JP2007283761A - Film peeling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film peeling method which enables the peeling of a film certainly from a substrate even if thickness of a sheet material including a substrate and a film sticking on one side or both sides of the substrate is very thin. <P>SOLUTION: A sheet material including a substrate having via holes filled up with conductive paste and a protective film sticking on one side or both sides of the substrate is held so that the thickness direction may be approximately perpendicular with the vertical direction, and the protective film is peeled from the substrate in the condition. According to this, even if it is a case that the thickness of the sheet material is very thin, since the condition that the sheet material is slackened under its own weight is suppressed, the crease of the substrate, the removal of the paste or the like is inhibited and the protective film can be certainly peeled from the substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a film peeling method used in, for example, a manufacturing process of a multilayer printed wiring board with IVH (Interstitial Via Hole).

  As an example, a multilayer printed wiring board with IVH is manufactured as follows. First, a sheet material is obtained by heating and pressure-bonding a plastic film on both front and back surfaces of a substrate such as glass cloth or aramid fiber cloth. Subsequently, through holes are formed by laser beam irradiation or the like at predetermined positions of the base material on which the plastic film is adhered to both the front and back surfaces, and the conductive paste is filled into the through holes by printing or the like. Thereafter, the plastic film is peeled from the base material to obtain a base material having a via hole filled with a conductive paste. And the multilayer printed wiring board with IVH is produced by the construction method, circuit patterning, etc. of a copper clad laminated board or a multilayer board | substrate using the base material.

Conventionally, the above-described peeling of the plastic film is generally performed by the following film peeling method (see, for example, Patent Document 1). That is, the sheet material is transported while being held horizontally, the non-contact portion at the front end of the sheet material is vacuum-sucked, the plastic film is turned up, and the front end of the base material is exposed. Subsequently, the tip of the substrate is taken out and held by a chuck, and the plastic film is peeled from the substrate by moving the plastic film and the substrate at a predetermined synchronized speed.
Japanese Patent No. 3473337

  However, in the conventional general film peeling method, both edges (for example, about 10 to 15 mm) of the sheet material in the direction perpendicular to the sheet material transfer direction (width direction) are sandwiched between rollers or chucks. Since the sheet material is transferred in a state where the sheet material is held horizontally, a sufficient tension cannot be applied in the width direction, and the sheet material is loosened by its own weight. It has been confirmed that such loosening of the sheet material becomes more conspicuous due to a decrease in rigidity as the thickness of the sheet material is reduced to 100 μm or less.

  And when the plastic film is peeled from the base material in a state where the sheet material is loose, the posture is unstable, so the tension in the width direction at the time of peeling becomes uneven, and as a result, the base material may be broken. There is a problem that the conductive paste in the via hole is taken along with the plastic film (hereinafter referred to as “paste removal”). Further, when the sheet material is slack, there is a problem that the tip of the base material cannot be taken out and held by the chuck.

  Therefore, the present invention has been made in view of such circumstances, and even when the thickness of a sheet material including a base material and a film attached to one or both surfaces of the base material is extremely thin. An object of the present invention is to provide a film peeling method capable of reliably peeling a film from a substrate.

  In order to achieve the above object, a film peeling method according to the present invention is a sheet material comprising a substrate and a film attached to one or both sides of the substrate, the thickness direction of which is substantially perpendicular to the vertical direction. It hold | maintains so that a film may be peeled from a base material in the state.

  According to this film peeling method, even when the thickness of the sheet material is extremely thin, the sheet material is restrained from being loosened by its own weight, so that the base material is broken or the paste is removed. And the film can be reliably peeled from the substrate.

  In the film peeling method according to the present invention, the holding of the sheet material may be performed by chucking at least two opposite sides, or may be performed by vacuum suction.

  The film peeling method according to the present invention is particularly effective when the thickness of the sheet material is 10 μm to 100 μm or when the thickness of the base material is 5 μm to 60 μm.

  In the film peeling method according to the present invention, the substrate may be formed of fibers impregnated with a resin or may be a prepreg. When the substrate is a prepreg, the prepreg is conductive. The member may have a filled through hole. The film may be a plastic film or a polyethylene film.

  According to the present invention, even when the thickness of a sheet material including a base material and a film attached to one or both sides of the base material is extremely thin, the film can be reliably peeled from the base material. .

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  The film peeling method in this embodiment is used, for example, in a manufacturing process of a multilayer printed wiring board with IVH, and is performed as follows. That is, a sheet material including a base material having a via hole filled with a conductive paste and a protective film attached (attached) to one or both surfaces of the base material, the thickness direction of the base material being substantially perpendicular to the vertical direction. The protective film is peeled off from the substrate in this state.

  At this time, the holding of the sheet material is preferably performed by chucking at least two opposite sides (for example, upper and lower sides of the base material) using a chucking device. Further, the holding of the sheet material is more preferably performed by vacuum suction using a vacuum suction stand erected in the vertical direction. According to these, the sheet material can be reliably held so that the thickness direction of the sheet material is substantially perpendicular to the vertical direction.

  According to the film peeling method described above, even when the thickness of the sheet material is extremely thin, the sheet material is prevented from being loosened by its own weight, so that the base material is bent or the paste is removed, etc. Generation | occurrence | production can be prevented and a protective film can be peeled reliably from a base material.

