JP2000216526A - Vacuum stencil printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid leaving unfilled parts and eliminate the bulk reducing trend of a resin filled layer by pushing and filling a part of a seal resin of an excessive supply layer into stencil holes, utilizing the air pressure difference. SOLUTION: A squeegee 5 is adjusted to locate above the top face of a stencil plate 3 with a space 7 required for excessively supplying between the stencil plate 3 top face and the squeegee 5. The squeegee 5 operation forms a resin excessive supply layer 8, including pass holes 6 on the stencil plate 3. After the push-filling of a seal resin 4 by the squeegee 5 operation. After the push-filling of the seal resin 4 in a vacuum atmosphere, the vacuum degree in the atmosphere is lowered to or near to the atmospheric pressure, thereby causing a pressure difference between unfilled parts and outside atmosphere. This pressure difference causes the seal resin 4 to be pushed into the unfilled parts, thus removing the unfilled parts, while the excessive resin layer 8 reduces its bulk to form recesses at regions above the pass holes 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a vacuum stencil printing method,
More specifically, the present invention relates to a vacuum stencil printing method which is useful when applied to resin sealing of an electronic component element in manufacturing an electronic component or supply and filling of a resin into a substrate hole portion in manufacturing a printed wiring board.

[0002]

2. Description of the Related Art The applicant of the present invention has previously proposed in Japanese Patent Publication No. 6-66350 a method of sealing a resin of an electronic component element by applying vacuum stencil printing means. According to this resin encapsulation method, a resin encapsulation layer that does not contain bubbles and does not lose its shape can be formed under fully automation, and high-quality, high-performance electronic components are manufactured under a consistent continuous line. Is possible,
It has attracted attention because it can contribute to improving the quality and performance of electronic components and reducing prices.

[0003]

The resin sealing method proposed by the present applicant has a structure in which the resin is sealed in a vacuum atmosphere, the pressure is once returned to normal pressure, and then the stencil is released. When returning to the above, the sealing resin layer inevitably has a tendency to decrease in volume. FIG. 10 is a schematic explanatory view exaggeratingly showing the situation immediately after the electronic component element b mounted on the substrate a is sealed with resin by applying vacuum stencil printing means. An unfilled portion f remains at the bottom of the sealed resin layer e.
It is considered that the unfilled portion f is generated due to insufficient filling pressure of the sealing resin. That is, generally, the press-filling of the sealing resin is performed by the operation of the squeegee g. However, the press-filling of the squeegee operation has a limited filling pressure, and the filling pressure is likely to be insufficient. It is considered something. When the unfilled portion f remains in the sealing resin layer e, when the pressure is returned from the vacuum atmosphere to the normal pressure, FIG.
As shown in FIG. 1, the sealing resin is pushed into the unfilled portion f by the pressure difference generated between the unfilled portion f and the outside air, and the unfilled portion f is erased. In this case, a recess h due to the decrease in volume occurs. This tendency to reduce the volume causes variations in the thickness of the resin sealing, and is not preferable.

[0004] The tendency to decrease in bulk can be temporarily solved by, for example, performing additional stencil printing to replenish the reduced volume after the pressure difference is filled and before the stencil is released. However,
For example when performing replenishment filled at atmospheric pressure, as shown in exaggerated in Figure 12, tends to unfilled portion f ₁ is generated between the resin filler layer e and supplemented filling portion e _1, the unfilled Part f ₁
Are left as voids and reduce the reliability of resin sealing. Also when performing replenishment filled than the vacuum degree during the filling in a vacuum atmosphere close to atmospheric pressure, as shown in FIG. 13, an unfilled portion f ₁ by a pressure difference filling is erased, bulk reduced tendency therefore concave h ₁ occurs Tokoro, which is not preferable.

