JP2003017712A - Bonding method of semiconductor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor substrate bonding method which is capable of keeping hermetic properties high and preventing an adhesive agent from protruding, and comprises no complicated processes. SOLUTION: Through this semiconductor substrate bonding method, an upper semiconductor is pasted on a lower semiconductor at the prescribed position to form a semiconductor substrate bonded body containing at least a sensor substrate member. The method comprises a process (ST11) of applying a permeation film that sets up a permeation range up to which an adhesive agent is allowed to permeate into the upper substrate on the upper substrate which is formed through a process (ST10) in which an etched part is provided, an adhesive agent applying process (ST12), and a pasting and bonding process (ST13). Gas rate sensor semiconductor members are manufactured by a process (ST14) of cutting the semiconductor bonded body formed through the above processes into pieces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining semiconductor substrates, and more particularly to a method for joining semiconductor substrates in a manufacturing process of micromachining elements such as minute gas rate sensors, pressure sensors and gas sensors.

[0002]

2. Description of the Related Art As a method of bonding upper and lower semiconductor substrates,
As disclosed in JP-A-3-29858,
Glass-Si anodic bonding and bonding methods using low-melting glass are known. However, these joining methods have a problem in that it is very difficult to maintain airtightness when there is unevenness, and that they stick out from a predetermined position where an adhesive is applied.

A method of adhering the upper and lower semiconductor substrates at a predetermined position to form a single semiconductor member for solving such a problem is disclosed in Japanese Patent Laid-Open No. 6-334315. The method is to use a film adhesive consisting of a reinforcing material and an adhesive layer as an adhesive, cut the film adhesive, die-cut, or press it as it is against the bonding surface of the chip component or circuit board. , The adhesive layer is heated to a temperature at which it softens but does not cure, the adhesive layer is transferred to the joint surface, and the joint surface of the chip component or circuit board that is the joint partner is aligned with the joint surface, and then the joint agent layer Is a method of curing.

That is, an adhesive formed into a predetermined shape is transferred to one semiconductor substrate by so-called thermal transfer, the other semiconductor substrate is bonded to the adhesive, and then heat having a temperature higher than that of the thermal transfer is applied to the adhesive. They are heat-cured and bonded to each other.

[0005]

[0006]

However, in the joining method disclosed in Japanese Patent Laid-Open No. 6-334315, different heating steps for thermal transfer of the adhesive and thermosetting of the adhesive are required, and Since it is necessary to remove the reinforcing material of the film adhesive between these heating steps, different heating steps cannot be continuously performed, and the step for joining the semiconductor substrates becomes complicated. There is a problem that it ends up.

Further, in the thermal transfer of the adhesive, it is necessary to strictly control and manage the heating temperature such that the adhesive is heated to a temperature at which it softens but does not cure. There is a problem that the process for joining becomes complicated.

An object of the present invention is to solve the above problems, to maintain good airtightness, to prevent the adhesive from squeezing out, and to join the semiconductor substrates in a complicated process for joining the semiconductor substrates. To provide a method.

[0009]

The semiconductor substrate bonding method according to the present invention is configured as follows in order to achieve the above object.

A first semiconductor substrate bonding method (corresponding to claim 1) is a semiconductor substrate bonded body including at least one sensor semiconductor member obtained by bonding an upper semiconductor substrate and a lower semiconductor substrate at a predetermined position. A method for joining semiconductor substrates, which comprises a step of directing a transparent film having a transparent range through which an adhesive is transmitted to either the upper semiconductor substrate or the lower semiconductor substrate, An adhesive applying step of applying an adhesive to the adhesive surface of either the upper semiconductor substrate or the lower semiconductor substrate in a shape according to the transmission range by transmitting the adhesive from above the film, and the upper semiconductor substrate. And a bonding step of bonding the lower semiconductor substrate with an adhesive at a predetermined position.

According to the first semiconductor substrate bonding method, the adhesive is applied to one of the bonding surfaces of the upper semiconductor substrate or the lower semiconductor substrate in a shape according to the transparent range of the transparent film, and then the other is bonded to the bonding surface. Since the semiconductor substrates are bonded and bonded together, good airtightness can be maintained, the adhesive does not stick out, and if the adhesive is a thermosetting adhesive, for example, the adhesive will be applied immediately after the adhesive is applied. Since it is possible to move to the curing work of No. 1, it is possible to avoid the complexity of the manufacturing process, which requires heating in multiple stages, which was required in the conventional technique.

The second semiconductor substrate bonding method (corresponding to claim 2) is the above method, preferably, at least one of the upper semiconductor substrate and the lower semiconductor substrate is provided with a touching portion. Characterized by.

