TW541413B - Two-layer thermo-electric stack sensor device - Google Patents

Abstract

There is provided a two-layer thermo-electric stack sensor device. Its structure is a two-layer floating board structure having a blackbody absorbing layer on a thermo-electric stack wire layer. Its manufacturing process uses two sacrificial layers and respectively etches the sacrificial layers to produce the two-layer floating board structure. The structure has the following advantages: (1) the area of sensor unit is decreased so as to increase the productivity and it is suitable for manufacturing array devices; (2) the manufacturing process is easy and there is no need to etch the silicon substrate so as to decrease the damage to the device in etching; (3) the blackbody absorbing layer on a thermo-electric stack wire layer is able to shield the radiation, thereby avoiding the temperature increase due to radiation on the cold terminal of the thermo-electric stack, and increasing the efficiency of the sensor; (4) the sensor is manufactured by sacrificial layers so that circuit such as multiplexer can be formed below the sensor, thereby forming the circuit and the sensor at the same time for reducing the noise.

Description

Ό 541413 V. Description of the invention (1) [Background of the invention] Field of the invention The description of the conventional technology of a double-layer thermopile sensing element uses an object to emit infrared light to measure the temperature of the object. It is widely used except temperature measurement. In addition, it can be applied to various aspects such as motion sensors, red cameras, cameras, and medical human body temperature distribution in industrial automation and security monitoring. The principle is mostly to change the physical characteristics of the material by infrared radiation on the component, and to convert it into electrical characteristic output. The sensing element includes a pyroelectric sensing element, a thermal resistance sensing element, and a sensing element. Since the pyroelectric sensing element uses materials such as ceramics or polymers, it is not suitable for high-volume semi-automated mass production methods, so the production cost is relatively high. In the measurement device, a bias voltage must be supplied to measure the resistance change and make the element noise. As a result, thermopile sensing elements that do not require external bias voltage, have only a small bit of accuracy, are less affected by room temperature, are easier to compensate, and can be manufactured using profitable process technology, are becoming more and more potential and cost competition. force. In terms of manufacturing methods, the conventional thermopile sensing elements can generally be divided into two types: (a) a closed structure that etches a silicon substrate from the back; (b) an open floating plate structure that etches a silicon substrate from the front (such as detection The body temperature sensing of the device, the temperature rise of the external photo, and the common temperature rise of the common thermopile non-semi-conductor, conductor and conductor industrial thermal resistance sensors produce AC and DC hybrid semiconductors with a market-shaped structure, floating board junctions, and four bridges. Knot

Page 4 541413 V. Description of the invention (3) The area of the black stack sensing element that requires a larger area. If the area of the black body absorber increases with the number of sensing elements, the number of sensing elements decreases. On the other hand, The hot end is subject to temperature rise, which affects the sensor's manufacturing practices to reduce production into a quasi-process, but the disadvantages of using this standard process. Due to the closed floating plate structure silicon substrate, the increase in demand results in countermeasures. Therefore, the present invention can reduce the production capacity per unit circle and is suitable for the invention to reduce the damage to the components caused by the simplified process. The temperature rise effect caused by the invention Many sensing elements can be combined with sensing elements [Summary of the Invention]

The bulk absorption layer 6 absorbs radiant heat. Also, in thermoelectricity, the area of the blackbody absorbing layer 6 accounts for a relatively large area of the layer 6. The area of the layer 6 will increase, which will inevitably make the entire sensing element smaller, resulting in fewer thermoelectric stacks per unit silicon wafer. In the structure of the conventional thermopile sensing element, while the black body absorbs radiation, the cold end C is also exposed to radiation and the output benefit is caused. In order to speed up production and speed up, the semiconductor CMOS standard thermopile sensing element system is a feasible method. The conventionally-made closed floating plate structure has the following system: the back silicon type etching technique is used to etch a large number of long etching times, and the parts may be damaged due to the etching time. The purpose is to provide a double-layer thermopile sensing element, which increases the area of the thermopile sensing element, increases the unit size, makes the array element, and makes packaging easier. In addition, it is easy to speed up the rest of the time and reduce the time of the long time. In addition, the invention can solve the problem of thermal radiation on the thermopile. In addition, the circuit such as the double-layer thermoelectric reactor provided under the present invention is made under the sensing element to make the circuit, thereby reducing the influence of noise from the external circuit.

