TECHNICAL FIELD

The present technology relates to a gas sensor module and a method of manufacturing the gas sensor module and in particular relates to a gas sensor module including a semiconductor chip on which a gas sensor element is integrated and a method of manufacturing the gas sensor module.

BACKGROUND ART

A gas sensor module has been conventionally provided as an integrated device obtained by forming a three-dimensional shape on a semiconductor substrate by etching process or the like in order to detect gas. For example, Japan Unexamined Patent Publication No. 2014-81367 describes a gas sensor module including a gas sensor element formed of a heater and a sensitive membrane in a Micro Electro Mechanical System (MEMS) structure; and a case configured to house the gas sensor element.

The gas sensor module described in Japan Unexamined Patent Publication No. 2014-81367 has a flattened outer shape such that a length in a direction orthogonal to a semiconductor chip on which the gas sensor element is formed is less than a length in a direction parallel to the semiconductor chip. The gas sensor module downsized as in Japan Unexamined Patent Publication No. 2014-81367 is applicable to be mounted in a small space of various devices. If a space of a device in which the gas sensor module is mounted has substantially the same height as that of the gas sensor module, it may be difficult for gas to flow through an opening formed in an upper surface of the gas sensor module. When it is difficult for the gas to flow through the opening, the gas sensor module has difficulty in detecting the gas.

SUMMARY

The present technology provides a gas sensor module configured to easily detect gas even in a case where the gas sensor module is attached in a mounting space having a short length in a direction orthogonal to a semiconductor chip on which a gas sensor element is formed.

Some aspects are described below. These aspects can be combined in any manner as needed.

A gas sensor module according to an aspect of the present technology includes: a semiconductor chip on which a gas sensor element is formed; and

a package with a flattened shape including a substrate to which the semiconductor chip is electrically connected and fixed, a side wall firmly attached to the substrate, and a cover firmly attached to the side wall, the package including a detection space in which gas flows around the semiconductor chip, the package having a length in a direction parallel to the semiconductor chip larger than a length in a direction orthogonal to the semiconductor chip. The package includes a plurality of openings formed in the side wall and/or between the side wall and the cover that communicate with the detection space.

In the gas sensor module according to the aspect above, at least one of the openings that communicate with the detection space allows gas from the outside to flow into the detection space and the rest of the openings allow the gas to be discharged. In addition, the openings are not closed by a housing that houses the gas sensor module, for example, even when the housing is brought into contact with an upper surface of the gas sensor module. Therefore, even when the gas sensor module is attached in a mounting space having a short length in a direction orthogonal to the semiconductor chip, the gas sensor module can easily detect gas.

In the foregoing gas sensor module, the package may include a plurality of openings that communicate with the detection space, the openings formed at least between the side wall and the cover, and the cover may have a thickness of from 0.01 mm to 2 mm. In the gas sensor module configured as just described, the thickness of the cover is 0.01 mm or greater; therefore, even when the gas sensor module is mounted in a narrow space in which the housing is in contact with an upper surface of the cover, gas can be guided through the openings to the detection space. Also, the thickness of the cover is 2 mm or less; therefore, for example, at the time of package dicing, a dicing tape is attached and foreign substances can be prevented from entering through the openings together with cooling water or the like. As a result, the gas sensor module is configured to increase the certainty of gas introduction into the detection space and improve quality when being mounted in a mounting space having a short length in a direction orthogonal to the semiconductor chip.

A gas sensor module according to another aspect of the present technology includes: a semiconductor chip to which a gas sensor element is formed; and a package with a flattened shape including a substrate on which the semiconductor chip is electrically connected and fixed, a side wall firmly attached to the substrate, and a cover firmly attached to the side wall, the package including a detection space in which gas flows around the semiconductor chip, the package having a length in a direction parallel to the semiconductor chip larger than a length in a direction orthogonal to the semiconductor chip. The package includes a plurality of openings that communicate with the detection space, the openings formed in the cover, and a protrusion for forming a passage through which gas is guided to the plurality of openings.

