JP5483921B2 - Method for manufacturing printed circuit board - Google Patents

Description

  The present invention relates to a method for manufacturing a printed circuit board, and more particularly to a method for manufacturing a double-sided or multilayer thin printed circuit board formed by a so-called single plate pressing method (transfer method).

Recently, various electric and electronic devices are rapidly becoming smaller, thinner, lighter, and multifunctional, and these trends are also increasing in the number of circuit boards incorporated in such electric and electronic devices. Thinning and miniaturization of circuits formed on a substrate are required.
Therefore, as a method for ensuring interlayer connection between the double-sided substrates, connecting particles made of a conductive material are placed in through holes (vias) formed in an insulating base material, and a conductive member is superimposed on both sides of the insulating material and heated and heated. There is known a double-sided printed circuit board in which a material for a double-sided printed circuit board is formed by electrically connecting the conductive members to form a circuit pattern on the conductive member. (Patent Document 1).

JP 2007-35716 A

  However, in the method for producing a printed circuit board disclosed in Patent Document 1, it is necessary to arrange fine connection particles of about 50 to 200 μm at each of the through-hole positions to be formed in advance on the insulating base material. Requires advanced technology. Further, even if a thin double-sided printed board material is formed using connecting particles, a circuit pattern is formed on the conductive member after that, so that the thickness of the entire printed board is increased by the height of the circuit pattern.

In addition, as described above, it is difficult to form a through hole after forming a circuit pattern on a double-sided printed board material. Therefore, even if a double-sided board can be produced, a multilayered printed board is manufactured by the same method. I can't.
Furthermore, even if both surfaces of the printed circuit board material are flat, unevenness is formed on both surfaces of the printed circuit board by the height of the circuit to be formed thereafter, that is, it is difficult to flatten both surfaces of the printed circuit board.

  The present invention has been made based on the above-described circumstances, and its object is to form a high-density micropattern while simultaneously realizing thinning and flattening of a substrate on which a circuit pattern is formed. It is an object of the present invention to provide a method for manufacturing a double-sided or multilayer printed circuit board that enables the improvement of interlayer connection reliability.

In order to achieve the above-described object, according to the first aspect of the present invention, the first and second support members and the first and second layers that are detachably stacked on the first and second support members, respectively. Step 1 for preparing first and second plate-like bodies made of a conductive layer, and forming first and second conductor circuits having a required pattern on each conductive layer of the first and second plate-like bodies. Forming a resist layer for providing a circuit formation scheduled region for forming the first and second conductor circuits in the circuit formation scheduled region provided by the resist layer, and removing the resist layer Thereafter, a step 3 of forming a bump on the second conductor circuit, a first conductor circuit formed on the first plate-like body, and a second conductor circuit and bump formed on the second plate-like body are semi-cured. Positioned opposite the required position with the insulation substrate in the state interposed And heating and pressing to embed the first conductor circuit on the first surface side of the insulating base material and the second conductor circuit on the second surface side of the insulating base material, and penetrate the insulating base material. After electrically connecting the layers of the first conductor circuit and the second conductor circuit with the bumps made, the step 5 of curing the insulating base material, and the step 6 of removing the first support member from the first plate-like body, Removing the second support member from the second plate-like body, and removing the first and second conductive layers by etching so that the first surface and the second surface of the insulating substrate are in the same plane as these. And a step of exposing each circuit surface of the flattened first and second conductor circuits. A method of manufacturing a printed circuit board is provided.

The plate-like body prepared in the step 1 has an important role in the formation of the conductor circuit in the step 2 and the transfer in the step 5, and the transfer of the conductor circuit is finished in the step 5, If curing is completed, it becomes unnecessary. In addition, in the laminating process for multi-layering to be described later, a plate-like body on the necessary side is left, and the remaining plate-like body may be removed after the laminating process is finished.
The conductive layer of the plate-like body has an anchor effect for fixing the conductive circuit formed by plating by the fine holes on this layer. Even if the conductive circuit to be formed is fine, it is suitable for forming the bump or to the insulating substrate. The conductor circuit is held even during the embedding transfer of the circuit to prevent circuit displacement and peeling.