[0005] Such a problem also occurs when a vacuum stencil printing means is applied to supply and fill a resin in a hole of a substrate to form a resin-filled layer in the manufacture of a printed wiring board.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vacuum printing method capable of preventing the unfilled portion from remaining and also eliminating the tendency of the resin-filled layer to decrease in bulk.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a vacuum stencil printing method applied to resin sealing of electronic component elements mounted on a substrate, wherein the squeegee is operated in a vacuum atmosphere to seal the squeegee. A step of filling and filling the sealing resin into the stencil through-hole portion while forming an excess supply layer of the sealing resin in a layer on the stencil, and pressing a part of the sealing resin of the excess supply layer into the stencil through-hole portion due to a pressure difference. A vacuum stencil printing method characterized by including a step of filling, and a step of removing the sealing resin of the excess supply layer remaining after the pressure difference filling from the top of the stencil, and then removing the stencil (hereinafter, the stencil printing method). 1 invention).

Further, the present invention relates to a vacuum stencil printing method applied to supply and filling of a resin into a hole in a printed wiring board, wherein a squeegee is operated in a vacuum atmosphere to transfer the resin to the hole in the stencil. Filling and filling an excess supply layer of the resin in a layered form on the stencil through the stencil through hole through the stencil through-hole through the stencil through-hole. And a step of removing the resin of the excess supply layer remaining after the pressure difference filling from the top of the stencil, and then removing the stencil, and a method of vacuum stencil printing (hereinafter, referred to as a second invention).

[0009]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 to 4 show an embodiment of the first invention of the present invention, and show an example in which the vacuum stencil printing method of the present invention is applied to resin sealing of an electronic component element 2 mounted on a substrate 1. I have.

FIG. 1 shows the situation immediately before the start of the press-filling step of the sealing resin. The press-filling step is performed in a vacuum atmosphere, and the sealing resin 4 supplied onto the stencil 3 is replaced by a squeegee 5.
Is pressed into the through hole 6 of the stencil 3 to be filled. The situation immediately after the indentation filling is shown in FIG.
An unfilled portion 9 remains at the bottom of.

In the present invention, when the sealing resin 4 is pushed into the stencil through-hole 6, it is necessary to supply the sealing resin 4 excessively so as to rise upward from the through-hole 6. . As shown in FIG. 1, the squeegee 5 is preliminarily adjusted so as to be positioned above the upper surface of the stencil 3, and a gap 7 necessary for excessive supply is provided between the upper surface of the stencil 3 and the squeegee 5. Is formed. Sealing resin 4 by squeegee 5 operation
After the indentation filling, an excess resin supply layer 8 including the through holes 6 is formed on the stencil 3.

After completion of the operation of injecting and filling the sealing resin in a vacuum atmosphere, the degree of vacuum in the atmosphere is reduced to atmospheric pressure or close to atmospheric pressure. Due to the decrease in the degree of vacuum, a pressure difference occurs between the unfilled portion 9 and the external atmosphere, and the sealing resin 4 is pushed toward the unfilled portion 9 due to the pressure difference, as shown in FIG. The unfilled portion 9 is deleted. On the other hand, in the area above the through hole 6, as shown in FIG.
The excess resin layer 8 is reduced in volume and a recess 10 is formed. It is necessary to stop this decrease in volume within the range of the thickness of the excess resin layer 8. The degree of bulk reduction can be predicted in advance by various conditions of stencil printing, and can be easily confirmed experimentally. The position of the squeegee 5 is adjusted based on the obtained data, and the size of the gap 7 and thus the thickness of the excess resin layer 8 are adjusted. May be set in advance.

After the pressure difference filling is completed, as shown in FIG. 4, the excess resin layer 8 remaining on the stencil 3 is slid or moved close to the scraping member 11 along the upper surface of the stencil 3. Actuation is removed, and at the same time, the upper surface of the resin-filled layer 4A formed in the through-hole portion 6 is flattened, and in this state, the stencil is removed according to a conventional method, without leaving the unfilled portion, In addition, resin sealing can be performed without a tendency to decrease in bulk.

FIGS. 5 to 8 show another embodiment of the first invention, except that the electronic component element 2 is mounted in the recess 12 of the substrate 1 with a gap 12a filled with a sealing resin around. Is not substantially different from the previous embodiment. In this case, as shown in FIG.
Occurs at the bottom of a. 5 corresponds to FIG. 1, FIG. 6 corresponds to FIG. 2, FIG. 7 corresponds to FIG. 3, and FIG. 8 corresponds to FIG. 4, respectively. The unfilled portion 9 can be erased without causing a tendency of the resin-filled layer 4A (see FIG. 8) to decrease in volume.

