JP2012058084A - Method of manufacturing infrared sensor device, and the infrared sensor device manufactured by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an infrared sensor device which is low-priced and superior in mass-productivity and productivity using a photosensitive dry film for an adhesive, and the infrared sensor device which is compact and low-priced.SOLUTION: When the infrared sensor device is manufactured which includes a silicon cover, a semiconductor chip, and a spacer layer for arranging the both opposite to each other at an interval, a spacer layer 11 as an adhesive layer is formed by patterning the photosensitive dry film 110 on an adhesion surface side of a silicon wafer 120 as a material of the silicon cover, and the silicon wafer 120 is bonded to a semiconductor wafer where a plurality of infrared sensor devices are formed, through the adhesive layer. The silicon wafer 120 and the semiconductor wafer which are joined together are diced thereafter into the individual infrared sensor devices. The adhesive layer is used for the spacer layer 11 of the individual infrared sensor device.

Description

  The present invention relates to a method of manufacturing an infrared sensor device using a thermopile element and an infrared sensor device manufactured by this method.

  The thermopile element is used in an infrared sensor device that receives infrared rays radiated from individual objects in a non-contact manner and generates a thermoelectromotive force according to the energy. In the prior art, there is an infrared sensor device in which a thermopile element and an amplifier are mounted on one chip. A conventional infrared sensor device is packaged in a metal can (usually referred to as TO-5 type) as disclosed in Patent Document 1. A silicon filter is attached to the metal can, and infrared rays are incident on the inside of the can through the silicon filter. In the invention disclosed in Patent Document 1, the inner surface of the metal can is mirror-finished or gloss-plated. By treating the inner surface of the metal can in this way, infrared radiation from the metal can to the thermal sensing element is greatly reduced, the operation is stabilized, and a highly reliable and highly accurate infrared detector is obtained.

Patent Document 2 discloses an infrared sensor that can efficiently extract the output of the sensor to the outside. This sensor is formed on the surface of the first substrate, covers the thermopile element having a hot junction and a cold junction, and the formation portion of the thermopile element of the first substrate, and is provided at an interval of 70 μm to 1 mm from the first substrate. A second substrate that transmits infrared light, and a spacer member made of resin such as epoxy that is provided on the cold junction portion of the thermopile element and bonds the first substrate and the second substrate at the intervals. It is a feature. In this infrared sensor, in the structure in which the upper substrate that can protect the element in the dicing process or the die bonding process is stacked, the temperature difference between the cold junction and the hot junction of the element due to the provision of the upper substrate. It is possible to prevent the decrease and efficiently extract the output of the sensor to the outside.
JP-A-1-307628 JP 2008-190992 A

Infrared sensor devices are being reduced in size and price. For such development direction, metal cans are one of the major factors that alienate their development. Moreover, since a metal can is indispensable for attaching an infrared transmission window or the like, a certain thickness is required. In addition, a footprint for mounting the surface mounting terminal parts for the pins (leads) of the stem may be necessary. In such a case, the mounting on a metal can limits the miniaturization thereof. . Moreover, although the thing of the form reduced in size by superimposing the 2nd board | substrate on the 1st board | substrate with which the thermopile element was formed is disclosed by patent document 2, both board | substrates are apply | coated by liquid epoxy resin etc. The adhesive layer is formed, and when the element is further miniaturized and miniaturized, it becomes difficult to apply and cannot be used. Furthermore, there is a case where it is desired to control the uniformity by reducing the size of the adhesive layer to about 20 μm, but the applied adhesive layer is difficult to control.
The present invention has been made under such circumstances, and provides a method for manufacturing a miniaturized and low-priced infrared sensor device excellent in mass productivity and productivity. An infrared sensor device, an infrared sensor device that can be easily mounted on a wiring board, and the like are provided.

