JPH0541148A - Manufacture of semi-conductor acceleration sensor - Google Patents

Abstract

PURPOSE:To simplify the stopper joining process and the dicing process by applying etching processing to an upper stopper to form a clearance, and forming a through hole at a position corresponding to a pad. CONSTITUTION:Etching is applied to an upper stopper 1 to form a window hole 6 of a pad part at a first stage, and next, etching is performed to form a clearance 10. In a lower stopper 7, a constant space 11 is formed by etching. At the time of dicing a sensor chip, scaling is performed at the window hole 6 for a pad 3 to cut two layers of a sensor wafer 2 and the lower stopper 7 at a virtual scribe line 5. Scaling of the upper stopper 1 and the sensor wafer 2 is thereby facilitated, and while since half scribe for forming an opening at a position corresponding to the pad 3 is not necessary, non-requirement factor at the process of stopper jointing and dicing is reduced to improve the workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor acceleration sensor, and more particularly to a method for manufacturing a semiconductor acceleration sensor in which the structure of a stopper portion is improved so that the sensor portion and the stopper portion are bonded together or diced.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a semiconductor acceleration sensor of this type, when sandwiching a sensor wafer between upper and lower stoppers, only the inner surfaces of the upper and lower stoppers are etched,
After that, a method of adhering is adopted.

FIG. 8 is a sectional view of a semiconductor acceleration sensor for explaining a conventional example. As shown in FIG. 8, the conventional method for manufacturing a semiconductor acceleration sensor is based on the sensor wafer 2
When sandwiching between the upper stopper 1 and the lower stopper 7, only one surface of each of the stoppers 1 and 7, that is, the surface to be bonded to the sensor wafer 2 is etched. Looking at the upper stopper 1, the weight portion 8 of the sensor wafer 2
A gap 10 is formed at a position corresponding to the beam 9, and a gap is formed at a position corresponding to the upper surface pad 3 of the sensor wafer 2. As for the lower stopper 7, a gap 11 is formed at a position corresponding to the weight portion 8. These gaps 10 and 11 are formed by etching so that the stoppers 1 and 7 function. The aligning process for bonding the stoppers 1 and 7 and the sensor unit 2 is mainly performed by one of two methods.

FIG. 9 is a plan view of the wafer for explaining the alignment of the sensor wafer and the stopper wafer in FIG. As shown in FIG. 9, the first conventional alignment method is such that the absolute coordinates of the formation position of the sensor chip 13 in the wafer 2 from the outer peripheral portion of the wafer 2 become constant values (c, d). Form. The absolute coordinates of the sensor chip 13 and the absolute coordinates (c, d) of the gaps 10 and 11 formed by etching the stoppers 1 and 7 on the upper and lower sides in the wafer 2 are previously matched. As a result, the relative positions of the gaps 10 and 11 between the sensor chip 13 and the stoppers 1 and 7 can be adjusted by aligning the outer circumference of the wafer 2 or the orientation flat (orientation flat) 14. After this, the wafers 1, 2 and 7 are bonded together to form.

On the other hand, the second alignment method is a method of aligning the sensor wafer 2 and the stopper wafers 1 and 7 by using infrared rays that pass through the silicon substrate, and then laminating them.

Next, after the positions of the stoppers 1 and 7 and the wafer of the sensor wafer 2 are aligned by either of the above-mentioned two methods, the substrates are bonded and the dicing process is started. This dicing position is aligned by the same method as the above-mentioned wafer aligning method, and then the wafer is cut with a horizontal scribe line (not shown) and a vertical scribe line 5 to separate it into chips. is doing.
Moreover, as shown in FIG. 8, in order to open the pad portion 3 of the sensor 2, another dicing step using the half scribe line 12 is required.

[0007]

In the conventional method for manufacturing a semiconductor acceleration sensor described above, it is difficult to align the outer periphery of the wafer with the internal pattern (sensor and stopper) in the wafer bonding process, and If the sensor and the upper and lower stoppers are aligned with each other based on the outer peripheral portion or orientation flat, not only the alignment accuracy will deteriorate, but also the equipment will be bulky and equipment costs will be incurred if infrared alignment is used. It has the drawback of being expensive. Also, in the next step, the dicing step,
It is difficult to detect the dicing position, and half cutting and full cutting are mixed at the time of dicing, so there is a drawback that workability is poor.

