JPH1093383A - Surface acoustic wave device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive surface acoustic wave device with a high reliability. SOLUTION: A surface acoustic wave device pattern 2 is formed on a piezoelectric substrate 1, and an enclosing wall 3 and a cover 4 are made by using a different resin so as to surround a part through which a surface acoustic wave is propagated. The element configured as above is connected to a lead frame 5 and sealed by sealing resins 6, 7. Through the constitution above, the inexpensive surface acoustic wave device is obtained with high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for packaging a surface acoustic wave device used for communication equipment and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, packaging of a surface acoustic wave device of this type generally requires a metal package, a laminated ceramic package, or the like.

[0003]

However, the metal package, the laminated ceramic package, and the like applied to the conventional surface acoustic wave device are very expensive packages.

[0004] It is an object of the present invention to provide a surface acoustic wave device having an inexpensive and highly reliable package.

[0005]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides an enclosing wall surrounding at least one surface acoustic wave device pattern formed on a piezoelectric substrate, an enclosing wall and a surface acoustic wave device pattern. In which the surrounding wall and the lid are formed of different materials. Thus, a surface acoustic wave device having an inexpensive and highly reliable package can be obtained.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides an enclosing wall surrounding at least one surface acoustic wave device pattern formed on a piezoelectric substrate, and an enclosing wall and a surface acoustic wave device pattern. It has a lid that covers the upper space,
This is a surface acoustic wave device in which the surrounding wall and the lid are made of different materials. By doing so, the restrictions on material selection are reduced as compared with the case where the surrounding wall and the lid are made of the same material, and Since a material having high mechanical strength can be used for the body, a highly reliable surface acoustic wave device can be obtained.

According to a second aspect of the present invention, the surrounding wall is made of a material having photosensitivity and developed by an organic solvent, and the lid is made of a material having photosensitivity and developed by an alkaline solution. This makes it possible to prevent the electrodes from being damaged in the developing step during the manufacturing process and to reduce the cost by using an inexpensive alkaline solution.

According to a third aspect of the present invention, there is provided a surface acoustic wave device in which the surrounding wall is made of a photosensitive material and the lid is made of a non-photosensitive material. It is possible to improve the mechanical strength by increasing the thickness of the lid without taking into account the restrictions on the thickness of the lid associated with the photolithography process, and a highly reliable surface acoustic wave device can be obtained.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a surface acoustic wave device, wherein a laser beam is used for processing a lid. It is possible to use a conductive material, eliminate the restriction on the thickness of the lid, improve the mechanical strength by increasing the thickness of the lid, and obtain a highly reliable surface acoustic wave device.

According to a fifth aspect of the present invention, there is provided a surface acoustic wave device characterized in that the material of the lid is made of a material having a higher Young's modulus than the material of the surrounding wall. Increasing the size prevents the roof from being deformed by its own weight and coming into contact with the comb-shaped electrodes, thereby deteriorating the device characteristics. Therefore, unnecessary surface acoustic waves are attenuated, so that a surface acoustic wave device having high reliability and excellent characteristics can be obtained.

The invention according to claim 6 of the present invention is a surface acoustic wave device characterized in that the material of the lid is a photosensitive resin containing a filler having a Young's modulus greater than that of the base resin. By doing so, the Young's modulus of the lid is increased and the lid is easily processed using photolithography, so that a highly reliable and inexpensive surface acoustic wave device can be obtained.

[0012] The invention according to claim 7 of the present invention is a surface acoustic wave device characterized in that the filler is talc. By doing so, the Young's modulus of the lid can be increased at low cost and reliability can be improved. And a low-cost surface acoustic wave device can be obtained.

According to an eighth aspect of the present invention, there is provided a surrounding wall surrounding at least one surface acoustic wave device pattern formed on a piezoelectric substrate, and a lid covering a space above the surrounding wall and the surface acoustic wave device pattern. A support member made of a material having a smaller coefficient of thermal expansion than the cover member on the cover so that one of the support members is located above the surrounding wall and the other is located above the surface acoustic wave device pattern. The surface acoustic wave device is characterized in that the stress caused by the difference in the coefficient of thermal expansion between the lid and the support material when the environmental temperature rises, The surface acoustic wave device is prevented from deteriorating due to the contact between the expanded lid and the surface acoustic wave device pattern, which occurs in the direction of lifting upward, and a highly reliable surface acoustic wave device can be obtained.