The bump has its base end joined to the first conductor circuit by plating, and the other end penetrates the insulating base material and is joined to the second conductor circuit, which is the other side of the joint, by heating and pressurizing to make electrical connection Is secured.
Furthermore, since the conductor circuit is embedded in the insulating base material by heating and pressurizing and both sides of the printed circuit board are flattened, the circuit can be easily multi-layered. Therefore, according to the invention of claim 2 There is provided a method for producing a printed circuit board comprising a step of laminating a multilayer conductor circuit layer on at least one side of the first surface and the second surface of the insulating base material to form a multilayer.

Furthermore, according to the invention which concerns on Claim 3, the process 1a which prepares the 3rd plate-shaped body which consists of a 3rd support member and the 3rd electroconductive layer laminated | stacked on this so that peeling is possible on a 3rd electroconductive layer A step 2a for forming a third conductor circuit having a required pattern; a step 3a for forming a bump on the third conductor circuit; a third conductor circuit and a bump formed on the third plate-like body; A step 4a for positioning the conductor circuit exposed on at least one side of the first surface and the second surface opposite to the required position with a semi-cured insulating base material interposed therebetween, and heating and pressurizing, After the three-conductor circuit is embedded on the outer surface side after the lamination of the insulating base material, and electrically connecting the conductor circuit exposed on the one side and the layer between the third conductor circuit by a bump penetrating the insulating base material, A step 5a for curing the insulating substrate;
A printed circuit board manufacturing method is provided.

  Due to the difference in the state of lamination on both sides of the substrate, the substrate has been warped, deformed, or deformed in the past, especially when the odd layers were laminated. And holding the plate-like body in a pressed state until the insulating base material is cured, such warpage and deformation can be prevented.

  The method for manufacturing a printed circuit board according to any one of claims 1 to 3 can simultaneously realize thinning and flattening of a substrate on which a circuit pattern is formed, enables formation of a high-density fine pattern, and reliability of interlayer connection. It is possible to improve the performance.

Is a cross-sectional view of a double-sided printed circuit board A ₀ obtained by the manufacturing method of the printed circuit board according to the present invention. When manufacturing the printed circuit board A ₀ by the process of the present invention, it is a cross-sectional view showing a plate-shaped body prepared at step 1. In step 2 according to the method of the present invention, it is a cross-sectional view showing an intermediate A ₁ in a state where the resist was formed in a plate-like body. In the step 2 is a sectional view showing an intermediate A ₂ in the state which has been subjected to pattern plating. In the step 2 is a sectional view showing an intermediate A ₃ of a state of being exposed conductor circuit by removing the resist. In the step 3, a cross-sectional view showing an intermediate A ₄ in the state having formed a bump. The intermediate A ₄ and Intermediate A ₅ and the insulating base material to be prepared in the step 4 was placed opposite a sectional view showing a before curing conditions. In the step 5, a cross-sectional view showing an intermediate A ₆ in the state that has embedded planar body heat, a conductor circuit and a bump on the insulating substrate under pressure. The procedure of the manufacturing method of manufacturing a multilayer circuit board according to the present invention, FIG. (A) is, when placing the insulating substrate between the intermediate A ₇ and Intermediate A ₈ which is prepared in step 4a sectional view, and FIG. (b), in step 5a, sectional view showing an intermediate a ₉ in a state where three conductor circuit are laminated, FIG (c) is, on the way to prepare a four-layer circuit board it is a cross-sectional view in which is disposed an insulating substrate between the intermediate a ₁₀ and intermediate a _11. In the step 5a, a cross-sectional view showing an intermediate A ₁₂ in a state where the conductor circuit of the four layers are stacked. It is a sectional view showing a four-layer printed board A ₁₃ that has been accomplished by the present invention method.

Hereinafter, as an example of a method for manufacturing a printed circuit board according to the present invention, a method for manufacturing a rigid double-sided printed circuit board will be described with reference to the drawings.
First, the rigid double-sided printed circuit board A ₀ obtained by the manufacturing method of the printed circuit board according to the present invention will be described with reference to FIG.
The double-sided printed circuit board _A0 includes one insulating base material 1 as an insulating layer, and conductor circuits 2a and 2b each having a required pattern formed on a lower surface (first surface) 1a and an upper surface (second surface) 1b. The bumps 3a electrically connect the conductor circuits 2a and 2b.

