JP4965219B2 - SEALING JOIN PERFORMANCE EVALUATION DEVICE, SEAL JOINING PERFORMANCE EVALUATION DEVICE MANUFACTURING METHOD, SEAL JOIN PERFORMANCE EVALUATION METHOD, AND SEAL JOIN PERFORMANCE EVALUATION SYSTEM - Google Patents

Description

  The present invention relates to a sealing bonding performance evaluation device for evaluating the sealing performance of a sealing bonding region of a MEMS (Micro Electro Mechanical Systems) device, a manufacturing method of a sealing bonding performance evaluation device, a sealing bonding performance evaluation method, And a sealing joint performance evaluation system.

With recent advances in semiconductor manufacturing process technology, it has become possible to form a sealed mounting structure in which mechanical elements and three-dimensional structures are provided in a hollow region and the hollow region is hermetically maintained by sealing bonding. According to such a sealed mounting structure, it is possible to protect the machine element and the three-dimensional structure from disturbances during the mounting process and during use. In the development of the manufacturing process of this sealed mounting structure, the sealing performance evaluation of the sealing joint is indispensable in order to ensure the airtightness in the hollow region. For this reason, until now, sealing performance evaluation of sealing bonding has been performed by observing the sealing bonding region with a microscope or performing a leak test by providing a Pirani gauge in the hollow region (non-patent document). 1).
"A Sensitive Pirani Vacuum Sensor and the electrothermal SPICE modeling", Sensor and Actuators, A53 (1996), 273-277

  However, according to the method for evaluating the sealing performance of the sealing bonding by observing the sealing bonding region with a microscope, the sealing performance can be evaluated even if the sealing bonding can be judged. Therefore, it is difficult to obtain knowledge for developing the manufacturing process of the sealing structure. On the other hand, according to the method for evaluating the sealing performance of the sealing joint by providing a Pirani gauge in the hollow region, it becomes necessary to form a terminal for taking out the output of the Pirani gauge, or the layout of other components is restricted. Since the manufacturing process becomes complicated by the addition of, it becomes difficult to easily evaluate the sealing performance of the sealing joint.

  The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a sealing bonding performance evaluation device and a sealing bonding performance evaluation device that can easily evaluate the sealing performance of sealing bonding. It is providing the manufacturing method of this, a sealing joining performance evaluation method, and a sealing joining performance evaluation system.

  As a result of intensive research, the inventors of the present invention have vibrated a vibrating body provided in a hollow structure sealed by sealing joining, irradiated light to the vibrating body, and reflected on the vibrating body. Receiving light, measuring the resonance characteristics of the vibrating body from the received light, calculating the degree of vacuum in the hollow region from the measured resonance characteristics, and determining the sealing performance of the sealing joint based on the calculated degree of vacuum It was found that the sealing performance of the sealing joint can be easily evaluated by the evaluation.

  Hereinafter, with reference to drawings, the structure of the sealing joining performance evaluation apparatus which becomes one Embodiment of this invention, and its manufacturing method are demonstrated.

  First, with reference to FIG. 1 thru | or FIG. 3, the structure of the sealing joining performance evaluation apparatus used as one Embodiment of this invention is demonstrated.

[Configuration of sealing bonding performance evaluation device]
As shown in FIG. 1, a plurality of sealed joint performance evaluation apparatuses 1 according to an embodiment of the present invention are formed on a semiconductor wafer 2 by a manufacturing method described later. In the example shown in FIG. 1, a plurality of sealing bonding performance evaluation apparatuses 1 are formed in an effective area (85 mmφ, broken line area) of a 4-inch semiconductor wafer (100 mφ) and sealed between the sealing bonding performance evaluation apparatuses 1. An optimum sealing structure can be evaluated by changing the dimensions of the structure.

  As shown in FIG. 2, each sealing performance evaluation apparatus 1 includes a frame portion 4 having a rectangular opening 3 and a plurality of vibrators 5 a and 5 b that are cantilevered in the opening 3 and have different lengths. , 5c, a light-transmitting cap portion 6 anodically bonded to the upper surface of the frame portion 4, and a silicon substrate 7 (sealed bonding structure) sealed and bonded to the lower surface of the frame portion 4. A hollow region is formed by hermetically sealing the upper and lower surfaces of the opening 3 with the silicon substrate 7.

