The embodiments discussed herein are related to a semiconductor device and a semiconductor device production method.
In the past, in a semiconductor device (LSI: semiconductor integrated circuit), a resistance device is made using, for example, polycrystalline silicon (“poly-silicon”) formed on a silicon substrate.
Such a poly-silicon resistance device (poly-silicon resistor) includes the advantages of having a higher sheet resistance than a resistance device using copper (Cu) or aluminum (Al) and of having a smaller fluctuation in resistance than a resistance device using a diffusion layer of a silicon (Si) substrate.
However, since a poly-silicon resistor includes a high sheet resistance, it generates a large Joule's heat per current and, for example, is liable to cause a drop in the reliability of a Cu interconnect which is provided near the poly-silicon resistor.
In this regard, in the past, various proposals are made for semiconductor devices which are designed to disperse heat from resistance devices to thereby suppress a rise in temperature in the surroundings.
According to an aspect of the embodiments, a semiconductor device includes a semiconductor substrate; a heat generating device provided on the semiconductor substrate; and a heat radiating part provided above the heat generating device. Wherein, the heat radiating part is thermally coupled with the semiconductor substrate through at least one contact part.
The object and advantages of the embodiments will be realized and attained by the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the embodiments, as claimed.
First, before explaining embodiments of a semiconductor device and a semiconductor device production method in detail, the resistance device part in a semiconductor device and the issues involved in the same will be explained with reference to
As illustrated in
Here, the resistor-use interconnects 2a and 2b are respectively coupled to two ends of the poly-silicon resistor 1 by two contact parts 41a, 42a and 41b, 42b and, for example, run current from the interconnect 2a toward the interconnect 2b through the poly-silicon resistor 1.
Note that, between the poly-silicon resistor 1 and the resistor-use interconnects 2a and 2b and Cu interconnect 3, an insulating layer is formed. Further, the resistor-use interconnects 2a and 2b and interconnect 3 are, for example, formed from the first layer Cu.
As explained above, in the semiconductor device which is illustrated in
Here, since the poly-silicon resistor 1 includes a high sheet resistance, it generates a large Joule's heat per current and causes a drop in of the reliability of the Cu interconnect 3 nearby (for example, provided above it). Note that, the poly-silicon of the poly-silicon resistor 1 includes a sufficiently high reliability compared with the Cu of the Cu interconnect 3.
For this reason, the allowable value of the amount of current of the poly-silicon resistor 1 is defined taking into consideration the drop in reliability of the nearby Cu interconnect 3 due to the Joule's heat which is generated from the poly-silicon resistor 1.
That is, the allowable value of the amount of current of the poly-silicon resistor 1 is defined so that the temperature of the reliability danger part RDP at the Cu interconnect 3 which is positioned above the poly-silicon resistor 1 becomes a given temperature (for example, 130° C.) or less.
The resistance device part of the semiconductor device which is illustrated in
Here, while omitted in
That is, the resistor-use interconnects 2a and 2b and heat radiating part 5 are, for example, formed from the first layer Cu, while the interconnect 3 is, for example, formed by a second layer Cu above the first layer Cu.
Note that, between the poly-silicon resistor 1 and the resistor-use interconnects 2a and 2b and heat radiating part 5 and between the heat radiating part 5 and the Cu interconnect 3, insulating layers are formed needless to say.
In the semiconductor device which is illustrated in
As clear from a comparison of
That is, the contact parts 41c and 42c are used to convey the heat from the poly-silicon resistor 1 to the heat radiating part 5 and increase the amount of heat which is dispersed from the heat radiating part 5.
Here, in the semiconductor devices of
In this way, the heat from the poly-silicon resistor 1 is dispersed through the metal heat radiating part 5 to the surroundings, and a rise in temperature of the reliability danger part RDP (not illustrated) of the Cu interconnect 3 which is provided above the heat radiating part 5 is suppressed.
However, in the semiconductor devices of
In this regard, to suppress the temperature rise of the Cu interconnect 3 (reliability danger part RDP), for example, it is possible to restrict the current which is run through the poly-silicon resistor 1, increase the thickness of the insulating layer between the heat radiating part 5 (poly-silicon resistor 1) and Cu interconnect 3, or increase the area of the heat radiating part 5.
