CN102879113B - A kind of method improving the built-in thermal sensing element measuring accuracy of integrated circuit and sensitivity - Google Patents

Abstract

The invention discloses a kind of method improving the built-in thermal sensing element measuring accuracy of integrated circuit and sensitivity, according to thermograde and the equitemperature line in chip slapper endogenous pyrogen, focus and temperature field thereof, the equitemperature line that a certain bar is special lays multiple temperature-sensing element (device), record multiple temperature measured value, and these temperature measured values are for data processing, to improve measuring accuracy and the sensitivity of built-in chip type thermal sensing element group.The present invention utilizes the arithmetic mean of all thermal sensing element measured value sums that the greatest gradient equitemperature line of focus in temperature field in ic core blade lays symmetrically and a certain constant sum, as the data processing method removing deviation, the Temperature numerical sensitivity of gained can be made the highest minimum with error.

Description

A Method for Improving the Measurement Accuracy and Sensitivity of Thermal Sensitive Elements Built in Integrated Circuits

technical field

The invention relates to the field of integrated circuits, in particular to a method for improving the measurement accuracy and sensitivity of a thermal sensor built in an integrated circuit.

Background technique

The number of transistors in an integrated circuit chip increases according to Moore's Law, and its operating clock frequency is also increasing rapidly, but its die area increases very slowly. As a result, the power consumption density of the chip increases sharply, and the temperature of the chip rises sharply, which poses a great threat to the reliability of the chip. In order to improve the reliability of integrated circuit chips and electronic systems, one of the first prerequisites is to improve the sensitivity and accuracy of on-chip temperature measurement.

A practical approach in the existing chip design technology is to arrange four heat-sensitive elements roughly evenly around the heat source and add a fifth thermal PN junction at the position of the heat source, in order to perform comprehensive error processing on the measured values of multiple heat-sensitive elements Finally, the accurate temperature value of the heat source in the core is obtained.

The inhomogeneity of chip thickness and packaging material will cause uneven heat conduction in the chip, resulting in an uncertain temperature field, including the position of the actual hot spot that deviates from the position of the heat source. As a result, the aforementioned existing actual deployment method cannot obtain the highest sensitivity.

In short, the existing deployment scheme does not take into account the characteristics of the temperature field, so its total measurement sensitivity and accuracy are greatly affected.

Contents of the invention

The purpose of the present invention is to provide a method for improving the measurement accuracy and sensitivity of the integrated circuit built-in thermal sensor, which solves the problem of low measurement accuracy and sensitivity of chip temperature in the prior art.

A method of improving the measurement accuracy and sensitivity of the integrated circuit built-in heat-sensitive element of the present invention, specifically, according to the temperature gradient and isothermal line of the heat source, hot spot and its temperature field in the chip, in a certain special isothermal line A plurality of temperature sensitive elements are arranged on the chip, and a plurality of measured temperature values are measured, and data processing is performed on these measured temperature values, so as to improve the measurement accuracy and sensitivity of the thermal sensor group built in the chip.

Preferably, the isothermal line is the isothermal line with the fastest temperature change (increase or decrease) on both sides of the temperature field in the integrated circuit chip found by using thermal simulation or thermal testing technology, That is, the maximum gradient isothermal line; and on the closed line corresponding to the maximum gradient isothermal line of the temperature field in the integrated circuit chip, more than 4 even-numbered thermal elements are evenly and symmetrically arranged; The arithmetic mean of the sum of the measured values of all thermal elements arranged uniformly and symmetrically on the maximum gradient isothermal line of the hot spot in the field and the sum of a certain constant are used as a data processing method for removing deviations.

Compared with the prior art, the present invention has the following advantages:

A method for improving the measurement accuracy and sensitivity of the integrated circuit built-in thermal sensor of the present invention considers the general law and characteristics of the temperature field in the integrated circuit chip, and utilizes the maximum gradient isothermal line of the hot spot in the integrated circuit chip internal temperature field The arithmetic mean of the sum of the measured values of all thermistors arranged uniformly and symmetrically on the surface and the sum of a certain constant are used as a data processing method to remove the deviation, so that the obtained temperature value has the highest sensitivity and the smallest error.

Description of drawings

Figure 1 is a schematic diagram of the temperature field near an actual hot spot of a certain integrated circuit chip based on Embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of the layout of the heat-sensitive element based on Embodiment 1 of the present invention.

Figure 3 is a schematic diagram of the offset of the hot spot relative to the heat source based on Embodiment 1 of the present invention.

Explanation of symbols in the figure: 1. heat source, 2. maximum gradient isothermal line.

Detailed ways

A method for improving the measurement accuracy and sensitivity of integrated circuit built-in heat-sensitive elements according to the present invention, according to the temperature gradient and isothermal line of the heat source, hot spot and its temperature field in the integrated circuit chip, lay out on a special isothermal line Put multiple temperature sensitive elements, measure multiple measured temperature values, and perform data processing on these measured temperature values, and use all thermal sensors that are evenly and symmetrically arranged on the isothermal line of the maximum gradient of the hot spot in the temperature field in the integrated circuit chip The arithmetic mean of the sum of the measured values of the components and the sum of a certain constant, as a data processing method to remove the deviation, can make the obtained temperature value have the highest sensitivity and the smallest error.

