JP2010230390A - Flow sensor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost flow sensor superior in productivity. <P>SOLUTION: The flow sensor 1 includes: a flow sensor chip 2 in which a detection part 7 detecting a flow of a fluid is formed; and a flow channel forming member 3 joined to the flow sensor chip 2 via a joining member 9 and forming a flow channel 4 flowing the fluid together with the flow sensor chip 2. The joining member 9 is formed so as to be divided into the circumferential part 9a of the flow channel 4 and the periphery part 9b of an overlapping region in which the flow sensor chip 2 and the flow channel forming member 3 are overlapped with each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a flow sensor and a manufacturing method thereof.

  For example, as a flow measurement device (flow sensor) that detects the flow rate of a fluid such as a gas used in a semiconductor manufacturing apparatus, heat that measures the flow rate by applying heat to the fluid and measuring the temperature difference of the fluid at a predetermined position A flow rate measuring device of the type has been proposed (see, for example, Patent Document 1).

  FIG. 3 shows a perspective view of the flow sensor a as viewed from obliquely above. In the flow sensor a, a flow sensor chip 2 and a lower surface 3a are joined to the upper surface 2a of the flow sensor chip 2 to form a minute flow path 4 of a fluid to be measured such as a gas in cooperation with the flow sensor chip 2. A path forming member 3. The flow path forming member 3 is made of a transparent glass chip. At both ends of the flow path 4, a fluid inlet 4 a and a fluid outlet 4 b that open to the upper surface 3 b of the flow path forming member 3 are formed. That is, the fluid to be measured (hereinafter referred to as “gas”) is introduced into the flow path 4 from the fluid introduction port 4 a of the flow path 4 and led out from the fluid outlet 4 b.

  The flow sensor chip 2 includes a silicon substrate 5. As shown in FIGS. 4 and 5, an insulating film (thin film) 6 of silicon nitride or silicon dioxide is formed on the upper surface of the silicon substrate 5. On the upper surface of the insulating film 6, a flow rate detection unit (sensor unit) 7 is formed at a position corresponding to the center position of the flow path 4. The flow rate detector 7 is covered with an insulating film 8 of silicon nitride or silicon dioxide. In FIG. 3, the insulating films 6 and 8 are drawn transparently to make the flow rate detection unit 7 easy to understand.

  At the center position of the upper surface 2 a of the flow sensor chip 2, a hollow recess 2 c is formed at a position below the flow rate detection unit 7. Thereby, the site | part which covers the recessed part 2c of the insulating film 6 in which the flow volume detection part 7 is formed is formed in a diaphragm shape, and the flow volume detection part 7 and the silicon substrate 5 are interrupted | blocked thermally. The flow rate detection unit 7 is a thermal detection unit, a heater as a heating element made of, for example, a platinum (Pt) thin film on the insulating film 6, and platinum, for example, disposed at equal intervals on the upstream side and the downstream side of the heater. It is composed of a temperature measuring element as a resistance element made of a thin film. When the heater of the flow rate detection unit 7 is energized, the heater is heated to a certain temperature higher than the temperature of the gas measured by an ambient temperature sensor (not shown) provided on the silicon substrate 5 by the control circuit. The gas flowing through 4 is heated.

  When gas does not flow in the flow path 4, a uniform temperature distribution is formed on the upstream side and the downstream side of the heater, and the upstream temperature measuring element and the downstream temperature measuring element have resistance values corresponding to substantially equal temperatures. Indicates. On the other hand, when there is a gas flow in the flow path 4, the uniform temperature distribution on the upstream side and downstream side of the heater collapses, the temperature on the upstream side decreases, and the temperature on the downstream side increases. And, for example, a resistance value difference of the temperature measuring element, that is, a temperature difference is detected by a Wheatstone bridge circuit constituted by the temperature measuring element on the upstream side and the temperature measuring element on the downstream side to measure the flow rate of the gas flowing in the flow path 4. To do.

