JP2016136564A - Manufacturing method of semiconductor element mounting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor element mounting substrate that facilitates control of half etching.SOLUTION: A manufacturing method includes the steps of: forming a first etching mask 5 that covers a portion to be resin-sealed while excluding a penetration portion on a front side to which plating 4 is applied, and forming a first etching mask 5 for covering the plating and applying half etching from a rear side while excluding the penetration portion at the rear side; performing first etching processing from the rear side in a portion where half etching is applied from both sides in the penetration portion; sticking a film 6 to the rear side to which the half etching processing has been applied, and forming a second etching mask 7 for covering the plating at the front side and applying etching from the front side; performing second etching processing from the front side in a portion where the second etching mask is formed at the front side and the film is stuck at the rear side; and exfoliating the second etching mask at the front side after the second etching processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a semiconductor element mounting substrate that facilitates half-etching control and eliminates the need for plating unnecessary portions.

  In Japanese Patent Application Laid-Open No. 2011-181964 shown as Patent Document 1, a resist plating mask is formed on both surfaces of a metal plate, plating is performed, and after the plating mask is peeled off, etching with a resist is performed to form a lead frame shape. A mask is formed on both sides of the metal plate, half-etching is performed from both sides, and an extremely thin metal part is left near the center of the metal plate in the thickness direction, ensuring the relative positional relationship between the pad and lead. In addition, a technique is described in which after the adhesive tape is attached, the ultrathin metal portion is dissolved and removed by etching.

JP 2011-181964 A

  However, in the process of performing half-etching from both sides of a metal plate as shown in Patent Document 1 and leaving an extremely thin metal portion near the center in the thickness direction of the metal plate, when performing half-etching, on the plane There is a problem that it is very difficult to control the thickness of the ultra-thin metal portion left in the wide area and the narrow area to be equal, and it is not suitable for mass production. And if an extremely thin metal part penetrates, the relative positional relationship of that part will collapse, and the position different from the design position will be fixed with adhesive tape, producing defective products There was also a problem.

  In addition, in order to use the plating layer as an etching resist, it is necessary to perform plating up to a pilot hole peripheral portion which is not originally necessary. In addition, in order to withstand etching processing, an expensive plating that can withstand etching is thickened. There is also a problem that the plating cost increases because it is necessary. In addition, if the plating layer is made thick enough to withstand the etching process, a stronger and stronger plating burr will be generated after etching, which will not only cause extra cost for removing this plating burr, but also remove it. However, there is also a problem that the yield is greatly affected by the occurrence of plating burrs that cannot be achieved.

  The present invention has been made in order to solve such problems, and the object of the present invention is to mount a semiconductor element that facilitates half-etching control and eliminates the need for plating unnecessary portions. It is to provide a method for manufacturing a substrate.

  In order to achieve the above object, a method for manufacturing a substrate for mounting a semiconductor element according to the present invention includes a step of forming a plating mask on both surfaces of a metal plate, and applying the necessary plating to the exposed metal plate; A first etching mask having a desired shape is formed to cover the portion to be resin-sealed as a semiconductor device except for a portion that becomes a penetrating portion on the surface side where the semiconductor element of the metal plate is to be peeled off, Forming a first etching mask having a desired shape for covering the plating except for a portion serving as the penetrating portion on the back surface side of the metal plate and performing half etching from the back surface side of the metal plate; After forming one etching mask, the portion to be the penetrating portion is from both sides of the metal plate, and the portion to be half-etched is from the back side of the metal plate. And after the first etching process, the first etching mask formed on both surfaces of the metal plate is peeled off and bonded to the back side of the metal plate subjected to the half etching process. Attaching a film having a layer, forming a second etching mask having a desired shape for covering the plating on the surface side of the metal plate and etching the metal plate from the surface side; and A second etching mask is formed, and a second etching process is performed from the surface side of the metal plate with the film pasted on the back surface side; The method includes a step of removing the second etching mask.

  Moreover, in the manufacturing method of the board | substrate for semiconductor element mounting of this invention, it is preferable that the said plating mask and said 1st and 2nd etching mask are formed with a resist, and the film which has the said contact bonding layer is a polyimide film.

  According to the method for manufacturing a substrate for mounting semiconductor elements of the present invention, half-etching can be easily controlled, plating burrs are not generated, and the relative positional relationship between the respective parts is not disturbed. A substrate for use can be obtained. Further, since the terminal shape is formed by an etching mask made of dry film resist, it is not necessary to perform plating on unnecessary portions, and generation of plating burrs after etching processing is eliminated.