  The material of the insulating base material 1 is not particularly limited, but a suitable material such as an epoxy resin or a polyimide resin is selected according to a rigid substrate, a flexible substrate, or the like. Further, an insulating sheet impregnated with an insulating resin such as an epoxy resin, a phenol resin, or an unsaturated polyester, or a prepreg material obtained by semi-curing the impregnated resin may be used with glass fiber, aramid fiber, or the like as a reinforcing material.

The thickness of the base material after lamination and curing in the state where the conductor circuits 2a and 2b are embedded can be formed to a desired thickness according to the usage mode. ) As a representative case.
As will be described later, the bump 3a of the present invention is formed by printing a conductive paste on a predetermined position of the conductor circuit 2a by a screen printing method and drying it. The bump 3a is formed in a conical shape with a pointed tip so as to easily penetrate the insulating substrate 1 to be described later, the intermediate A ₄ is obtained as shown in FIG. Examples of the conductive paste used at this time include XH9626-7 (trade name, conductive adhesive for solder replacement manufactured by NAMICS). Accordingly, the base end of the bump 3a is joined to the conductor circuit 2a, and the tip is joined to the conductor circuit 2b by heating and pressurization. The bump 3a is electrically and reliably connected between the conductor circuits 2a and 2b. doing.

The conductor circuits 2a and 2b are embedded in the lower surface 1a and the upper surface 1b of the insulating base material 1, respectively, and are planarized in the same plane as the lower surface 1a and the upper surface 1b of the insulating base material 1, and the conductor circuits 2a and 2b. Are exposed on the outer surface of the insulating substrate 1.
The exposed circuit surfaces of the conductor circuits 2a and 2b have various shapes depending on the application and form part of the circuit pattern. For example, pad shapes and bumps matched to the terminal shapes of the components to be surface mounted It is formed in a land shape, a wiring shape for connecting pads and lands, and the like.

Next, a procedure of manufacturing a rigid double-sided printed circuit board A ₀ according to the present invention with reference to FIGS. 2-8.
The method of the present invention is called a so-called single plate pressing method (transfer method), and FIG. 2 shows a cross-sectional view of the plate-like body 4 serving as a single plate.
The plate-like body 4 has a two-layer structure in which a conductive layer 4A made of a conductive material and a support member 4B thicker than the conductive layer 4A are detachably stacked, and is prepared in step 1. Since the conductive layer 4A is peeled off from the support member 4B and the circuit pattern after the circuit pattern is formed and laminated, the conductive layer 4A may be any material that can be easily peeled off from the support member 4B and the circuit pattern, and the printed circuit board A ₀ which is the final product. Therefore, the thickness may be any thickness that does not hinder the formation of the circuit pattern. Although it does not specifically limit as 4 A of conductive layers, For example, nickel etc. are suitable. The conductive layer 4A may be formed by plating nickel or the like on the support member 4B, or a nickel foil may be attached to the support member 4B. Further, the support member 4B is a support material for supporting the conductive layer 4A, and is not necessarily a conductive material, but for example, a SUS plate is suitable.

Each surface between the conductive layer 4A and the support member 4B is subjected to surface polishing so that an appropriate peel strength can be obtained. Further, the surface of the conductive layer 4A on which the conductor circuit 2a is formed is appropriately roughened so that pattern displacement, deformation, and peeling do not occur at the time of transfer or in the layering process of the multilayered layer.
Step 2. As shown in FIGS. 3 to 5, this process is a photolithography process for forming the pattern A of the conductor circuit 2 a on the conductive layer 4 </ b> A of the plate-like body 4 by an additive pattern plating technique. The conductor circuit 2a is composed of the above-described pads, lands to be bonded to bumps 3a (see FIG. 6) described later, wiring portions connecting these pads and lands, and the like.

A dry film resist is applied or coated with a thickness substantially equal to the height of the conductor circuit 2a to be formed on the upper surface of the conductive layer 4A of the plate-like body 4, and exposed to form a resist layer 5, which is shown in FIG. making body a _1.
Further, this resist layer 5 is formed by the region of the conductor circuit 2a and patterned with copper plating, to prepare an intermediate A ₂ shown in FIG. 4, then removing the resist layer 5, as shown in FIG. 5 It is intermediate a ₃ having a first conductor circuit 2a is obtained.

