JP2005229065A - Method for manufacturing multi-layer and double-sided substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a multi-layer and double-sided substrate in a laminate type for reducing the percent defective of a product. <P>SOLUTION: At least one or more protrusions 1 are formed on the surface of a flat first base material 3, and an insulating film and an elastic body 7 are successively arranged so as to be overlapped on the surface of the first base material 3 formed with the protrusions 1; and the elastic body 7 is pressurized with a fixed pressure, while the film is heated so that the film arranged on the protrusions can be adhered to the first base material 3 with the elastic force of the elastic body 7, and that the film thickness on the protrusions can be thinly expanded. The surface of the thinly expanded film is removed by a plasma etching method so that the film can be removed with a uniform thickness in the atom level. As a result, the insulating film of even a thin substrate, which is easily folded such as a flexible substrate, can be removed with uniform thickness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer type multilayer board and a double-sided board used in any electronic device, and more particularly, to a method for manufacturing a multilayer type multilayer board and a double-sided board using a protrusion to realize interlayer conduction between the multilayer board and the double-sided board About.

  With reference to FIG. 2, the manufacturing method of the lamination type multilayer using a protrusion and a double-sided board | substrate is demonstrated. Here, FIGS. 2A to 2C are process diagrams showing a method for manufacturing a multilayer and double-sided substrate having protrusions.

  First, as shown in FIG. 2A, a first base material 103 having a flat surface made of a conductive material (for example, copper foil) is prepared, and a plating method or an etching method is provided on the surface of the first base material 103. The protrusion 101 is formed using For example, in the case where the projection is formed using a plating method, the region other than the region where the projection is to be formed is covered with a mask, and the projection 101 is formed by laminating a conductive material in the opened mask opening by the plating method. On the other hand, in the case of forming protrusions using an etching method, an etching resist layer (not shown) is stacked on the first base material 103, and a protrusion forming pattern is formed at a required position (not shown) on the upper surface of the etching resist layer. The conductive material is disposed, exposed to ultraviolet light from the surface, developed, and after removing the etching resist layer other than the protrusion forming pattern, the conductive film is left with the protrusion forming pattern protected by the etching resist layer using an etching solution. Is removed, and finally the etching resist layer on the protrusion formation pattern is peeled to form the protrusion 101.

  Next, as shown in FIG. 2B, the protrusion 101 formed by the above process is coated with an insulating resin so as to cover the surface of the first base material 103 and have a film thickness at which the tip of the protrusion 101 protrudes. An insulating layer 105 is formed.

  Subsequently, as shown in FIG. 2C, the second base material 107 made of a conductive material is disposed on the insulating layer 105 where only the protrusion tip is exposed, and the second base material 107 is attached to the first base material 103. Bonding with two substrates by pressing in the direction. At this time, the protrusions 101 formed on the first base material 103 are crushed on the surface of the second base material 107, whereby the two base materials are electrically connected. Multilayer and double-sided substrates having such a configuration are disclosed in Patent Document 1 and Patent Document 2.

  On the other hand, in the step of forming the insulating layer 105 shown in FIG. 2B, a method of forming the insulating layer 105 by covering with an insulating film instead of the method of forming the insulating layer 105 by applying an insulating resin. There is also. FIGS. 3A and 3B show a manufacturing method when an insulating film is applied.

As shown in FIG. 3 (a), a first base material 103 on which a protrusion 101 is formed is prepared, an insulating film is placed on the protrusion formation surface, and the film is pressed from above to form the first base material 103 and A film is brought into close contact with the protrusion 101. Next, as shown in FIG. 3B, the surface of the film is physically polished by using a polishing roll or the like, and the film disposed on the protrusion 101 is scraped to expose the protrusion 101. Then, by placing and pressing the second base material 107 on the insulating layer 105 where the protrusion 101 is exposed, electrical conduction between the first base material 103 and the second base material 107 is obtained.
JP 2003-129259 A JP 2002-359471 A

  By the way, in the physical polishing method described above, it is difficult to uniformly polish an insulating layer formed on a thin substrate that is easily bent such as a flexible substrate. When such a substrate that is easily bent is physically polished, the layer thickness is different for each polishing region, and the projection height after polishing is also different. As a result, there is a problem that conduction between substrates may not be stable.