However, the above such approaches run counter to the recent demands for smaller size and higher precision of semiconductor devices and further lead to a reduction in the freedom of circuit design.
Below, examples of a semiconductor device and a semiconductor device production method will be explained with reference to the attached figures.
As illustrated in
Furthermore, the resistance device part of the semiconductor device of the first embodiment includes a heat radiating part 5 which is provided above the poly-silicon resistor 1 and an interconnect (for example, Cu interconnect) 3 which is provided above the heat radiating part 5.
That is, the resistor-use interconnects 2a and 2b and heat radiating part 5 are, for example, formed by the first layer Cu, while the interconnect 3 is, for example, formed by a second layer Cu above the first layer Cu.
Note that, the heat radiating part 5 is not limited to one formed by the same interconnect layer as the resistor-use interconnects 2a and 2b. Further, the material may be, in addition to Cu, tungsten (W) or another metal or carbon nanotubes and other substances with large heat dispersion rates.
Here, the resistor-use interconnects 2a and 2b are coupled respectively by the two contact parts 41a, 42a and 41b, 42b to the two ends of the poly-silicon resistor 1 and, for example, run current from the interconnect 2a toward the interconnect 2b through the poly-silicon resistor 1.
Note that, between the poly-silicon resistor 1 and the resistor-use interconnects 2a and 2b and heat radiating part 5, an insulating layer (first insulating layer 11) is formed. Further, between the heat radiating part 5 (resistor-use interconnects 2a and 2b) and Cu interconnect 3 (not illustrated), an insulating layer (second insulating layer 12) is formed.
The two ends of the heat radiating part 5 are coupled by two respective contact parts 61a, 62a and 61b, 62b to the active regions 7a and 7b of the substrate (semiconductor substrate: silicon substrate 8).
Due to this, the heat from the poly-silicon resistor 1 is received at the heat radiating part 5, while the heat of the heat radiating part 5 is dispersed through the contact parts 61a, 62a and 61b, 62b to the substrate 8.
That is, in the semiconductor device of the first embodiment, it is possible to release the heat of the heat radiating part 5 through the contact parts 61a, 62a; 61b, 62b at the substrate 8 to thereby effectively disperse the heat which is generated from the poly-silicon resistor 1 and suppress a rise in temperature of the Cu interconnect 3 which is provided nearby.
This indicates that it is possible to raise the upper limit value of the allowable amount of current of the poly-silicon resistor 1 or reduce the size of the poly-silicon resistor 1. Furthermore, it enables improvement of the circuit integration degree of the semiconductor device. Note that, this effect is similarly exhibited in the following embodiments as well.
Note that, the resistance device 1 is not limited to a poly-silicon resistor. Further, it may be a heat generating device which generates heat other than a resistance device.
As clear from a comparison of
In this way, the heat radiating part 5 and the substrate 8 (active region 7a) may be coupled at one end or both ends of the heat radiating part 5. Note that, the connections between the heat radiating part 5 and the substrate 8 are not limited to two (contact parts 61a and 62a) at one end of the heat radiating part 5 needless to say.
That is, the Cu interconnect 3, for example, as illustrated in
Note that,
Here, between the heat radiating part 5 (resistor-use interconnects 2a and 2b) and Cu interconnect 3, an insulating layer (second insulating layer 12) is formed.
As illustrated in
The heat radiating part 5 is formed with aperture holes 5a and 5b. Inside of these aperture holes 5a and 5b, the resistor-use interconnects 2a′ and 2b′ are positioned.
Specifically, as illustrated in
Note that, as illustrated in
That is, the resistor-use interconnect 2a is electrically coupled through the contact parts 41a′ and 42a′ to the resistor-use interconnect 2a′, while the resistor-use interconnect 2a′ is electrically coupled through the contact parts 41a and 42a to one end of the poly-silicon resistor 1.
Similarly, the resistor-use interconnect 2b is electrically coupled through the contact parts 41b′ and 42b′ to the resistor-use interconnect 2b′, while the resistor-use interconnect 2b′ is electrically coupled through the contact parts 41b and 42b to the other end of the poly-silicon resistor 1.