  One aspect of the infrared sensor device of the present invention includes a semiconductor chip, a thermopile array formed of a plurality of thermopile elements formed in the semiconductor chip and arranged in rows and columns, a silicon cover disposed on the semiconductor chip, A spacer layer formed on a semiconductor chip and surrounding a peripheral portion of the thermopile array, the spacer layer comprising a photosensitive dry film patterned by photolithography, and the silicon cover includes The semiconductor chip is adhered to the surface of the semiconductor chip by the spacer layer. A cutout portion corresponding to the bonding pad portion formed on the semiconductor chip may be provided in the peripheral portion of the silicon cover. The side surface of the silicon cover may be inclined so as to widen the bottom.

  Further, according to one aspect of the method for manufacturing an infrared sensor device of the present invention, a step of forming a plurality of infrared sensor devices arranged vertically and horizontally on a semiconductor wafer, a step of attaching a photosensitive dry film to a silicon wafer surface, Patterning a photosensitive dry film by photolithography to form a spacer layer disposed around each infrared sensor device of the plurality of infrared sensor devices; mounting the silicon wafer on the semiconductor wafer; and Adhering a wafer to the semiconductor wafer by the spacer layer, and dicing the semiconductor wafer and the silicon wafer to separate the plurality of infrared sensor devices into individual infrared sensor devices. It is a feature. The silicon wafer is provided with a through hole in a portion corresponding to the bonding pad portion formed on the semiconductor wafer, and when the plurality of infrared sensor devices are separated, the bonding pad portion of each infrared sensor device is the silicon wafer. You may make it expose from. The patterned photosensitive dry film may cover boundaries of the plurality of infrared sensor devices provided on the semiconductor wafer, and a dicing line may be applied to the boundaries.

  The manufacturing method of the infrared sensor device of the present invention can be used even when the element is further miniaturized and miniaturized because the adhesive layer is formed by patterning with a photosensitive dry film and printing or coating is not used. Moreover, since the photosensitive dry film is also formed on the dicing line in the wafer state, chipping during dicing can be prevented. And the manufacturing method of the infrared sensor apparatus which is low-cost and excellent in mass productivity and productivity is obtained. Further, since the semiconductor chip and the silicon cover are joined by a spacer layer made by processing a photosensitive dry film, a uniform space is formed between the two, and the infrared sensor is small and inexpensive. A device is obtained. Moreover, when the side surface of the silicon cover is inclined, the infrared sensor device can be easily mounted on a wiring board or the like.

1 is a perspective view of an infrared sensor device according to Embodiment 1. FIG. The top view of the infrared sensor apparatus of FIG. 1 except the surface silicon cover. The top view and sectional drawing of the semiconductor chip in which the thermopile element which comprises the infrared sensor apparatus shown in FIG. 2 was formed. The top view of the silicon wafer in which the adhesive bond layer which consists of a patterned photosensitive dry film was formed in the adhesive surface side in the infrared sensor apparatus which concerns on Example 1. FIG. The top view of the semiconductor wafer in which the chip | tip area | region in which the infrared sensor apparatus was built in the infrared sensor apparatus which concerns on Example 1 was formed. The top view which affixed the silicon wafer of FIG. 4 on the semiconductor wafer of FIG. The perspective view of the part which follows the AA 'line of FIG. 2 is a process cross-sectional view illustrating a patterning process of a photosensitive dry film used in Example 1. FIG. Sectional drawing of the infrared sensor apparatus which concerns on Example 2 mounted in the printed circuit board.

Hereinafter, embodiments of the invention will be described with reference to examples.
When manufacturing an infrared sensor device including a silicon cover, a semiconductor chip, and a spacer layer that is opposed to each other with a gap therebetween, the present invention is sensitive to the bonding surface side of a silicon wafer that is a material of the silicon cover. An adhesive layer that finally becomes a spacer layer is formed by patterning the conductive dry film, and the silicon wafer is bonded to the semiconductor wafer on which the plurality of infrared sensor devices are formed via the adhesive layer, and then bonded. A silicon wafer and a semiconductor wafer are diced to separate the infrared sensor device.

First, Embodiment 1 will be described with reference to FIGS.
The infrared sensor device has thermopile elements formed and arranged in an array. A thermopile is a device that generates a thermoelectromotive force according to energy when receiving infrared rays radiated from an individual object in a non-contact manner, and the absolute amount (temperature) of the energy can be detected.
1 to 3 show details of an infrared sensor device formed by the method according to this embodiment.