FIGS. 9A to 9E show an embodiment of the second invention of the present invention, in which the vacuum stencil printing method of the present invention is applied to a hole in a printed wiring board 13, for example, a through-hole (or a via-hole) 14. An example of the case where the present invention is applied to the supply and filling of the resin 15 into a substrate is shown in the order of steps.

FIG. 9 (a) schematically shows the situation at the time of starting the filling of the resin 15. Since the through hole 14 is a through hole, its lower end opening 14a is previously provided with an easily peelable closing member, for example, an adhesive tape 16 Apply and sealed. Sealing of the lower end opening 14a of the through hole 14 is necessary for filling the pressure difference.

In the state shown in FIG. 9A, after aligning the through hole 18 of the stencil 17 with the through hole 14, the squeegee 19 is operated in a vacuum atmosphere to remove the liquid resin 15 from the stencil through hole. From 18, the material is pushed into the through hole 14 communicating therewith and filled. The state after the filling is shown in FIG. 9B, and the unfilled part 20 remains at the bottom of the through hole 14.

In the present invention, the resin 15 is pushed and filled into the through-hole 14 when the resin 15 is filled with the stencil hole 17.
It is necessary to oversupply so that it rises upward from the top. The squeegee 19 is preliminarily adjusted so as to be positioned above the upper surface of the stencil 17 as shown in FIG. 9A, and the space required for excess supply is provided between the upper surface of the stencil 18 and the squeegee 19. 21 are formed. Squeegee 19
After the resin 15 is pushed and filled by the operation, the resin excess supply layer 22 including the through hole 18 is formed on the stencil 17.
Are formed. After the press-filling operation of the resin 15 in the vacuum atmosphere is completed, the degree of vacuum in the atmosphere is reduced to the atmospheric pressure or close to the atmospheric pressure. Due to this decrease in the degree of vacuum, a pressure difference occurs between the unfilled portion 20 and the external atmosphere, and the resin 15 is pushed toward the unfilled portion 20 due to the pressure difference, as shown in FIG. , Unfilled part 20
Is deleted. On the other hand, in the region above the stencil hole 18, as shown in FIG. 9C, the excess resin layer 22 is reduced in volume and a recess 23 is formed. It is necessary to stop this reduction in volume within the range of the thickness of the excess resin layer 22. The degree of bulk reduction can be predicted in advance by various conditions of vacuum stencil printing, and can be easily confirmed experimentally. The position of the squeegee 19 is adjusted based on the obtained data, and the size of the gap 21 and thus the excess resin layer 22 are adjusted. The thickness may be set in advance.

After the pressure difference filling is completed, the excess resin layer 22 remaining on the stencil 17 is slid along the upper surface of the stencil 17 from the state of FIG. The scraping member 11 (see FIGS. 4 and 8) which is moved in proximity is actuated and removed, and then the stencil is removed in accordance with a conventional method, so that the resin is placed in the through hole 14 as shown in FIG. The filling layer 15A can be formed, and after the resin filling layer 15A is formed, the adhesive tape 16 is peeled off as shown in FIG. The resin-filled layer 15 thus formed
A does not contain an unfilled portion, has no bulk reduction, and has high quality and high performance.

In the second invention, the term “printed wiring board” refers to not only a printed wiring board applied to the manufacture of printed wiring boards (including single-sided, double-sided, and multilayer) but also semiconductor devices, chip components, and the like. Includes all printed wiring boards applied to the manufacture of IC cards and memory cards, the manufacture of coil boards, and the like. The substrate hole includes not only a through hole and a via hole but also a hole having a relatively large opening area formed on a substrate, which is observed when a package is manufactured.