  Therefore, in order to ensure more stable conduction between the substrates, it is necessary to form the substrate so that each protrusion has a uniform height. For this purpose, an advanced polishing technique is required in the polishing process for polishing the insulating layer.

  In addition, as described above, when the insulating layer is physically polished, polishing scraps are generated, which may cause a wiring short circuit in the subsequent fine wiring process and may damage the surface of the layer. There is a problem of increasing the number of defective products.

  This invention is made | formed in view of the said subject, The objective is to provide the manufacturing method of the multilayer type multilayer and double-sided board which can reduce a product defect rate.

  In order to solve the above-mentioned problem, the present invention according to claim 1 includes a step of forming at least one protrusion on a first base material surface having a flat surface, and the first base material surface on which the protrusion is formed. A step of disposing an insulating film, a step of disposing an elastic body on the film, pressing the film at a constant pressure by the elastic force of the elastic body, And a step of removing a film on the protrusion by a dry etching method and a step of disposing a second base material having a flat surface on the protrusion exposed by removing a certain film thickness and joining the protrusion to the protrusion. And

  The gist of the present invention of claim 2 is that the elastic body is made of a material softer than the composition of the protrusions in the method for manufacturing a multilayer board and a double-sided board of claim 1.

  According to a third aspect of the present invention, in the method for manufacturing a multilayer board and a double-sided board according to the first aspect, in the pressing step, the heating temperature is equal to or higher than the temperature at which the insulating layer softens, and the elastic characteristics of the elastic body are maintained. The gist is that the temperature is lower than the temperature.

  According to the present invention, at least one protrusion is formed on the surface of the first substrate having a flat surface, and an insulating film is disposed on the surface of the first substrate on which the protrusion is formed. Further, an elastic body made of a material softer than the composition of the protrusions is disposed, and then the elastic body 7 is pressed while heating, so that only the film is stretched while maintaining the shape of the protrusions. 3 and the surface of the protrusion, and the film thickness on the protrusion can be reduced. Then, by removing only the film thickness on the protrusion using a dry etching method such as a plasma etching method, the film can be uniformly removed in the surface, and the protrusion formed on the insulating layer can be further accurately formed. Can be exposed at a uniform height. As a result, when joining to the second substrate, the two substrates can be joined only by applying a constant pressure, and stable conduction can be obtained. As a result, the defective rate of the product can be reduced.

  Moreover, since polishing scraps such as metal particles are not generated by using the plasma etching method, it is possible to suppress a product defect rate due to short-circuiting of the wiring or damage to the layer surface.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a process diagram for explaining a method of manufacturing a multilayer type multilayer and double-sided substrate according to an embodiment of the present invention.

  The manufacturing method of the present invention includes a step of forming at least one protrusion 1 on the surface of the first base 3 having a flat surface, and an insulating property on the surface of the first base 3 on which the protrusion 1 is formed. The film (insulating layer 5) is covered, an elastic body 7 is further disposed on the film, and the film is stretched by applying a certain pressure to the elastic body 7, and the surface of the stretched film is plasma etched. A step of removing a certain thickness by a method, and a step of placing the second base material 11 on the protrusion exposed by the removal of the constant thickness and joining the first base material 3 and the second base material 11 by pressing. Have.

  One feature of the present invention is that the insulating layer 5 disposed on the protrusion 1 is pressed using the elastic body 7 and then in-plane by the thickness of the insulating layer 5 on the protrusion 1 by applying a plasma etching method. The point is that dry etching is performed uniformly. Thereby, the insulating layer 5 can be removed with a uniform thickness by high-precision etching at the atomic level. In addition, the tip of the projection 1 (formed by applying an etching method, a plating method, or the like) formed with high accuracy can be protruded from the insulating layer 5 at a uniform height.