  The frame portion 4 is formed of a known SOI (Silicon On Insulator) substrate in which a buried oxide film 10 (film thickness of about 0.5 μm) is sandwiched between a silicon substrate 8 and an active layer 9, and the vibrators 5a, 5b, 5c are It is formed by processing the active layer 9 by a manufacturing method described later. Further, a concave portion 11 is formed on the surface (lower surface) of the cap portion 6 on the frame portion 4 side so that the vibrating bodies 5a, 5b, and 5c can vibrate in the vertical direction (z-axis direction).

  According to the sealing bonding performance evaluation apparatus 1 having such a configuration, the sealing portion between the frame portion 4 (silicon substrate 8) and the silicon substrate 7 is used by using a sealing bonding performance evaluation system as shown in FIG. The sealing performance of the stop bonding can be easily evaluated. Specifically, when evaluating the sealing performance of the sealing bonding between the frame portion 4 and the silicon substrate 7, first, the semiconductor wafer 2 is placed on the stage 22 in the chamber 21, and the upper surface of the stage 22 is By energizing the piezoelectric plate 23 disposed in the position, the entire semiconductor wafer 2 is swung to excite the vibrating bodies 5a, 5b, 5c.

  Next, the vibrating bodies 5a, 5b, and 5c are irradiated with light from the laser Doppler vibrometer 24 through the cap portion 6 with the vibrating bodies 5a, 5b, and 5c excited, and the surfaces of the vibrating bodies 5a, 5b, and 5c are irradiated. The reflected light is received by the camera 25, the resonance characteristic (resonance mechanical Q value) of the vibrating body is measured from the received light, and the degree of vacuum in the opening 3 is calculated from the measured resonance characteristic. And the sealing performance of the sealing joining between the frame part 4 and the silicon substrate 7 is evaluated based on the measured degree of vacuum. In general, since the resonance characteristic has a pressure dependency, the degree of vacuum in the opening 3 can be calculated according to the pressure dependency of the resonance characteristic by evaluating the pressure dependency in advance (for example, Sensors). & Actuators A61, 249 (1997)).

  In addition, since the said resonance characteristic changes according to the area (length or width) of vibrating body 5a, 5b, 5c, the degree of vacuum which can be calculated from the resonance characteristic of each vibrating body 5a, 5b, 5c is vibrating body 5a. , 5b, and 5c. Specifically, a vibrating body having a small area exhibits a high mechanical Q value even at a low vacuum level, but the mechanical Q value is saturated at a relatively low vacuum level. In contrast, a vibrating body having a large area does not resonate at a low vacuum level, but the mechanical Q value is saturated at a high vacuum level. Therefore, by providing a plurality of vibrators having different areas in the opening 3 (in the example shown in FIG. 2, a plurality of vibrators having different widths and lengths), a measurable range of vacuum degree is expanded (0.1. [Pa] to atmospheric pressure), the sealing performance of the sealing joint between the frame part 4 and the silicon substrate 7 can be evaluated in a wider range.

  In the sealing performance evaluation system shown in FIG. 3, the chamber 21 includes a pressure sensor 26, a gas introduction unit 27, and a gas discharge unit 28, and can change the degree of vacuum in the chamber 21, and the pressure sensor 26. Thus, the degree of vacuum in the chamber 21 can be measured. Further, the laser Doppler vibrometer 24 and the camera 25 are attached to the XYZ stage 30 and configured to be movable in a three-dimensional direction.

  Next, with reference to FIG. 4 thru | or FIG. 10, the manufacturing method of the said sealing joining performance evaluation apparatus 1 is divided into the manufacturing process of the cap part 6, and the manufacturing process of the frame part 4, and is demonstrated in order.

[Manufacturing process of cap part]
When manufacturing the cap portion 6, first, a glass substrate 6 a as shown in FIG. 4A is prepared, and after forming the Cr sputter layer 31 and the Au sputter layer 32 in this order on the surface of the glass substrate 6 a, As shown in FIG. 4B, the resist film 33 is patterned in a region other than the region R <b> 1 where the recess 11 is formed in the surface region of the Au sputter layer 32.

  Next, as shown in FIG. 4C, wet etching is performed using the resist film 33 as a mask to remove the Cr sputter layer 31 and the Au sputter layer 32 exposed on the surface. Next, as shown in FIG. 5D, after the resist film 33 is removed by wet etching, the glass substrate 6b is etched by performing wet etching using the Cr sputter layer 31 and the Au sputter layer 32 as a mask. A recess 11 is formed. Finally, the Au sputter layer 32 and the Cr sputter layer 31 are sequentially removed by wet etching, thereby completing the manufacturing process of the cap portion 6.