Page 6 541413 V. Description of the invention (4) In order to solve the above problems, the double-layer thermopile sensing element provided by the present invention has the following advantages: reducing the area of a unit thermopile sensing element and increasing the unit silicon wafer Production capacity, making it suitable for making array elements, making packaging easier, providing simple processes, reducing etching time and component damage. In addition, the invention can solve the temperature rise effect caused by the thermal radiation to the thermopile sensing element, and can use circuits such as a multiplexer under the sensing element, so that the circuit and the sensing element are completed together, thereby reducing noise. Impact.

According to a first aspect of the present invention, it relates to a double-layer thermopile sensing element, which uses a first metal pad and a second metal pad as the output of the above-mentioned double-layer thermopile sensing element. The method includes: a stone substrate; a first insulating film on the silicon substrate; a plurality of first wires on the first insulating film; each first wire having a hot end and a cold end in the first wire; The cold end of the first first lead is electrically connected to the first metal pad; the plurality of second leads, each second lead has a hot end and a cold end, and the hot end of each second lead is respectively connected to each of the first leads. The hot end is in one-to-one contact, and in the second wire, the cold end of the last second wire is electrically connected to the second metal pad; a third insulating film is interposed between the first wire and the second wire '' Used to isolate the first wire and the non-contact parts of each of the first wire and the second wire; a fourth insulating film to isolate the second wire; and a black body absorption layer on the fourth insulating film To absorb heat; characterized by: The double-layer thermopile sensing element further includes: a second insulating film interposed between the first insulating film and the third insulating film; a first gap opened in the second insulating film; a first etching hole To allow the first gap to communicate with the outside world; a fifth insulating film interposed between the fourth insulating film and the black

Page 7 541413 V. Description of the invention (5) Between the body absorption layers; a second gap is opened in the fifth insulating film; and a second etching hole is used to allow the second gap to communicate with the outside. According to a second aspect of the present invention, a double-layer thermopile sensing element uses a first metal pad and a second metal pad as output of the double-layer thermopile sensing element, including : A silicon substrate; a first insulating film on the silicon substrate in a cantilever structure; a first gap interposed between the first insulating film and the silicon substrate; a first etching hole for allowing the first gap and The outside is in communication; a plurality of first wires are located on the first insulating film, and each of the first wires has a hot end and a cold end. Among the first wires, the cold end of the first first wire is electrically connected to the first wire. Metal plutonium; a plurality of second wires, each of which has a hot end and a cold end, the hot end of each second wire is in one-to-one contact with the hot end of each first wire, and is in the second wire The cold end of the last second wire is electrically connected to the second metal pad; a third insulating film is interposed between the first wire and the second wire to isolate the first wire and isolate each first wire from Non-contact portions of each second wire; a fourth insulating film To isolate the second wire; and a blackbody absorbing layer on the fourth insulating film to absorb heat; characterized in that the double-layer thermopile sensing element further includes: a fifth insulating film interposed between Between the fourth insulating film and the black body absorbing layer; a second gap is opened in the fourth insulating film; and a second etching hole is used to allow the second gap to communicate with the outside. In addition, the present invention can also complete a CMOS or BiCMOS circuit with this double-layer thermopile sensing element to reduce the noise impact of external circuits. In addition, the first lead and the second lead of the double-layer thermopile sensing element may be composed of a semiconductor or non-semiconductor material, and the shape may be made into a square flat plate.