The resist layer 5 can also be formed by screen printing.
Then, Intermediate A ₃ is transferred to step 3.
Step 3. This step, as shown in FIG. 6, a portion of the first conductor circuit 2a of the intermediate A ₃ obtained in step 2 is a step of forming a bump 3a.
The bump 3a is formed by printing a conductive paste on a predetermined position of the conductor circuit 2a by a screen printing method and drying it. The bump 3a is formed in a substantially conical shape whose tip pointed so as to penetrate through the insulating substrate 1 to be described later, the intermediate A ₄ is obtained as shown in FIG. Examples of the conductive paste used at this time include XH9626-7 (trade name, conductive adhesive for solder replacement manufactured by NAMICS).

Similarly, the second conductor circuit 2b is produced. The conductor circuit 2b is produced by pattern plating so as to form a pattern B different from the pattern A of the first conductor circuit 2a. Since the bump 3 is not necessary for the conductor circuit 2b, it can be manufactured by a process similar to the process shown in FIGS. 2 to 5 described above, and the description of the process is omitted.
Step 4. In this step, the intermediates A ₄ and A ₅ including the first and second conductor circuits 2a and 2b are arranged to face the required positions with the insulating base 1 interposed therebetween.

The insulating substrate 1 is made of a semi-cured resin material and has a length substantially equal to the width of the support member 4B and the conductive layer 4A.
As a material of the insulating substrate 1, the bump 3a must be easily penetrated, and a prepreg material obtained by semi-curing the impregnated resin, a liquid resin as a precursor, an uncured resin, For example, an insulating sheet made of an insulating resin such as an epoxy resin, a phenol resin, a polyimide resin, or an unsaturated polyester may be used.

Step 5. The intermediate body A ₄ , the intermediate body A _5, and the insulating base material 1 arranged as in step 4 are heated and pressurized, and the conductor circuit 2 a is placed on the lower surface (first surface) 1 a side of the insulating base material 1. Second surface) A step of embedding the conductor circuits 2b on the 1b side. At this time, it is preferable to heat the intermediates A ₄ and A ₅ together with the conductive layer 4A and the plate-like body 4B at about 150 ° C. to 350 ° C. and pressurize them in the range of about 10 to 100 kg / cm ² .

The heating temperature and the applied pressure are appropriately selected according to the resin material used as the insulating substrate 1, the circuit shape of the fine pattern to be formed, and the like.
In this manner, the bump 3a and the conductor circuit 2b formed on the conductor circuit 2a are joined together under heat and pressure, and these are electrically connected. Thereafter, to prepare the intermediate A ₆ to cure the insulating substrate 1.

Step 6 and Step 7. These step is a step of peeling off the support member 4B from both the outer surface of the intermediate A _6.
As described above, since the conductive layer 4A and the support member 4B are detachably attached, it is possible to physically peeled off the support member 4B from intermediate A _6. At the time of peeling, the conductive layer 4A prevents the conductor circuits 2a and 2b from peeling. Note that this step of separating the support member 4B, when stacking the multilayer layer may be carried out only the outer surface side of the intermediate A _6.

Step 8. This step is a step of removing the conductive layer 4A exposed in the steps 6 and 7 by etching.
The conductive layer 4A can be removed from the insulating base material 1 and the conductor circuits 2a and 2b by etching the nickel of the conductive layer 4A at an etching rate different from that of copper. As a result, the lower surface 1a and the upper surface 1b of the insulating base material 1 can be removed. The surfaces of the conductor circuits 2a and 2b flattened in the same plane are exposed, and as shown in FIG. 1, the conductor circuits 2a and 2b are embedded in the insulating substrate 1, and the interlayer connection is made via the bumps 3a. A double-sided printed circuit board _A0 is obtained.

Thus, as shown in FIG. 1, the conductor circuits 2a and 2b are embedded in the insulating base 1, and the conductor circuit 2a and the conductor circuit 2b are connected by the bumps 3a formed on the conductor circuit 2a. the thickness of the printed circuit board a ₀ is substantially determined by the thickness of the insulating substrate 1, thin conductor circuit 2a, minute sided plate PCB a ₀ with embedded 2b is facilitated.
The conductor circuits 2a and 2b are embedded in the insulating base 1, from being exposed in the same plane as the upper surface 1a and the lower surface 1b of the insulating base 1, both the outer surface of the double-sided board PCB A ₀ is an insulating material consistent with the first upper surface 1a and the lower surface 1b, flattening the both outer surfaces of the double-sided board PCB a ₀ is realized. Therefore, it can be a multilayer printed circuit board was further laminated on both sides plate printed board A ₀ obtained easily.