  In addition, when the cap part 6 is manufactured with the said manufacturing method, a pinhole may be formed in the glass substrate 6a surface in which the Cr sputter layer 31 and Au sputter layer 32 were formed. The inventors of the present invention consider that the reason why the pinhole is formed is that a pinhole exists in the Cr sputtered layer 31 or the Au sputtered layer 32 and the etching solution penetrates from the pinhole into the glass substrate 6a. .

  Therefore, it is more desirable to manufacture the cap portion 6 by the following manufacturing method. That is, after removing the Cr sputter layer 31 and the Au sputter layer 32 exposed on the surface by performing a wet etching process through the resist film 33 (state shown in FIG. 4C), FIG. 6A. As shown in FIG. 5, the glass substrate 6a is etched to form the recess 11 by performing wet etching using the Cr sputtered layer 31, the Au sputtered layer 32, and the resist film 33 as a mask. Then, as shown in FIG. 6B, after the resist film 33 is removed by wet etching, the Cr sputter layer 31 and Au sputter layer 32 are removed by wet etching as shown in FIG. 6C. The cap part 6 is manufactured.

  According to such a manufacturing method, in order to prevent the resist film 33 from penetrating into the glass substrate 6a from pinholes or poor adhesion portions existing in the Cr sputter layer 31 or the Au sputter layer 32, the Cr sputter It is possible to suppress the formation of pinholes on the surface of the glass substrate 6a on which the layer 31 and the Au sputter layer 32 have been formed, thereby improving the yield. Further, it is possible to suppress the side surfaces of the Cr sputter layer 31 and the Au sputter layer 32 from being broken by the etching process, and the pattern accuracy of the Cr sputter layer 31 and the Au sputter layer 32 from being lowered.

[Frame manufacturing process]
When manufacturing the frame portion 4, first, as shown in FIG. 7A, an insulating film 34 (film thickness of about 1 μm) is provided on the back surface, and the shapes of the vibrators 5 a, 5 b, 5 c are formed in the active layer 9. The SOI substrate thus formed and the cap portion 6 are anodically bonded.

  Next, as shown in FIG. 7B, after patterning the resist film 33 in a region other than the region R3 corresponding to the lower part of the vibrating bodies 5a, 5b, and 5c in the surface region of the insulating film 34, FIG. As shown in FIG. 7C, the insulating film 34 exposed on the surface is removed by etching.

  Next, as shown in FIG. 8D, after the silicon substrate 8 in the region corresponding to the lower part of the vibrators 5a, 5b, and 5c is removed by dry etching, a resist film as shown in FIG. 8E is obtained. 33 is removed. Finally, the buried oxide film 10 exposed on the back side is removed by wet etching, thereby completing the manufacturing process of the frame portion 4.

  According to the above manufacturing method, silicon deposits generated on the side walls and bottom surface of the silicon substrate 8 during the dry etching process of the silicon substrate 8 float during the subsequent wet etching process of the buried oxide film 10, and the silicon substrate 8. There is a possibility that the yield of the sealing joint may be reduced or the vibration of the vibrating bodies 5a, 5b, 5c may be hindered.

  Therefore, it is more desirable to manufacture the frame portion 4 by the following manufacturing method. That is, when the frame portion 4 is manufactured, first, as shown in FIG. 9A, an SOI substrate having the insulating film 34 on the back surface and the shapes of the vibrators 5a, 5b, 5c formed on the active layer 9 And the cap portion 6 are anodically bonded.

  Next, after the insulating film 34 is removed by etching as shown in FIG. 9B, the vibration bodies 5a, 5b, and 5c in the surface region of the silicon substrate 8 are removed as shown in FIG. 9C. The resist film 33 is patterned in a region other than the region R3 corresponding to the lower side.

  Next, after removing the silicon substrate 8 exposed on the surface as shown in FIG. 10D by dry etching, the buried oxide film exposed on the back side as shown in FIG. 10 is removed by dry etching. Finally, the resist film 33 is removed as shown in FIG. 10F, whereby the manufacturing process of the frame portion 4 is completed.

  According to such a manufacturing method, silicon deposits generated on the side walls and the bottom surface during the dry etching process of the silicon substrate 8 cause the bottom of the silicon substrate 8 and the vibrators 5a and 5b during the subsequent etching process of the buried oxide film 10. , 5c can be suppressed.