Page 8 541413 V. Description of the invention (6) Shape, ring shape, or four bridge shape. [Simplified description of the figure] Fig. 1 (a) shows a cross-sectional view of a ring-shaped thermopile with a closed floating plate structure. Fig. 1 (b) is a schematic diagram showing the wire connection method of the thermopile of Fig. 1 (a). Fig. 2 (a) shows a cross-sectional view of a double-layer thermopile sensing element according to a first embodiment of the present invention. Fig. 2 (b) shows the schematic diagram of the wire connection method of the thermopile of Fig. 2 (a). 3 (a) to Fig. 3 (η) show the manufacturing method of the double-layer thermopile sensing element according to the first embodiment of the present invention. . Fig. 4 shows a cross-sectional view of a ring-shaped double-layer thermopile sensing element according to a first embodiment of the present invention. Fig. 5 shows a cross-sectional view of a dual-layer thermopile sensing element with a CMOS circuit according to a second embodiment of the present invention. Fig. 6 shows a cross-sectional view of another double-layer thermopile sensing element according to the first embodiment of the present invention. [Description of symbols] C ~ Cold end Η ~ Hot end 2 1 ~ First insulating film 2 2 ~ Second insulating film 2 3 ~ Third insulating film

541413 V. Description of the invention (7) 24- 'Fourth insulation film 25--Fifth insulation film 3' Shishi substrate 32, 'Gap 33-', Gap 34- 'Cap_35 First wire 36 ~, second wire 37 ~, first metal pad 38 ~ second metal pad 39 ~ blackbody absorption layer 40 ~ second etched hole 41-first sacrificial layer 42 ~ first-sacrificial layer 4 3 ~ contact Window [Detailed description of the preferred embodiment] 1. First Embodiment FIG. 2 (a) shows a cross-sectional view of a double-layer thermopile sensing element according to the first embodiment of the present invention. As shown in FIGS. 2 (a) and 2 (b), the double-layer thermopile sensing element of this embodiment has a silicon substrate 31, a plurality of first conductive wires 35 and a plurality of second conductive wires 36, and First metal pad 37 and a second metal pad 38, a black body absorbing layer 39, a first etched hole 3 4, a first gap 3 2, a second etched hole 40, a second gap 3 3 And the first, second, third, fourth, and fifth insulating films 2b and 25.

Page 10 541413 V. Description of the invention (8) Please refer to the second wire 3 6 in the figure and the plural belonging to the third line 3 8 and the most line and the first line are used as heat in this embodiment. The gap 3 2 and The second 40th configuration of this thermoelectric point will be described later in this embodiment with reference to the detailed figure 3 (a) to the manufacture of the thermopile sensing element embodiment (a) provided (b) in Shi Xi (c) in the first I. Insect the first sacrifice (d) on the first limbal membrane 22, and then form a first remainder 41; (e) In the second (a) and FIG. 2 (b), in the structure of this embodiment, the plural is A plurality of contact windows 43 are opened through the third insulating plate 23, and a wire 35 is contacted to form a plurality of hot ends η. The second metal is electrically connected to a second lead 36, and the first metal pad 37 is electrically connected to a lead 35 (Fig. 2 (b)). The two metal electrodes are output from the 38 stack sensor. It is characterized by the S-shaped cantilever structure of the first gap 33, directly under the blackbody absorbing layer 39, and the first etched hole 34 and the second etched hole stack sensing element. This structure is excellent. The manufacturing method of the double-layer thermopile sensing element will be explained in detail. Fig. 3 (n) shows a method for manufacturing a double-layered part according to the first embodiment of the present invention. Corresponding to FIGS. 3 (a) to 3 (η), the method includes the following steps (a) to (η): a silicon substrate 3 1; a first insulating film 2 1 is formed on the substrate 3 1; an insulating film 2 1 A first sacrificial layer 41 is deposited on the two sides of the layer 41; ..., a second insulation and a first insulating film 22 are deposited on the two sacrificial layers 41 and the first insulating film 21 for planarization and rest. By forming the hole 34 ′ and exposing the first sacrificial layer insulating film 22 and the first sacrificial layer 41 through the first etching hole 34, a plurality of first sacrificial layers are formed.