According to the second semiconductor substrate bonding method, even a semiconductor substrate having a touching portion and a more complicated bonding surface can be bonded smoothly.

According to a third method for joining semiconductor substrates (corresponding to claim 3), preferably, one touching portion is formed on at least one of the upper semiconductor substrate and the lower semiconductor substrate, The semiconductor substrate bonded body formed by bonding the semiconductor substrate and the lower semiconductor to each other is characterized by forming one sensor semiconductor member.

The fourth semiconductor substrate bonding method (corresponding to claim 4) is the above method, preferably, a plurality of touching portions are formed on at least one of the upper semiconductor substrate and the lower semiconductor substrate, and the upper semiconductor substrate is formed. A semiconductor substrate bonded body formed by bonding a semiconductor substrate and a lower semiconductor substrate is characterized by including a plurality of sensor semiconductor members.

In a fifth method for joining semiconductor substrates (corresponding to claim 5), preferably, in the adhesive applying step, pressure is applied to the adhesive to allow it to permeate the permeation range of the permeable film. This is characterized by the step of applying an adhesive.

According to the fifth semiconductor substrate bonding method, by applying pressure to the adhesive, the adhesive can surely permeate the permeable film, and the adhesive can be surely applied to the semiconductor substrate.

In a sixth method for joining semiconductor substrates (corresponding to claim 6), in the above method, preferably, the upper semiconductor substrate and the lower semiconductor substrate are bonded together by an adhesive, and then the individual sensor semiconductors are bonded. It is characterized by being subdivided into members.

According to the sixth method of joining semiconductor substrates, after the upper semiconductor substrate and the lower semiconductor substrate are bonded together with an adhesive, they are subdivided into individual semiconductor members for sensors. The member can be made.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

The configurations, shapes, sizes, and arrangement relationships described in the embodiments are merely schematic ones to the extent that the present invention can be understood and practiced, and numerical values and compositions (materials) of the respective configurations. Is merely an example. Therefore, the present invention is not limited to the embodiments described below, and can be modified into various forms without departing from the scope of the technical idea shown in the claims.

An embodiment of the method for joining semiconductor substrates according to the present invention will be described by taking as an example the production of a semiconductor member used in a gas rate sensor.

FIG. 1 is an exploded perspective view of a semiconductor member for a gas rate sensor manufactured by using the semiconductor joining method according to the present invention. The semiconductor member 10 for gas rate sensor is
The lower semiconductor substrate 11, the upper semiconductor substrate 12, and the heat wire bridge 15 having the heat wires 13 and 14 which are the functional portions are formed as constituent members.
The upper semiconductor substrate 12 and the upper portion of the semiconductor substrate 12 have a touching portion 1 serving as a gas passage.
6, 17 are formed. The lower semiconductor substrate 11 and the upper semiconductor substrate 12 are made of a semiconductor such as Si. The heat wires 13 and 14 are detection parts, and the heat wire bridge 15 is for fixing the detection part to the gas passage.

The gas rate sensor semiconductor member 10 is used in a state where the lower semiconductor substrate 11 and the upper semiconductor substrate 12 are bonded. FIG. 2 is a schematic diagram showing the configuration of the gas rate sensor. The gas rate sensor 18 includes a sensor chip 19 and a piezo pump 20. Sensor chip 19
Is the semiconductor member 10 for the gas rate sensor and the gas inlet 2
It consists of 1. The piezo pump 20 is for supplying gas to the gas introduction part 21 and creating a gas flow in the sensor chip 19 as indicated by an arrow.

The gas rate sensor 18 is the piezo pump 2
0 introduces gas from the inlet 22 of the gas passage, and the gas flows through the gas passage, so that the heat wire 1
It is sprayed on 3,14. The left and right heat wires 13, 14 whose temperature rises due to the current at that time are cooled by the blown gas. These sensors form a bridge circuit (not shown), and when the flow velocity of the gas blown to the left and right heat wires 13 and 14 is equal, 2
The heat wires 13 and 14 of the book have the same temperature, and as a result, the output voltage of the bridge circuit becomes zero. But,
When the gas rate sensor has an angular velocity, Coriolis force acts on the gas flow, and the gas flow is lopsided. As a result, a difference occurs in the velocity of the gas flow blown to the left and right heat wires 13 and 14, so that the electric resistance of the heat wires becomes different between the left and right, and the bridge circuit is out of balance and the output voltage is detected. To be done. Thereby, the angular velocity can be measured.