Note that, the heat radiating part 5 and the active region 7 (substrate 8) are thermally coupled by a plurality of contact parts 60 which are provided at given intervals. Heat from the poly-silicon resistor 1 is received by the heat radiating part 5. The heat from the heat radiating part 5 is diffused through the plurality of contact parts 60 to the substrate 8.
By providing the heat radiating part 5 so as to cover the entire surface of the poly-silicon resistor 1 and diffusing the heat from the heat radiating part 5 through a plurality of contact parts 60 to the substrate 8, for example, it is possible to greatly suppress the rise in temperature of the Cu interconnect 3 which is provided above the heat radiating part 5.
Here, as illustrated in
First, as illustrated in
Next, as illustrated in
Furthermore, as illustrated in
Note that, in
Next, as illustrated in
Inside the via holes 11a and 11b, a substance having a high heat diffusion rate and conductivity (for example, Cu, Al, W, or another metal or carbon nanotubes etc.) is filled to thereby form contact parts 62a and 62b.
Note that, while the explanation is omitted here, the via holes 11a and 11b are for example, formed by coating the insulating layer 11 with a resist, using a mask (reticle) for patterning, then etching etc.
Further, as illustrated in
Here, the heat radiating part 5 is formed from a substance 3 which includes a high heat dispersion rate and conductivity (for example, Cu, Al, W, or another metal or carbon nanotubes etc.) Further, the heat radiating part 5, for example, may be formed from the first layer Cu at the same time as various other interconnects.
Due to this, as explained above, the heat which is emitted from the poly-silicon resistor 1 is taken by the heat radiating part 5 and is dispersed through that heat radiating part 5 and contact parts 61a and 62a (61b and 62b) to the substrate 8 (well 81).
Note that, the contact locations of the well 81 with the contact parts 61a and 62a are made the silicide parts 83a and 83b and the active regions 82a and 82b, so it is possible to effectively disperse the heat from the contact parts 61a and 62a to the well 81 (substrate 8).
Further, by giving the well 81 a fixed potential (for example, ground potential) and making the contact parts 61a and 62a (61b and 62b) and the heat radiating part 5 conductive substances, it is possible to shield against noise (electrical field) from the poly-silicon resistor 1.
Furthermore, the above-mentioned insulating layers 10, 11, and 12, via holes 11a and 11b, contact parts 62a and 62b, and heat radiating part 5 (for example, heat radiating part made of Cu) may be formed as they are by the manufacturing process of various circuits in a semiconductor device.
In the above, the resistor 1 which generates the heat is not limited to a poly-silicon resistor and may be various resistance devices. Furthermore, it may also be a heat generating device other than a resistor as explained earlier.
As illustrated in
First, as illustrated in
At this time, the temperature near the center of the Cu interconnect 3 (reliability danger part RDP) (maximum temperature) was 128.505° C. That is, it was confirmed that if running a 0.40 mA current through the poly-silicon resistor 1 at the resistance device part of
Next, as illustrated in
Therefore, it was confirmed that to maintain the temperature of the Cu interconnect 3 at 130° C. or less in an ambient temperature of 125° C., it is only possible to run a current of 0.478 mA through the poly-silicon resistor 1.
As illustrated in
That is, a simulation was run for the poly-silicon resistor 1 and Cu interconnect 3 assuming similar conditions to
Further, as illustrated in
Here, the length of the heat radiating part 5 is made one similar to the Cu interconnect 3, that is, 3.0 μm, while the width of the heat radiating part 5 was made half of the width of 2.0 μm of the poly-silicon resistor 1, that is, 1.0 μm, for the simulation.
First, as illustrated in
At this time, the maximum temperature of the Cu interconnect 3 was 126.772° C. That is, it was confirmed that if running a current of 0.40 mA to the poly-silicon resistor 1 at the resistance device part of
Next, as illustrated in
Therefore, it was confirmed that to maintain the temperature of a Cu interconnect 3 at 130° C. or less at an ambient temperature of 125° C., it is only possible to run a current of 0.672 mA through the poly-silicon resistor 1.
From a comparison of
From a comparison of
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
This application is a continuation application and is based upon PCT/JP2009/061866, filed on Jun. 29, 2009, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2009/061866 | Jun 2009 | US |
Child | 13303313 | US |