Semiconductor device and method of writing data
A semiconductor device includes: an electric fuse circuit including first electric fuses used as data bits and second electric fuses used as polarity bits; and a write circuit configured to selectively pass a current through the first electric fuses and the second electric fuses and thereby write data in the electric fuse circuit. The write circuit is configured to perform a first process when number of write bits included in write data is larger than a value obtained by dividing total number of bits in the write data by 2. The first process includes writing of inverted write data in a plurality of first electric fuses, and including writing of inversion data in one of the second electric fuses. The plurality of first electric fuses are part of the first electric fuses. The inverted write data is inverted data of the write data. The inversion data represents inversion.
1. A semiconductor device comprising:
an electric fuse circuit including a first plurality of first electric fuses arranged in a matrix and a plurality of second electric fuses arranged in one column in a column direction and each allocated to one or a plurality of rows of the first plurality of first electric fuses arranged in the matrix, the first plurality of first electric fuses being configured to be used as data bits, and the plurality of second electric fuses being used as polarity bits; and
a write circuit configured to selectively pass a first current through the first plurality of first electric fuses and the plurality of second electric fuses and thereby write data in the electric fuse circuit,
the write circuit being configured to divide all write data into a plurality of pieces of the write data based on a number of the first electric fuses included in the one or the plurality of rows as a division unit, and to perform one of a first process and a second process on each of the plurality of pieces of the write data,
the write circuit being configured to perform the first process when a number of write bits included in the write data is larger than a value obtained by dividing a total number of bits in the write data by 2 and to perform the second process when the number of the write bits included in the write data is not larger than the value obtained by dividing the total number of the bits in the write data by 2,
the first process including writing of an inverted write data in a second plurality of first electric fuses, and including writing of an inversion data in one of the plurality of second electric fuses included in the electric fuse circuit, the second plurality of first electric fuses being part of the first plurality of first electric fuses included in the electric fuse circuit, the inverted write data being inverted data of the write data, and the inversion data representing inversion,
the second process including writing the write data in a third plurality of first electric fuses and including writing non-inversion data in one of the plurality of second electric fuses included in the electric fuse circuit, the third plurality of first electric fuses being part of the first plurality of first electric fuses included in the electric fuse circuit, and the non-inversion data representing non-inversion.
2. The semiconductor device according to claim 1 , wherein
the plurality of second electric fuses are each allocated to one row of the first plurality of first electric fuses arranged in the matrix, and
the write circuit divides the all write data into the plurality of pieces of the write data based on the number of the first electric fuses included in one row as the division unit.
3. The semiconductor device according to claim 2 , wherein
the electric fuse circuit includes a plurality of word lines and a plurality of bit lines, the plurality of word lines extending in a row direction and each being allocated to one row of the first plurality of first electric fuses arranged in the matrix and the plurality of second electric fuses arranged in the one column in the column direction, and the plurality of bit lines extending in the column direction and each being allocated to one column of the first plurality of first electric fuses arranged in the matrix and the plurality of second electric fuses arranged in the one column in the column direction, and
the write circuit selectively passes the first current through the plurality of word lines and the plurality of bit lines and thereby performs a writing operation on the first plurality of first electric fuses and the plurality of second electric fuses one by one.
4. A method of writing data in a semiconductor device comprising an electric fuse circuit including a first plurality of first electric fuses arranged in a matrix and a plurality of second electric fuses arranged in one column in a column direction and each allocated to one or a plurality of rows of the first plurality of first electric fuses arranged in the matrix, the first plurality of first electric fuses being configured to be used as data bits, and the plurality of second electric fuses being used as polarity bits; and a write circuit configured to selectively pass a first current through the first plurality of first electric fuses and the plurality of second electric fuses and thereby write data in the electric fuse circuit, the method comprising:
dividing all write data into a plurality of pieces of the write data based on a number of the first electric fuses included in the one or the plurality of rows as a division unit, and performing one of a first process and a second process on each of the plurality of pieces of the write data; and
when a number of write bits included in the write data is larger than a value obtained by dividing a total number of bits in the write data by 2, performing the first process including:
selectively passing a first current through the second plurality of first electric fuses and thereby writing an inverted write data in the second plurality of first electric fuses, as well as passing the first current through one of a plurality of second electric fuses and thereby writing an inversion data in the one of the plurality of second electric fuses, the second plurality of first electric fuses being part of a first plurality of first electric fuses, the inverted write data being inverted data of the write data, and the inversion data representing inversion; and
when the number of write bits included in the write data is not than the value obtained by dividing the total number of the bits in the write data by 2, performing the second process including:
selectively passing the first current through a third plurality of the first electric fuses and thereby writing the write data in the third plurality of first electric fuses, as well as passing the first current though one of the plurality of second electric fuses and thereby writing non-inversion data in the one of the plurality of second electric fuses, the third plurality of first electric fuses being part of the first plurality of first electric fuses included in the electric fuse circuit, and the non-inversion data representing non-inversion.
5. The semiconductor device according to claim 1 , wherein the first current has a value sufficient to vary a resistance of respective ones of the second plurality of first electric fuses and respective ones of the plurality of second electric fuses.
6. The semiconductor device according to claim 1 , wherein a structure of respective ones of the first plurality of first electric fuses is the same as a structure of respective ones of the plurality of second electric fuses.
7. The semiconductor device according to claim 1 , further comprising:
a read circuit configured to detect whether a potential at a predetermined location is larger than a threshold when a second current is selectively passed through the electric fuse circuit, and thereby read the data in the electric fuse circuit.
8. The semiconductor device according to claim 1 , wherein
the plurality of second electric fuses are each allocated to the plurality of rows of the first plurality of first electric fuses arranged in the matrix, and
the write circuit divides the all write data into the plurality of pieces of the write data based on the number of the first electric fuses included in the plurality of rows as the division unit.
9. The method according to claim 4 , wherein
the plurality of second electric fuses are each allocated to one row of the first plurality of first electric fuses arranged in the matrix, and
the dividing includes dividing the all write data into the plurality of pieces of the write data based on the number of the first electric fuses included in one row as the division unit.
10. The method according to claim 4 , wherein
the plurality of second electric fuses are each allocated to the plurality of rows of the first plurality of first electric fuses arranged in the matrix, and
the dividing includes dividing the all write data into the plurality of pieces of the write data based on the number of the first electric fuses included in the plurality of rows as the division unit.
11. The method according to claim 4 , wherein the first current has a value sufficient to vary a resistance of respective ones of the second plurality of first electric fuses and respective ones of the plurality of second electric fuses.
12. The method according to claim 4 , wherein a structure of respective ones of the first plurality of first electric fuses is the same as a structure of respective ones of the plurality of second electric fuses.
13. The method according to claim 4 , further comprising:
detecting whether a potential at a predetermined location is larger than a threshold when a second current is selectively passed through the electric fuse circuit, and thereby reading the data in the electric fuse circuit.