FIG. 3 is a flow chart showing the manufacturing steps in the embodiment of the semiconductor substrate bonding method of the present invention. In this semiconductor substrate joining method, a step (ST11) of applying a transparent film to the upper semiconductor substrate formed by the step (ST10) of forming a touching portion on the upper semiconductor substrate, and an adhesive application step (ST12) are combined. And adhesion process (ST1
The semiconductor member for a gas rate sensor is manufactured by the step (ST14) of 3), in which the semiconductor substrate bonded body formed by these steps is cut out and subdivided.

In the step of applying the permeable film (ST11), the permeable film provided with a permeable range for allowing the adhesive to penetrate to the semiconductor substrate is accurately addressed, and the adhesive coating step is performed with the permeable film being addressed. By (ST12), attach the adhesive to the permeable membrane,
When pressure is applied, the adhesive permeates the permeable film and is applied only to the portion of the semiconductor substrate where the adhesive is to be applied. Then, a bonding step (ST13) is performed to accurately bond the upper semiconductor substrate, the lower semiconductor substrate having the heat wire bridge provided with the heating wire and the touching portion previously serving as the gas passage, to form a semiconductor substrate bonded body. To be done.

Next, each step will be described in detail. Figure 4
It is a flowchart which shows the process (ST10) of forming the touching part of an upper semiconductor substrate. In this step, a resist coating step (ST20) of applying a resist to an upper semiconductor substrate for forming a touched portion and a mask having an opening so as to expose a portion of the resist for forming the touched portion, are exposed. Thus, the photolithography process (ST21) for removing the resist and the process (ST22) for etching the upper semiconductor substrate are performed.

In the resist coating step ST20, a positive resist which becomes soluble by light is coated with a uniform thickness by a spin coater (not shown). A cross section of the upper semiconductor substrate at that time is shown in FIG. The entire surface of the upper semiconductor substrate 23 is
The positive resist 24 is applied.

Next, a photolithography process (ST2
In 1), a mask in which openings are formed so as to correspond to portions of a touching portion for forming gas passages of a plurality of gas rate sensors is brought into close contact with an upper semiconductor substrate coated with a resist, and an exposure device is used. The resist is exposed to light of a wavelength that it reacts with. Then, by immersing the upper semiconductor substrate in a solvent, the resist in the exposed portion is melted and the resist in the portion forming the etched portion is removed. A cross section of the upper semiconductor substrate at that time is shown in FIG. On the surface of the upper semiconductor substrate 23, a resist opening 25 is formed in a portion where the etched portion is formed.

In the etching step (ST22), the semiconductor substrate is immersed in an etchant for a predetermined time,
The semiconductor in the opening 25 of the resist is etched to form an etched portion. FIG. 7 shows a cross section of the semiconductor substrate at that time. A touching part 26 is formed on the upper semiconductor substrate 23. Then, the resist 24 is removed to obtain an upper semiconductor substrate having a touched portion.

FIG. 8 (a) shows an upper semiconductor substrate having a touching portion manufactured by using a Si wafer in this manner. The upper semiconductor substrate 23 is formed with a touching portion 26, and each etching portion has a shape shown in FIG.
It is shown in (b) and comprises an engraving part 27 corresponding to the nozzle part 27a for guiding the gas flow supplied from the piezo pump 20 to the detecting part and an engraving part 28 on which the heat wire is placed.

FIG. 9 is a diagram showing a step (ST11) of directing the transparent film to the upper semiconductor substrate. This step (ST11)
For this, an adhesive permeation device 29 is used. Adhesive permeation device 2
9 is a substrate fixing part 30, an adhesive permeable film frame 31, and a permeable film 3.
It consists of two. The substrate fixing portion 30 is for fixing the upper semiconductor substrate to which the adhesive is applied, and the adhesive permeable film frame 31 is for fixing the permeable film 32. The adhesive permeable film frame 31 holds the permeable film 32 so that an appropriate tension is applied to the permeable film 32.

FIG. 10 shows a partially enlarged view of the permeable membrane. The permeable membrane 32 is made of stainless steel wire, silk, nylon,
It is composed of a woven fabric 33 made of a wire such as Tetron fiber and a resist 34. The woven fabric 33 has fine eyes, and the portion 35 where the eyes are closed by the resist and the portion 3 where there is no resist
6 is present, and the closed portion 35 is a portion that exactly corresponds to the touched portion of the upper semiconductor substrate. The adhesive is
A portion without the resist 34 is transmitted. A portion 36 where the resist 34 is not present is a transmission range through which the adhesive is transmitted.

