JPH11258086A - Forming method for metallizing layer of pedestal for semiconductor pressure sensor and manufacture for jig for metallizing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method for a metallizing layer of a pedestal for a semiconductor pressure sensor having good joining reliability without forming a metallizing layer in the inner wall of a through hole of the pedestal and without increasing the number of processes. SOLUTION: This method is for forming a metallizing layer 8 on the side of a pedestal 2 that is not joined to a semiconductor pressure sensor chip in a semiconductor pressure sensor having semiconductor pressure sensor chip and the pedestal 2 formed with a through hole 21 for introducing pressure into a diagram and joined to the semiconductor pressure sensor chip. A metallizing jig 30 comprises a disc-like part 31 larger than an opening part of the side of the through hole 21 where the metallizing layer 8 of the pedestal 2 is formed and a fine line-like member 32 for fixing the disc- like member 31 to correspond to the arrangement of the through hole 21 of the pedestal 2. Under the condition where the jig 30 is installed in such a manner that the disc-like member 31 blocks up the opening part of the through hole 21, the metallizing layer 8 is formed sputtering or evaporation from the side where to form the metallizing layer 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a metallized layer of a pedestal for a semiconductor pressure sensor and a method of manufacturing a metallizing jig by joining a pedestal to a semiconductor pressure sensor chip having a diaphragm formed thereon. is there.

[0002]

2. Description of the Related Art Generally, a semiconductor pressure sensor measures a pressure in a micro pressure region. As shown in FIG. 7, a semiconductor pressure sensor having a diaphragm 11 formed in a thin shape by forming a concave portion. Chip 1 is glass pedestal 2
To the center by Kovar or 4
PPS or PBT on which metal pipe 4 such as 2 alloy is arranged
And so on, in a plastic package 3. The aluminum pad on the surface of the semiconductor pressure sensor chip 1 and the lead 5 are connected by a gold or aluminum wire 6. Note that 7
Is a lid of the plastic package 3, 12 is a strain gauge resistor formed on the semiconductor pressure sensor chip 1, and 13 is an overcoat for protecting the surface of the semiconductor pressure sensor chip 1. As a material of the glass pedestal 2,
For example, Pyrex glass (Corning's product number # 7
740).

A through hole 21 for applying pressure to the diaphragm 11 of the semiconductor pressure sensor chip 1 is formed in the center of the glass pedestal 2.
1 and the through-hole 41 of the metal pipe 4 are joined to the metal pipe 4 in such an arrangement that they face each other. In order to join the glass pedestal 2 and the metal pipe 4, a metallization layer 8 is formed on the surface of the glass pedestal 2 on the side not joined to the semiconductor pressure sensor chip 1.
Is formed.

In forming the metallized layer 8 on the glass pedestal 2, first, as shown in FIG. 8A, the surface on which the metallized layer 8 is to be formed is roughened, and then, FIG. As shown in (1), the glass pedestal 2 is placed in close contact with the flat plate 10, and the metallized layer 8 is formed on the surface roughened by sputtering or vapor deposition. Examples of the metallized layer 8 include Cr (bottom layer) / Ni / Au (top layer), Ti
(Bottom layer) / Ni / Au (top layer), Ti (bottom layer) /
Pt / Au (top layer) and the like. Then, FIG.
(C) As shown in FIG.
Remove from

[0005] Then, the metal pipe 4 and the glass pedestal 2 are joined by solder (tin, tin-antimony alloy, lead, tin-lead alloy, gold-silicon alloy, tin-silver alloy, etc.) 9 via the metallized layer 8. Is done. A of the uppermost layer of the metallized layer 8
The solder 9 can be applied to the surface of u.

[0006]

However, according to the method for forming the metallized layer 8 on the glass pedestal 2 as described above, the surface of the glass pedestal 2 that is in contact with the flat plate 10 is not metallized. However, metal particles adhere to the inner wall of the through hole 21 and the metallized layer 8 is formed.

