1. A semiconductor device comprising:
a wiring;
a conductive film formed on an upper surface of the wiring to prevent diffusion of a wiring material; and
an insulating film which is constituted of low dielectric constant insulating films stacked to form at least two layers, an interface thereof being positioned in a side face of the wiring.
2. The semiconductor device according to claim 1, wherein the insulating film is constituted of low dielectric constant insulting film layers of the same material.
3. The semiconductor device according to claim 2, wherein the conductive film is made of a high-melting point metal alloy containing cobalt-tungsten.
4. The semiconductor device according to claim 2, wherein the conductive film is made of a high-melting point metal nitride to prevent diffusion of the wiring material.
5. The semiconductor device according to claim 1, wherein the insulating film comprises low dielectric constant insulating films of at least two kinds of materials.
6. The semiconductor device according to claim 5, wherein the conductive film is made of a high-melting point metal alloy containing cobalt-tungsten.
7. The semiconductor device according to claim 5, wherein the conductive film is made of a high-melting point metal nitride to prevent diffusion of the wiring material.
8. A semiconductor device comprising:
a first wiring;
a second wiring formed above the first wiring;
a conductive film formed on an upper surface of each wiring to prevent diffusion of a wiring material;
a plug which interconnects the first and second wirings;
a first insulating film made of a first low dielectric constant material stacked to form at least two layers, an interface thereof being positioned in a side face of the first wiring;
a second insulating film to prevent diffusion of the wiring material formed on at least one interface within the first insulating film and on surfaces of the first wiring positioned above the interface excluding a contact between the plug and the first wiring; and
a third insulating film made of a second low dielectric constant material different from that of the first insulating film formed between the first and second wirings.
9. The semiconductor device according to claim 8, wherein the conductive film is made of a high-melting point metal alloy containing cobalt-tungsten.
10. The semiconductor device according to claim 8, wherein the second insulating film contains one of a silicon nitride, a silicon carbide, or a silicon carbonitride.
11. A method for manufacturing a semiconductor device, comprising:
depositing a first insulating film made of a low dielectric constant material;
depositing a second insulating film having mechanical strength larger than that of the first insulating film thereon;
forming a wiring trench in the first and second insulating films;
forming a wiring by filling the wiring trench with a wiring material;
forming a conductive film on an upper surface of the wiring to prevent diffusion of the wiring material;
removing the second insulating film; and
depositing a third insulating film made of a low dielectric constant material on the first insulating film and the wiring.
12. The method according to claim 11, wherein the third insulating film is made of the same low dielectric constant material as that of the first insulating film.
13. The method according to claim 12, wherein the conductive film is made of a high-melting point metal alloy containing cobalt-tungsten.
14. The method according to claim 12, wherein the conductive film is made of a high-melting point metal nitride to prevent diffusion of the wiring material.
15. The method according to claim 11, wherein the third insulating film is made of a second low dielectric constant material different from that of the first insulating film.
16. The method according to claim 15, wherein the conductive film is made of a high-melting point metal alloy containing cobalt-tungsten.
17. The method according to claim 15, wherein the conductive film is made of a high-melting pint metal nitride to prevent diffusion of the wiring material.
18. A method for manufacturing a semiconductor device, comprising:
depositing a first insulating film made of a first low dielectric constant material;
depositing a second insulating film having mechanical strength larger than that of the first insulating film thereon;
forming a wiring trench in the first and second insulating films;
forming a first wiring by filling the wiring trench with a wiring material;
forming a conductive film on an upper surface of the first wiring to prevent diffusion of the wiring material;
removing the second insulating film;
depositing a third insulating film on the first insulating film and the first wiring to prevent diffusion of the wiring material;
depositing a fourth insulating film made of the first low dielectric constant material on the third insulating film;
planarizing the fourth insulating film to a level of an upper surface of the first wiring;
forming a fifth insulating film made of a second low dielectric constant material on the fourth insulating film and the first wiring; and
forming a plug in the fifth insulating film to interconnect the first wiring and a second wiring to be formed thereon.