According to a ninth aspect of the present invention, there is provided a surface acoustic wave device characterized in that the material of the supporting material is a photosensitive resin containing a filler having a smaller coefficient of thermal expansion than the material of the lid. By doing so, the shape can be processed using photolithography, and a support material having a smaller thermal expansion coefficient than the lid can be realized, and a highly reliable surface acoustic wave device can be obtained.

According to a tenth aspect of the present invention, there is provided a surface acoustic wave device characterized in that the filler of the support material is talc. In this way, the shape can be processed by photolithography. In addition, a support member having a smaller coefficient of thermal expansion than the lid can be realized at low cost, and a highly reliable and inexpensive surface acoustic wave device can be obtained.

According to an eleventh aspect of the present invention, there is provided a surrounding wall made of resin surrounding at least one surface acoustic wave device pattern formed on a piezoelectric substrate, and a space above the surrounding wall and the surface acoustic wave device pattern. A metal film is provided on the outer surface of the lid and the surrounding wall, and a cross-shaped gap is provided in at least a part of the metal film positioned above the surface acoustic wave device pattern. A surface acoustic wave device characterized by grounding,
By doing so, when the environmental temperature rises, stress due to the difference in thermal expansion coefficient between the lid and the metal film is generated in a direction in which the lid is pulled upward, and the expanded lid and the elastic surface The characteristics of the surface acoustic wave device are prevented from deteriorating due to the contact of the wave device pattern, and the grounded metal film has the function of an electromagnetic shield. A surface acoustic wave device can be obtained.

According to a twelfth aspect of the present invention, a chip, which is a unit element composed of a surface acoustic wave device pattern formed on a piezoelectric substrate, an enclosing wall and a lid, is bonded to a lead frame, and a wire is formed. After making electrical connection by bonding, a first region covering at least the surrounding wall and the lid around the chip and the wire bonding portion, and a second region provided so as to cover at least the first region and the wire bonding metal fine wire. A surface acoustic wave device which is divided into two regions and covers the first region with an injection pressure lower than the injection pressure of the resin covering the second region. Thereby, the injection pressure of the resin applied to the surrounding wall and the lid is reduced, and the deformation of the surrounding wall and the lid due to the applied injection pressure is prevented,
Deterioration of device characteristics due to contact between the surface of the surface acoustic wave chip and the lid can be prevented.

According to a thirteenth aspect of the present invention, a region covered with the resin is provided so as to cover at least the first region covering the surrounding wall and the lid and the second region provided so as to cover at least the first region. The surface acoustic wave device is characterized in that the resin covering the first region and the resin covering the second region are made of different materials. The most suitable material can be selected for the resin to cover the lid to prevent the deformation of the lid and the resin to mold the entire device, and a highly reliable surface acoustic wave device can be obtained.

According to a fourteenth aspect of the present invention, there is provided a surface acoustic wave device wherein the first region is covered with a resin harder than a resin forming the surrounding wall and a resin forming the lid. By doing so, the deformation of the surrounding wall and the lid due to the injection pressure of the resin covering the second region is prevented, and the device characteristics due to the contact between the surface of the surface acoustic wave chip and the lid are reduced. Deterioration can be prevented.

According to a fifteenth aspect of the present invention, the first aspect
Is a method for manufacturing a surface acoustic wave device, characterized in that the coating of the area is performed by potting, whereby the coating of the first area can be performed easily and without applying injection pressure, and the surrounding wall and Deformation of the lid can be prevented, and deterioration of device characteristics due to contact between the surface of the surface acoustic wave chip and the lid can be prevented.

According to a sixteenth aspect of the present invention, the first aspect
A method for manufacturing a surface acoustic wave device, characterized in that the coating of the first region is performed by spraying with a spray, whereby the coating of the first region can be performed easily and without applying injection pressure. Deformation of the wall and the lid can be prevented, and deterioration of device characteristics due to contact between the surface of the surface acoustic wave chip and the lid can be prevented.

