1. A method of detecting and correcting a transmission error in a configuration bitstream for a programmable logic device (PLD), the method comprising:
receiving the configuration bitstream;
retrieving first and second error correcting codes from the configuration bitstream;
changing a value of at least one bit in the configuration bitstream based on each of the first and second error correcting codes, whereby corrected data is generated; and
configuring the PLD utilizing the corrected data, wherein:
the configuration bitstream comprises a plurality of bitstream words comprising at least one instruction word and a plurality of configuration data words; and
the first error correcting code is applied to the instruction word and the second error correcting code is applied to the configuration data words.
2. The method of claim 1, wherein at least one of the first and second error correcting codes is a Hamming code.
3. The method of claim 1, wherein:
the configuration bitstream comprises a plurality of bitstream words; and
changing the value of at least one bit in the configuration bitstream comprises changing the value of at least one bit in an erroneous bitstream word prior to receipt of a following bitstream word.
4. The method of claim 3, wherein the plurality of bitstream words comprises at least one instruction word and a plurality of configuration data words, and the erroneous bitstream word comprises an instruction word.
5. The method of claim 3, wherein the plurality of bitstream words comprises at least one instruction word and a plurality of configuration data words, and the erroneous bitstream word comprises a configuration data word.
6. The method of claim 1, wherein:
the configuration bitstream comprises a plurality of bitstream words; and
changing the value of at least one bit in the configuration bitstream comprises changing the value of at least one bit in an erroneous bitstream word after receiving at least one additional bitstream word.
7. The method of claim 1, wherein changing the value of at least one bit in the configuration bitstream occurs after receiving an entirety of the configuration bitstream.
8. The method of claim 1, wherein at least one of the first and second error correcting codes is a product code.
9. The method of claim 1, wherein:
the configuration bitstream comprises a plurality of bitstream words comprising at least one instruction word and a plurality of configuration data words; and
each of the configuration data words has a size equal to a size of a configuration frame for the PLD.
10. The method of claim 1, wherein the first error correcting code is a Hamming code and the second error correcting code is a product code.
11. The method of claim 1, wherein receiving the configuration bitstream comprises receiving an encrypted bitstream, the method further comprising:
decrypting the configuration bitstream after receiving the configuration bitstream and prior to retrieving the first and second error correcting codes.
12. The method of claim 1, wherein receiving the configuration bitstream comprises receiving an encrypted bitstream, the method further comprising:
decrypting the configuration bitstream after the receiving, the retrieving, and the changing and prior to the configuring.
13. The method of claim 1, further comprising:
prior to receiving the configuration bitstream, encrypting the configuration bitstream and transmitting the encrypted configuration bitstream to the PLD; and
after receiving the configuration bitstream, decrypting the configuration bitstream.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of manufacturing a complimentary metal-oxide semiconductor (CMOS) circuit on a semiconductor substrate of a first conductivity type to adjust threshold voltages (VT) of devices in the circuit, the method comprising:
forming a first photoresist mask on a surface of the substrate, the first photoresist mask defining a well boundary around an area in which a well is to be formed;
implanting ions into the substrate at an angle substantially perpendicular to the surface of the substrate to form a well of a second conductivity type in the substrate, wherein a region proximal to the well boundary is effected by lateral scattering by the first photoresist mask of the ions implanted to form the well; and
forming at least one of the devices in the region proximal to the well boundary which is effected by lateral scattering, wherein a channel of the device is formed by implanting ions into the substrate at an acute angle to the surface thereof to shadow the portion of the channel from at least some of the ions implanted to form the channel.
2. A method according to claim 1, wherein forming the channel of one of the devices comprises:
implanting a first portion of a total dose to be implanted to form the channel;
rotating the substrate around a rotation axis perpendicular to the surface of the substrate; and
implanting a second portion of the total dose to be implanted.
3. A method according to claim 1, wherein the step of forming the channel of one of the devices comprises:
implanting a fraction of a total dose to be implanted to form the channel equal to about the (total dose)N, where N is a whole number greater than 1;
rotating the substrate around a rotation axis perpendicular to the surface of the substrate by an angle equal to about 360\xb0N and implanting another fraction of the total dose equal to about the (total dose)N; and
repeating the rotating until the total dose has been implanted.