541413

Area 39 (k) is the central area of the fifth insulating film 25, so that the black body absorbing layer 39 covers the fifth insulation; 25 :; = ^ 44 (ϋ 9 f is composed of the first etching hole 34 and the second etching hole 4 0 The exposed first -Ϊ is etched to form a second gap 33, and the material constituting the second wire 36 located in the first etched hole 34 is oblique, 隹 exposed by the first etched hole 34 The material composing the first conductive wire 35 is removed to expose the first sacrificial layer 41, and then the first sacrificial layer 41 is shifted to form a first gap 3 2; and (η) The fifth insulating film 25 'covering the first and second metal pads 37 and 38 is removed to expose the first and second metal pads 37 and 38. According to the structure and principle of this embodiment, a double-layer type The thermopile sensing element is made into a ring shape and a four-bridge shape. For example, the structural cross-section of a ring-shaped double-layer thermopile sensing element is shown in Figure 4. 2. The second embodiment is shown in Figure 5. Cutaway view of a two-layer thermopile sensing element with a CMOS circuit according to a second embodiment of the present invention. As shown in FIG. 5, the two-layer thermopile of this embodiment The sensing element is substantially the same as the first embodiment, and is characterized in that a CMOS circuit is formed in advance on the silicon substrate 31 in this embodiment, so that the thermopile sensing element and the CMOS circuit are completed together. Therefore, the source S is further included. , Drain D, gate polycrystalline silicon 27, and gate oxide layer 26. For those skilled in the art, the fabrication of CMOS circuits has become obvious. Therefore, 'the manufacturing process of this embodiment, in addition to the previous process Except for the program provided by the CMOS circuit, the rest of the programs are similar to the first embodiment, so the description is omitted.

Page 13 541413 V. Description of Invention (11) Description. [Effects of the Invention] The effects of the present invention will be described below with reference to Figs. 2 (a) and 1 (a). In terms of area efficiency, due to the double-layer thermopile sensing element proposed by the present invention, the black body absorbing layer 39 and the second lead 36 and the first lead 3 5 can be stacked in a nearly overlapping relationship. Therefore, for the thermopile sensing element of the same specification, the structure of the present invention can greatly reduce the area of the sensing element. Therefore, the area benefit of the double-layer thermopile sensing element of the present invention is greater than that of the conventional structure, so the yield per unit wafer can be increased. In terms of radiation absorption characteristics, the thermopile sensing element is based on the unit area. The more heat absorbed by the blackbody absorption layer, the better, and the less heat absorbed by the cold end of the thermopile wire, the better. In the double-layer thermopile sensing element of the present invention, since the blackbody absorbing layer covers most of the thermopile wires, the amount of radiation received by the thermopile wires is the re-radiation emitted by the blackbody after absorbing the radiant heat. . The effect of such re-radiation, in terms of the double-layer thermopile sensing element of the present invention, is smaller than the conventional closed floating plate structure in which the thermopile wires are directly exposed to radiation. In terms of manufacturing procedures, the conventional sensing elements of the closed floating plate structure and the open floating plate structure both need to etch the silicon substrate for a long time, which may cause damage to the sensing element. However, the double-layer thermopile sensing element of the present invention uses the sacrificial layer manufacturing technology, which does not require the silicon substrate to be engraved for a long time as in conventional technology, so it can shorten the manufacturing time and reduce the long-term etching on the sensing element. Damage. Due to this characteristic, we can use circuits such as multiplexers in

Page 14 541413 V. Description of the invention (12) Under the sensor, the circuit and the sensor are completed together to reduce the noise generated by the conventional thermopile sensor that must be externally connected to the circuit. In summary, the structure of the present invention is better than the conventional structure in terms of area efficiency and gas radiation absorption characteristics, and in terms of gas thermal conductivity, the structure of the present invention is slightly worse than the conventional 'floating plate structure, but it is quite The degree of vacuum is also acceptable compared to solid thermal conductivity. In terms of manufacturing, the structure of the present invention is superior to the conventional structure. The specific embodiments proposed in the detailed description of the preferred embodiments are only for easy explanation of the technical content of this creation, and are not limited to the above embodiments in a narrow sense. They do not exceed the spirit of this creation and the following patent applications The scope of the situation can be implemented in various changes. For example, in the double-layer thermopile sensing elements of the first and second embodiments, the sacrificial layer is etched to form a double-layer structure. However, we can also use front etching of the silicon substrate and etching sacrifices. The layer structure is made into a double-layer structure, and the detailed structure is shown in FIG. 6. Therefore, the scope of the present invention is defined by the following patent application scopes:

Claims (1)

541413 6. Scope of patent application: Use of a first metal pad 1. A double-layer thermopile sensing element and a second metal pad for outputting the double-layer thermopile sensing element, including: a Shixi substrate A first insulating film located on the silicon substrate; a first first plurality of first conductive wires in each of the first conductive wires on the edge film, and a hot end and a cold end on the first insulated wire At the ends of the first wires, the cold ends at the opposite ends are electrically connected to the plurality of second wires of the first metal pad, and the hot ends of the second wires and the hot ends of the second wires are respectively in contact with the contacts. And among the second wires, are most electrically connected to the second metal pad; a third insulating film is interposed on the first to isolate the first wires, and isolate each of the first wires from A non-contact portion of each of the wires, a fourth insulation film for isolating the first black body absorbing layers, the fourth insulation has a hot end and a cold first wire, and a hot second end is followed by a second Cold of the wire · The wire and the second wires Two wires; and a film for absorbing heat; characterized in that the double-layer thermopile sensing element further comprises: a second insulating film interposed between the first insulating film and the third insulating film In the film; the gap communicates with the outside world; a first gap is opened in the second insulating first etching hole for allowing the first Page 16 541413 Sixth, the scope of the application for a patent a fifth insulation film interposed between the fourth insulation; a second gap is opened in the fifth insulation a second etching hole to allow the second 2. A double-layer type thermopile sensing element and a second metal pad are used as the double-layer type and include: a silicon substrate; a first insulating film; a first gap in a cantilever structure; The first insulation and a first etched hole are used to allow the first plurality of first wires to have a hot end and a cold end, and the cold ends of the first wires are electrically connected to The plurality of second wires of the first metal pad, each of the second wire ends, and the hot end of each of the second wires are in contact with each of the pair, and the ends of the second wires are electrically connected to the A second metal pad; a third insulating film interposed between the first rooms to isolate the first wires and isolate them; non-contact portions of the second wires; a fourth insulating film to isolate The first blackbody absorbing layers are located at the fourth insulation amount; . It belongs to the absorption of the gold body, the first element black, and the boundary. The other sense is ·, and the heap ° 3771JJ in the gap between the electric edge of the membrane; spear heat between the membranes; In the plate phase, the first and second substrates of the plate and the substrate are broken, and the silicon and the upper, middle, and gap film lines conduct cold at the edge of the film to form one end line and two heat lines. Each of the rear lead and the second lead, each of the first lead and each of the two leads, and a film for absorbing heat Page 17 541413 6. The scope of the patent application is characterized by: The double-layer thermopile sensing element further includes: a fifth insulating film interposed between the fourth insulating film and the black body absorbing layer; a second A gap is opened in the fourth insulating film; and a second etching hole is used to allow the second gap to communicate with the outside. 3. The two-layer thermopile sensing element according to item 1 of the patent application scope, wherein the silicon substrate further includes a CMOS circuit. 4. The dual-layer thermopile sensing element according to item 1 of the application, wherein the silicon substrate further includes a BiCMOS circuit. 5. For the double-layer thermopile sensing element of claim 1, 2, 3 or 4, the shape of the double-layer thermopile sensing element is a square flat plate. 6. For the double-layer thermopile sensing element of claim 1, 2, 3, or 4, the shape of the double-layer thermopile sensing element is circular. 7. For a double-layer thermopile sensing element with the scope of patent applications 1, 2, 3, or 4, the shape of the double-layer thermopile sensing element is four bridges. 8. For a double-layer thermopile. Sensing element according to the scope of patent application 1, 2, 3, or 4, wherein the first wire or the second wire is composed of a semiconductor material. 9. For a double-layer thermopile sensing element according to claim 1, 2, 3 or 4, wherein the first wire or the second wire is made of a non-semiconductor Page 18 541413 T i VI. Scope of patent application Material composition. Hill Page 19