The substrate fixing portion 30 and the adhesive permeable film frame 31 are
The upper semiconductor substrate 23 is sandwiched by the substrate fixing portion 30 so that the adhesive permeable film frame 31 can be accurately closed.
A recess in the shape of the upper semiconductor substrate 23 is formed in the substrate fixing portion 30 so that the fixing position of the upper semiconductor substrate 23 is accurately aligned with and fixed to the transmission range of the transparent film 32. FIG. 11 shows a cross section of the substrate fixing portion 30. There is a recess 37 having a depth such that the adhesive surface of one semiconductor substrate can be slightly protruded, and a hole 38 is provided below the recess 37.
Is for opening so that the bonded semiconductor substrate can be pushed out from the substrate fixing portion 30. Moreover, the adhesive permeable film frame 31 can be removed from the substrate fixing portion 30.

Using this adhesive permeation device 29, first,
The upper semiconductor substrate 23 to be coated with the adhesive having the touched portion is set in the recess 37 of the substrate fixing portion 30. Then, the adhesive permeable film frame 31 is closed and the permeable film 32 is directed to the upper semiconductor substrate 23.

FIG. 12 is a diagram showing an adhesive applying step (ST12). A paste adhesive 39 is attached to the permeable membrane 32. After that, the adhesive 39 is spread by applying a pressure with a spatula 40 or the like, so that the adhesive 39 permeates the resist-free eyes of the permeable film. As a result, the adhesive is reliably applied only to the periphery of the touched part of the upper semiconductor substrate 23, and the adhesive is applied to a uniform thickness without interruption.

FIG. 13 shows the step of bonding and adhering (S
T13) is shown. A semiconductor substrate bonding lid 41 having a cross section shown in FIG. 14 is used for this step. The lid 41 for adhering to the semiconductor substrate is provided with a recess 42 for accommodating the lower semiconductor substrate in which a heat wire bridge having an engraved portion and a heat wire is previously formed, and an opening 43 for a suction device.
Using this semiconductor substrate bonding lid 41, the lower semiconductor substrate is placed in the recess 42 of the lid 41, the lower semiconductor substrate is sucked and fixed in the recess 42 by a suction device (not shown), and the lid 41 is coated with an adhesive. The upper semiconductor substrate is covered with the fixed substrate fixing portion 30. Thereby, the upper semiconductor substrate and the lower semiconductor substrate are accurately put together and bonded. After that, the fixing by the suction device is stopped, and in that state, a time is allowed until the adhesive is cured. When the adhesive is a thermosetting adhesive, the entire device is placed in an electric furnace and heated. Thereby, the upper semiconductor substrate and the lower semiconductor substrate are bonded.

FIG. 15 is a perspective view of the semiconductor member after being cut out and subdivided. As a result, one semiconductor member 44 is completed. At this time, by making a cut in the portion to be cut in advance, the semiconductor member can be easily divided into individual pieces by the cleavage of the semiconductor.

By using this semiconductor substrate bonding method, the airtightness is maintained, the adhesive does not stick out, and
The semiconductor substrates can be joined in a manufacturing process without complication.

In this embodiment, a plurality of touched portions are formed on the upper semiconductor substrate, and the semiconductor substrate assembly formed by bonding the upper semiconductor substrate and the lower semiconductor substrate is a plurality of semiconductors for gas rate sensors. Although shown as including members, a semiconductor substrate bonded body formed by forming one touched portion on the upper semiconductor substrate and bonding the upper semiconductor substrate and the lower semiconductor to each other is a semiconductor for gas rate sensor. You may make it form a member. At that time, it is not necessary to divide the semiconductor member into individual pieces. Also,
Although the adhesive is applied to the upper semiconductor substrate in the above description, the adhesive may be applied to the lower semiconductor substrate. Furthermore, in this embodiment, an example in which the semiconductor substrate of both the upper semiconductor substrate and the lower semiconductor substrate has the touching portion is shown, but the touching portion is provided in either the upper semiconductor substrate or the lower semiconductor substrate. In this case also, this semiconductor substrate joining method can be applied.

In the embodiment of the present invention, the paste adhesive is used for explanation, but the adhesive may be applied by using a spray adhesive. At this time, the adhesive can be applied without pressing the adhesive with a spatula or the like. Further, although the Si substrate is used as the semiconductor substrate, it is also possible to perform the bonding using another semiconductor substrate. In addition, in the embodiment of the present invention, the production of the gas rate sensor has been described, but in addition to the gas rate sensor, a semiconductor substrate for a micromachining element such as a pressure sensor or a gas sensor can be preferably joined.

[0043]

As is apparent from the above description, the present invention has the following effects.

