Color display film changing along with temperature and forming method thereof

Abstract

The invention discloses a color display film changing along with temperature and a forming method of the color display film. The color display film comprises an ITO covering layer, an SST layer, an ITO dielectric layer II, a VO2 layer, an ITO dielectric layer I and an Ag layer which are vertically stacked from top to bottom. The SST layer, the ITO dielectric layer II, the VO2 layer, the ITO dielectric layer I and the Ag layer form a resonant cavity of multi-order Fabry-Perot resonance; when the temperature is 68 DEG C and the film temperature is less than 200 DEG C, the film is changed from the initial color, and when the temperature is reduced to less than 68 DEG C, the film color is recovered to the initial color; when the temperature of the film is 200 DEG C, the film is changed into another color, and the color is not changed when the temperature is reduced. The thin film is processed in a magnetron sputtering mode, the temperature range of the processed color display thin film can be visually obtained, and large-range detection can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of temperature detection, and in particular to a color display film that changes with temperature and a forming method thereof. Background Art

[0002] When the chip in a semiconductor structure device heats up, the difference in thermal expansion between different materials will cause stress and deformation inside the chip; the drain electrode of the transistors and circuit devices inside the chip will increase, and the power consumption will also increase; the oxidation process of various components inside the chip will be accelerated, reducing the performance of the chip. Commercial-grade chips have very good accuracy in the temperature range of 0-70℃, and the accuracy will become very poor outside this temperature range. Some chips can still maintain very good accuracy at -55℃-155℃. When the temperature is about 185℃-200℃, the temperature increase will make the operation of the silicon chip unpredictable. Once the chip temperature exceeds 200℃, the chip is already damaged. Therefore, it is also very important to intuitively observe the approximate temperature of the semiconductor device through color changes.

[0003] Traditional temperature detection methods include: (1) thermocouple temperature measurement, which has complex signal conditioning, requires precise amplification and cold-end compensation, has poor noise immunity, and is sensitive to stray electric and magnetic fields; (2) thermistors, which require calibration and complex signal processing, have a limited temperature range, and may drift at high temperatures; (3) temperature sensors, which require calibration and are affected by mechanical stress and welding processes. The above temperature measurement structures or methods all require data processing before output, which is not intuitive and requires the setting of specific temperature measurement components, which is costly and takes up space. Summary of the invention

[0004] In view of this, the present invention provides a color display film that changes with temperature and a forming method thereof, which can intuitively obtain the temperature range and can detect over a large range.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A temperature-dependent color display film, comprising an ITO cover layer, an SST layer, an ITO dielectric layer II, a VO2 layer, an ITO dielectric layer I and an Ag layer vertically stacked from top to bottom;

[0007] The SST layer, ITO dielectric layer II, VO2 layer, ITO dielectric layer I and Ag layer constitute a resonant cavity of multi-order Fabry-Perot resonance;

[0008] When the film temperature is 68℃≤<200℃, the film changes color from the initial color, and when the temperature drops to <68℃, the film color returns to the initial color; when the film temperature is ≥200℃, the film changes to another color, and the color remains unchanged when the temperature drops.

[0009] Furthermore, the color display film is plated on the chip with the chip as the substrate;

[0010] The initial color of the film is orange; when the film temperature is ≥68°C, the film turns green for warning; when the film temperature is ≥200°C, the film turns yellow, indicating that the chip is damaged.

[0011] Furthermore, the SST layer is replaced by a GeTe layer or a GeSbTe layer.

[0012] Furthermore, the ITO material used in the ITO dielectric layer I and the ITO dielectric layer II is replaced by TiO2 or SiO2 or ZnS.

[0013] Furthermore, the thickness of the ITO dielectric layer I and the ITO dielectric layer II is 20-200 nm.

[0014] Furthermore, the Ag layer has a thickness of 50 nm.

