TW483183B - Manufacture method of thermopile sensor device using combined sacrificial layer and silicon bulk etching process - Google Patents

Abstract

This invention provides a manufacture method of thermopile sensor device using polysilicon or amorphous silicon as a sacrificial layer and employing combined etching process of sacrificial layer and silicon bulk to etch the silicon substrate underneath the floating plate. This reduces the etching time and improves yield and also device performance. A resistor is made on the floating plate as a heater for electrical calibration and measurement. The heater has a radiation shape, which makes the hot end of the thermocouple go deep into the floating plate to improve radiation absorption characteristics of device and also makes the hot end of the thermocouple contact with the heater to increase heat transfer efficiency of the heater.

Description

483183 Case No. 89128366 Modification V. Description of Invention (1) < Scope of Invention >

The invention relates to a thermopile sensing element and a method for manufacturing the same, using an etching method in which a sacrificial layer of polycrystalline silicon or amorphous silicon is combined with a silicon body type etching to accelerate the etching rate, and a radiant heater is used to heat the heater and the thermopile. When the same material layer is used for the material layer, the hot end of the thermopile can penetrate the inside of the black body absorption plate, increase the efficiency of infrared absorption, and make the hot end of each thermocouple adjacent to the heater to increase heating. Heat transfer efficiency. The use of a sacrificial layer can shorten the etching time to avoid a reduction in yield caused by long-term etching. The use of a heater can be used for electronic correction of components to avoid measurement errors caused by material aging, and its radial structure The infrared absorption efficiency of the element and the heat transmission efficiency of the heater can be improved at the same time, and the same material layer can be used for the heater and the thermopile without increasing the number of photomasks and processes to simplify the process and reduce the cost. < Background of invention >

Temperature detectors that use objects to emit infrared rays to measure object temperature are widely used. In addition to temperature measurement, they can also be used for human body sensing, such as motion sensors, infrared cameras, Camera, and medical measurement of human body temperature distribution and other aspects. The principle is mostly to change the physical characteristics of the material by the temperature rise caused by infrared radiation on the element, and to convert it into electrical characteristic output. Common sensing elements include pyroelectric sensing elements, thermal resistance sensing elements, and thermopile sensing elements. If the above components are compared in terms of manufacturing methods, if the manufacturing process of the sensor is compatible with the existing semiconductor manufacturing process, the cost of development and manufacturing will also increase.

Page 4 483183 Case No. 89128366 A_η Revision V. Description of the invention (2) Low, and if the infrared type can be increased but the component types can be increased, the development and manufacturing process are simplified, and the micro-electromechanical production of the finished product is floating. Board structure; time to complete the etching and engraving to hollow out the characteristics of the easy-engraving element on the front of the floating plate. Use the sacrificial layer and silicon to shorten the etching time. Besides, the temperature of the floating plate caused by the heat changes from the voltage difference environment. This patent proposes a resistive heater. The above-mentioned reasons cause the radiation to shape, and the thermoelectric heating. The device can be adjacent to components and functions. In the device, the CMOS system has its own micro-process and back. The silicon on the floating plate is specifically etched to amplify the electricity and can reduce the thermoelectric stack. The process is quite large. The electromechanical process is usually etching.法 面 # Engraved substrate, Liuli below engraved and known thermoelectric temperature rise, directly calculates the new heat of the stack material and can be used to develop the characteristics of the CMOS electrical low signal such as the thermocouple path on the hot end of the thermocouple Interface sensing elements have the advantages of thermopile sensing. From the perspective of process, the rule of Xi from the back or positive etching depth must be produced from a new hot etching method, but also noisy. For the above-mentioned CMOS process-compatible measuring elements, it is necessary to etch the silicon substrate to make it deeper in terms of cost and know-how of the thermopile sensing element, and it must take a long time to etch the crystal surface sideways for a long time. In addition, the residual silicon substrate affects the manufacturing method of the stack, so that the stack sensor can be converted into the measured object by accelerating the etching speed, which will be described later. The stack and the deep stack can be penetrated into the hot end. The structure of the film, such as temperature degradation, and the erroneous heater caused by electronic correction, increase infrared absorption and increase the end of the floating plate. And this caused its error to be measured in float. And the difference of the radiation voltage absorbed by the same infrared radiation is used, but the method is susceptible to drift. There is an electric quantity on the board to avoid its heater as a material layer inside and make the absorption efficiency and