Next, a specific example of the present invention will be described with reference to the drawings. (Embodiment 1) FIGS. 1 and 2 are sectional views of an embodiment of a surface acoustic wave device according to the present invention. Here, the manufacturing process is shown in the order of FIGS. 1A to 1D and FIG.
First, as shown in FIG. 1A, a surface acoustic wave device pattern 2 of aluminum or an aluminum alloy is formed on a piezoelectric substrate 1 of lithium niobate, lithium tantalate, quartz, or the like. Next, as shown in FIG. 1B, an enclosing wall 3 is formed in a portion surrounding the portion where the surface acoustic wave propagates and excluding a portion of the bonding pad from which an electric signal is extracted. The formation is performed using photolithography, and a surface acoustic wave device pattern 2 of an aluminum alloy is formed.
In order not to damage the surrounding wall, a photosensitive resin which is developed with an organic solvent is used as a material of the surrounding wall 3, and an organic solvent is used as a developer. Subsequently, as shown in FIG. 1C, a lid 4 is formed to cover the surrounding wall 3 and a space above a portion where the surface acoustic wave propagates. A photosensitive resin sheet developed with an alkaline solution is used for the lid 4, and an alkaline solution is used for the developing solution. Here, the use of the alkaline solution is intended to reduce the production cost.

A plurality of chips, each of which is a unit element composed of the surface acoustic wave device pattern 2, the surrounding wall 3, and the lid 4, are formed on the surface of the piezoelectric substrate 1 as described above. After that, as shown in FIG. 1D, the chip and the wire bonding portion are sealed with a sealing resin 6 after bonding to a lead frame 5 and making electrical connection by wire bonding. In order to prevent the device characteristics from deteriorating due to deformation of the surrounding wall 3 and the lid 4, a resin having a low viscosity is used as the sealing resin 6, and the resin is sealed at a low injection pressure. Subsequently, as shown in FIG.
The periphery of the sealing resin 6 is sealed with a sealing resin 7 having a higher viscosity than the sealing resin 6. The injection of the sealing resin 7 is performed at a higher pressure than when sealing with the sealing resin 6. Here, even if the injection pressure is increased, the surrounding wall 3 and the lid 4 are not deformed, so that a sealing resin having poor moldability can be used, and the range of material selection for device protection and cost reduction can be used. Spreads.

Conventionally, the surface acoustic wave device could not be sealed with resin. However, with the structure of the present invention, resin sealing can be performed, and an inexpensive surface acoustic wave device can be obtained.

(Embodiment 2) FIG. 3 is a sectional view of a surface acoustic wave device according to a second embodiment of the present invention. Here, the manufacturing process is shown in the order of (a) to (e). First, as shown in FIG. 3A, a surface acoustic wave device pattern 2 of aluminum or an aluminum alloy is formed on a piezoelectric substrate 1 of lithium niobate, lithium tantalate, quartz or the like. Next, as shown in FIG. 3B, the surrounding wall 3 surrounds the portion where the surface acoustic wave propagates and the portion where the bonding pad portion for extracting the electric signal is removed is removed.
To form The formation is performed using photolithography,
In order not to damage the surface acoustic wave device pattern 2 made of an aluminum alloy, a photosensitive resin developed with an organic solvent is used as a material of the surrounding wall 3 and an organic solvent is used as a developing solution.
Subsequently, as shown in FIG. 3C, a lid 4 is formed to cover the surrounding wall 3 and the space above the portion where the surface acoustic wave propagates. A photosensitive resin sheet developed with an alkaline solution is used for the lid 4, and an alkaline solution is used for the developing solution. Here, the use of the alkaline solution is intended to reduce the production cost.

After dicing the plurality of chips formed on the surface of the piezoelectric substrate 1 as described above and separating them into individual chips, the chips are bonded to the lead frame 5 as shown in FIG. After the electrical connection is made, the sealing resin 8 is applied around the element and the wire bonding portion by using a spray. As the material of the sealing resin 8, a resin whose hardness after curing is harder than the resin forming the surrounding wall and the resin forming the lid body is used. This can prevent the device characteristics from deteriorating due to the deformation of the surrounding wall 3 and the lid 4. Subsequently, as shown in FIG. 3E, the periphery of the element is sealed with a sealing resin 7.