  Each lead pattern 7a-7c as a signal extraction wiring of the heater and the temperature measuring element of the flow rate detection unit 7 passes between the upper surface 2a of the flow sensor chip 2 and the lower surface 3a of the glass chip 3 on both sides (width). Direction). Further, a notch 3c is formed at the center position of both side portions along the longitudinal direction of the glass chip 3, and the connection end portion at the tip of the lead patterns 7a to 7c is exposed so that it can be connected to an external measurement circuit. Yes.

  The flow rate detector 7 and the insulating films 6 and 8 are located on the upper surface 2 a of the flow sensor chip 2, and the lead patterns 7 a to 7 c are between the upper surface 2 a of the flow sensor chip 2 and the lower surface 3 a of the glass chip 3. It will be in the state extended to the side through. Therefore, the upper surface 2a of the flow sensor chip 2 and the lower surface 3a of the glass chip 3 cannot be directly joined by the flow rate detection unit 7, the insulating films 6 and 8, and the lead patterns 7a to 7c.

  The upper surface 2a of the flow sensor chip 2 having such a structure and the lower surface 3a of the glass chip 3 are joined, and the flow rate detection unit 7 and the insulating films 6 and 8 are positioned on the upper surface 2a of the flow sensor chip 2, and a lead pattern 7a to 7c are bonded members that are connected to each other while ensuring the airtightness of the flow path 4 while extending between the upper surface 2a of the flow sensor chip 2 and the lower surface 3a of the glass chip 3. And a low melting point glass (for example, frit glass) 9 as shown in FIGS.

JP 2008-70323 A

  The frit glass 9 is applied to one of the upper surface 2a of the flow sensor chip 2 and the lower surface 3a of the glass chip 3 to be joined by screen printing or the like. The flow sensor chip 2 and the glass chip 3 are bonded together by applying pressure while heating the frit glass 9. Here, FIG. 6 is a plan view showing a region where the frit glass 9 is formed. As shown by the shaded portion in FIG. 6, the frit glass 9 was formed on substantially the entire joining surface. Since the frit glass 9 is expensive, there is a problem in cost. Further, it is necessary to inspect the applied frit glass 9 after screen printing and before joining. In the case of the whole surface application, since there are many inspection target portions, the inspection takes time and there is a problem that productivity is inferior.

  An object of this invention is to provide the flow sensor which is low cost and excellent in productivity.

The flow sensor according to the present invention includes:
A flow sensor chip in which a detection unit for detecting the flow of fluid is formed;
A flow path forming member that is bonded to the flow sensor chip via a bonding member and forms a flow path for flowing the fluid together with the flow sensor chip, and
The joining member is formed by being divided into a peripheral portion of the flow path and a peripheral portion of an overlapping region where the flow sensor chip and the flow path forming member overlap.
Thereby, the flow sensor which is low-cost and excellent in productivity can be provided.

In the periphery of the rectangular overlapping region, it is preferable that the joining member is formed symmetrically with respect to a first center line that bisects the long side of the rectangle. Moreover, it is preferable that the said joining member is formed in line symmetry with respect to the 2nd centerline which bisects the rectangular short side. Furthermore, it is preferable that the joining member is divided into four corners of the rectangle.
The joining member is preferably low-melting glass.

A manufacturing method of a flow sensor according to the present invention includes:
A flow sensor chip in which a detection unit for detecting the flow of fluid is formed;
A flow path forming member which is bonded to the flow sensor chip via a bonding member and forms a flow path for flowing the fluid together with the flow sensor chip,
On the flow sensor chip or the flow path forming member, the joining member is divided into a peripheral portion of the flow path and a peripheral portion of an overlapping region where the flow sensor chip and the flow path forming member overlap. Applying, and
Joining the flow sensor chip and the flow path forming member via the joining member.
Thereby, the flow sensor which is low-cost and excellent in productivity can be provided.