Page 5 483183 Case No. 89128366 ΛYue Yue Amendment V. Description of the invention (3) The heat transfer of the heater feels like this. The main point is that the generation of the element and its combination with the amorphous silicon can be increased. The other purpose of the thermoelectric heat transfer of the resistance-type plus material phase coupler is to achieve this goal. The invention of the manufacturer's component is unique to the component at the time of new production. The heat exchanger of the present invention achieves the above-mentioned transmission efficiency with the same thermal efficiency of the same hot end energy. The advantage of the detector is that the manufacturing process is simple and the yield of mass production is high. The structure of the characteristics of the sensor is exactly what is claimed in this patent. The main purpose of the invention is to provide a thermopile sensing element method. To improve the shortcomings and disadvantages of the conventional process. Functions and features. Such a thermopile sensing element uses a polycrystalline silicon pad or a sacrificial layer during etching, and the sacrificial layer etching and silicon body type etching process are used to shorten the etching time of the silicon substrate and improve the yield. This structure can also improve the flatness of the etched bottom, the stability of the properties, and the performance of the device. This is the method of the present invention, which is used to correct the electrode layer and thermopile sensor and is completed. An external line absorbing plate element is provided in which the heater can be heated and formed inside, and an external line absorption effect is another object of the invention. The use of electricity and the thermopile radiation type are added on the floating board to make the heat to the heater and the heater manufacturing method. The first part of the product sacrifices the red end to increase the i at the same time. A method for forming a first sacrificial layer on a substrate material to form a first sacrificial layer; depositing a first invention provides a thermopile sensing element including the following and the steps thereof: providing a silicon substrate; a sunken surface, and a mask definition and money Carved off.

• Page 6 483183 _Case No. 89128366_ Year and Month Amendment _ V. Description of the Invention (4) The edge layer is on the surface of the silicon substrate and the first sacrificial layer; a first thermoelectric material is deposited on the surface of the first insulating layer; the definition of the cover In addition, a portion of the first thermoelectric material layer is removed to form a first wire and a heater; a second insulating layer is deposited on a surface of the wire and the first insulating layer; a portion of the second insulating layer is removed to form a plurality of A contact window; depositing a second thermoelectric material layer on the surface of the second insulating layer; a mask defining and etching to remove a portion of the second thermoelectric material layer to form a second wire, and passing the second wire and the first wire through the aforementioned contact window Touching a plurality of hot and cold ends; depositing a third insulating layer on the surface of the second wire and the second insulating layer; etching part of the third insulating layer and the second insulating layer to make a part of the last second wire Exposed to connect to the output of the formed metal pad, and the first first wire can also be connected to the output of another metal pad to be formed through the second lead; a first metal layer is deposited on the three insulating layers ; Etching part of the first metal layer Forming a plurality of metal pads; depositing a fourth insulating layer on the third insulating layer and the plurality of metal pads; depositing a first blackbody layer on the fourth insulating layer; and defining a blackbody absorbing layer by etching or Liftoff For absorbing incident infrared rays; depositing a fifth insulating layer on the surfaces of the fourth insulating layer and the black body absorbing layer; engraving a portion of the fourth insulating layer and the fifth insulating layer to form a plurality of wired windows to expose the metal pads; A plurality of etching holes are formed to penetrate the fifth, fourth, third, second and first insulating layers, so that part of the surface of the first sacrificial layer is exposed to the outside; finally, the technique of combining the sacrificial layer etching and the front silicon type etching is used. The aforementioned etching holes are etched to hollow out the silicon substrate under the floating plate. According to the manufacturing method described above, the obtained thermopile sensing element uses the metal pad exposed under the wire window as the thermoelectric stack sensing element layer connection and the exposed warp system 483183. No. 89128366_ Year, month, and year of revision_ V. Description of the invention (5)