It is explanatory drawing which showed the manufacturing method of the board | substrate for semiconductor element mounting of this invention in order of the process. (A) is a cross section when the resist layer 2 is formed on both surfaces of the metal plate 1 and then exposed and developed to form the plating mask 3, and the plating 4 is formed on the metal plate 1 exposed from the plating mask 3. FIG. (B) peels the plating masks 3 on both sides, forms the resist layer 2 on both sides again, and then performs exposure and development to form the first etching mask 5 and performs the first etching process. It is sectional drawing when the penetration shape 10 and a half etching shape are formed. (C) After peeling the first etching mask 5 on both sides and forming the resist layer 2 on the front surface side, exposure and development are performed to form the second etching mask 7 and an adhesive layer is formed on the back surface side. It is sectional drawing when the film 6 which has is stuck. (D) is sectional drawing when the metal plate 1 exposed from the 2nd etching mask 7 carries out the 2nd etching process from the surface side. (E) is sectional drawing of the board | substrate for semiconductor element mounting obtained by peeling the 2nd etching mask 7. FIG. It is explanatory drawing which showed the process of manufacturing a semiconductor device using the board | substrate for semiconductor element mounting manufactured by the method of this invention.

Next, the manufacturing method of the semiconductor element mounting substrate of this invention is demonstrated based on FIG.
First, as shown in FIG. 1A, a resist layer 2 is formed on both surfaces of a metal plate 1, and a plating mask 3 for forming plating is formed with the resist layer 2.

  Then, after the necessary plating process is performed to form the plating 4, the plating mask 3 formed on both surfaces is peeled off.

  Next, as shown in FIG. 1B, a resist layer 2 is formed again on both surfaces of the metal plate 1 on which the plating 4 is formed, and a first etching mask 5 is formed on both surfaces. The first etching mask 5 on the surface side is formed so that a part of the penetrating shape 10 such as a pilot hole is formed. The first etching mask 5 on the back side is formed so as to form a pattern necessary for a substrate for mounting a semiconductor element, in addition to a part of the penetrating shape such as a pilot hole.

  At this time, the first etching mask 5 on the back side sufficiently covered the previously formed plating 4 so that the metal plate directly under the plating was not etched by the etching process of the next step and plating burrs were not generated. A shape etching mask is formed.

  Then, a first etching process is performed. At this time, part or all of the portion of the penetrating shape 10 is formed by etching from both sides. In addition, half etching is performed on the back surface side so that a shape necessary for a semiconductor element mounting substrate remains. As for the half etching depth (distance) on the back surface side, it is desirable to etch about 55 to 80% of the thickness of the metal plate. Since half etching is performed only from one side (back side), the control of the etching depth is greatly facilitated as compared to the case where etching is performed simultaneously from both sides.

  Next, as shown in FIG. 1C, the first etching masks 5 on both sides are peeled off. And the film 6 which has a contact bonding layer is affixed on the whole back side by which half etching was carried out. Further, a resist layer 2 is formed on the surface side, and the previously formed through shape 10 is covered so as not to be etched, and a second etching mask 7 for obtaining a shape necessary as a semiconductor element mounting substrate is formed. .

  Next, when a second etching process is performed from the surface side as shown in FIG. 1D, a semiconductor element mounting substrate attached to the film 6 is obtained.

  Next, as shown in FIG. 1E, the target semiconductor element mounting substrate can be obtained by removing the second etching mask 7 on the surface side.

  Using a copper material having a thickness of 0.127 mm as the metal plate 1, a dry film resist (Asahi Kasei E-Materials Co., Ltd .: AQ-2058) was pasted on both sides to form a resist layer 2.

  Next, by performing exposure and development using the glass mask for the front side and the back side on which the pattern for forming the plating 4 is formed, the resist in the part where the plating 4 is formed is removed. Thus, the plating mask 3 with the metal plate surface exposed was formed.

  Next, the plating process was performed and the plating 4 was formed in the exposed part of the metal plate surface. In this example, Ni plating with a set value of 1.0 μm, Pd plating with a set value of 0.05 μm, and Au plating with a set value of 0.02 μm were applied in order from the metal plate surface side to form three layers of plating 4. . (See FIG. 1 (a).)

  Next, the plating mask 3 formed on both surfaces of the metal plate 1 was peeled off with a 3% aqueous sodium hydroxide solution, and further washed with 3% sulfuric acid.

  Next, a dry film resist (Asahi Kasei E-Materials Co., Ltd .: AQ-4096) is pasted on both surfaces of the metal plate 1 on which the plating 4 is formed, and the resist layer 2 is formed, thereby forming a pattern only for the through shape 10 part. The first etching mask 5 was formed by performing exposure and development using the glass mask for the front surface side and the back side glass pattern on which the pattern of the substrate for mounting the semiconductor element was formed in addition to the 10 portions of the through shape.

  At this time, the first etching mask 5 on the surface side on which the semiconductor element is mounted is formed so as to be an etching mask that covers the entire surface except for a part that forms a part of the through hole such as a pilot hole. Further, the first etching mask 5 on the back surface side is a pattern necessary for obtaining a semiconductor element mounting substrate in addition to the through hole, and is formed so as to be an etching mask covering the previously formed plating 4. . The “etching mask covering the plating” refers to an etching mask having a distance necessary for the copper material immediately under the plating to remain without being etched in order to prevent plating burrs from being generated by the etching process. .