[0015] The present invention also provides a method for forming a color display film that changes with temperature, and the method steps are as follows:

[0016] Step 1, sputtering a Ag film of a set thickness on the surface of the substrate by magnetron sputtering;

[0017] Step 2: sputtering an ITO film of a set thickness on the Ag film by magnetron sputtering as the dielectric layer I of the Fabry-Perot resonant cavity;

[0018] Step 3, sputtering a VO2 thin film on the dielectric layer I by magnetron sputtering;

[0019] Step 4, sputtering an ITO film of a set thickness on the VO2 film by magnetron sputtering as the dielectric layer II of the Fabry-Perot resonant cavity;

[0020] Step 5, sputtering an SST film on the dielectric layer II by magnetron sputtering, thereby forming a resonant cavity of multi-order Fabry-Perot resonance;

[0021] Step six, sputtering an ITO film as a covering layer on the SST film by magnetron sputtering.

[0022] Furthermore, the set thickness of the Ag film is 50 nm; the set thickness of the ITO film in step 2 and step 4 is 20-200 nm.

[0023] Beneficial effects:

[0024] 1. The phase change material SST of the present invention is non-volatile and the phase change material VO2 is volatile. A multilayer film structure is constructed based on the Fabry-Perot cavity. The thin film structural material will undergo changes in material morphology at different temperatures, thereby changing the refractive index and reflectivity of the structural material, so that the film can change color at different temperatures. A large range of coating can be performed on the object to be measured for temperature monitoring. Compared with traditional temperature detection, the temperature range can be obtained more intuitively, and it has the advantages of low cost, no additional space occupation, high accuracy, and a large range.

[0025] 2. The present invention coats a color display film on the chip, and intuitively displays the temperature rise of a specific device part or the chip is damaged through color changes. This application can be coated on a large scale on the surface of the original device / instrument, with low cost, accurately displaying the temperature change of a specific part, without the need for a temperature sensor, saving more space, and accurately locating problems that occur during chip debugging.

[0026] 3. The phase change material SST of the present invention can be replaced by a similar phase change material, and the dielectric layer can be replaced by ITO by a similar material with an extinction coefficient of about 0 in the visible light band, which has strong versatility and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the film structure of the present invention.

[0028] Figure 2 This is the reflectivity curve of the film at different temperatures. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0030] The Fabry-Perot (FP) cavity is a film structure system formed by stacking multiple layers of metal, transparent medium, etc. based on the thin film interference effect. It consists of two parallel reflectors with high reflectivity. When light is incident on the space between the reflectors at a specific angle, it propagates back and forth in the cavity, forming a standing wave and causing interference. In the study of Fabry-Perot cavity thin film structural color display, a cavity is set in the thin film structure to allow the elastic echo of the incident light to be transmitted, and then the return wave is refracted to the external detection end, thereby producing different color displays. By adjusting the wavelength reflected from the stack, a color of a specific hue is produced in the reflection.

[0031] Sulfur phase change materials can be reversibly and rapidly transformed between amorphous and crystalline states in the form of light, electricity, and heat on a sub-nanosecond time scale, and this state is non-volatile, that is, only the energy required for the conversion process is required, rather than maintaining a specific state, and they will maintain their optical properties. This means that once sulfur phase change materials undergo a conversion, they will maintain their optical properties until they are switched again, which means that sulfur phase change materials can be used to cause structural color changes due to temperature changes. In the visible light band, the sulfur phase change material Sc0.2Sb2Te3 (SST) has a large refractive index difference (Dn≈1.1) and a large extinction coefficient difference (Dk≈1) between the crystalline and amorphous states. This feature helps SST to be used in tunable color display films.

[0032] Taking advantage of the monoclinic-rutile phase transition of nano vanadium dioxide VO2, when the temperature of VO2 exceeds 68°C, it will change from amorphous to crystalline, and when the temperature is lower than 68°C, it will return to amorphous. The extinction coefficient of amorphous and crystalline VO2 is about 0.7.