It is preferable to apply the joining member in line symmetry with respect to a first center line that bisects the long side of the rectangle at the periphery of the rectangular overlapping region. Moreover, it is preferable that the joining member is applied symmetrically with respect to a second center line that bisects the rectangular short side. Furthermore, it is preferable that the joining member is divided and applied to the four corners of the rectangle.
The joining member is preferably low-melting glass.

  According to the present invention, it is possible to provide a flow sensor that is low in cost and excellent in productivity.

It is a top view which shows the flow sensor of embodiment which concerns on this invention. It is a top view which shows the modification of the flow sensor of embodiment which concerns on this invention. It is a perspective perspective view which shows a general flow sensor. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is a figure for demonstrating the subject of this invention, Comprising: It is a top view which shows the formation area of the frit glass 9. FIG.

  An embodiment of a flow sensor according to the present invention will be described. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

  Since the flow sensor 1 according to the present invention is substantially the same as the configuration of the flow sensor a described above, a duplicate description is omitted, but also includes a flow sensor chip 2 and a glass chip 3 that is a flow path forming member. . In particular, in the flow sensor 1 of the present embodiment, as shown in FIG. 1, the frit glass 9 includes a flow passage peripheral portion 9 a formed in an annular shape around the flow passage 4, a rectangular flow sensor chip 2, and It is characterized by being divided into chip peripheral portions 9b formed at the four corners of the glass chip 3.

  That is, the frit glass 9 is formed so as to be separated from the periphery of the flow path 4 and the periphery of the region where the flow sensor chip 2 and the glass chip 3 overlap. Further, the chip peripheral portion 9 b is formed by dividing into four corners of the rectangular flow sensor chip 2 and the glass chip 3. In FIG. 1, the insulating films 6 and 8 are omitted.

  As described above, conventionally, as shown in FIG. 6, the frit glass 9 has been formed on substantially the entire joining surface. Therefore, there was a problem in cost. Further, in the inspection of the coated frit glass 9 after the screen printing and before the joining, since there are many inspection object portions, the inspection takes time and the productivity is inferior. In the flow sensor 1 according to the present embodiment, since the frit glass 9 is not formed on the entire bonding surface, the consumption of the frit glass 9 can be reduced. In addition, the time required for the inspection is reduced and the productivity is improved due to the reduction of the application area of the frit glass 9, that is, the inspection target portion.

  Here, the flow path periphery 9a formed in an annular shape around the flow path 4 prevents fluid leakage. Therefore, it needs to be formed continuously over the entire periphery of the flow path 4. On the other hand, the chip peripheral portions 9b formed at the four corners of the rectangular flow sensor chip 2 and the glass chip 3 have a function of evenly distributing the external force when an external force is applied to the flow sensor chip 2 and the glass chip 3. is doing.

  Here, if the chip peripheral portion 9b is not formed, an external force is applied to one peripheral portion of the flow sensor chip 2 or the glass chip 3, and when the distance between the two becomes narrow, the distance between the two is extremely small in the peripheral portion on the opposite side. There is a risk of peeling or breaking. By providing the chip peripheral portion 9b, this can be prevented.

  As shown in FIG. 1, the four chip peripheral portions 9 b are preferably arranged symmetrically with respect to the longitudinal center lines of the flow sensor chip 2 and the glass chip 3. Further, the four chip peripheral portions 9b are preferably arranged symmetrically with respect to the center line in the width direction of the flow sensor chip 2 and the glass chip 3. Thereby, the external force can be more evenly distributed more effectively.

  FIG. 2 is a plan view showing a modification of the flow sensor according to the embodiment of the present invention. Of the four chip peripheral portions 9b in FIG. 1, the two on the short side are formed to be connected. In other words, the chip peripheral portion 9 b is not necessarily divided into four corners of the rectangular flow sensor chip 2 and the glass chip 3. In FIG. 2, the chip peripheral portion 9b is divided into two parts. Even if it is such a structure, the same effect can be acquired.