When the metallized layer 8 is formed on the inner wall of the through hole 21, as shown in FIG. 9, when the glass pedestal 2 and the semiconductor pressure sensor chip 1 are anodically bonded, a high temperature (about 300 ° C. to 400 ° C.) is applied. ) In high bias (about 50
0 V to 800 V) is applied between the metallization layer 8 formed at the upper end of the inner wall of the through-hole 21 and the portion near the through-hole 21 on the joint surface of the semiconductor pressure sensor chip 1 with the glass pedestal 2. As a result, there is a problem that a discharge occurs and the semiconductor pressure sensor chip 1 is broken.

In order to solve such a problem, there is a method of filling the through hole 21 of the glass pedestal 2 with the wax 20 when forming the metallized layer 8 as shown in FIG. That is, as shown in FIG. 10A, the surface on which the metallized layer 8 is to be formed is roughened, and as shown in FIG. 10B, the glass pedestal 2 is placed on the flat plate 10 in close contact therewith. At this stage, the wax 20 is filled in the through holes 21. The wax 20 used is one that melts with heat of about 100 ° C. to 150 ° C., but the type of the wax 20 may be appropriately changed depending on the temperature applied when the metallized layer 8 is formed. The method of filling the wax 20 into the through hole 21 is performed by, for example, discharging the wax from the needle tip using a dispenser or the like. Thereafter, as shown in FIG. 10C, a metallized layer 8 is formed on the surface roughened by sputtering or vapor deposition. After the formation of the metallized layer 8 is completed, the glass pedestal 2 is removed from the flat plate 10 and the glass pedestal 2 is heated to melt the wax 20 filled in the through holes 21 as shown in FIG. And remove. This prevents the metallized layer 8 from being formed in the through hole 21.

However, in this case, the through holes 21
The step of filling the inside of the wax 20 is extraly increased, and the cost is increased. Also, if the wax scatters on the surrounding glass pedestal 2 surface other than in the through hole 21, the metallized layer 8 will be formed on the wax, and the adhesive strength of the metallized layer 8 to the surface of the glass pedestal 2 will be reduced. descend.
Further, after the metallized layer 8 is formed, the wax 20 filled in the through-hole 21 is melted and removed, but when the residue of the wax 20 wraps around the surface of the glass pedestal 2 to be joined to the semiconductor pressure sensor chip 1. This significantly affects the bonding quality between the glass pedestal 2 and the semiconductor pressure sensor chip 1. In other words, the bonding strength is reduced due to voids being generated without bonding. Washing with a molten organic solvent (acetone, isopropyl alcohol, etc.) may be considered to remove the residue of the wax 20, but the number of washing steps is increased, and quality control such as checking the residue level after washing is difficult. In particular, when the wax 20 is opaque, there is a problem that a visual inspection cannot be performed and a cleaning property cannot be evaluated.

[0010] The present invention has been made in view of the above points, and an object thereof is to form a metallized layer on the inner wall of a through-hole of a pedestal without increasing the number of steps and improving the bonding reliability. It is an object of the present invention to provide a method for forming a metallized layer of a pedestal for a semiconductor pressure sensor and a method for manufacturing a metallizing jig, which have good properties.

[0011]

According to the first aspect of the present invention,
A semiconductor pressure sensor chip having a diaphragm formed in a thin shape by forming a concave portion, and a pedestal formed with a through hole for introducing pressure to the diaphragm and joined to the semiconductor pressure sensor chip. A method of forming a metallized layer on a surface of the pedestal that is not bonded to the semiconductor pressure sensor chip in the semiconductor pressure sensor, wherein the shape of the opening is larger than the shape of the opening on the surface of the pedestal on which the metallized layer is formed. A metallizing jig comprising a disk-shaped member having a shape and a thin line-shaped member for fixing the disk-shaped member so as to be arranged in accordance with the arrangement of the through holes of the pedestal, wherein the disk-shaped member is The metallized layer is formed by sputtering or vapor deposition from the side where the metallized layer is to be formed in a state where it is installed so as to cover the opening of the through hole. It is characterized in.

According to a second aspect of the present invention, in the first aspect of the present invention, the thin wire member is formed in a loop shape.

