Thin film resistor, thermistor and method of producing the same

1 . An apparatus comprising:

a thin film resistor structure within a back end of line (BEOL) via level, the thin film resistor structure comprising:

a lower resistor film;

a first insulating layer over the lower resistor film;

an upper resistor film over the first insulating layer; and

a second insulating layer over the upper resistor film, and

first and second upper metal lines above the second insulating layer,

wherein a first end of the upper resistor film is coupled to the first upper metal line by a first upper via, and a second end of the upper resistor film is coupled to the second upper metal line by a second upper via,

wherein a width of the lower resistor film is the same as a width of the first insulating layer, and a width of the upper resistor film is the same as a width of the second insulating layer.

2 . The apparatus of claim 1 , wherein a temperature coefficient of resistance of the lower resistor film is different from a temperature coefficient of resistance of the upper resistor film.

3 . The apparatus of claim 2 , wherein one of the upper and lower resistive films has a negative temperature coefficient, and the other of the upper and lower resistive films has a positive temperature coefficient.

4 . The apparatus of claim 1 , wherein the lower resistor film includes a first cermet material and the upper resistor film includes a second cermet material.

5 . The apparatus of claim 4 , wherein each of the first and second cermet materials includes one or more of ruthenium oxide, tantalum nitride, nickel chromium, silicon chromium, tungsten carbide and silicon carbide.

6 . The apparatus of claim 1 , wherein the upper resistor film is a resistive element in a thermistor device.

7 . The apparatus of claim 1 , wherein a thickness of the first insulating layer is less than a thickness of the second insulating layer.

8 . An apparatus comprising:

a thin film resistor structure within a back end of line (BEOL) via level, the thin film resistor structure comprising:

a lower resistor film;

a first insulating layer over the lower resistor film;

an upper resistor film over the first insulating layer; and

a second insulating layer over the upper resistor film, and

first and second upper metal lines above the second insulating layer,

wherein a first end of the upper resistor film is coupled to the first upper metal line by a first upper contact, and a second end of the upper resistor film is coupled to the second upper metal line by a second upper contact,

wherein a width of the lower resistor film is the same as a width of the first insulating layer, and a width of the upper resistor film is the same as a width of the second insulating layer.

9 . The apparatus of claim 8 , wherein the lower resistor film and the upper resistor film are made of the same material.

10 . The apparatus of claim 9 , wherein the material of the upper and lower resistor films is a cermet material.

11 . The apparatus of claim 10 , wherein the cermet material includes one or more of ruthenium oxide, tantalum nitride, nickel chromium, silicon chromium, tungsten carbide and silicon carbide.

12 . The apparatus of claim 8 , wherein a first end of the lower resistor film is coupled to a first lower metal line by a first lower contact, and a second end of the lower resistor film is coupled to a second lower metal line by a second lower contact.

13 . The apparatus of claim 12 , wherein the first and second lower vias include at least one of tantalum nitride and tungsten, and the first and second upper vias include copper.

14 . The apparatus of claim 8 , wherein the upper and lower resistor films have a flat two-dimensional shape with at least one turn.

15 . A method comprising:

forming a lower metal layer including first and second lower metal lines;

forming a thin film resistor structure by:

forming a lower resistor film over the lower metal layer;

forming a first insulating layer over the first resistor film;

forming an upper resistor film over the first insulating layer; and

forming a second insulating layer over the second resistor film,

forming first and second upper vias that extend through the upper resistor film to contact first and second ends of the upper resistor film, respectively; and

forming first and second upper metal lines coupled to the first and second upper vias, respectively,

wherein a width of the lower resistor film is the same as a width of the first insulating layer, and a width of the upper resistor film is the same as a width of the second insulating layer.

16 . The method of claim 15 , wherein a temperature coefficient of resistance of the lower resistor film is different from a temperature coefficient of resistance of the upper resistor film.

17 . The method of claim 16 , wherein one of the upper and lower resistive films has a negative temperature coefficient, and the other of the upper and lower resistive films has a positive temperature coefficient.

18 . The method of claim 15 , wherein the lower resistor film includes a first cermet material and the upper resistor film includes a second cermet material.

19 . The method of claim 18 , wherein each of the first and second cermet materials includes one or more of ruthenium oxide, tantalum nitride, nickel chromium, silicon chromium, tungsten carbide and silicon carbide.

20 . The apparatus of claim 15 , wherein the second insulating layer is formed to have a greater thickness than the first insulating layer.