  Also in this case, the two chip peripheral portions 9 b are arranged symmetrically with respect to the center line in the longitudinal direction of the flow sensor chip 2 and the glass chip 3. The two chip peripheral portions 9b are also arranged symmetrically with respect to the center line in the width direction of the flow sensor chip 2 and the glass chip 3.

Next, the manufacturing process of the flow sensor 1 will be described.
First, the platinum thin film formed on the flow sensor chip 2 is patterned to form the detection unit 7.
Next, the frit glass 9 is applied to one of the upper surface 2a of the flow sensor chip 2 and the lower surface 3a of the glass chip 3 by screen printing or the like. Here, the frit glass 9 is divided and applied to the periphery of the flow path 4 and the four corners of the flow sensor chip 2 or the glass chip 3.
Finally, the frit glass 9 is bonded by applying pressure while the flow sensor chip 2, the glass chip 3 and the frit glass 9 are heated.

  As described above, in this embodiment, the frit glass 9 is formed at the four corners of the flow path peripheral portion 9a formed in an annular shape around the flow path 4 and the rectangular flow sensor chip 2 and glass chip 3. The chip is divided into chip peripheral portions 9b. Therefore, it is possible to provide a flow sensor that is low in cost and excellent in productivity.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Flow sensor 2 Flow sensor chip, 2a The upper surface of a flow sensor chip, 2c The recessed part of a flow sensor chip 3 Glass chip (flow path formation member), 3a The lower surface of a glass chip, 3b The upper surface of a glass chip, 3c The notch part 4 of a glass chip Flow path, 4a Fluid inlet port, 4b Fluid outlet port 5 Silicon substrate 6, 8 Insulating film 7 Flow rate detectors 7a to 7c Lead pattern 9 Frit glass (joining member), 9a Flow channel peripheral part, 9b Chip peripheral part a Flow sensor

Claims (10)

A flow sensor chip in which a detection unit for detecting the flow of fluid is formed;
A flow path forming member that is bonded to the flow sensor chip via a bonding member and forms a flow path for flowing the fluid together with the flow sensor chip, and
The flow sensor in which the joining member is divided into a peripheral portion of the flow path and a peripheral portion of an overlapping region where the flow sensor chip and the flow path forming member overlap. The overlapping region is rectangular,
2. The flow according to claim 1, wherein the joining member formed in a peripheral portion of the overlapping region is formed in line symmetry with respect to a first center line that bisects the long side of the rectangle. Sensor. The overlapping region is rectangular,
The said joining member formed in the peripheral part of the said overlap area | region is formed in line symmetry with respect to the 2nd centerline which bisects the rectangular short side. Flow sensor. The overlapping region is rectangular,
The flow sensor according to any one of claims 1 to 3, wherein the joining member formed in a peripheral portion of the overlapping region is formed by being divided into four corners of the rectangle.   The flow sensor according to claim 1, wherein the joining member is low-melting glass. A flow sensor chip in which a detection unit for detecting the flow of fluid is formed;
A flow path forming member which is bonded to the flow sensor chip via a bonding member and forms a flow path for flowing the fluid together with the flow sensor chip,
On the flow sensor chip or the flow path forming member, the joining member is divided into a peripheral portion of the flow path and a peripheral portion of an overlapping region where the flow sensor chip and the flow path forming member overlap. Applying, and
Joining the flow sensor chip and the flow path forming member via the joining member.   The flow according to claim 6, wherein the joining member is applied in line symmetry with respect to a first center line that bisects the long side of the rectangle at a peripheral portion of the rectangular overlapping region. Sensor manufacturing method.   The peripheral member of the rectangular overlapping region is coated with the joining member symmetrically with respect to a second center line that bisects the short side of the rectangle. Manufacturing method of the flow sensor.   The method for manufacturing a flow sensor according to any one of claims 6 to 8, wherein the joining member is divided and applied to four corners of the rectangle at a peripheral portion of the rectangular overlapping region.   The said joining member is low melting glass, The manufacturing method of the flow sensor as described in any one of Claims 6-9 characterized by the above-mentioned.

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