Thus, it is possible to realize a thinner and planarization of a double-sided board PCB A ₀ at the same time.
A method of manufacturing a double-sided printed circuit board A ₀ is heated from the formation of the conductor circuit 2 during the lamination process by pressurization, since the support member 4B and the conductive layer 4A is adhered, the conductor circuit 2 is high density as well as a possible formation of a fine pattern, also hardly causes the position Families in interlayer connection, it is possible to improve the reliability of the double-sided printed circuit board a _0.

Will now be described with reference to FIGS. 9 (a) and (b) the method of laminating the double-sided board PCB A ₀ to further multi layer A ₈ according to the present invention.
Upon laminating the multilayer layer A ₈ on both sides substrate A _0, to prepare the following. First, one plate-like body from Intermediate A ₆ shown in FIG. 8, in the embodiment shown in FIG. 9 (a), to remove only the first plate member located below the FIG (4A, 4B) Intermediate Preparing the body _{a 7.} This intermediate A _7, as is clear from the figure, the lower surface and the circuit surface of the (first surface) 1a flattened flush with the conductors circuit 2a is exposed, described later on the land portion of the exposed circuit surface bumps 3c multilayered layer a ₈ to are electrically joined.

Next, an intermediate A ₈ similar to the intermediate A ₄ is prepared by steps 1a to 3a similar to the steps shown in FIGS. 2 to 6 described above. The intermediate A _8, and Intermediate A ₄ and Intermediate A ₅ corresponding to the land position of the third conductor circuit 2c is formed, the conductor circuit 2a to be connected with a different circuit patterns C Bumps 3c are formed.
Next, in step 4a, as shown in FIG. 9A, the intermediate body A ₇ from which the conductor circuit 2a is exposed and the intermediate body A ₈ provided with the bumps 3c are opposed to each other, and the insulating substrate 1 is attached. These are arranged at a required position in an intervening state.

Step 5a. In this step, as shown in FIG. 9B, heating and pressurization are performed in the same manner as in the above-described step 5, and the bump 3c and the conductor circuit 2c are embedded in the insulating member 1, and the conductor circuit 2a, the conductor circuit 2c, the so connected via the bumps 3c is a step to prepare intermediate a _9.
By separating the intermediate support from both sides of the A ₉ member 4B and the conductive layer 4A, it is possible to obtain a printed circuit board A ₉ three-layer _'(not shown), in this case, the conductor circuit 2c is an insulating substrate 1, the thickness of the printed circuit board A ₉ ′ is determined only by the thickness of the insulating base material 1, regardless of the height of the conductor circuit 2 c, and the three-layer printed circuit board A ₉ ′ is thin. It becomes easy.

The three-layer printed circuit board is a so-called odd-numbered circuit board, and since a multilayer board is usually laminated on one side of a core board (intermediate body A ₇ ), the board is often warped or deformed due to thermal strain or the like. In the single plate pressing method, the two plate-like bodies 4B are sandwiched from both sides and heated and pressurized, and the state is maintained until the insulating base is completely cured, so there is no concern about warpage or deformation.
Further, the intermediate A ₇ has cured insulating substrate 1 while being supported by the support member 4B, also, since even Intermediate A ₈ is supported by the support member 4B, 3-layer printed circuit board A ₉ ' In both cases, both outer surfaces are flattened. Therefore, it is also possible to further laminate and multilayer.

As shown in FIG. 9 (c) connection, an intermediate A ₁₀ conductor circuit 2b is peeled off the support of the upper surface 1b of the Intermediate A ₉ member 4B and the conductive layer 4A is exposed, and the conductor circuit 2b are opposed to the intermediate a ₁₁ having a bump 3d and a conductor circuit 2d to be arranged so as to connect with insulating substrate 1.
Heating in the same manner as in Step 5 described above, the buried conductive circuits 2d and bumps 3d insulating substrate 1 by pressurizing, and a conductor circuit 2b and the conductor circuit 2d to prepare Intermediate A ₁₂ by connecting via the bumps 3d (FIG. 10), the support member 4 </ b> B and the conductive layer 4 </ b> A are peeled from both outer surfaces to obtain a four-layer printed board A <b> ₁₃ shown in FIG. 11.