  As shown in FIG. 1, the infrared sensor device includes a semiconductor chip 1 made of silicon having thermopile elements formed in an array, a spacer layer (not shown) disposed on the surface of the semiconductor chip 1, a semiconductor It is comprised from the silicon | silicone cover 12 which coat | covers the chip | tip 1 surface. The infrared sensor device detects infrared light incident through the silicon cover 12. Cutouts 13 are formed at the four corners of the silicon cover 12, and the four corners of the semiconductor chip 1 are exposed from the silicon cover 12 correspondingly. A plurality of electrode pads 14 are formed at the four corners. FIG. 2 shows the surface of the semiconductor chip 1 with the silicon cover of the infrared sensor device removed. In the central portion of the surface area of the semiconductor chip 1, for example, 64 thermopile elements 10 are arranged in an array in the vertical and horizontal directions, and a plurality of pads (connection electrodes) 14 such as aluminum are formed in the four corners. . A spacer layer 11 obtained by patterning a photosensitive dry film is formed on the periphery of the surface of the semiconductor chip 1 between the region where the pad 14 is formed and the central portion.

The array area of the thermopile element has, for example, 2930 μm on one side. The space between the semiconductor chip 1 on which the array area is formed and the area on which the pad 14 is formed is very narrow, for example, about 30 μm, and an adhesive that bonds the semiconductor chip 1 and the silicon cover 12 therebetween. It is very difficult to use a liquid material as the process. On the other hand, the photosensitive dry film as in the present invention is very advantageous to be applied to a narrow area.
A photosensitive dry film is, for example, a film-like etching resist used for circuit formation of single-sided, double-sided, and multilayer substrates. After drying the photoresist layer applied on the base film, the protective film is laminated to the photoresist layer. Is formed.
The spacer layer 11 can keep the distance between the silicon cover and the semiconductor chip constant.

FIG. 3 shows a detailed structure of the thermopile element constituting the infrared sensor device. The thermocouple that constitutes the thermopile element is a kind of thermometer, measuring the temperature by joining both ends of fine wires of two different kinds of conductive materials and measuring the potential difference caused by the temperature difference between the two joining points. It is a device to do.
A thermopile element 10 having a structure in which a plurality of thermocouples 6 made of different conductive materials are connected in series is provided on the semiconductor chip 1. The hot junction 5 of the thermocouple 6 is arranged near the center of the semiconductor chip 1, and the cold junction 4 is arranged around the semiconductor chip 1. The thermocouple 6 is covered with a black body insulating film 8. A heat absorption film (black body) 9 is disposed on the black body insulating film 8 so as not to cover the hot junction portion 5 and the cold junction portion 4 of the thermocouple 6. Although not shown, a temperature detection element for measuring a reference temperature, that is, a temperature of the cold junction portion 4 is installed on the semiconductor chip 1. As this temperature detection element, a thin film thermistor or a PN junction type element can be used.

  The thermopile element 10 is provided on the diaphragm structure on the semiconductor chip 1. The diaphragm structure on which the thermopile element 10 is placed includes a cavity 2 and a membrane 3 that covers the cavity 2 and is formed on the surface of the silicon substrate 1. The cavity 2 is formed by etching or the like, and the membrane 3 is formed by, for example, a silicon nitride film by, for example, the LP-CVD method. The thickness is about 100 nm. A thermocouple 6 is formed on the membrane 3. When infrared rays are incident from the measurement object, the heat absorption film 9 absorbs the infrared rays, the temperature of the hot junction part 5 of the thermocouple 6 rises, and the temperature difference between the hot junction part 5 and the cold junction part 4 is increased. This generates a thermoelectromotive force in each of the thermocouples 6. The thermopile element 10 adds the thermoelectromotive forces of these thermocouples 6 and takes out the output from the thermopile lead electrode 7. In this case, by measuring the temperature of the cold junction portion 4 serving as the reference temperature using a thin film thermistor, the amount of infrared rays of the measurement object can be accurately measured, and therefore the temperature of the measurement object can be measured. For example, a thermopile type area sensor constituting an infrared sensor device is formed by arranging a plurality of thermopile elements as described above, for example, 3 × 3 or 8 × 8 in an array.