  By the way, it has been confirmed that the looseness due to the weight of the sheet material when the sheet material is held horizontally becomes more conspicuous due to the decrease in rigidity as the thickness of the sheet material is reduced to 100 μm or less. Therefore, the film peeling method described above is particularly effective when the thickness of the sheet material is 10 μm to 100 μm or when the thickness of the base material is 5 μm to 60 μm.

  The base material may be formed of fibers impregnated with a resin or may be a prepreg. When the base material is a prepreg, the prepreg is made of a conductive member such as a conductive resin. May have filled through holes. The protective film may be a plastic film or a polyethylene film. Also in these cases, the above-described film peeling method can be preferably used.

[Example 1]
As shown in FIG. 1, a plastic film (film) 2 having a thickness of 21 μm and an outer dimension of 514 mm × 612 mm is heated and pressure-bonded to a prepreg (base material) 1 having a thickness of 50 μm and an outer dimension of 512 mm × 612 mm. Thus, a sheet material was obtained. Then, the conductive paste (conductive member) was filled in the via hole (through hole) 3 formed in the sheet material to produce a sheet material 4 containing the conductive paste.

  Subsequently, on the two upper and lower sides (two opposite sides) of the sheet material 4, a part 2 a of the plastic film 2 is peeled from the prepreg 1 by about 10 mm to provide a chucking allowance. After chucking, the sheet material 4 was suspended vertically downward. Thereby, the sheet | seat material 4 hung down straight with the dead weight. In this state, when the plastic film 2 was peeled from the prepreg 1 at an elevation angle of 45 ° C. with respect to the sheet material 4, the prepreg 1 could be peeled stably without causing breakage or the like.

[Example 2]
As shown in FIG. 2, a sheet material 4 similar to that of Example 1 is prepared, and the peripheral edge of the sheet material 4 is vacuum-sucked by a suction pad 7 using a vacuum suction stand 6 erected in the vertical direction. Thus, the sheet material 4 was held. In this state, when the plastic film 2 was peeled from the prepreg 1 at an elevation angle of 45 ° C. with respect to the sheet material 4, the prepreg 1 could be peeled stably without causing breakage or the like. The method using the vacuum suction table 6 is more preferable because it does not require a chucking allowance unlike the method using the chucking device 5.

[Comparative Example 1]
As shown in FIG. 3, a sheet material 4 similar to that of Example 1 is prepared, and a portion 2a of the plastic film 2 is peeled from the prepreg 1 by about 10 mm on the left and right sides of the sheet material 4 to provide a chucking allowance. Then, the chucking allowance was chucked using the chucking device 5, and the sheet material 4 was placed horizontally on the support base 8 with an interval of 612 mm. In this state, the plastic film 2 was peeled from the prepreg 1 at an angle of elevation of 45 ° C. with respect to the sheet material 4. At this time, tension was not applied to the chucking device 5 and the end portion was suppressed. This is to reproduce the “state in which no conveyor tension is applied” in the conventional peeling conveyance holding method.

  Next, using the film peeling methods of Example 1 and Comparative Example 1, peeling experiments were performed on 50 sheet materials 4 respectively. The evaluation was performed based on the rate of occurrence of folding in 50 prepregs 1 and the rate of occurrence of paste removal in 4000 via holes 3. The results are shown in Table 1.

  As shown in Table 1, the occurrence rate of folds was 0% in the film peeling method of Example 1, whereas it was 4% in the film peeling method of Comparative Example 1. Also, the rate of occurrence of paste removal was 0.06% in the film peeling method of Example 1, whereas it was 1.8% in the film peeling method of Comparative Example 1, and the film of Example 1 It became clear that it was 30 times the peeling method.

1 is a schematic view showing a film peeling method of Example 1. FIG. 6 is a schematic view showing a film peeling method of Example 2. FIG. It is the schematic which shows the film peeling method of the comparative example 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Prepreg (base material), 2 ... Plastic film (film), 3 ... Via hole (through hole), 4 ... Sheet material.

Claims (10)

  A sheet material comprising a substrate and a film attached to one or both sides of the substrate is held so that the thickness direction is substantially perpendicular to the vertical direction, and the film is removed from the substrate in that state. A film peeling method characterized by peeling.   2. The film peeling method according to claim 1, wherein the holding of the sheet material is performed by chucking at least two opposite sides.   The film peeling method according to claim 1, wherein the holding of the sheet material is performed by vacuum suction.   The thickness of the said sheet | seat material is 10 micrometers-100 micrometers, The film peeling method as described in any one of Claims 1-3 characterized by the above-mentioned.   The thickness of the said base material is 5 micrometers-60 micrometers, The film peeling method as described in any one of Claims 1-4 characterized by the above-mentioned.   The film peeling method according to any one of claims 1 to 5, wherein the substrate is formed of fibers impregnated with a resin.   The film peeling method according to claim 1, wherein the substrate is a prepreg.   8. The film peeling method according to claim 7, wherein the prepreg has a through hole filled with a conductive member.   The film peeling method according to claim 1, wherein the film is a plastic film.   The film peeling method according to any one of claims 1 to 8, wherein the film is a polyethylene film.

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