Conventionally, the surface acoustic wave device could not be sealed with resin. However, with the configuration of the present invention, resin sealing can be performed, and an inexpensive surface acoustic wave device can be obtained.

(Embodiment 3) FIG. 4 is a sectional view of a surface acoustic wave device according to a third embodiment of the present invention. Here, the manufacturing process is shown in the order of (a) to (e). First, FIGS. 4A and 4B are performed in the same manner as in FIGS. 1A and 1B and FIGS. 3A and 3B described in the first and second embodiments. FIG. 4C shows a lid 4 that covers the surrounding wall 3 and a space above the portion where the surface acoustic wave propagates, and a non-photosensitive resin sheet is used for the lid 4. A laser beam 9 is used for cutting unnecessary portions of the lid 4. It is difficult to make the lid 4 thick when using photolithography due to the restriction on the patterning accuracy at the time of exposure. However, the lid 4 can be easily processed by processing the lid 4 using a laser beam 9.
Can be made thicker.

As described above, a plurality of chips on the surface of the piezoelectric substrate 1 are diced and separated into individual chips. Then, as shown in FIG. 4D, the chips are bonded to a lead frame 5 and electrically connected by wire bonding. After the connection is established, the periphery of the chip and the wire bonding portion is potted using the sealing resin 10. By performing potting, a thick sealing resin region can be provided around the chip and the wire bonding portion without applying stress to the surrounding wall 3 and the lid 4. As the material of the sealing resin 10, a resin whose hardness after curing is harder than the resin forming the surrounding wall and the resin forming the lid body is used. This can prevent the device characteristics from deteriorating due to the deformation of the surrounding wall 3 and the lid 4. Subsequently, the periphery of the chip is sealed with a sealing resin 7 as shown in FIG.

Conventionally, the surface acoustic wave device could not be sealed with resin. However, with the structure of the present invention, resin sealing can be performed, and an inexpensive surface acoustic wave device can be obtained.

(Embodiment 4) FIG. 5 shows a configuration diagram of a surface acoustic wave device according to a fourth embodiment of the present invention. Here, a surface acoustic wave device pattern 2 made of aluminum or an aluminum alloy is provided on a piezoelectric substrate 1 made of lithium niobate, lithium tantalate, quartz, or the like. An enclosing wall 3 made of a photosensitive resin is provided in a portion where a portion of a bonding pad for extracting a signal is removed, and a lid 4 is provided to cover a space above a portion where a surface acoustic wave propagates. A filler 11 having a larger Young's modulus than a photosensitive resin typified by talc [Mg ₃ (Si ₄ O ₁₀ ) (OH) ₂ ] or silicon oxide [SiO ₂ ] is mixed into the lid 4 and only the photosensitive resin is used. The Young's modulus of the lid 4 is made larger than when it is formed. By making the Young's modulus of the lid 4 larger than that of the surrounding wall 3, the lid 4 is prevented from being deformed by its own weight and coming into contact with the surface acoustic wave device pattern 2 to degrade the device characteristics. The effect of reducing stress caused by the difference in thermal stress between the lid 4 and the piezoelectric substrate 1 and attenuating unnecessary surface acoustic waves can be obtained.

The device chip configured as described above is electrically connected to the extraction electrode 12 using a thin metal wire for wire bonding, and hermetically sealed by the package 13.

Conventionally, in the case of a large-sized surface acoustic wave device, there has been a case where a device characteristic defect occurs due to deformation of the lid. However, according to the configuration of the present invention, deformation of the lid is prevented and a highly reliable surface acoustic wave is obtained. Device is obtained.