According to a third aspect of the present invention, there is provided the method for manufacturing a metallizing jig according to the second aspect, wherein a metal plate is attached to one surface of a resin substrate, and the metal plate is etched. The disk-shaped members are formed at substantially equal intervals, and then the adjacent disk-shaped members are connected with a loop-shaped thin line-shaped member,
Next, the resin substrate is peeled off.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a metallizing jig according to the second aspect, wherein the thin metal wires are arranged in a grid at substantially equal intervals, and the intersections of the thin metal wires are welded. Connect and crush the weld in a flat plate,
Next, the metal thin wire is deformed on a loop by a mold.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process chart showing a method for forming a metallized layer of a pedestal for a semiconductor pressure sensor according to an example of an embodiment of the present invention. First, as shown in FIG. 1A, a disk-shaped glass pedestal 2 (with a diameter of about 100 mm to 1 mm).
The through-hole 21 is formed at an area of 50 mm and a thickness of about 0.5 mm to 3 mm) by an ultrasonic processing method or the like. Through hole 2
The size of 1 is about 0.6 mm to 1.5 mm in diameter.
One surface of the glass pedestal 2 is roughened. In other words, one surface of the glass pedestal 2 is polished with a coarse grindstone, or sprayed by sandblasting to roughen the surface, so that metal can easily adhere when forming a metallized layer described later. deep.

Next, as shown in FIG. 1B, the glass pedestal 2 is placed on the flat plate 10 with the roughened surface facing upward. Then, as shown in FIG. 2, a disk-shaped member 31 having a shape slightly larger than the shape of the opening of the through hole 21 on the roughened surface of the glass pedestal 2 (the surface on which the metallized layer of the pedestal is formed), A metallizing jig 30 including a thin metal wire 32 as a thin wire member for fixing the disk member 31 so as to be arranged in accordance with the arrangement of the through holes 21 of the pedestal 2, Is installed so as to close the opening of the through hole 21. Here, the metal wire 32 is formed in a loop shape. Further, as the disc-shaped member 31, for example, copper or a material obtained by plating nickel or gold on the surface of copper is used. The thickness is about 50 μm to 200 μm, and the shape is slightly larger than the shape of the opening of the through hole 21.
A circle having a diameter of 7 to 1.5 mm is used.

In this state, as shown in FIG. 1C, a metallized layer 8 is formed on the roughened surface of the glass pedestal 2 by sputtering or vapor deposition. In the case of sputtering, the pressure around the target (the plate used as the material of the metallized layer 8) is set to 10 ⁻² Torr to 10 ⁻⁴ Torr, and several hundred volts are applied between the target and the substrate or the vacuum vessel (ground).
A voltage of ~ several KV is applied to generate plasma. The ions in the plasma bounce off the atoms on the target surface and adhere to the substrate (glass) to form a film. By changing the target in this manner, a plurality of metal layers are stacked, and the metallized layer 8 is formed. As an example of the metallized layer 8, Cr (lowest layer) / N
i / Au (top layer), Ti (bottom layer) / Ni / Au (top layer), Ti (bottom layer) / Pt / Au (top layer), and the like. Note that sputtering is performed from the direction of the surface on which the metallized layer is to be formed (the surface having been subjected to surface roughening). At this time, the metal wire 32 fixing the plurality of disc-shaped members 31
Is formed of a thin member and is formed in a loop shape, so that the metallized layer 8 does not become uneven due to the shielding of the metal wires 32. Thereafter, as shown in FIG. 1D, the metallizing jig 30 is removed.

As shown in FIG. 3, the glass pedestal 2 on which the metallized layer 8 is formed is joined to the metal pipe 4 via the solder 9 on the side on which the metallized layer 8 is formed, as shown in FIG. The surface is bonded to the semiconductor pressure sensor chip 1 by anodic bonding. The conditions for the anodic bonding are as follows: heating to about 400 ° C. in a vacuum atmosphere and applying a DC voltage of about 500 V to 800 V so that the semiconductor pressure sensor chip 1 side becomes a positive electrode, the atomic bonding is performed by electrostatic attraction. It is.