[0033] Therefore, the present invention is based on the Fabry-Perot resonant cavity structure, combining the non-volatile phase change material SST and the volatile phase change material VO2, such as Figure 1 , Figure 2 As shown, a temperature-dependent color display film is provided, which includes an ITO cover layer, an SST layer, an ITO dielectric layer II, a VO2 layer, an ITO dielectric layer I and an Ag layer vertically stacked from top to bottom; the SST layer, the ITO dielectric layer II, the VO2 layer, the ITO dielectric layer I and the Ag layer constitute a resonant cavity of multi-order Fabry-Perot resonance; that is, the SST layer, the VO2 layer and the Ag layer are all used as reflectors to form two resonant cavity cavities. A light wave resonance of a specific wavelength can be formed in the resonant cavity.

[0034] Under the stimulation of heat, SST and VO2 can be rapidly converted into two solid states (crystalline and amorphous), that is, the color of the film can be dynamically changed with temperature changes. The middle cavity layer is designed as an ITO dielectric layer with multi-order FP resonance. The dielectric layer is covered with a phase compensation medium ITO and a high reflective mirror is added in the middle. ITO has a high refractive index and a negligible extinction coefficient in the visible light band, which can suppress multi-order resonance wavelengths and produce bright saturated colors. Since silver Ag has extremely low absorptivity and extremely high reflectivity in the visible light region, it can increase the peak of the reflection spectrum, so it is used as a metal reflective layer. SST is used to build a resonant cavity with the Ag layer, and VO2 is used to separate multi-order resonant cavities. Among them, VO2 and SST can change the refractive index of the material through temperature changes, thereby changing the band of the resonance of the resonant cavity. The VO2 and SST phase change layers change the resonance in the cavity through phase shifts and absorption changes. The absorption intensity of the crystalline state is higher than that of the amorphous state, and the electric field peak of the amorphous state is higher than that of the crystalline state. This leads to the color difference between the amorphous and crystalline structures.

[0035] When the film temperature is 68℃≤<200℃, the film changes color from the initial color, and when the temperature drops to <68℃, the film color returns to the initial color; when the film temperature is ≥200℃, the film changes to another color, and the color remains unchanged when the temperature drops.

[0036] The SST layer is replaced by a GeTe layer or a GeSbTe layer, that is, the phase change material SST can be replaced by a similar phase change material such as a compound material such as GeTe and GeSbTe.

[0037] The ITO material used in the ITO dielectric layer I and the ITO dielectric layer II is replaced with TiO2 or SiO2 or ZnS, that is, the dielectric layer can be replaced with the ITO material with the same material having an extinction coefficient of about 0 in the visible light band, such as TiO2, SiO2, and ZnS.

[0038] Specifically, the present invention can use the chip as the substrate, and plate the color display film on the chip. The thickness of the ITO dielectric layer I and the ITO dielectric layer II is 20-200nm. After changing the thickness of the dielectric layer, the color of the film structure will also change to a certain extent. The thickness of the Ag layer is 50nm.

[0039] The initial color of the film is orange, that is, the temperature is <68°C at this time, and both SST and VO2 are amorphous; the chip has high precision and good performance.

[0040] When the film temperature is ≥68℃, the film turns green to warn, indicating that the temperature of the chip under test is rising and the chip accuracy is deteriorating. At this time, the volatile phase change material VO2 has changed from amorphous to crystalline. When the film temperature drops to <68℃, the film color returns to its original color and turns orange.

[0041] When the film temperature is ≥200℃, the film turns yellow, and both SST and VO2 change from amorphous to crystalline. Moreover, as the temperature rises, the crystallinity of SST will be very high, that is, the color will gradually deepen, and this SST change is non-volatile. Even after the temperature drops, the color will be fixed at the film color in the SST crystalline state, that is, yellow, thereby indicating that the chip is damaged and issuing a warning.