(Embodiment 5) FIG. 6 shows a configuration diagram of a surface acoustic wave device according to a fifth embodiment of the present invention. Here, a surface acoustic wave device pattern 2 made of aluminum or an aluminum alloy is provided on a piezoelectric substrate 1 made of lithium niobate, lithium tantalate, quartz, or the like. An enclosing wall 3 made of a photosensitive resin and a lid 4 made of a photosensitive resin that covers a space above a portion where a surface acoustic wave propagates are provided in a portion where a portion of a bonding pad for extracting a signal is removed. Further, a support member 14 is provided on the lid such that one of the support members 14 is located above the surrounding wall 3 and the other is located above the surface acoustic wave device pattern 2. Support material 14
Is mixed with a filler 11 having a smaller thermal expansion coefficient than a photosensitive resin represented by talc [Mg ₃ (Si ₄ O ₁₀ ) (OH) ₂ ] or silicon oxide [SiO ₂ ]. The coefficient of thermal expansion is made smaller than that formed when Lid 4
When the environmental temperature rises by making the thermal expansion coefficient of the supporting member 14 smaller than that of the supporting member 14, the stress caused by the difference in the thermal expansion coefficient between the lid 4 and the supporting member 14 causes the central portion of the lid 4 to move upward. The central portion of the lid 4 bulges upward in the direction in which the surface acoustic wave device is raised, and the deterioration of the characteristics of the surface acoustic wave device due to the contact between the expanded lid 4 and the surface acoustic wave device pattern 2 is prevented.

The device chip configured as described above is electrically connected to the extraction electrode 12 using a thin metal wire for wire bonding, and hermetically sealed by the package 13.

Conventionally, in a surface acoustic wave device, the thermal expansion of the lid may cause contact between the lid and the surface acoustic wave device pattern, resulting in poor device characteristics. The contact of the surface acoustic wave device pattern is prevented, and a highly reliable surface acoustic wave device can be obtained.

(Embodiment 6) FIG. 7 shows a configuration diagram of a surface acoustic wave device according to a sixth embodiment of the present invention. Here, a surface acoustic wave device pattern 2 made of aluminum or an aluminum alloy is provided on a piezoelectric substrate 1 made of lithium niobate, lithium tantalate, quartz, or the like. An enclosing wall 3 made of a photosensitive resin and a lid 4 made of a photosensitive resin that covers a space above a portion where a surface acoustic wave propagates are provided in a portion where a portion of a bonding pad for extracting a signal is removed. Further, a metal film 15 such as aluminum is provided on the outer surfaces of the lid 4 and the surrounding wall 3, and a cross-shaped gap is provided in a portion of the metal film 15 located above the surface acoustic wave device pattern 2. Then, at least one portion of the metal film 15 is connected to the ground electrode of the surface acoustic wave device pattern 2.

In this way, when the environmental temperature rises, a stress due to the difference in the coefficient of thermal expansion between the lid 4 and the metal film 15 is generated in a direction in which the central portion of the lid 4 is pulled upward. The cover 4 at the portion where the cross-shaped gap is provided swells upward, and the expanded cover 4 and the surface acoustic wave device pattern 2
This prevents characteristic deterioration of the surface acoustic wave device due to contact with the surface. Further, since the grounded metal film 15 has a function of an electromagnetic shield, unnecessary radiation of electromagnetic waves can be reduced. Here, the width of the cross-shaped gap is sufficiently narrower than the wavelength of the radio wave at the operating frequency of the device, thereby preventing the gap from impairing the shielding effect.

The device chip configured as described above is electrically connected to the extraction electrode 12 using a thin metal wire for wire bonding, and hermetically sealed by the package 13.

Conventionally, in the surface acoustic wave device, the thermal expansion of the lid may cause contact between the lid and the surface acoustic wave device pattern, resulting in poor device characteristics. The surface acoustic wave device pattern is prevented from contacting, and the electromagnetic shielding, which used to be a package that hermetically seals the surface acoustic wave device, can now be performed on the device chip, so the package can be reduced in cost and reliable. A highly reliable and inexpensive surface acoustic wave device can be obtained.

[0041]

As described above, according to the present invention, a surface acoustic wave device having a small, inexpensive and highly reliable package can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a surface acoustic wave device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a final shape of the surface acoustic wave device according to the embodiment of FIG. 1 according to the present invention;

FIG. 3 is a sectional view of a surface acoustic wave device according to a second embodiment of the present invention;

FIG. 4 shows a third example of the surface acoustic wave device according to the present invention.
Sectional view according to the embodiment of the present invention.

