Abstract:
A metal stack (35) for use in an integrated circuit demonstrating improved electromigration properties. A base layer (31) of approximately 185 ANGSTROM of titanium is formed on an ILD followed by the formation of the bulk conductor layer (32) such as an aluminum-copper alloy layer. A capping layer (33) of approximately 185 ANGSTROM of titanium is formed on the bulk conductor layer (32). Finally, an antireflective coating (ARC) (34) of titanium nitride is formed on the capping layer (33).
Abstract:
A method of forming a novel high density interconnection structure. According to the present invention, first an insulating layer (206) is formed over a semiconductor substrate. The first insulating layer is then planarized. Next, a second insulating layer (212) is formed above the first planarized insulating layer. An opening is then etched through the first and second insulating layers. A conductive material (226) is then deposited into the opening and onto the top surface of the second insulating layer. Next, the conductive material is polished back from the second insulating layer so as to form a conductively filled opening which is substantially planar with the second insulating layer.
Abstract:
A method of performing multiple writes before erasing a memory cell (500) is described. M bits are stored in a first group of levels of the memory cell. M subsequent superseding bits are stored in a second group of levels of the memory cell (550) without erasing the memory cell. Another method of writing to a memory cell includes the step of storing m bits in a first group of levels of the memory cell. A group indicator is adjusted to identify a subsequent group of levels of the memory cell. Next, m superseding subsequent bits are stored in the subsequent group of levels, without erasing the memory cell. The steps of adjusting the group indicator and storing m superseding subsequent bits are repeated. A method of deferring an erase for a memory cell is also described. A group indicator is adjusted to identify a group of 2 adjacent levels of the memory cell available for storing an m bit value. A method of reading a memory cell includes providing a group indicator. The group indicator identifies a group of 2 adjacent levels of the memory cell. An m bit value is then read by sensing the group of 2 adjacent levels identified by the group indicator.
Abstract:
A method of performing multiple writes before an erase to a nonvolatile memory cell is described. A first bit is stored at a first level of a nonvolatile memory cell (110, 120, 130 and 140). A second bit is stored at a second level of nonvolatile memory cell (110, 120, 130 and 140). A method of erasing a nonvolatile memory cell is also described. A level indicator that indicates the next level of the nonvolatile memory cell to write to is incremented. A method of reading a nonvolatile memory cell includes recalling a level indicator. The nonvolatile cell is then sensed at a level indicated by the level indicator to determine the state of the memory cell.
Abstract:
A power control circuit and corresponding technique for reducing power consumption by an electronic device and thereby increasing performance. The power control circuit comprises a controller (120), a clock generation circuit (160) and a power supply circuit (170). The controller (120) detects whether a condition exists to scale the voltage and frequency of the electronic device and in response, signals the clock generation circuit (160) to perform frequency scaling on the electronic device and the power supply circuit (170) to perform voltage scaling on the electronic device. The condition may include a situation where the temperature of the electronic device is detected to have exceeded a thermal band. The condition may also include a situation where the electronic device is detected to be idle for a selected percentage of its run time.
Abstract:
A method and apparatus for access control in a computer system are disclosed. A storage unit receives a block of data having an encrypted executable image and a signature component. A separation unit coupled to the storage unit separates the signature component from the encrypted executable image. A decryption unit coupled to the separation unit decrypts the encrypted executable image using the signature component as a key. This yields a decrypted executable program. An identification unit coupled to the decryption unit locates an identification mark in the decrypted executable program and identifies a composite key assigned to the identification mark. A signature generation unit coupled to the identification unit performs a keyed cryptographic hash algorithm on the decrypted executable program using the composite key as a key. A verification unit coupled to the signature generation unit compares the signature component with the computed keyed cryptographic hash value to verify the source of the block of data and to determine whether it has been modified. If the signature matches the keyed cryptographic hash value, a rights assignment unit coupled to the verification unit assigns appropriate access rights to the decrypted executable program and allows it to be executed by a computer system.
Abstract:
A memory marking unit in the shared memory is read to determine whether the shared memory is currently being accessed by another processor (block 802). If the shared memory is not being accessed by another processor, a processor seeking access is granted access and changes the contents of the memory marking unit to lock out other processors from the shared memory (block 803). The last task performed on the shared memory space is identified and used to determine whether a task with high priority exists. If a task with high priority exists, the task is performed (block 804). If a task with high priority doesn't exist, the processor having access to the shared memory space accesses the shared memory space for its intended purpose (block 807). After the processor is finished accessing the shared memory space, it records the identity of the task performed (block 808) and unlocks the shared memory space (block 809).
Abstract:
A low power termination method and apparatus. The termination circuit (250) is typically coupled to a bus (260) through an interface node (150) to receive a rising edge of an input voltage signal. A clamping device (200, 210) is coupled to the interface node (150) and coupled to receive a clamping voltage, the clamping voltage being less than a termination voltage. The termination circuit also includes a bias supply providing a bias supply voltage. A control terminal (205, 215) of the clamping device (200, 210) is coupled to receive the bias voltage and clamps the interface node (150) when the input voltage signal exceeds a termination voltage. A bias excursion of the bias voltage may be provided responsive to the rising edge so that the clamping device clamps the interface node before the input voltage signal exceeds the termination voltage. Similarly, a second clamping device biased by a second bias supply may be used. The second clamping device clamps the interface node after the input voltage signal falls below an excursion responsive to a falling edge of the input voltage signal so that the second clamping device clamps the interface node before the input falls below the expected low voltage.
Abstract:
An oscillator output selector (26) and complementary control circuitry (28) are provided to a computer system. The oscillator output selector (26) is used to select a series of clock pulses for usage as a system bus clock. The control circuitry (28) controls the selection being made by the oscillator output selector, in accordance to control inputs received. In one embodiment, the control circuitry receives system bus clock frequency preferences from the CPU boards (12a-12b) as control inputs, and in response, the control circuitry causes the oscillator output selector to select the series of clock pulses having a frequency that is equal to or slower than the slowest preferred frequency. In an alternate embodiment, the control circuitry receives CPU types from the CPU boards as control inputs, and in response, the control circuitry causes the oscillator output selector to select a series of clock pulses having a frequency that will allow maximum total CPU clock frequency utilization.
Abstract:
A modular PCMCIA card comprises a base member (10) conforming to the Type I or Type II physical dimensions and an add on section which mechanically and electrically connects through pins (26) and sockets (28) with the base member and has dimensions such that when the base member and the add on section are joined, they conform to the dimensions of a PCMCIA Type III card. The add on section may contain one or more functional units of a stand alone computer system and may contain a battery, a modem, pager and/or an infrared transceiver for communicating with printers, computers or controlling devices.