[Other Embodiments]
The sealing bonding performance evaluation apparatus 1 of the above embodiment evaluates the sealing performance of the sealing bonding between the silicon substrate 8 and the silicon substrate 7 by bonding the silicon substrate 7 to the lower surface of the frame portion 4. However, the sealing performance of the sealing bonding between the metal film and the silicon substrate 7 may be evaluated by forming a metal film on the lower surface of the silicon substrate 8. However, when a metal film is formed on the lower surface of the silicon substrate 8 by a normal manufacturing process, the vibration performance of the vibrators 5a, 5b, 5c may be affected by the metal film adhering to the vibrators 5a, 5b, 5c. There is sex.

  Therefore, when evaluating the sealing performance of the sealing bonding between the metal film and the silicon substrate 7, it is desirable to form the metal film on the lower surface of the silicon substrate 8 by the manufacturing method described below. That is, when forming a metal film on the lower surface of the silicon substrate 8, first, the frame portion 4 and the cap portion 6 are anodically bonded as shown in FIG. In the surface region of the silicon substrate 8, the resist film 33 is patterned in a region other than the region R3 corresponding to the lower part of the vibrators 5a, 5b, and 5c.

  Next, as shown in FIG. 11C, the silicon substrate 8 exposed on the surface is removed by a deep-RIE etching process leaving an appropriate thickness, and then a resist film 33 is formed as shown in FIG. Remove. Next, after forming the metal film 35 on the back surface of the silicon substrate 8 as shown in FIG. 12E, the metal film 35 is left in the surface region of the metal film 35 as shown in FIG. The resist film 33 is patterned in a region other than the region (sealed bonding region).

  Next, as shown in FIG. 13G, the metal film 35 is removed using the resist film 33 as a mask, and then the resist film 33 is removed as shown in FIG. 13H. Next, as shown in FIG. 13I, after the resist film 33 is patterned in a region other than the region below the vibrating bodies 5a, 5b, and 5c in the back surface region of the frame portion 4, FIG. As shown in (j), the silicon substrate 8 is removed using the resist film 33 as a mask. Finally, the series of manufacturing steps is completed by removing the resist film 33. According to such a manufacturing method, it can suppress that the metal film 35 adheres to the vibrating bodies 5a, 5b, and 5c.

  As mentioned above, although the embodiment to which the invention made by the present inventors was applied has been described, the present invention is not limited by the description and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it should be added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above embodiments are all included in the scope of the present invention.

It is a figure which shows the example of a layout on the wafer of the sealing joining performance evaluation apparatus used as embodiment of this invention. It is the upper side figure and sectional drawing which show the structure of the sealing joining performance evaluation apparatus used as embodiment of this invention. It is a schematic diagram which shows the structure of the sealing joining performance evaluation system used as embodiment of this invention. It is sectional process drawing which shows the flow of the manufacturing process of the cap part used as embodiment of this invention. FIG. 5 is a cross-sectional process diagram illustrating a continuation of the cross-sectional process diagram illustrated in FIG. 4. It is sectional process drawing which shows the flow of the application example of the manufacturing process of the cap part used as embodiment of this invention. It is sectional process drawing which shows the flow of the manufacturing process of the flame | frame part used as embodiment of this invention. FIG. 8 is a cross-sectional process diagram illustrating a continuation of the cross-sectional process diagram illustrated in FIG. 7. It is sectional process drawing which shows the flow of the application example of the manufacturing process of the flame | frame part used as embodiment of this invention. FIG. 10 is a cross-sectional process diagram illustrating a continuation of the cross-sectional process diagram illustrated in FIG. 9. It is sectional process drawing which shows the flow of the manufacturing process of the application example of the sealing joining performance evaluation apparatus used as embodiment of this invention. FIG. 12 is a cross-sectional process diagram illustrating a continuation of the cross-sectional process diagram illustrated in FIG. 11. FIG. 13 is a cross-sectional process diagram illustrating a continuation of the cross-sectional process diagram illustrated in FIG. 12. FIG. 14 is a cross-sectional process diagram illustrating a continuation of the cross-sectional process diagram illustrated in FIG. 13.