An object of the present invention is to provide a method of manufacturing a semiconductor acceleration sensor, which can simplify the stopper bonding step and the dicing step and improve workability.

[0009]

According to a method of manufacturing a semiconductor acceleration sensor of the present invention, a plurality of sensors are formed by forming a weight portion and a beam portion on a semiconductor substrate for a sensor by three-dimensional processing and attaching a pad on the upper surface. A step of forming chips, and a step of forming a plurality of upper stoppers by forming gaps on the lower surface of the upper stopper semiconductor substrate by etching to form a plurality of upper stoppers and at least one through hole at a position corresponding to the pad. And a step of forming a plurality of lower stoppers by forming gaps on the upper surface of the lower stopper semiconductor substrate by etching, and the upper stopper semiconductor substrate and the lower stopper semiconductor above and below the sensor semiconductor substrate. A step of adhering a substrate, and a first step performed from above the upper stopper semiconductor substrate along the through hole; The second dicing configured to include a step of separating the individual semiconductor acceleration sensor.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a plan view of a semiconductor acceleration sensor for explaining an embodiment of the present invention. As shown in FIG. 1, this embodiment shows a state in which an upper stopper 1 is attached to the upper surface of a sensor wafer 2 and a pad 3 is attached to the sensor wafer 2. The pad 3 of the sensor wafer 2 can be seen through the window hole 6 formed as a through hole in the upper stopper 1. The semiconductor acceleration sensor is diced one by one by the horizontal scribe line 4 and the vertical scribe line 5 along the window hole 6 as a through hole. That is, the upper stopper 1 and the sensor wafer 2 are the pad 3 and the upper stopper 1 of the sensor wafer 2.
Align with the window holes 6 and install. Next, the scribe of the wafer is performed with the window hole 6 and the window hole 6 corresponding to the pad 3.
Is performed along the virtual scribe line 4 which is the center line of the pad, and the virtual scribe line 5 is used to perform the dicing with the width of the window hole 6 corresponding to the pad 3 aligned.

FIG. 2 is a structural sectional view taken along line AA shown in FIG. As shown in FIG. 2, the upper stopper 1 is bonded to the upper portion of the sensor chip 2 and the lower stopper 7 is bonded to the lower portion. The upper stopper 1 bonded on the sensor chip 2 is etched on the bonding side to form a constant gap (for example, 3 to 20 μm) 10. Similarly, the lower stopper 7 is also formed with a constant interval 11 by etching. The constant intervals 10 and 11 are for preventing the weight portion 8 from being displaced beyond this interval and destroying the beam 9. Moreover, the upper stopper 1 has a window hole 6 formed in the portion corresponding to the pad 3 by etching.
This window hole 6 is formed by etching the upper stopper 1 in two steps. That is, the window hole 6 of the pad portion is etched in the first stage, and then the gap 10 is etched. When dicing the sensor chip, the window holes 6 for the pads 3 are aligned with each other, and the two layers of the sensor chip 2 and the lower stopper 7 are cut at the virtual scribe line 5.

FIG. 3 is a structural sectional view taken along line BB shown in FIG. As shown in FIG. 3, the upper stopper 1 is bonded to the sensor chip 2 and the rim portion of the sensor chip 2. The weight portion 8 of the sensor chip 2 is separated from the sensor chip 2 by the groove. Therefore, dicing is performed by cutting the three layers of the upper stopper 1, the rim portion of the sensor chip 2 and the lower stopper 7 along the dotted scribe line 4.

FIG. 4 is a structural sectional view taken along the line CC of FIG. As shown in FIG. 4, the upper stopper 1 here has a window corresponding to the pad 3, so that only a part of the upper stopper 1 can be seen. Therefore, in this state, the upper stopper 1, the sensor chip 2, and the lower stopper 7 are cut along the dotted scribe line 4.

FIGS. 5A and 5B are cross-sectional views of the upper stopper, which are shown in the order of steps for explaining the two etching processes in FIG. First, as shown in FIG. 5A, in order to form a window hole 6 in a portion of the sensor wafer (chip) 2 corresponding to the pad 3, etching is performed from one side. Therefore, the window hole 6 has a large etching side and a small opposite side. Next, FIG.
As shown in (b), etching for forming the gap 10 is performed from the same side. Thus, the etching is done in two steps from the same side.