[0042] The present invention also provides a method for forming a color display film that changes with temperature, and the steps of the method are as follows:

[0043] Step 1: sputtering a Ag film of a set thickness on the surface of the substrate by magnetron sputtering; the set thickness of the Ag film can be 50 nm.

[0044] Step 2: sputtering an ITO film of a set thickness on the Ag film by magnetron sputtering as the dielectric layer I of the Fabry-Perot resonant cavity; the set thickness of the ITO film can be adjusted within the range of 20-200 nm.

[0045] Step three, sputtering a VO2 thin film on the dielectric layer I by magnetron sputtering.

[0046] Step 4: sputter an ITO film of a set thickness on the VO2 film by magnetron sputtering as the dielectric layer II of the Fabry-Perot resonant cavity; the set thickness of the ITO film can be adjusted within the range of 20-200nm.

[0047] Step 5: sputtering an SST film on the dielectric layer II by magnetron sputtering, thereby forming a resonant cavity of multi-order Fabry-Perot resonance.

[0048] Step six, sputtering an ITO film as a covering layer on the SST film by magnetron sputtering.

[0049] The substrate can be any chip or any designated part of the original device / instrument surface. The magnetron method can be used to coat a large area, thus bringing low cost and wide range effects.

[0050] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A color display film that changes with temperature, characterized in that: It includes an ITO cover layer, an SST layer, an ITO dielectric layer II, a VO2 layer, an ITO dielectric layer I and an Ag layer which are stacked vertically from top to bottom; The SST layer, ITO dielectric layer II, VO2 layer, ITO dielectric layer I and Ag layer constitute a resonant cavity of multi-order Fabry-Perot resonance; When the film temperature is 68℃≤<200℃, the film changes color from the initial color, and when the temperature drops to <68℃, the film color returns to the initial color; when the film temperature is ≥200℃, the film changes to another color, and the color remains unchanged when the temperature drops.

2. The temperature-dependent color display film according to claim 1, characterized in that: Using the chip as a substrate, coating the color display film on the chip; The initial color of the film is orange; When the film temperature is ≥68℃, the film turns green to warn; when the film temperature is ≥200℃, the film turns yellow to indicate that the chip is damaged.

3. The temperature-dependent color display film according to claim 1, characterized in that: The SST layer is replaced by a GeTe layer or a GeSbTe layer.

4. The temperature-dependent color display film according to claim 1, characterized in that: The ITO material used in the ITO dielectric layer I and the ITO dielectric layer II is replaced by TiO2 or SiO2 or ZnS.

5. The temperature-dependent color display film according to claim 1 or 4, characterized in that: The thickness of the ITO dielectric layer I and the ITO dielectric layer II is 20-200nm.

6. The temperature-dependent color display film according to claim 5, characterized in that: The thickness of the Ag layer is 50 nm.

7. A method for forming a color display film that changes with temperature, characterized in that: The method steps are as follows: Step 1, sputtering a Ag film of a set thickness on the surface of the substrate by magnetron sputtering; Step 2, sputtering an ITO film of a set thickness on the Ag film by magnetron sputtering as the dielectric layer I of the Fabry-Perot resonant cavity; Step 3, sputtering a VO2 thin film on the dielectric layer I by magnetron sputtering; Step 4, sputtering an ITO film of a set thickness on the VO2 film by magnetron sputtering as the dielectric layer II of the Fabry-Perot resonant cavity; Step 5, sputtering an SST film on the dielectric layer II by magnetron sputtering, thereby forming a resonant cavity of multi-order Fabry-Perot resonance; Step six, sputtering an ITO film as a covering layer on the SST film by magnetron sputtering.

8. The temperature-dependent color display film according to claim 7, characterized in that: The set thickness of the Ag film is 50nm; the set thickness of the ITO film in step 2 and step 4 is 20-200nm.

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