Next, a method for manufacturing the infrared sensor device shown in FIGS. 1 to 3 will be described with reference to FIGS.
As shown in FIG. 4, the silicon wafer 120 has a plurality of through holes 130 formed therein. A region surrounded by the four through holes 130 adjacent to each other serves as a silicon cover 12 constituting the infrared sensor device. That is, a plurality of silicon cover 12 regions are arranged and formed on the silicon wafer 120 in an array. Further, a patterned photosensitive dry film 110 is attached to the silicon wafer 120. As shown in FIG. 5, dicing lines 101 are formed vertically and horizontally on the semiconductor wafer 100, and the region of the semiconductor chip 1 constituting the infrared sensor device is partitioned. In this region, a thermopile portion 15 in which thermopile elements are arranged in an array is formed at the center, and a plurality of pads 14 are formed at four corners. The photosensitive dry film is used as an adhesive layer for bonding the silicon wafer 120 and the semiconductor wafer 100, and as an infrared sensor device, as shown in FIG. The spacer layer 11 is used to maintain the distance between the silicon cover and the semiconductor chip 1.

A process of attaching a photosensitive dry film to a silicon wafer and patterning it is shown in FIG. The photosensitive dry film 110 is placed on the surface of the silicon wafer 120 that has been pretreated by polishing, chemicals, etc., and vacuum lamination is performed under conditions such as 60 to 80 ° C. and 1.0 kPa (FIG. 8A, ( b)). Next, ultraviolet rays (UV) (for example, 80 to 250 mJ / cm ² ) are irradiated 103 on the photosensitive dry film 110 laminated on the silicon wafer 120 through the UV mask 102 (FIG. 8C). The irradiated photosensitive dry film 110 is developed, for example, under the conditions of a 1% NaCO ₃ solution, 45 to 90 seconds, and 30 ° C. to form a spacer layer 11 used as an adhesive layer (FIG. 8D). ).
Thereafter, as shown in FIG. 6, the silicon wafer 120 is placed on the semiconductor wafer 100, and the spacer layer 11 is cured under conditions of, for example, 160 to 200 ° C. and 30 to 90 seconds. The wafer 120 is bonded.

FIG. 7 is a perspective view of a portion along the line AA ′ in FIG. 6.
The semiconductor wafer 100 is bonded to the silicon wafer 120 by an adhesive layer (spacer layer 11), and a constant interval is maintained between the two by the spacer layer 11. In the figure, a part of a semiconductor chip region adjacent to the left and right via a scribe line 101 is formed on the semiconductor wafer 100. A plurality of thermopile elements 10 are formed in each region. A through hole 130 of the silicon wafer 120 is provided on the scribe line 101.
Next, the semiconductor wafer 100 and the silicon wafer 120 shown in FIGS. 4 to 6 are diced along the dicing line 101 and separated into chips for each infrared sensor device (see FIGS. 1 and 2).
As described above, in this embodiment, since the semiconductor chip and the silicon cover are joined by the spacer layer made by processing the photosensitive dry film, a uniform space is formed between the two and the size is reduced. A low-cost infrared sensor device can be obtained. In particular, it is also effective when it is desired to control uniformity by reducing the thickness of the adhesive layer to 20 μm or more by downsizing. In addition, the method of manufacturing the infrared sensor device can be used even when the element is further miniaturized and miniaturized because the adhesive layer is formed by patterning with a photosensitive dry film and printing or coating is not used. Moreover, since the photosensitive dry film is also formed on the dicing line in the wafer state, chipping during dicing can be prevented. And it is low price and excellent in mass productivity and productivity.

Next, Embodiment 2 will be described with reference to FIG.
In this example, the same manufacturing method as in Example 1 is used, but the infrared sensor device formed by this method is characterized by the structure of the spacer layer formed from a photosensitive dry film.
The semiconductor chip 20 on which the infrared sensor device is formed is mounted on the printed board 200. The infrared sensor device joins the semiconductor chip 20 on which the array 21 of thermopile elements is formed, the silicon cover 22 formed on the semiconductor chip 20 so as to cover the array 21, and the semiconductor chip 20 and the silicon cover 22. And a plurality of bonding pads 26 formed on the notch 23 of the silicon cover 22 on the semiconductor chip 20.
In this embodiment, a wire bonding tool (hereinafter referred to as a capillary) 210 is used to connect the pads 22 of the semiconductor chip 20 and the wiring 201 on the printed wiring 200 with the bonding wires 220.