FIG. 6 is a sectional view of a semiconductor acceleration sensor for explaining another embodiment of the present invention. As shown in FIG. 6, the basic structure of this embodiment is the same as that of the embodiment of FIG. 1 described above, but the structure of the upper stopper 1 and its manufacturing method are different. FIG. 6 also shows a cross-sectional structure taken along the line AA of FIG. 1, and the method of forming the window hole 6 is different. That is, in one embodiment, the etching is performed only from the surface of the upper stopper 1 on the sensor chip side.
Etching is performed from both sides.

7 (a) and 7 (b) are cross-sectional views of the upper stopper showing the order of steps for explaining the two etching processes in FIG. 6, respectively. As shown in FIG. 7A, the upper stopper 1 first etches the window hole 6 corresponding to the pad 3 from the upper surface. Next, as shown in FIG. 7B, etching for forming the gap 10 is performed from the opposite side of the upper stopper 1. In the method of the present embodiment, the area of the opening differs depending on the plane orientation of the silicon substrate between the etching start surface and the etching end surface, so that the area of the window hole for alignment can be increased. In addition, the adhesion area with the sensor wafer 2 is reduced on the contrary.

Although two embodiments have been described above, the method for manufacturing a semiconductor acceleration sensor according to the present invention performs etching from one direction or both directions of the stopper wafer to form a gap between the stopper and the sensor, and a pad for the sensor. Since the formation of the window hole is performed at the same time, the process can be simplified and the workability can be improved.

[0019]

As described above, the method of manufacturing a semiconductor acceleration sensor according to the present invention facilitates the alignment of the upper stopper and the sensor chip and requires the half scribing for opening the pad portion of the sensor chip. Therefore, there is an effect that the unnecessary rate in the stopper laminating process and the dicing process can be reduced and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of a semiconductor acceleration sensor for explaining an embodiment of the present invention,

FIG. 2 is a sectional view taken along the line AA shown in FIG.

FIG. 3 is a sectional view taken along line BB shown in FIG.

FIG. 4 is a cross-sectional view taken along the line CC shown in FIG.

5A to 5C are cross-sectional views of an upper stopper showing the order of steps for explaining two etching processes in FIG.

FIG. 6 is a sectional view of a semiconductor acceleration sensor for explaining another embodiment of the invention.

7A to 7C are cross-sectional views of the upper stopper showing the order of steps for explaining the two etching processes in FIG.

FIG. 8 is a cross-sectional view of a semiconductor acceleration sensor for explaining a conventional example.

9 is a plan view of the wafer for explaining the alignment of the sensor wafer and the stopper wafer in FIG.

[Explanation of symbols]

 1 Upper Stopper 2 Sensor Wafer 3 Pad 4, 5 Scribing Line 6 Window Hole 7 Lower Stopper 8 Weight 9 Beam 10, 11 Gap

Claims (3)

[Claims] 1. A step of forming a weight portion and a beam portion on a semiconductor substrate for a sensor by three-dimensional processing and depositing a pad on the upper surface to form a plurality of sensor chips, and an etching processing on the semiconductor substrate for an upper stopper. To form a plurality of upper stoppers by forming gaps on the lower surface and to form at least one through hole at a position corresponding to the pad, and to form a gap on the upper surface by etching the lower stopper semiconductor substrate. Forming a plurality of lower stoppers, bonding the upper stopper semiconductor substrate and the lower stopper semiconductor substrate to the upper and lower sides of the sensor semiconductor substrate, and forming an upper stopper semiconductor substrate on the upper stopper semiconductor substrate. To separate into individual semiconductor acceleration sensors by first and second dicing along the through hole A method of manufacturing a semiconductor acceleration sensor, comprising: 2. The method of manufacturing a semiconductor acceleration sensor according to claim 1, wherein the semiconductor substrate for the upper stopper is formed so that the lower side of the through hole is enlarged by etching only from the lower surface. 3. The upper stopper semiconductor substrate is formed by first etching the lower surface to form the gap and the through hole, and then etching the upper surface to form the upper side of the through hole larger. The method for manufacturing a semiconductor acceleration sensor according to claim 1, wherein