The output has a structure including at least: a silicon substrate; a first insulating layer formed on the surface of the silicon substrate; a plurality of first wires formed on the surface of the first insulating layer, wherein each first wire has a hot end and A cold end, and the cold end of the first first wire is electrically connected to the metal pad output through the second wire to be formed; a second insulating layer is formed on the surface of the first wire; and a plurality of second wires is formed On the surface of the second insulation layer, and each second wire also has a hot end and a cold end, and the hot end of the second wire is in one-to-one contact with the hot end of the first wire, and in the second wire, finally The cold end of a second wire is electrically connected to another metal pad, and the metal pad is formed by the first metal layer; a third insulating layer is formed on the surface of the second insulating layer and the second wire; a first Four insulating layers are formed on the surface of the third insulating layer and the aforementioned metal grate; a black body absorbing layer is formed on the surface of the fourth insulating layer to absorb infrared rays; a fifth insulating layer is formed on the fourth insulating layer and the black body Surface of absorbing layer A number of wired windows are formed above the plurality of metal pads and penetrate through the fifth and fourth insulation layers to expose the surface of the metal pads; and a plurality of etching holes are formed on the surface of the fifth insulation layer and extend downward through The fifth, fourth, third, second and first insulating layers are used to allow the first sacrificial layer to communicate with the outside world.

In addition, when the first or second wire layer is manufactured on the above process, a heating resistor or a resistor for measuring ambient temperature can be manufactured at the same time. The two ends of these resistors are also electrically connected to other metal pads for output and input of power and signals. In order to make the above and other objects, features, and advantages of the present invention more obvious and easy to understand, a preferred embodiment is hereinafter described in detail with reference to the accompanying drawings.

Page 8 483183 _Case No. 89128366_ Year Month Day Amendment _ V. Description of the invention (6) < Detailed description of the preferred embodiment > First, please refer to "Figure 1", which is the thermoelectricity of the present invention Top view of a stack of sensing elements. This thermopile sensing element has: a plurality of first wires 1 1, a plurality of second wires 1 2, a plurality of etched holes 1 3, a black body absorbing layer 1 4, four wire windows 1 5, 1 6, 17, 7, 8, a central radiant heater 19, a plurality of first and second wires connected to the hot end Η, and a plurality of first and second wires connected to the cold end C. It can be seen from the figure that the second wire 12 passes through the contact window Η of the hot end and contacts the first wire 11 to form an electrical connection. The first wire 11 and another adjacent second wire form an electrical connection through the cold-end contact window C, so that they are connected to form a series structure. Finally, the two ends are connected by the first wire window 15, The second wire window 18 is used as the output of the thermopile sensing element. The third wiring window 16 and the fourth wiring window 17 are used as input and output terminals of the heater for electronic calibration. Figures 2 and 3 show the sectional views of Figure 1 along A-A 'and B-B', respectively. The structure of the above-mentioned structure, the manufacturing method of which is coordinated with each of the "4th (a) to 4th (0) drawing" and "5th (a) to 5th (0) drawing", the cross-sectional views of each manufacturing step are detailed below. A silicon substrate 20 is provided, and a first sacrificial layer material 21 is deposited on the aforementioned silicon substrate 20, and then masked and etched to define the first sacrificial layer 31, as shown in FIG. 4 (b) and 4 (c). "Figure 5 (b), 5 (c)". Thereafter, a first insulating layer 22 is deposited thereon; then a first thermoelectric material layer is deposited on the surface of the first insulating layer 22, and the material may be metal or polycrystalline silicon or amorphous silicon,