Example 1

The temperature field formed by the actual heat conduction movement in the integrated circuit chip has the characteristics of uniform distribution (that is, concentric circles) in the area close to the hot spot and non-uniform distribution in the area far from the hot spot. In other words, even though the actual temperature field formed by the actual non-uniform heat conduction is generally irregular in shape, the temperature field within a certain short distance is still closer to concentric circular symmetry than the temperature field at a distance. Combined with the temperature field near an actual hot spot of a certain integrated circuit chip in Figure 1, and according to its steady-state temperature field simulation results under a certain constant load, the actual measurement results of the steady-state temperature field under a certain constant load and other forms of expression It can be seen that there is a closed isotherm that is close to a circle, and the gradient of the temperature field is the largest near the inside and outside of this isotherm, and the change of temperature is approximately linear. The present invention refers to this line as the maximum gradient isothermal line.

As shown in FIG. 2, for any specific integrated circuit chip, through effective methods, such as thermal simulation or thermal testing or other techniques, find out the maximum gradient isothermal line 2 of the actual temperature field in the integrated circuit chip. If due to technical reasons such as simulation accuracy or testing methods, the exact "line" cannot be found, but only a band (strip, ring)-shaped area can be found, it can also be called the temperature band such as the maximum gradient, or the maximum gradient Isothermal strips, or maximum gradient isothermal loops.

On the closed line corresponding to the maximum gradient isothermal line 2, more than 4 even-numbered thermal elements are evenly and symmetrically arranged. A heat sensitive element is also arranged at the expected heat source 1 in the chip.

Through an effective method, the difference T _off between a certain thermal element on the maximum gradient isothermal line and the measured value of the thermal element at the heat source is measured in advance through actual measurement, and saved, and its value represents the maximum gradient, etc. The difference between the temperature at the temperature line and the temperature at the heat source. Obviously, T _off is a function of temperature, it should be written as T _off ( T ) precisely.

Due to the central symmetry of the temperature field, the sum of the temperature deviations measured by thermal elements N ₁ , N ₂ , N ₃ , …, N _k will be the same as that of thermal elements N ₁ ', N ₂ ', N ₃ ', …, N _k 'The sum of the measured temperature deviations cancels out.

Even in the actual integrated circuit chip, the hot spot has a slight offset relative to the heat source (as shown in Figure 3), the actual temperature measured by an even number of thermal elements symmetrically arranged on the maximum gradient isothermal line will be Guaranteed to offset each other in pairs.

For example, when the actual hot spot deviates from the theoretically predicted heat source, and thus the actual temperature field also deviates from the theoretically predicted temperature field, as shown in Figure 3, the temperature measured by almost every thermal sensor placed in advance Deviations will occur, but the sum of the deviations of any two pairs of symmetrically arranged thermosensitive elements is offset. As shown in N _k and N _k ' in Figure 3, in the case of offset, if N _k has a measurement increment of Δ T _k (≥0), then N _k has a measurement increment of Δ T _{k '} (≤0) , and the algebraic sum of the two must be zero, namely . Other thermal element pairs such as N ₁ and N ₁ ′, N ₂ and N ₂ ′, N ₃ and N ₃ ′, etc., all have this feature.

Find the sum of the measured temperature values of the thermal elements placed according to the above arrangement method, that is, .

In the case of hot spot and heat source offset, T _i includes the ideal expected temperature measurement value T _{i 0} without offset and the temperature deviation value ΔT _i with offset. The case of T _{i '} is similar.

Divide the sum of the resulting measurements by 2 k , that is .

Then add the aforementioned T _off ( T ) to the above formula, namely , this formula is a mathematical processing method that can remove the deviation.

The above-mentioned embodiments are just to illustrate the technical conception and characteristics of the present invention. The purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement it accordingly, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the essence of the present invention shall fall within the protection scope of the present invention.

Claims (5)

1. A method for improving the measurement accuracy and sensitivity of integrated circuit built-in thermosensitive elements is characterized in that, according to the temperature gradient and isothermal lines of thermal sources, hot spots and temperature fields thereof in the chip, the isothermal lines close to the closed circle are A plurality of temperature sensitive elements are arranged on the maximum gradient isothermal line, and a plurality of measured temperature values are measured, and data processing is performed on these measured temperature values, so as to improve the measurement accuracy and sensitivity of the thermal sensor group built in the chip. 2. The method for improving the measurement accuracy and sensitivity of integrated circuit built-in thermal elements according to claim 1, wherein the maximum gradient isothermal line is found by thermal simulation or thermal testing technology. 3. The method for improving the measurement accuracy and sensitivity of integrated circuit built-in thermal elements according to claim 2, wherein the maximum gradient isotherm is an isotherm with the fastest temperature changes on both sides. 4. The method for improving the measurement accuracy and sensitivity of integrated circuit built-in thermal elements according to claim 1, characterized in that, on the closed line corresponding to the maximum gradient isothermal line of the temperature field in the integrated circuit chip, uniformly and symmetrically Arrange more than 4 even-numbered thermal elements. 5. The method for improving the measurement accuracy and sensitivity of integrated circuit built-in thermosensitive elements according to claim 1, wherein said data processing is uniform on the maximum gradient isothermal line of the hot spot in the temperature field of the integrated circuit chip. The arithmetic mean of the sum of the measured values of all thermosensitive elements arranged symmetrically and the sum of the temperature function T _off is used as a data processing method to remove the deviation.