separation gap. A routing channel is included, coupling the analog block with the digital block for conducting electrical signals between the circuitry blocks.
According to still another aspect of the invention, a semiconductor wafer includes an array of numerous integrated circuit chips, each encompassed by two substantially parallel scribe seal structures at its periphery. The scribe seal structures include a separation gap.
According to another embodiment of the invention, a semiconductor wafer has an array of integrated circuit chips bordered by scribe streets and separated by scribe lines. Each of the integrated circuit chips thereon includes two substantially parallel scribe seal structures at the periphery with a separation gap at the wafer substrate. Each chip also has an analog circuitry block and a digital circuitry block with an intra-chip scribe seal separating the blocks. The intra-chip seal also includes two substantially parallel scribe seal structures between each circuitry block, the two scribe seal structures having a separation gap, and a routing channel coupling the analog block with the digital block for conducting electrical signals between them.
The invention has numerous advantages including but not limited to providing a reliable edge seal and intra-chip seal for inhibiting noise propagation among chip blocks. These and other features, advantages, and benefits of the present invention can be understood by one of ordinary skill in the arts upon careful consideration of the detailed description of representative embodiments of the invention in connection with the accompanying drawings.
The present invention will be more clearly understood from consideration of the following detailed description and drawings in which:
References in the detailed description correspond to like references in the various figures unless otherwise noted. Descriptive and directional terms used in the written description such as first, second, top, bottom, upper, side, etc., refer to the drawings themselves as laid out on the paper and not to physical limitations of the invention unless specifically noted. The drawings are not to scale, and some features of embodiments shown and discussed are simplified or amplified for illustrating the principles, features, and advantages of the invention.
In general, the invention relates to semiconductor wafers and to integrated circuit chips constructed using semiconductor wafers. In the preferred embodiments described, a semiconductor wafer includes multiple system-on-chip (SOC) devices, each of which in turn preferably includes two or more distinctive blocks of circuitry, such as an analog block and a digital block.
Preferably, a plurality of chips are formed simultaneously on a wafer of semiconductor material. After completion of the fabrication processes, the individual devices are singulated by sawing along scribe lines centered upon the scribe streets. The scribe streets are sufficiently wide to allow for the sacrifice of some material due to the saw kerf, with enough material at the edge of the singulated chip to leave an outer seal about the periphery of the device.
Protection against damage from electrostatic discharge (ESD) events is preferably provided concurrently with the seals of the invention. As shown in
Now referring primarily to
The example of a preferred embodiment of the scribe seal architecture of the invention shown in
It should be appreciated by those skilled in the arts that seals according to the invention may use fabrication techniques and processes common for semiconductor wafer manufacture. The invention provides advantages including but not limited to providing noise isolation for and among blocks of a multi-block integrated circuit, as well as providing an isolated intra-chip electrical connection among circuit blocks. While the invention has been described with reference to certain illustrative embodiments, the devices described are not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other advantages and embodiments of the invention will be apparent to persons skilled in the art upon reference to the description and claims.