-^^ 89128366 Description of the invention (7) The sub-layer uses a standard yellow light process to cover the electric material f 'and the central heater 43 in the -insulating layer 22, as shown in "Figure 4 (e)". The second insulating layer 24 is etched on the surfaces of 22 and the first conductive line 11 so that the bottom of the contact window is exposed first; then, during the surface of the second insulating layer 24, the second thermoelectric material layer will plug the front As the first wire, it communicates with the subsequent wires. After the deposition is completed, a standard yellow material layer is used, as shown in the "Figure 4 (g)" of the second insulating layer 24. After the conductive wire 12 contacts to form a heat contact with another second conductive wire (not shown), after the second conductive wire 12 is formed, a third insulating layer and an insulating layer 26 are deposited on the surface of the subsequent layer 24 to perform etching, so that After that, a first metal layer is deposited, and a plurality of metal pads 37 are defined, so as to be used for the first signal-wheel output end. Then deposit a fourth insulating layer on the metal pad, as shown in "Figure 4 (j)" on the aforementioned fourth insulating layer 28, and amend the definition and etch to remove part of the first heat to form the first 5 (e) of lead 11 and middle "; the first insulation layer 24 of the second child, and then, a plurality of contact windows 34, 44 are formed, and lead 11 of lead 11 is shown as" 4 (f) " The second metal layer is accumulated, and the deposited 4 contact windows 34, 44 are filled to form a connection of the second wire 12 formed by the bolt. The light-conducting process mask defines the second wire 1 formed on the second thermoelectric surface 2. For example, the wire 11 can form the cold end C through the contact terminal 34 of the contact window 34 and through the other contact window 44. Continuing on the second wire 12 and the second insulation 26, the mask defines and exposes a part of a part of the third second wire and engraved part of the first metal layer to form an electrical connection with the two wire layers. As 2 8 is shown in the third insulating layer 26 and plural, and a black body material layer is deposited by the method of money engraving or Lift 0ff.

483183 Case No. 89128366 Modification V. Explanation of the invention (8) The black body absorbing layer 39 is used for absorbing diagram "shown in the" 5 (k) diagram ". After the black body absorbing layer 39 is formed, a fifth insulating fifth layer (28,40) is deposited on the surface of the body absorbing layer 39 to form a metal pad 37; then, a surface of the fifth insulating layer 40 is defined by a mask. The etch process that etched through the fourth, third, second and first part of the surface of the first sacrificial layer 31, such as "Figure 5 (n)". The surface of layer 31 is etched to plate 20, and the component structure is released, as shown in ". Figures 5 (a) to 5 (〇) show the manufacturing process steps. After explaining the process steps, now provided Features of manufacturing process and structure. The sacrificial layer and the frontal Shi Xi's body shape are collected in the preferred embodiment of the present invention, which is shown in comparison with the traditional structure. The traditional structure requires the Si Xi substrate's silicon substrate. Due to the side etching, the etching rate is slow, and as the incident infrared rays, such as "4 (k), continue to etch the fourth insulating layer 28 and the black edge layer 40, and etch part of the Fourth, a plurality of wire-windows 41 are used to expose the fifth insulating layer 40 which is engraved on the money so that The insulating layer (28, 26, 24, Μ) under the etched hole 13 can be exposed to the outside for subsequent display. After the table, the sacrificial layer is engraved and operated to remove the sacrifice through the aforementioned engraved hole j 3 to expose. Layer 4 1 and part of the broken base Figure 4 (〇), "Figure 5 (〇)" shows the element viewed from another section BB ′ from several aspects to explain the etching technology combined with the present invention In terms of: Use polycrystalline silicon or amorphous silicon as a pad, as shown in Figure 6 (a) and Figure 6 (b), the side of the floating plate 5 1 in the lateral direction is engraved. The demonstration formed a pyramid in the middle

^ 183 ^ 183 Fifth, the amount of the shape element is added by making the structure known to the electricity. The Wh case No. 89128366 half month Description of the invention ~ ^ --- 3 ^ characteristics. This j hill will affect the gas thermal conductivity of the floating plate and eventually affect it. If the bismuth engraving technique disclosed in the present invention is used, it is because sacrifice = frontal stone eve shape merger-sacrifice μ @t etch rate is higher than the silicon substrate Fast, so on the uranium magic, Liu Shi # Ganji under the silicon substrate of the "100" side, and the element in a short time to etch a flat π rate is faster, so it is OK. Eleven recesses release the floating floating plate junction. As for the structure of the electronically calibrated heater:

The conventional thermopile element is the temperature rise of the floating plate directly converted into A, which is converted into heat radiation, and the size of the compressed voltage is the same as that of the output voltage of the ** tube, 4 *, and the stack. The light measurement method that directly measures the test object from its S size is often affected by the temperature and the degree. However, this practice, or the long-standing thermopile sensor proposed by the thermoelectric stack material of the reading circuit, can be found in the second: drift. This patented heater can be used as described below; add a resistance line to the board as a way to avoid the above-mentioned method of measuring the plate with the positive measurement method to measure the electronic correction method ::: The error caused. The heater is used, and the day is first shielded when measuring: the resistance line on the board is used as the resistance line to energize the radiation to the sensing element, and then the temperature rises. Among them, the 2222 thermal floating plate is used to simulate the rise in thermal radiation, and the ratio between the power provided by the radiation and the resulting power. Therefore, as long as the temperature of 1 and the temperature rise caused by it are equal to the heat radiation absorbed by a stack element and the temperature of the object to be measured, they are shielded, and the heat caused by the electricity is heated. A power is applied to the device ___ rebel voltage Vh. Then remove the cover,