4. A method according to claim 3, wherein N is at least 4.
5. A method according to claim 3, wherein forming the channel comprises tilting the surface of substrate relative to a direction from which ions to be implanted are accelerated to implant ions into the substrate at an angle of from about 30\xb0 to about 60\xb0 to the surface thereof.
6. A method according to claim 5, wherein the angle by which the substrate is tilted and N are selected to control the VT of the device having a channel at least a portion of which is formed in the region proximal to the well boundary that is effected by lateral scattering.
7. A method according to claim 1, wherein forming at least a portion of a channel of at least one of the devices comprises forming a second photoresist mask on the surface of the substrate to define the channel of the at least one of the devices in the region proximal to the well boundary before implanting ions into the substrate to form the channel, and wherein the second photoresist mask shadows the portion of the channel from at least some of the ions implanted to form the channel.
8. A method according to claim 1, wherein forming a first photoresist mask on a surface of the substrate, comprises forming a first photoresist mask defining a well boundary around an area in which a well is to be formed, and defining the channel of the at least one of the devices in the region proximal to the well boundary before implanting ions into the substrate to form the well, and wherein the first photoresist mask shadows the portion of the channel from at least some of the ions implanted to form the channel.
9. A method of manufacturing a complimentary metal-oxide-semiconductor (CMOS) circuit including a number of devices on a semiconductor substrate of a first conductivity type, the method comprising:
forming a first photoresist mask on a surface of the substrate using a photolithographic process from a reticule having a drawn well boundary, the first photoresist mask defining a well boundary around an area in which a well is to be formed;
implanting ions into the substrate at an angle substantially perpendicular to the surface of the substrate to form a well of a second conductivity type in the substrate, wherein a region proximal to the well boundary which is effected by lateral scattering by the first photoresist mask of the ions implanted to form the well;
forming at least one of the devices in the region proximal to the well boundary which is effected by lateral scattering, wherein a channel of the device is formed by implanting ions into the substrate at an acute angle to the surface thereof to shadow the portion of the channel from at least some of the ions implanted to form the channel; and
wherein the location of the drawn well boundary and the acute angle at which ions are implanted into the substrate to form the channel are selected to control threshold voltages (VT) of devices in the circuit proximal to the well boundary.
10. A method according to claim 9, the acute angle at which ions are implanted into the substrate to form the channel is selected based on the location of the drawn well boundary, the further the drawn well boundary is away from the nearest of the devices the closer the acute angle is to perpendicular to the surface of the substrate.
11. A method according to claim 9, wherein forming the channel of one of the devices comprises:
implanting a fraction of a total dose to be implanted to form the channel equal to about the (total dose)N, where N is a whole number greater than 1;
rotating the substrate around a rotation axis perpendicular to the surface of the substrate by an angle equal to about 360\xb0N and implanting another fraction of the total dose equal to about the (total dose)N; and
repeating the rotating until the total dose has been implanted.
12. A method according to claim 11, wherein N is at least 4.
13. A method according to claim 9, wherein forming the channel comprises tilting the surface of substrate at an angle of from about 3 to about 60 relative to direction from which ions to be implanted to form the channel are accelerated.
14. A method according to claim 9, wherein forming at least a portion of a channel of at least one of the devices comprises forming a second photoresist mask on the surface of the substrate to define the channel of the at least one of the devices in the region proximal to the well boundary before implanting ions into the substrate to form the channel, and wherein the second photoresist mask shadows the portion of the channel from at least some of the ions implanted to form the channel.
15. A method according to claim 9, wherein forming a first photoresist mask on a surface of the substrate, comprises forming a first photoresist mask defining a well boundary around an area in which a well is to be formed, and defining the channel of the at least one of the devices in the region proximal to the well boundary before implanting ions into the substrate to form the well, and wherein the first photoresist mask shadows the portion of the channel from at least some of the ions implanted to form the channel.