In the gas sensor module according to the aspect above, at least one of the openings that communicate with the detection space allows gas from the outside to flow into the detection space and the rest of the openings allow the gas to be discharged. In addition, the protrusion is provided; therefore, for example, even when the housing that houses the gas sensor module is brought into contact with an upper portion of the gas sensor module, the openings are not closed by the housing. Consequently, even when being attached in a mounting space having a short length in a direction orthogonal to the semiconductor chip, the gas sensor module can easily detect gas.

In the gas sensor module according to the foregoing aspect, the protrusion of the package may have a height of from 0.01 mm 2 mm. In the gas sensor module configured as just described, the height of the protrusion is 0.01 mm or greater; therefore, for example, even when the gas sensor module is mounted in a narrow space in which the housing is in contact with an upper portion of the cover, gas can be guided through the openings to the detection space. In addition, the height of the protrusion is 2 mm or less; therefore, for example, at the time of package dicing, the dicing tape is attached and foreign substances can be prevented from entering through the openings together with cooling water or the like. As a result, the gas sensor module is configured to increase the certainty of gas introduction into the detection space and improve quality when being mounted in a mounting space having a short length in a direction orthogonal to the semiconductor chip.

A method of manufacturing a gas sensor module according to an aspect of the present technology includes: forming a side wall forming member on a collective substrate or a cover forming member by injection molding such that the side wall forming member including a plurality of dents corresponding to a chip arrangement space surrounds a plurality of the chip arrangement spaces; fixing by die bonding a plurality of semiconductor chips, each of which is provided with a gas sensor element, in a plurality of areas of the collective substrate, which corresponds to the plurality of chip arrangement spaces, and electrically connecting the plurality of semiconductor chips by wire bonding to terminals of the collective substrate; assembling a gas sensor module by bonding the side wall forming member to the cover, the cover forming member, or the collective substrate; and separating the gas sensor modules formed on the collective substrate by dicing at least the side wall forming member and the collective substrate such that the plurality of dents are formed as openings that communicate with the chip arrangement space.

In the method of manufacturing a gas sensor module according to the aspect above, the dents are formed in the side wall forming member by injection molding. Therefore, even when the gas sensor module is configured such that a length in a direction orthogonal to the semiconductor chip is, for example, 3 mm or less, the openings can be easily formed in the side wall.

A method of manufacturing a gas sensor module according to another aspect of the present technology includes: forming a side wall forming member by injection molding on a collective substrate or a cover forming member such that the side wall forming member surrounds a plurality of chip arrangement spaces; fixing by die bonding a plurality of semiconductor chips, each of which is provided with a gas sensor element, in a plurality of areas of the collective substrate, which corresponds to the plurality of chip arrangement spaces, and electrically connecting the plurality of semiconductor chips by wire bonding to terminals of the collective substrate; assembling a plurality of gas sensor modules by bonding the side wall forming member such that a plurality of openings that communicate with the plurality of chip arrangement spaces are formed between covers and the side wall forming member, corresponding to the plurality of chip arrangement spaces; attaching a dicing tape to close the plurality of openings; and separating the plurality of gas sensor modules formed on the collective substrate by pouring coolant on a dicing blade while dicing at least the side wall forming member and the collective substrate by the dicing blade.

In the method of manufacturing a gas sensor module according to the aspect above, a gap is formed between the side wall forming member and the cover. Therefore, even when the gas sensor module is configured such that a length in a direction orthogonal to the semiconductor chip is, for example, 3 mm or less, the openings can be easily formed between the side wall and the cover. In addition, the coolant can be prevented by the dicing tape from entering the chip arrangement space.

A gas sensor module according to the present technology can easily detect gas even when being attached in a mounting space having a short length in a direction orthogonal to a semiconductor chip on which a gas sensor element is formed. In addition, a method of manufacturing a gas sensor module according to the present technology provides such a gas sensor module.