According to the present embodiment, the inner wall 22 of the through-hole 21 of the glass pedestal 2 is closed by the disc-shaped member 31 during the step of forming the metallized layer 8, so that the metallized layer is formed. And is formed only on the joint surface with the metal pipe 4. Therefore, when the glass pedestal 2 and the semiconductor pressure sensor chip 1 are anodic-bonded, the semiconductor pressure sensor chip 1 is not broken by electric discharge, and an extra step such as filling with wax is not increased. Further, the joining reliability between the glass pedestal 2 and the semiconductor pressure sensor chip 1 or the metal pipe 4 is also improved.

FIG. 4 is a process chart showing an example of a method of manufacturing the metallizing jig 30. First, as shown in FIG. 4 (a), a copper foil is adhered to a resin substrate 40 of phenol or the like, and this is etched with ferric chloride or the like to form a circular pattern (disc) arranged at substantially equal intervals. ) 31 is formed. Next, as shown in FIG. 4B, the pattern (disc-shaped member)
31 are connected by wire bonding with a wire (metal wire) 32 of copper, aluminum, gold or the like. Wire (metal wire) 3
2 has a diameter of about 50 μm to 300 μm. Next, as shown in FIG. 4C, the resin substrate 40 is dissolved in a solvent such as trichlene or acetone and peeled off. Here, a circular pattern (disk-shaped member) 31 and a wire (metal wire) 3
The connection of 2 may be performed by connecting a long wire (metal wire) 32 to the pattern (disc-like member) 31 by welding 33 as shown in FIG.

FIG. 6 is a process chart showing another example of a method of manufacturing the metallizing jig 30. First, as shown in FIG. 6 (a), a plurality of metal wires (metal wires) 32 are arranged in a grid at predetermined intervals, and as shown in FIG. 6 (b),
Each intersection is welded and the intersection is crushed into a flat plate to form a disc-shaped member 31. Next, as shown in FIG. 6C, the wire (metal wire) 32 is fitted into the lower mold 51 having a convex portion in contact with the wire (metal wire) 32, and the wire (metal wire) 32 is It is pressed down from above by the upper mold 52 whose contacting part is concave. afterwards,
When the lower mold 51 and the upper mold 52 are removed, a wire (metal wire)
The metallization jig 30 in which the loop 32 has a loop shape is completed. Here, the disk-shaped members 31 are arranged at a predetermined pitch.

According to the method of manufacturing the metallizing jig 30 described above, the metallizing jig 30 used in the method of forming the metallized layer of the pedestal for the semiconductor pressure sensor of the present invention can be easily manufactured.

[0023]

As described above, according to the first aspect of the present invention, a semiconductor pressure sensor chip having a diaphragm formed in a thin shape by forming a concave portion, and a semiconductor pressure sensor chip for introducing pressure to the diaphragm. A through hole is formed,
A method of forming a metallized layer on a surface of a semiconductor pressure sensor having a pedestal joined to the semiconductor pressure sensor chip and a surface of the pedestal not joined to the semiconductor pressure sensor chip, wherein the pedestal of the through hole is provided. A disk-shaped member having a shape larger than the shape of the opening on the surface side on which the metallized layer is formed, and a thin line-shaped member for fixing the disk-shaped member so as to be arranged corresponding to the arrangement of the through holes of the pedestal. Since the metallizing jig consisting of, in a state where the disc-shaped member is installed so as to close the opening of the through-hole, the metallized layer is formed by sputtering or vapor deposition from the surface on which the metallized layer is formed, A metallized layer is not formed on the inner wall of the through hole of the pedestal, and the method for forming the metallized layer of the pedestal for the semiconductor pressure sensor with high joining reliability without increasing the number of steps is described. I was able to today.

According to the second aspect of the present invention, in the first aspect of the present invention, since the thin linear member is formed in a loop shape, a more uniform metallized layer can be formed.