  Another feature of the present invention is that an elastic body 7 having a predetermined elastic force is used to press the insulating layer 5 with a uniform pressure. Thereby, the thickness of the insulating film on the protrusion 1 can be reduced without damaging the protrusion 1 formed with high accuracy.

  The feature of the present invention is that when the elastic body 7 is pressed, it is pressed at a temperature equal to or higher than the Tg temperature. The Tg temperature is a glass transition temperature, and is a temperature at which the elastic modulus of physical properties drops sharply. When the temperature is equal to or higher than Tg, the elastic force of the elastic body 7 is softened, so the pressing step is performed at a temperature lower than the Tg temperature.

Further, the present invention is characterized in that a plasma etching method is used. Thus, the insulating layer 5 can be removed with a uniform thickness without generating polishing scraps. In addition, if the gas after etching is discarded, the cleanliness can be further improved, so that the occurrence of wiring short-circuit can be suppressed. Further, if O ₂ cleaning is further performed, all the foreign matters can be removed, so that the product defect rate can be further reduced.

  Here, the first base material 3 and the second base material 11 applied to the embodiment of the present invention are thin film substrates made of a conductive material such as copper foil. However, the first base material 3 and the second base material 11 are not limited to conductive materials, and may be, for example, a semiconductor chip (or a multilayer printed wiring board) in which integrated circuits are stacked in advance on the substrate inner layer. In this case, the output end of the integrated circuit is connected to the protrusion 1 formed on the substrate so as to be conductive.

  The protrusion 1 is a conductive material, specifically, a metal material such as copper, silver, or gold. Any metal material can be used to form the protrusions, but copper is preferable. By applying copper, the cost can be reduced compared to other metals.

  Here, the elastic body 7 is made of a material softer than the composition of the protrusions. The material is, for example, a cushioning material, and its elastic force is such that the film can be brought into close contact with the surface of the first substrate 3 and the surface of the protrusion without deforming the shape of the protrusion even when the film is pressed. It shall have power. Specifically, a pet film, a liquid crystal polymer (fully aromatic polyester), rubber or the like is preferable.

  The material of the insulating layer 5 is preferably a material that is easily stretched by the elastic force of the elastic body 7 when pressed by the elastic body 7. For example, a thermoplastic resin that is softened by heating, polyimide, Teflon (registered trademark), or the like can be given. In addition, it is preferable to have a property of not adhering to the elastic body 7 when pressed. That is, it is preferable that the insulating layer 5 or the elastic body 7 is subjected to corona treatment so that the insulating layer 5 and the elastic body 7 do not adhere even if the pressing force is slightly increased. These insulating materials are processed into a film or sheet before use.

  Next, with reference to FIG. 1, the manufacturing method of the multilayer type multilayered and double-sided substrate which concerns on embodiment of this invention is demonstrated concretely.

  First, as shown to Fig.1 (a), the 1st base material 3 in which the at least 1 or more protrusion 1 was formed is prepared. The protrusion 1 is formed by laminating a conductive material such as copper on the surface of the first base material 3 made of, for example, copper foil by sputtering or CVD, and further etching resist layer (not shown) on this layer. The projection resist pattern is disposed at a required position (not shown) on the upper surface of the etching resist layer, and the etching resist layer other than the projection formation pattern is removed by exposing and developing the ultraviolet ray from above. Then, leave the pattern for forming protrusions protected on the etching resist layer using an etching solution, remove the other copper, and finally remove the etching resist layer on the pattern for protrusion formation. Can do.

  And the 1st base material 3 produced in this way is arrange | positioned on the upper surface of the board 9a for a press. Next, an insulating film is placed on the upper surface of the first base material 3. Further, an elastic body 7 is disposed thereon, and a pressing plate (upper plate) 9b is disposed above the elastic body 7.