In the present invention, the degree of vacuum during stencil printing is:
From the viewpoint of not allowing air bubbles to remain, any of low, medium, and high vacuum levels may be used. Since it may cause the efficiency to decrease, the degree of vacuum is low, for example, 0.01 to 30 torr, preferably 0.1 to 10 torr, more preferably 0.1 to 5 torr.
It is sufficient to maintain a low vacuum of about rr. By the way, if the degree of vacuum is lower than 30 torr and it is too close to normal pressure, bubbles may be generated in the resin filled layer,
Not preferred.

Reduction of the degree of vacuum in a vacuum atmosphere after vacuum stencil printing is usually performed by releasing the vacuum atmosphere to the atmosphere and lowering the pressure to the atmospheric pressure. However, the reduction to the atmospheric pressure is not always necessary. The degree of vacuum may be reduced so that a pressure difference of at least about 30 torr, for example, about 30 to 60 torr is generated between the degree of vacuum at the time of stencil printing. If the pressure difference does not reach 30 torr, the effect of injecting and filling the resin and the effect of erasing the unfilled portion become insufficient, which is not preferable.

The resin applied to the resin sealing of the electronic component element and the supply and filling into the hole of the substrate are in a liquid state, and various known compositions can be applied. The viscosity can be selected from a wide range, and is usually appropriately selected and determined from a range of about 200 to 2000 poise. Generally speaking, relatively high-viscosity resin is applied for filling holes having a relatively large opening area and low depth, while filling holes having a relatively small opening area and high depth is used. A resin having a relatively low viscosity may be used.

The thickness of a stencil applied to vacuum stencil printing is as follows:
There is no particular limitation. For example, a stencil used for filling a resin into a hole in a substrate such as a through hole is preferably as thin as possible, and suitably about 0.01 to 3.0 mm.

The operation of removing the excess supply layer and the operation of removing the stencil need not necessarily be performed under atmospheric pressure. For example, when the pressure difference filling is performed in a vacuum atmosphere, the above-described removal and the stencil removal operation are performed after the pressure difference filling. After that, the pressure may be returned to the atmospheric pressure.

[0026]

The present invention can provide a vacuum stencil printing method capable of preventing the remaining of the unfilled portion as well as eliminating the tendency of the sealing resin layer or the filled resin layer to decrease in bulk.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the first invention of the present invention, and is an explanatory view schematically showing a situation at the start of a resin sealing step.

FIG. 2 is an explanatory view schematically showing a situation immediately after the completion of a resin sealing step.

FIG. 3 is an explanatory view schematically showing a situation at the time of filling a pressure difference.

FIG. 4 is an explanatory view schematically showing a state where an excess supply layer is removed.

FIG. 5 is a view showing another embodiment of the first invention, corresponding to FIG. 1;

FIG. 6 is a diagram corresponding to FIG. 2;

FIG. 7 is a diagram corresponding to FIG. 3;

FIG. 8 is a diagram corresponding to FIG. 4;

FIG. 9 is an explanatory view showing one embodiment of the second invention of the present invention in the order of steps.

FIG. 10 is an explanatory diagram showing a state of occurrence of an unfilled portion.

FIG. 11 is an explanatory diagram of a pressure difference filling.

FIG. 12 is an explanatory diagram in the case where refilling is performed under atmospheric pressure.

FIG. 13 is an explanatory diagram in the case where refilling is performed in a vacuum atmosphere.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 substrate 2 electronic component element 3 stencil 4 sealing resin 5 squeegee 6 through hole 7 interval 8 excess supply layer 9 unfilled portion 10 recess 11 rubbing member 12 recess 13 wiring board 14 through hole 15 resin 16 adhesive tape 17 stencil Reference Signs List 18 through hole 19 squeegee 20 unfilled part 21 interval 22 excess supply layer 23 recess

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[Procedure amendment]

[Submission date] May 2, 2000 (2005.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

SUMMARY OF THE INVENTION The present invention relates to a vacuum stencil printing method applied to resin sealing of electronic component elements mounted on a substrate, wherein the squeegee is operated in a vacuum atmosphere to seal the squeegee. A step of filling and filling the sealing resin into the stencil through-hole portion while forming an excess supply layer of the sealing resin in a layer on the stencil, and pressing a part of the sealing resin of the excess supply layer into the stencil through-hole portion due to a pressure difference. filling, and sealing resin oversupply layer remaining after pressure difference filling removed from the stencil, then the step of releasing the stencil includes a raw by air pressure difference filling
Of the excess supply layer within the range of the thickness of the excess supply layer
The thickness is set so that
The present invention relates to a stencil printing method (hereinafter, referred to as a first invention).