In this embodiment, the side surface 24 of the silicon cover 22 is inclined so as to widen the bottom. With such a configuration, in the bonding process using the capillary 210, the distance d between the tip of the capillary 210 and the side surface 24 of the silicon cover can be made larger than the vertical side surface of the silicon cover of the first embodiment. The pad 26 is disposed close to the spacer layer 25 used as an adhesive layer, and the operating range of the capillary 210 is greatly limited. However, the configuration of this embodiment eases the limitation of the operating range of the capillary. Is done.
As described above, in this embodiment, since the semiconductor chip and the silicon cover are joined by the spacer layer formed by processing the photosensitive dry film, a uniform space is formed between the two, and the size is reduced. A priced infrared sensor device is obtained. Moreover, since the side surface of the silicon cover is inclined, the infrared sensor device can be easily mounted on a wiring board or the like. In addition, the method for manufacturing the infrared sensor device is inexpensive and excellent in mass productivity and productivity.

DESCRIPTION OF SYMBOLS 1, 20 ... Semiconductor chip 2 ... Cavity 3 ... Membrane 4 ... Cold junction part 5 ... Hot junction part 6 ... Thermocouple 7 ... Thermopile extraction electrode 8 ... Black Body insulating film 9 ... Heat absorption film 10 ... Thermopile element 11, 25 ... Spacer layer 12, 22 ... Silicon cover 13, 23 ... Notch 14 ... Pad / bonding pad DESCRIPTION OF SYMBOLS 15 ... Thermopile part 21 ... Array 26 ... Bonding pad 100 ... Semiconductor wafer 101 ... Dicing line 102 ... UV mask 103 ... Ultraviolet irradiation 110 ... Photosensitive dry film 120 ... Silicon cover 130 ... Through hole 200 ... Printed wiring 201 ... Wiring 210 ... Wire bonding tool (capillary
220: Bonding wire

Claims (6)

Forming a plurality of infrared sensor devices arranged vertically and horizontally on a semiconductor wafer; attaching a photosensitive dry film to a silicon wafer surface; patterning the photosensitive dry film by photolithography; and Forming a spacer layer disposed around each infrared sensor device of the sensor device; mounting the silicon wafer on the semiconductor wafer; and bonding the silicon wafer to the semiconductor wafer by the spacer layer; And a step of dicing the semiconductor wafer and the silicon wafer to separate the plurality of infrared sensor devices for each infrared sensor device. The silicon wafer is provided with a through hole in a portion corresponding to the bonding pad portion formed on the semiconductor wafer, and when the plurality of infrared sensor devices are separated, the bonding pad portion of each infrared sensor device is the silicon wafer. The method for manufacturing an infrared sensor device according to claim 1, wherein the infrared sensor device is exposed from the surface. 3. The infrared sensor according to claim 1, wherein the patterned photosensitive dry film covers a boundary of the plurality of infrared sensor devices, and a dicing line is applied to the boundary. 4. Device manufacturing method. A semiconductor chip, a thermopile array formed of a plurality of thermopile elements arranged in an array formed on the semiconductor chip, a silicon cover disposed on the semiconductor chip, and the thermopile array formed on the semiconductor chip A spacer layer formed so as to surround the periphery of the substrate, and the spacer layer is made of a photosensitive dry film patterned by photolithography, and the silicon cover is bonded to the surface of the semiconductor chip by the spacer layer. An infrared sensor device. The infrared sensor device according to claim 4, wherein a notch portion corresponding to a bonding pad portion formed on the semiconductor chip is provided in a peripheral portion of the silicon cover. 6. The infrared sensor device according to claim 4, wherein a side surface of the silicon cover is inclined so as to spread toward the bottom.

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