Subsequently, as shown in FIG. 1 (b), the first base material 3, the insulating layer 5 and the second base material 11 sandwiched by the pressing plates 9a and 9b are arranged in a high temperature atmosphere and pressed in this state. By applying pressure to the plates 9a and 9b, the insulating layer 5 is brought into close contact with the surface of the protrusion 1 and the surface of the first substrate 3, and the insulating layer 5 on the protrusion 1 is thinly stretched (or stretched). The heating temperature at this time is equal to or higher than a temperature at which the film is sufficiently softened and is equal to or lower than a temperature at which the elastic characteristics of the elastic body 7 can be maintained. Specifically, when polyimide is used for the insulating layer 5 and a pet film is used for the elastic body 7, the heating temperature is preferably about 60 to 100 ° C., and the pressure is about 30 to 50 kg / cm ^2. Is appropriate. The film thickness of the insulating layer 5 on the protrusion 1 after being stretched in this way is about 1 to 5 μm.

  Next, as shown in FIG. 1C, the surface of the insulating layer 5 is removed with a uniform thickness by performing isotropic etching with the substrate set in a plasma desmear apparatus. That is, by setting a base material laminated in a cylindrical reaction chamber for generating plasma, isotropic etching is performed on the surface of the insulating layer 5 by plasma of oxygen + CF 4 to obtain a uniform thickness (1 to 5 μm). Etch with.

  And as shown in FIG.1 (d), each processus | protrusion 1 is made to protrude by the same length from the surface of the insulating layer 5 by etching the insulating layer 5 with uniform thickness. Although the protrusion length varies depending on the etching time, at least, if the tip protrudes, the bonding with the second base material 11 can be realized.

  And finally, as shown in FIG.1 (e), the 2nd base material 11 which consists of copper foil etc. is covered on the upper surface which the protrusion 1 protruded, and the 1st base material 3 is pressed by pressing this 2nd base material 11. And the 2nd base material 11 is joined and electrical continuity is obtained through the protrusion 1. That is, by pressing the second base material 11, the tip of the protrusion 101 that protrudes from the insulating layer 5 is crushed, so that electrical continuity with the second base material 11 is obtained.

  Through the above steps, a multilayer (double-layer type) and a double-sided substrate having protrusions having a uniform height can be manufactured without performing physical polishing.

It is process drawing explaining the manufacturing method of the multilayer type multilayer and double-sided substrate which concern on embodiment of this invention. It is process drawing explaining the manufacturing method of the multilayer type multilayer and the double-sided board | substrate using the conventional protrusion. It is process drawing which showed the film grinding | polishing process which is an essential process in the manufacturing method of the conventional multilayer type multilayer and double-sided board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Protrusion 3 ... 1st base material 5 ... Insulating layer 7 ... Elastic body 9a, 9b ... Pressing plate 11 ... 2nd base material 101 ... Protrusion 103 ... 1st base material 105 ... Insulating layer 107 ... 2nd base material

Claims (3)

Forming at least one protrusion on the first substrate surface having a flat surface;
Disposing an insulating film on the first substrate surface on which the protrusions are formed;
Disposing an elastic body on the film and pressing the film at a constant pressure by the elastic force of the elastic body;
Removing the film on the protrusion stretched by the constant pressure by a dry etching method;
A method of manufacturing a multilayer substrate and a double-sided substrate, comprising: placing a second base material having a flat surface on the protrusion exposed by the removal of the predetermined film thickness and bonding the protrusion to the protrusion.   The method for manufacturing a multilayer board and a double-sided board according to claim 1, wherein the elastic body is made of a material softer than the composition of the protrusions.   The multilayer and both surfaces according to claim 1, wherein, in the pressing step, the heating temperature is equal to or higher than a temperature at which the insulating layer is softened and is equal to or lower than a temperature at which the elastic body has elastic characteristics. A method for manufacturing a substrate.

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