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Further, the present invention relates to a vacuum stencil printing method applied to supply and filling of a resin into a hole in a printed wiring board, wherein a squeegee is operated in a vacuum atmosphere to transfer the resin to the hole in the stencil. Through the stencil and press-filling the excess supply layer of resin into the substrate hole through the stencil through-hole through the stencil through hole to fill to process, and the resin of the over-supply layer remaining after pressure difference filling removed from the stencil, then the step of releasing the stencil includes a, air pressure difference filling
The decrease in the volume of the excess supply layer caused by the
The thickness is set to be within the range of
The present invention relates to a vacuum stencil printing method (hereinafter referred to as a second invention).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

In the present invention, the degree of vacuum during stencil printing is:
From the viewpoint of not allowing air bubbles to remain, any of low, medium, and high vacuum levels may be used. Since there is a possibility that the efficiency may be reduced, a low vacuum degree, for example, 1.33 to 3990P
a , preferably a low vacuum of about 13.3 to 1330 Pa , more preferably about 13.3 to 665 Pa is sufficient. Incidentally, if the degree of vacuum is lower than 3990 Pa and the pressure is too close to normal pressure, bubbles may be generated in the resin-filled layer, which is not preferable.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

Reduction of the degree of vacuum in a vacuum atmosphere after vacuum stencil printing is usually performed by releasing the vacuum atmosphere to the atmosphere and lowering it to the atmospheric pressure. However, the reduction to the atmospheric pressure is not always necessary. At least about 3990 Pa , for example, between 3990 and 79
The degree of vacuum may be reduced so that a pressure difference of about 80 Pa is generated. If the pressure difference does not reach 3990 Pa , the effect of injecting and filling the resin and the effect of erasing the unfilled portion become insufficient, which is not preferable.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

The resin applied to the resin sealing of the electronic component element and the supply and filling into the hole of the substrate are in a liquid state, and various known compositions can be applied. The viscosity can be selected from a wide range, and is usually appropriately selected and determined from a range of about 20 to 200 Pa · s . Generally speaking, relatively high-viscosity resin is applied for filling holes having a relatively large opening area and low depth, while filling holes having a relatively small opening area and high depth is used. A resin having a relatively low viscosity may be used.

Continued on the front page F term (reference) 5E314 AA24 BB06 CC06 DD05 FF01 FF08 GG15 GG26 5F061 AA01 BA04 CA12 DE06

Claims (4)

[Claims] 1. A vacuum stencil printing method applied to resin sealing of an electronic component element mounted on a substrate, wherein a squeegee is actuated in a vacuum atmosphere to bring sealing resin into a stencil through-hole. Press-filling while forming an excess supply layer of the sealing resin in a layer on the stencil; pressing and filling a part of the sealing resin of the excess supply layer into the stencil through-hole portion due to a pressure difference; A method of vacuum stencil printing, comprising the steps of: removing a sealing resin of an excess supply layer remaining after the stencil from the stencil; and subsequently removing the stencil. 2. A vacuum stencil printing method applied to supplying and filling a resin into a hole in a printed wiring board, wherein a squeegee is operated in a vacuum atmosphere to allow the resin to pass through the stencil through hole into the substrate hole. Step of press-filling while forming an excess supply layer of resin on the stencil while forming a layer on the stencil; step of filling a portion of the resin of the excess supply layer into the substrate hole through the stencil hole through a pressure difference; Removing the resin of the excess supply layer remaining after filling from the stencil, and then removing the stencil. 3. The vacuum stencil printing method according to claim 1, wherein the degree of vacuum in the vacuum atmosphere in the press-filling step is 0.01 to 30 torr. 4. The vacuum stencil printing method according to claim 1, wherein the pressure difference filling is performed under a pressure difference of at least 30 torr.