According to a third aspect of the present invention, there is provided the metallizing jig manufacturing method according to the second aspect, wherein a metal plate is attached to one surface of the resin substrate and the metal plate is etched. Since the disk-shaped members are formed at substantially equal intervals, then, adjacent disk-shaped members are connected by a loop-shaped thin line-shaped member, and then the resin substrate is peeled off. The metallizing jig used in Item 2 can be easily manufactured.

According to a fourth aspect of the present invention, there is provided the metallizing jig manufacturing method according to the second aspect, wherein the metal thin wires are arranged in a grid at substantially equal intervals, and the intersection of the metal thin wires is determined. The metallizing jig used in claim 2 is easily connected by welding and crushing the welded portion into a flat plate shape, and then deforming the thin metal wire on a loop by a mold. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a process diagram showing a method for forming a metallized layer of a pedestal for a semiconductor pressure sensor according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a metallizing jig 30 according to the embodiment.

FIG. 3 is a schematic view showing a state where the pedestal according to the above is joined to a semiconductor pressure sensor chip and a metal pipe.

FIG. 4 is a process chart showing an example of a method of manufacturing the metallizing jig 30 according to the present invention.

FIG. 5 is a schematic view showing an example of a method of connecting the metal wire and the disk-shaped member according to the above.

FIG. 6 is a process chart showing another example of a method of manufacturing the metallizing jig 30 according to the present invention.

FIG. 7 is a schematic configuration diagram of a semiconductor pressure sensor.

FIG. 8 is a process chart showing a method of forming a metallized layer of a pedestal for a semiconductor pressure sensor according to a conventional example.

FIG. 9 is a schematic diagram showing a state where the pedestal according to the above is joined to a semiconductor pressure sensor chip and a metal pipe.

FIG. 10 is a process chart showing a method of forming a metallized layer of a pedestal for a semiconductor pressure sensor according to another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor pressure sensor chip 2 Glass pedestal 3 Plastic package 4 Metal pipe 5 Lead 6 Wire 7 Cover 8 Metallization layer 9 Solder 10 Flat plate 11 Diaphragm 12 Strain gauge resistance 13 Overcoat 20 Wax 21 Through hole 22 Inner wall 30 Metallizing jig 31 Disc-shaped member 32 Metal wire 40 Resin substrate 51 Lower mold 52 Upper mold

Claims (4)

[Claims] 1. A semiconductor pressure sensor chip having a diaphragm formed thin by forming a concave portion, and a through hole for introducing pressure to the diaphragm are formed and joined to the semiconductor pressure sensor chip. A method of forming a metallized layer on a surface of the semiconductor pressure sensor having a pedestal and a surface of the pedestal that is not bonded to the semiconductor pressure sensor chip, the method comprising: forming a metallized layer on the pedestal of the through hole; A metallizing jig comprising a disc-shaped member having a shape larger than the opening shape and a thin wire-shaped member for fixing the disc-shaped member so as to be arranged corresponding to the arrangement of the through holes of the pedestal, With the disk-shaped member installed so as to close the opening of the through-hole, a metallized layer is formed by sputtering or vapor deposition from the side where the metallized layer is to be formed. A method for forming a metallized layer of a pedestal for a semiconductor pressure sensor. 2. The method for forming a metallized layer of a pedestal for a semiconductor pressure sensor according to claim 1, wherein said thin linear member is formed in a loop shape. 3. The method for manufacturing a metallizing jig according to claim 2, wherein a metal plate is attached to one surface of the resin substrate, and the metal plate is etched to substantially remove the disk-shaped member. Manufacturing a metallizing jig, wherein the jigs are formed at equal intervals, and then adjacent disk-shaped members are connected by loop-shaped thin line-shaped members, and then the resin substrate is peeled off. Method. 4. The method for manufacturing a metallizing jig according to claim 2, wherein the thin metal wires are arranged in a grid at substantially equal intervals, and the intersections of the thin metal wires are connected by welding and the welding is performed. A method for manufacturing a metallizing jig, comprising: crushing a portion into a flat plate shape; and deforming the thin metal wire into a loop by a mold.