483183 _ Case No. 89128366_year month__ V. Description of the invention (10) The floating plate absorbs the power W t radiated from the measured object to the floating plate, and measures the thermopile output V t caused by it. In this way, from the measured W h, V h, and V t, the absolute radiation amount W t emitted by the measured object can be calculated, and the temperature of the measured object can be calculated. The formula can be expressed as follows: Heating by light The equivalence with electric heating, where k is a proportional constant, can be accurately measured in advance from a black body and a known temperature. Because the output benefits of thermopile components are affected by the environment, time, or output circuit, the drift will affect Vh and Vt in the same proportion, so Vh / V t will not drift with it, and an accurate target can be measured. Radiation and temperature. 'And the manufacture of this heater usually uses the material of the first thermoelectric material layer or the second thermoelectric material layer as the resistance of the heater, but it is also because the heater and the thermopile material use the same layer of material. The heating will prevent the hot end from going deep into the floating plate. In fact, in the design of the thermopile, the hotter the deeper the floating end is, the output, responsiveness and sensitivity will increase (Reference 1). Therefore, the deeper the hot end design in the component design should be the better design. The radiant heater disclosed in the present invention can not only make the hot end of each thermocouple go deep into the center of the floating plate, but also make the hot end of each thermocouple adjacent to the heater when the heater is used for heating. Increase its heat transfer efficiency. The features of this patent are summarized as follows: (1) Etching technology combining the sacrificial layer and the front silicon type: Using the etching method combining the sacrificial layer etching and the silicon type etching can accelerate the etching speed, shorten the etching time, and improve Yield. And can improve etching

483183 _Case No. 89128366_ 年月 日 __ 5. Description of the invention (11) The flatness of the bottom improves the characteristics and uniformity of the component. (2) As far as the structure of the electronically calibrated heater is concerned, the present invention uses a radiant heater as the electronically calibrated heater. Its design not only allows each hot end of the thermocouple to penetrate into the interior of the floating plate, but also allows it to heat. The terminals are adjacent to the heater, and at the same time, the heat absorption efficiency of the radiation absorption and the resistance heater is improved.

Page 14 483183 Case No. 89128366 Revised diagrams Brief description The first figure is a top view of the thermopile sensing element of the present invention; the second figure is the extension of the thermopile sensing element of the present invention. Figure 1A -A 'cross-sectional view; Figure 3 is the extension of the thermopile sensing element of the present invention; Figure 1 is a cross-sectional view of B-B' cut; Figures 4 (a) ~ 4 (〇) are the present invention The extension of the disclosed method for manufacturing a thermopile sensing element is shown in Figs. 1A-A '; Figs. 5 (a) to 5 (〇) are drawings of the method for manufacturing a thermopile sensing element disclosed in the present invention. A cross-sectional view along the B-B 'cut plane of Fig. 1; Fig. 6 (a) is a schematic view of the etching progress of a conventional thermopile structure; and Fig. 6 (b) is a sacrificial layer and a silicon-type etching according to the present invention. Schematic diagram of the progress of etching of the thermopile structure of the combined process. < Comparison of component names and symbols in the drawings >

C: Cold junction: Hot junction 11 First wire 12 Second wire 13 Money cut hole 14 Love body M ,, rliL · Absorptive layer 15 First wire window 16 Third wire window 17 Fourth wire window Page 15 483183 _Yueyue Modified Illustration Brief Description Case No. 89128366 18 Second Wire Window 19 Amplifier 20 Silicon Substrate 21 First Sacrificial Layer Material 22 First Insulation Layer 24 Second Insulation Layer 26 Second Insulation Layer 28 Fourth Insulation Layer 31 The first sacrificial layer 34 The contact window at the end 37 Metal pad 39 g Body absorbing layer 40 The fifth insulation layer 41 Wired window 43 Central heater 44 Cold end contact window 51 Floating plate 52 Sacrificial layer

