METHOD AND SYSTEM FOR DETERMINING MINIMUM OPERATIONAL VOLTAGE FOR TRANSISTOR MEMORY-BASED DEVICES
A mechanism is provided by which a failure analysis during design of one or more memory arrays used in a system on a chip can take into account an operational voltage use profile over the projected life of the chip. The failure analysis is then used in chip redesign decision-making or modification of the use profile. As a result, memory arrays used in chip design can be more closely matched to the actual use of the chip, rather than being overly-conservatively designed, thereby resulting in physically smaller or more efficient memory arrays and thus smaller chips.
1 . A semiconductor device design system comprising:
a schematic editor configured to generate a schematic for a semiconductor device, wherein the schematic comprises a memory architecture for the semiconductor device; and
an electronic design automation system configured to
receive the schematic from the schematic editor, and
determine a future time failure probability for the memory architecture using a use profile between an initial time and a future time and an ageing model for the memory architecture.
2 . The semiconductor device design system of claim 1 wherein the electronic design automation system is further configured to
determine whether the future time failure probability for the memory architecture conforms to a design specification for the semiconductor device at that future time; and
modify one or more of the schematic or the use profile in response to a determination that the future time failure probability for the memory architecture does not conform to the design specification.
3 . The semiconductor device design system of claim 1 wherein the electronic design automation system is further configured to
determine an initial time failure probability for the memory architecture; and
use the initial time failure probability for the memory architecture to perform said determining the future time failure probability for the memory architecture.
4 . The semiconductor device design system of claim 3 wherein the electronic design automation system is further configured to
perform said determining the initial time failure probability for the memory architecture using information associated with the memory architecture provided by a foundry used to fabricate the semiconductor device.
5 . The semiconductor device design system of claim 1 wherein the electronic design automation system is configured to perform said determining the future time failure probability for the memory architecture by being further configured to
determine a future time read failure probability over a range of operational voltages; and
determine a future time write failure probability over the range of operational voltages.
6 . The semiconductor device design system of claim 5 wherein the electronic design automation system is configured to perform said determining the future time read failure probability by being further configured to perform a sensitivity analysis to approximate a linear pass/fail boundary for each operational voltage.
7 . The semiconductor device design system of claim 5 wherein the electronic design automation system is configured to perform said determining the future time write failure probability by being further configured to interpolate over a minimum operation voltage space for the semiconductor device.
8 . The semiconductor device design system of claim 1 wherein the electronic design automation system is further configured to
generate a netlist from the schematic, wherein the netlist comprises identification of the memory arrays included in the semiconductor device, a number of bits of each type found in the memory arrays, definitions of critical paths for the bits in the memory arrays and the memory arrays, and a definition of peripheral circuitry in the critical paths for the memory arrays.
9 . The semiconductor device design system of claim 1 wherein the use profile comprises one or more of a supply voltage use profile and a device temperature use profile.
10 . A method for determining a failure probability of a semiconductor device, the method comprising:
generating a schematic for the semiconductor device comprising a memory architecture;
converting the schematic to a netlist for the semiconductor device;
determining a future time failure probability of the memory architecture using the netlist, a use profile between an initial time and a future time, and an ageing model for the memory architecture.
11 . The method of claim 10 further comprising:
determining whether the future time failure probability for the memory architecture conforms to a predetermined design specification for the semiconductor device at that future time.
12 . The method of claim 11 further comprising:
modifying one or more of the schematic or the use profile in response to a determination that the future time failure probability for the memory architecture does not conform to the design specification.
13 . The method of claim 10 further comprising:
determining an initial time failure probability for the memory architecture; and
using the initial time failure probability for the memory architecture as an initial condition for determining the future time failure probability for the memory architecture.
14 . The method of claim 13 further comprising:
using information associated with the memory architecture provided by a foundry used to fabricate the semiconductor device to perform said determining the initial time failure probability for the memory architecture.
15 . The method of claim 10 wherein performing said determining the future time failure probability for the memory architecture further comprises:
determining a future time read failure probability over a range of operational voltages; and
determining a future time write failure probability over the range of operational voltages.
16 . The method of claim 15 wherein performing said determining the future time failure probability for the memory architecture further comprises:
setting a future time failure probability for an operational voltage within the range of operational voltages as the highest of the future time read failure probability and the future time write failure probability for that operational voltage.
17 . The method of claim 15 wherein performing said determining the future time read failure probability comprises:
performing a sensitivity analysis to approximate a linear pass/fail boundary for each operational voltage.
18 . The method of claim 15 wherein performing said determining the future time write failure probability further comprises:
interpolating over a minimum operational voltage space for the semiconductor device.
19 . The method of claim 10 wherein the use profile comprises one or more of a supply voltage use profile and a temperature use profile.