Explanation of symbols

1: Seal bonding performance evaluation apparatus 2: Wafer 3: Opening portion 4: Frame portions 5a, 5b, 5c: Vibrating body 6: Cap portion 6a: Glass substrate 7, 8: Silicon substrate 9: Active layer 10: Buried oxidation Film 11: Recess 21: Chamber 22: Stage 23: Piezoelectric plate 24: Laser Doppler vibrometer 25: Camera 26: Pressure sensor 27: Gas introduction part 28: Gas discharge part 30: XYZ stage 31: Cr sputter layer 32: Au sputter Layer 33: Resist film 34: Back surface insulating film 35: Metal film

Claims (11)

A frame portion having an opening;
A vibrating body supported in the opening of the frame portion;
A light-transmitting cap portion formed on the upper surface of the frame portion;
A sealing joint structure joined to the lower surface of the frame part,
The opening is hermetically sealed by the cap portion and the sealing joint structure,
The vibrating body is irradiated with light through the cap portion while the vibrating body is vibrated, the light reflected by the vibrating body is received, the resonance characteristics of the vibrating body are measured from the received light, and the measured resonance An apparatus for evaluating sealing joint performance, wherein the sealing degree between the frame part and the sealing joint structure can be evaluated by calculating a degree of vacuum in the opening from characteristics.   The sealing joining performance evaluation apparatus according to claim 1, wherein a plurality of vibrators having different areas are supported in the opening.   3. The sealing bonding performance evaluation apparatus according to claim 1, wherein a recess is formed on the surface of the cap portion on the frame side. 4.   4. The sealing bonding performance evaluation apparatus according to claim 1, wherein the frame portion is formed of an SOI substrate in which a buried oxide film is sandwiched between a silicon substrate and an active layer, and the vibration is performed. The sealing bonding performance evaluation apparatus, wherein the body is formed of an active layer of the SOI substrate. It is a manufacturing method of the sealing joining performance evaluation device according to claim 4,
Forming a recess on the frame side surface of the cap portion;
Forming a vibrator shape in an active layer of the SOI substrate;
Anodic bonding of the cap and the SOI substrate so that the recess and the vibrating body face each other;
Removing the silicon substrate and the buried oxide film below the vibrating body to bring the vibrating body into a state capable of vibrating;
And a step of bonding the sealing bonded structure to the lower surface of the silicon substrate.   It is a manufacturing method of the sealing joining performance evaluation apparatus of Claim 5, Comprising: The process of forming the said cap part forms in order a glass layer surface on a glass substrate surface as a mask using a metal layer and a resist film, and glass through the said mask. A method of manufacturing a sealing bonding performance evaluation apparatus, comprising: forming a recess by etching a substrate; and removing the mask after completion of etching.   7. The manufacturing method of a sealing joint performance evaluation apparatus according to claim 5, wherein the step of bringing the vibrating body into a vibratable state includes a step of removing the silicon substrate by a dry etching process, and the embedding. A method for manufacturing a sealing bonding performance evaluation apparatus, comprising: sequentially performing a step of removing an insulating film by dry etching.   8. The method for manufacturing a sealing / bonding performance evaluation apparatus according to claim 5, wherein an SOI substrate having an insulating film on a back surface is used as the SOI substrate. A manufacturing method of a stop bonding performance evaluation device. In the manufacturing method of the sealing joining performance evaluation device according to claim 4,
Forming a recess on the frame side surface of the cap portion;
Forming a vibrator on an active layer of the SOI substrate;
Anodic bonding of the cap and the SOI substrate so that the recess and the vibrating body face each other;
Removing the silicon substrate below the vibrating body leaving a predetermined thickness;
Forming a metal film on the silicon substrate surface;
Removing the metal film in a region other than the region for forming the sealing bonding structure;
And a step of removing the silicon substrate and the buried oxide film below the vibrating body. Oscillating a vibrator provided in a hollow structure sealed by sealing joining;
Irradiating the vibrator with light;
Receiving light reflected by the vibrator;
Measuring the resonance characteristics of the vibrating body from the received light, and calculating the degree of vacuum in the hollow region from the measured resonance characteristics;
Evaluating the sealing performance of the sealing bonding based on the calculated degree of vacuum, and determining a process condition of the sealing bonding based on the evaluation result. A frame having an opening, a vibrating body supported in the opening of the frame, a light-transmitting cap formed on the upper surface of the frame, and a sealing bonding structure bonded to the lower surface of the frame A sealing joint performance evaluation device in which the opening is hermetically sealed by the cap part and the sealing joint structure;
A vibration applying unit that excites the vibrating body by vibrating the sealing bonding performance evaluation device;
An irradiating unit that irradiates light to the vibrating body through the cap unit;
A light receiving unit that receives light reflected by the vibrating body;
A sealing joint performance evaluation system, comprising: a calculation unit that measures a resonance characteristic of a vibrating body from light received by the light receiving unit, and calculates a degree of vacuum in the opening from the measured resonance characteristic.

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