In this case, since the conductive circuit 2d is embedded in the insulating substrate 1, the thickness of the four-layer printed board A _13, regardless of the height of the conductor circuit 2d, only a thickness of the insulating base 1 will be determined, it is easy to thin the four-layer printed board a _13.
Further, since also been flattened both outer surfaces of the four-layer printed board A _13, it can be further laminated.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the embodiment of the present invention.
For example, the formation of the conductor circuit 2 in the step 2 is not limited to the above-described method. For example, the conductor circuit 2 may be formed by a subtractive method.

Although laminated in step 4a and 5a on both sides of the printed board A _0, it is also possible to sequentially laminated on one side.
Further, in the three-layer printed circuit board A ₉ ′ and the four-layer printed circuit board A ₁₃ , the bump 3 a and the bump 3 c are connected so as to vertically penetrate at the same horizontal position of the conductor circuit 2 a (in this case, the ground wire The bump 3a and the bump 3c may be connected to different positions of the conductor circuit 2a, and the same applies to the positional relationship between the bump 3a and the bump 3d.

Furthermore, multi-layered layer stacked substrate A ₇ Core substrate is not limited to those manufactured in the manufacturing method described above, a variety of surface mount board or component-embedded substrate that is created by a conventionally known production method It is also possible to laminate. Also in this case, the core substrate manufactured according to the present invention is easily laminated because the outer surface is flattened.

DESCRIPTION OF SYMBOLS 1 Insulating base material 1a Upper surface 1b of insulating base material Lower surface 2a, 2b, 2c, 2d of insulating base material 3a, 3c, 3d Bump 4 Plate-like body 4A Conductive layer 4B Support member 5 Resist layer

Claims (3)

Step 1 for preparing first and second plate-like bodies comprising first and second support members and first and second conductive layers that are detachably stacked on each of the first and second support members; ,
A resist layer is provided on each conductive layer of the first and second plate-like bodies to provide a circuit formation scheduled area for forming first and second conductor circuits of a required pattern, and is provided by the resist layer. Forming each of the first and second conductor circuits in the circuit formation scheduled region, and
Forming a bump on the second conductor circuit after removing the resist layer; and
The first conductor circuit formed on the first plate-like body and the second conductor circuit and bump formed on the second plate-like body are opposed to a required position with a semi-cured insulating base interposed therebetween. And positioning step 4;
The first conductor circuit is embedded on the first surface side of the insulating base material and the second conductor circuit is embedded on the second surface side of the insulating base material by heating and pressurizing, and the first conductive circuit is formed by a bump penetrating the insulating base material. Step 5 of curing the insulating base material after electrically connecting the layers of the first conductor circuit and the second conductor circuit;
Removing the first support member from the first plate-like body;
Removing the second support member from the second plate-like body ,
The first and second conductive layers are removed by etching, and the first and second conductive circuits planarized in the same plane as the first and second surfaces of the insulating base are exposed. Step 8;
A printed circuit board manufacturing method comprising:   2. The method of manufacturing a printed circuit board according to claim 1, further comprising a step of stacking multiple conductor circuit layers on at least one side of the first surface and the second surface of the insulating base material to form a multilayer. Preparing a third plate-like body comprising a third support member and a third conductive layer peelably laminated thereon;
Forming a second conductor circuit of a required pattern on the third conductive layer;
Forming a bump on the third conductor circuit 3a;
A semi-cured insulating base material is interposed between the third conductive circuit and the bump formed on the third plate-like body and the conductive circuit exposed on at least one side of the first surface and the second surface of the insulating base material. A step 4a positioned opposite to the required position in the
Heat and pressure are applied to embed the third conductor circuit on the outer surface side after the lamination of the insulating base material, and between the conductor circuit exposed on the one side and the third conductor circuit is electrically connected by a bump penetrating the insulating base material. After the connection, the step 5a of curing the insulating substrate;
The manufacturing method of the printed circuit board of Claim 2 characterized by the above-mentioned.

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