FIG. 5 shows a fourth surface acoustic wave device according to the present invention.
Configuration diagram according to an embodiment

FIG. 6 shows a fifth example of the surface acoustic wave device according to the present invention.
Configuration diagram according to an embodiment

FIG. 7 shows a sixth embodiment of the surface acoustic wave device according to the present invention.
Configuration diagram according to an embodiment

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 piezoelectric substrate 2 surface acoustic wave device pattern 3 surrounding wall 4 lid 5 lead frame 6, 7, 8, 10 sealing resin 9 laser beam 11 filler 12 extraction electrode 13 package 14 support material 15 metal film

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takashi Okada 1006 Kadoma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (16)

[Claims] An enclosure that surrounds at least one surface acoustic wave device pattern formed on a piezoelectric substrate; and a lid that covers a space above the enclosure wall and the surface acoustic wave device pattern. A surface acoustic wave device in which a wall and the lid are made of different materials. 2. The method according to claim 1, wherein the surrounding wall is made of a material having photosensitivity and developed by an organic solvent, and the lid is made of a material having photosensitivity and developed by an alkaline solution. Surface acoustic wave device. 3. The surface acoustic wave device according to claim 1, wherein the surrounding wall is made of a photosensitive material, and the lid is made of a non-photosensitive material. 4. The method for manufacturing a surface acoustic wave device according to claim 3, wherein a laser beam is used for processing the lid. 5. The surface acoustic wave device according to claim 1, wherein the material of the lid is made of a material having a higher Young's modulus than the material of the surrounding wall. 6. The surface acoustic wave device according to claim 5, wherein the material of the lid is a photosensitive resin containing a filler having a Young's modulus greater than that of the base resin. 7. The surface acoustic wave device according to claim 6, wherein the filler is talc. 8. An enclosing wall surrounding at least one surface acoustic wave device pattern formed on a piezoelectric substrate, and a lid covering a space above the enclosing wall and the surface acoustic wave device pattern; A support made of a material having a smaller coefficient of thermal expansion than the lid was provided on the body so that one of the supports was above the surrounding wall and the other was above the surface acoustic wave device pattern. A surface acoustic wave device characterized by the above-mentioned. 9. The surface acoustic wave device according to claim 8, wherein the material of the supporting material is a photosensitive resin containing a filler having a smaller coefficient of thermal expansion than the material of the surrounding wall. 10. The surface acoustic wave device according to claim 9, wherein the filler is talc. 11. At least one of the piezoelectric substrates formed on a piezoelectric substrate
An enclosing wall made of resin surrounding two surface acoustic wave device patterns, and a lid made of resin covering an upper space of the enclosing wall and the surface acoustic wave device pattern, and outer surfaces of the lid and the enclosing wall A surface acoustic wave device, wherein a cross-shaped gap is provided in at least a part of the metal film located above the surface acoustic wave device pattern, and the metal film is grounded. 12. The surface acoustic wave device according to claim 1 is adhered to a lead frame, and after electrical connection is established by wire bonding, the periphery of the piezoelectric substrate, the surrounding wall, the lid, and the wire bonding portion. A first region covering at least the surrounding wall and the lid, and a second region provided so as to cover at least the first region and the thin metal wire for wire bonding.
A method for manufacturing a surface acoustic wave device, comprising: injecting and covering the first region with the resin at an injection pressure lower than the injection pressure of the resin that covers the region. 13. A region covered with the resin is divided into a first region covering at least the surrounding wall and the lid, and a second region provided so as to cover at least the first region. The resin covering the first region and the second resin
13. The surface acoustic wave device according to claim 12, wherein the resin covering the region is made of a different material. 14. The surface acoustic wave device according to claim 13, wherein the first region is covered with a resin harder than a resin forming the surrounding wall and a resin forming the lid. 15. The method for manufacturing a surface acoustic wave device according to claim 13, wherein the coating of the first region is performed by potting. 16. The method for manufacturing a surface acoustic wave device according to claim 13, wherein the coating of the first region is performed by spraying.