19. The method according to claim 18, wherein the conductive film is made of a high-melting point metal alloy containing cobalt-tungsten.
20. The method according to claim 18, wherein the third insulating film contains one of a silicon nitride, a silicon carbide, and a silicon carbonitride.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A packet-based encryption system comprising:
a transmitting device to encrypt data and to insert a pseudo-random key in a transmitted packet; and
a receiving device to receive and to decrypt said data in said transmitted packet using said pseudo-random key.
2. The system of claim 1 wherein said transmitting device further comprises:
means to generate a random number;
a first one-way cryptographic hash function means to generate a hashed number from said random number;
a first streaming cipher algorithm using a seed to encrypt said hashed number;
encryption means to encrypt said data using results of said first streaming cipher algorithm; and
means to insert said random number in a specified field of said transmitted packet.
3. The system of claim 2 wherein said receiving device further comprises:
means to remove said random number from said specified field of said transmitted packet;
a second one-way cryptographic hash function means to generate a second hashed number from said random number;
a second streaming cipher algorithm using a seed to encrypt said second hashed number; and
decryption means to decrypt said data using results of said second streaming cipher algorithm.
4. The system of claim 3 wherein said first one-way cryptographic hash function and said second one-way cryptographic hash function use the same algorithm and use a same first seed or key.
5. The system of claim 4 wherein said first streaming cipher algorithm and said second streaming cipher algorithm are the same and use a same second seed or key.
6. The system of claim 5 wherein said encryption means and said decryption means use the same third key and algorithm.
7. The system of claim 1 wherein said transmitting device further comprises:
means to generate a random number;
a first one-way cryptographic hash function means to generate a hashed number from said random number;
a third one-way cryptographic hash function using a seed to encrypt said hashed number;
encryption means to encrypt said data using results of said third one-way cryptographic hash function; and
means to insert said random number in a specified field of said transmitted packet.
8. The system of claim 7 wherein said receiving device further comprises:
means to remove said random number from said specified field of said transmitted packet;
a second one-way cryptographic hash function means to generate a second hashed number from said random number;
a fourth one-way cryptographic hash function using a seed to encrypt said second hashed number; and
decryption means to decrypt said data using results of said fourth one-way cryptographic hash function.
9. The system of claim 8 wherein said third one-way cryptographic hash function and said fourth one-way cryptographic hash function are the same and use a same fourth seed or key.
10. A method of encryption of packetized data using a symmetric key-based stream cipher, in which each packet includes self-synchronizing information comprising the steps of:
encrypting data and inserting a pseudo-random key in a transmitted packet with said encrypted data; and
decrypting said data in said transmitted packet with said inserted pseudo-random key.
11. The method of claim 10 further comprising the steps of:
at the transmitting end:
generating a random number;
generating a hashed number from said random number using a first one-way cryptographic hash function;
providing a first streaming cipher algorithm using said hashed number as a seed;
encrypting said data using results of said first streaming cipher algorithm; and
inserting said random number in a specified field of said transmitted packet.
at the receiving end:
removing said random number from said specified field of said transmitted packet;
generating a second hashed number from said random number using a second one-way cryptographic hash function;
providing a second streaming cipher algorithm using said hashed number as a seed; and
decrypting said data using results of said second streaming cipher algorithm using said second hashed number as a seed.
12. The method of claim 10 further comprising the steps of:
at the transmitting end:
generating a random number;
generating a hashed number from said random number using a first one-way cryptographic hash function;
providing a third one-way cryptographic hash function using a seed to encrypt said hashed number;
encrypting said data using results of said first streaming cipher algorithm; and
inserting said random number in a specified field of said transmitted packet.
at the receiving end:
removing said random number from said specified field of said transmitted packet;
generating a second hashed number from said random number using a second one-way cryptographic hash function;
providing a fourth one-way cryptographic hash function using a seed to encrypt said second hashed number; and
decrypting said data using results of said second streaming cipher algorithm using said second hashed number as a seed.