Page 16

Claims (1)

483183 Case No. 89128366 Modified six-step layer line surface contact surface noodle belongs to patent application scope 1. A method for manufacturing a thermopile sensing element, which includes at least the following steps: providing a silicon substrate; depositing a first sacrificial layer Material on the surface of the silicon substrate; the mask defines and etches away a portion of the material layer to form a first sacrificial y; deposits a first insulating layer on the surface of the sacrificial layer and the silicon substrate; deposits a layer of thermoelectric material on the first insulation Layer surface; the mask defines and etches away part of the material layer to form a first conductor and deposits a second insulating layer on the surface of the first wire and the first insulating layer to remove part of the second insulating layer to form A plurality of contact windows; depositing a second thermoelectric material layer on the surface of the second insulating layer; a mask defining and etching to remove a portion of the second thermoelectric material layer to form a two-wire, and passing the contact window to make the second The conductive line and the first conductive line are connected to a plurality of hot ends and cold ends; a third insulating layer is deposited on the surface of the second conductive line and the second insulating layer, and the third insulating layer and the A second insulation layer, so that a part of the last second wire is exposed to connect to the gold pad to be formed, and the first first wire is also connected to the to-be-shaped via the second wire A second metal pad; depositing a first metal layer on the third insulating layer; Page 17 483183 Case No. 89128366 Amendment VI. Patent application scope Erosion and sinking (Lift outer wire; sinking surface; a plurality of insulating layers are formed with a scribe L to 2. Engraving part of the first metal layer to form a plurality of metal cymbals; A fourth insulating layer is stacked on the third insulating layer and the metal pad; a black body layer is stacked on the fourth insulating layer, and a black body absorbing layer is defined by etching or lifting away from the substrate, and is used for Absorb incident red product a fifth insulating layer in the fourth insulating layer and the black body absorbing part of the metal of the engraved part of a contact, and make the sacrificial layer of the silicon-based as in the manufacturing method, in which 3. — 种 热 一 ί In the evening, a substrate is formed, a deposit is formed, a deposit is formed in a plurality of shapes, a plurality of cold ends are formed, and the fourth and fifth insulating layers are heated to form a wire window to expose the pad; a notch hole runs through the fifth The surfaces of the fourth, third, second, and first sacrificial layers are exposed to the outside; and a method of combining etching and frontal etching techniques, etching is performed through the etching plate to hollow out a part of the silicon substrate. The material of the thermopile sensing element described in the first item of the patent scope The material of the sacrificial layer may be polycrystalline or amorphous. The stack sensor includes: a first sacrificial layer on the surface of the silicon substrate; a second insulating layer on the surface of the silicon substrate and the first sacrificial layer; a first wire on the first insulating layer; a first wire on the surface of the first insulating layer A second insulating layer; a contact window formed on the second insulating layer; a second conductive line on the second insulating layer and in contact with the first conductive line on the multiple end; Page 18 483183 _Case No. 89128366_ Years and months Amendment_ Sixth, the scope of the application for patents-a third insulation layer deposited on the surface of the second wire and the second insulation layer; most metal pads formed on the third insulation layer; The last second wire and the first first wire are directly or indirectly connected to the metal pad; a fourth insulating layer deposited on the third insulating layer and the metal pad; a black body formed on the fourth insulating layer Absorbing layer; a fifth insulating layer deposited on the fourth insulating layer and the blackbody absorbing layer; a wiring window formed on the fourth and fifth insulating layers to expose a plurality of metal pads; and penetrating through the fifth, fourth, third, The second and first insulating layers make a hole for exposing the surface of the first sacrificial layer. 4. For the thermopile sensing element in item 3 of the patent application, a resistance wire heater can be made on the central floating plate, and the external power input is used for electronic calibration measurement. 5. The thermopile sensing element as described in the patent application No. 3, wherein the resistance wire heater is radiated. 6. The thermopile sensing element according to item 3 of the patent application scope, wherein the silicon substrate faces the etching holes penetrating through the fifth, fourth, third, second and first insulating layers. The state of being hollowed out. Page 19