Since an adhesive is applied to one of the bonding surfaces of the upper semiconductor substrate or the lower semiconductor substrate in a shape according to the transmission range of the transparent film, and the other semiconductor substrate is bonded and adhered thereto, it is preferable. Airtightness can be maintained, the adhesive does not stick out, and if the adhesive is a thermosetting adhesive, for example, the adhesive can be immediately cured after the application of the adhesive. It is possible to avoid the complexity of the manufacturing process in which heating must be performed in multiple steps. Further, even in the case where the semiconductor substrate has the touching portion and the bonding surface has a more complicated shape, the bonding work can be performed smoothly. Furthermore, since a large number of semiconductor members can be smoothly bonded at one time, extremely efficient bonding work can be provided when a large number of semiconductor members are obtained from a single semiconductor substrate.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a semiconductor member for a gas rate sensor manufactured by using a semiconductor bonding method according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a gas rate sensor.

FIG. 3 is a flowchart showing a manufacturing process in an embodiment of a semiconductor substrate bonding method of the present invention.

FIG. 4 is a flowchart showing a process of forming a touched portion of a semiconductor substrate.

FIG. 5 is a cross-sectional view of a semiconductor substrate when a resist is applied.

FIG. 6 is a cross-sectional view of a semiconductor substrate with a resist partially removed.

FIG. 7 is a cross-sectional view of a semiconductor substrate on which a touched portion is formed.

8A and 8B are diagrams showing a semiconductor substrate having an etched portion manufactured using a Si wafer, FIG. 8A is the entire Si wafer, and FIG. 8B is a diagram showing the shape of one etched portion. Is.

FIG. 9 is a perspective view showing a step of placing a transparent film on a semiconductor substrate.

FIG. 10 is a partially enlarged view of a permeable membrane.

FIG. 11 is a cross-sectional view of a substrate fixing portion.

FIG. 12 is a perspective view showing an adhesive applying step.

FIG. 13 is a perspective view showing a step of laminating and adhering.

FIG. 14 is a view showing a lid for bonding a semiconductor substrate.

FIG. 15 is a perspective view of the semiconductor member after being cut out and subdivided.

[Explanation of symbols]

10 Gas Rate Sensor Semiconductor Member 11 Lower Semiconductor Substrate 12 Upper Semiconductor Substrates 13, 14 Heat Wire 15 Heat Wire Bridge 16, 17 Engraved Section ST10 Step ST11 of Forming Engraved Section on Semiconductor Substrate Step ST12 Adhesive coating step ST13 Step of adhering ST14 Step of cutting out and subdividing a semiconductor joining member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomohiro Sakoe             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd. F-term (reference) 4M112 AA01 DA02 EA02

Claims (6)

[Claims] 1. A method of joining semiconductor substrates, comprising: bonding an upper semiconductor substrate and a lower semiconductor substrate at a predetermined position to form a semiconductor substrate joined body including at least one semiconductor member for a sensor. A permeable film provided with a permeable range for transmission, a permeable film-addressing step of allocating one of the upper semiconductor substrate and the lower semiconductor substrate, and transmitting the adhesive from above the permeable film. An adhesive application step of applying the adhesive to the adhesive surface of one of the upper semiconductor substrate and the lower semiconductor substrate in a shape according to the transmission range, the upper semiconductor substrate and the lower semiconductor substrate A bonding method of a semiconductor substrate, comprising: a bonding step of bonding and bonding with the adhesive at the predetermined position. 2. The method of bonding a semiconductor substrate according to claim 1, wherein an engraved portion is formed on at least one of the upper semiconductor substrate and the lower semiconductor substrate. 3. The semiconductor substrate bonded body obtained by forming the touching portion on at least one of the upper semiconductor substrate and the lower semiconductor substrate, and bonding the upper semiconductor substrate and the lower semiconductor to each other. The method for joining semiconductor substrates according to claim 2, wherein one of the sensor semiconductor members is formed. 4. A plurality of semiconductor substrate bonded bodies obtained by forming a plurality of the touched portions on at least one of the upper semiconductor substrate and the lower semiconductor substrate and bonding the upper semiconductor substrate and the lower semiconductor substrate together. 3. The method for bonding a semiconductor substrate according to claim 2, wherein the semiconductor member for sensor is included. 5. The adhesive applying step is a step of applying the adhesive by applying a pressure to the adhesive to allow the adhesive to pass through a permeation range of the permeable membrane. 5. The method for joining semiconductor substrates according to any one of 4 above. 6. The bonding of a semiconductor substrate according to claim 4, wherein the upper semiconductor substrate and the lower semiconductor substrate are bonded to each other by the adhesive and then subdivided into individual sensor semiconductor members. Method.