  Next, the 1st etching process was performed by the spray etching process using the ferric chloride liquid. At this time, the penetration shape 10 portion was etched from both sides. The pattern necessary for obtaining the semiconductor element mounting substrate was etched so that the opening of the etching mask 5 was half-etched with a depth of 0.095 to 0.10 mm from the back side. Since the half etching process is performed only from the back side, the etching depth can be easily controlled. (See FIG. 1 (b).)

  In this first etching process, a ferric chloride solution having a liquid temperature of 70 ° C. and a specific gravity of 1.47 was used, sprayed at a set pressure of 0.3 MPa by a peristaltic spray nozzle, and the treatment was performed for about 110 seconds.

  Then, the 1st etching mask 5 of both surfaces was peeled using sodium hydroxide aqueous solution, and the acid treatment with a sulfuric acid was performed.

  Next, a polyimide tape (INNOX 05F) 6 with an adhesive layer was attached to the entire back side subjected to half etching. Affixing is performed using a pressure roller at a conveyance speed of 1.0 m / min. Pasted with.

  On the surface side, a dry film resist (Asahi Kasei E-Materials Co., Ltd .: AQ-4096) was applied, and the pattern of the semiconductor element mounting substrate was formed using the pilot hole formed as the through shape 10 as a reference position. Exposure and development were performed using a glass mask to form a second etching mask 7. (See FIG. 1 (c).)

  Next, a second etching process was performed for about 20 seconds using the same ferric chloride solution as described above. (See FIG. 1 (d).)

  At this time, since the surface shape side of the already formed through shape 10 is covered with the second etching mask 7 covered with the dry film resist and the back surface side is covered with the polyimide tape 6, the portion of the through shape 10 is again formed. It is not etched. Further, since the second etching mask 7 on the surface side becomes an “etching mask covering the plating”, the copper material immediately below the plating remains without being etched so that no plating burr is generated by the etching process. Thus, the etching mask has a necessary distance.

  Next, the second etching mask 7 was stripped and post-cleaning was performed. By performing these processes, it was possible to obtain a semiconductor element mounting substrate in which the polyimide tape 6 was adhered to the back side. (See FIG. 1 (e).)

  As described above, in the manufacturing method of the present invention, since the half etching process is performed from one side, the etching depth can be easily controlled, and the half etching part does not penetrate, so the relative positional relationship between the pad part and the lead part. There is no problem that collapses. In addition, since the pilot hole is formed by one etching process from both sides, there is no dimensional change, so that a dimensionally stable substrate for mounting a semiconductor element can be obtained.

  When a semiconductor device is manufactured using a semiconductor element mounting substrate manufactured by the method of the present invention, the semiconductor element 12 is mounted on the pad portion 11 as shown in FIG. The lead part 13 is electrically connected, and the pad part 11, the semiconductor element 12 and the lead part 13 are resin-sealed to form a resin sealing body 14. Then, as shown in FIG. 2B, the polyimide tape 6 is peeled and removed. Thereafter, as shown in FIG. 2C, the semiconductor device is cut into individual semiconductor devices. Since the polyimide tape 6 is peeled and removed after the resin sealing, the relative positions of the pad portion 11 and the lead portion 13 are accurately maintained.

DESCRIPTION OF SYMBOLS 1 ... Metal plate 2 ... Resist layer 3 ... Plating mask 4 ... Plating 5 ... 1st etching mask 6 ... Film which has an adhesive layer (polyimide tape)
7 ... Second etching mask 10 ... Through shape 11 ... Pad part 12 ... Semiconductor element 13 ... Lead part 14 ... Resin sealing body

Claims (2)

Forming a plating mask on both surfaces of the metal plate, and applying the necessary plating to the exposed metal plate;
A first etching mask having a desired shape covering the portion to be resin-sealed as a semiconductor device excluding the portion to be a through portion on the surface side where the plating element is peeled off and the semiconductor element of the metal plate is mounted. Forming a first etching mask having a desired shape for forming a half-etching from the back side of the metal plate, covering the plating except for a portion to be the through portion on the back side of the metal plate When,
After the first etching mask is formed, a step of performing a first etching process from the both sides of the metal plate for the portion to be the through portion, and a portion to be half-etched from the back side of the metal plate;
After the first etching process, the first etching mask formed on both surfaces of the metal plate is peeled off, and a film having an adhesive layer is pasted on the back side of the metal plate subjected to the half etching process, Forming a second etching mask having a desired shape for covering the plating on the surface side of the metal plate and etching the metal plate from the surface side;
A step of performing a second etching process from the surface side of the metal plate in which the second etching mask is formed on the front side and the film is attached to the back side;
A method of manufacturing a substrate for mounting a semiconductor element, comprising the step of peeling off the second etching mask on the surface side of the metal plate after the second etching process. 2. The method for manufacturing a substrate for mounting a semiconductor element according to claim 1, wherein the plating mask and the first and second etching masks are formed of a resist, and the film having the adhesive layer is a polyimide film.

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