JPH03104874A - Method for constituting electroless nickel plating layer on metallic mold surface and metallic mold for resin sealing of electronic parts - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Industrial Field of Application] This invention is aimed at, for example, improving the method of forming an electroless nickel plating layer on the surface of a mold for resin molding, and sealing electronic components such as ICs, diodes, and capacitors with resin materials. The improvement of molds for permanent molding is particularly concerned with improving the adhesion of the electroless nickel plating layer to the mold surface, improving the releasability of the resin molded product from the mold surface, and improving the overall resin. Related to shortening molding cycle time. [Prior Art] As a resin sealing molding apparatus for sealing and molding thunderbolt parts with a resin material such as a thermosetting resin, for example, a transfer resin sealing apparatus as shown in FIGS. 4 and 5 is used. Molding molds are known. The mold includes a fixed upper mold 1, a movable lower mold 2 disposed opposite to the fixed upper mold 1, and P. The cavity (it・2■) for resin sealing molding of electronic component 3 placed opposite to the L (parting line) surface and the lower mold? A bot 5 for supplying the resin material 4 disposed on the side, a plunger 6 for pressurizing the resin material fitted in the bot 5, and a bot 5 for supplying the molten resin material placed in communication with the bot 5 and the upper mold cavity 1 side. A transfer passage 7 and heating heaters 8 disposed in both the upper and lower molds (1 and 2) are provided, and resin sealing molding of the electronic component 3 using this mold is carried out as follows. . First, when opening both molds (1 and 2) shown in Fig. 4,
The lead frame 9 with the electronic component 3 mounted thereon is placed in the P. of the lower mold 2.
The resin material 4 is fitted and set in a predetermined position of the setting groove 22 formed on the L surface, and the resin material 4 is supplied into the pot 5. Next, as shown in FIG. 5, the lower mold 2 is moved upward to clamp both the upper and lower molds (1 and 2), and in this state, the plunger 6 pressurizes the resin material 4 in the pot 5. Since the resin material 4 is heated and melted by the heater 8 and pressurized by the plunger 6, it is injected and filled from the bot 5 through the passage 7 into both the upper and lower cavities (Il.21). Therefore, after the required curing time, both molds (1 and 2) are opened, and the cured resin in both cavities (1 and 2 l) and in the passage 7 is removed by the upper and lower ejector machines.
By simultaneously releasing the molds at step 10, the electronic components 3 in both cavities (11, 2+) can be sealed and molded into a resin molded body molded to correspond to the shapes of both cavities. It is. [Problems to be Solved by the Invention] By the way, it is customary to use a thermosetting material for the resin material 4 described above, and therefore, after the resin molding, curing is further performed to accelerate the curing. I'm trying to figure it out. The purpose of the curing described above is to maintain the airtightness of the electronic component 3 and improve its mechanical stability.
Both upper and lower types 1 and 2) P. Another purpose is to efficiently release the resin molded body from the L-plane. That is, when the resin molded body is in an uncured state, the releasing (ejecting) action of the resin molded body after the mold is opened is inhibited, causing the following problem. For example, are there any scratches or defects on the surface of the resin molded product? There is a problem with product quality assurance, such as impairing the airtightness and mechanical stability of electronic parts, or if a part of the resin material is mixed with both types of P. There are problems in terms of resin molding efficiency, such as the fact that residual adhesion on the L side requires time and effort to remove. In addition, after molding, a part of the resin material is deposited in the cull (71> and gate (7■) in the passage 7, as well as in both cavities (L+
・21) Or, if there is residual adhesion in the air vent 12 that communicates with the upper mold cavity 1l, if the next resin molding is performed without removing it, the resin material in both cavities will be damaged. Problems such as filling and voids forming in the resin molding occur. Therefore, the curing time for accelerating the curing of the molten resin material is determined by taking into account the curing time of the resin in the channel (7I), which requires the most curing time, for example, when the mold temperature is 165°C. In this case, the curing time is set to about 70 sec.For this reason, the setting of the curing time described above has been considered to be a factor in lengthening the overall resin molding cycle time. A resin for electronic parts that can improve the releasability of a resin molded body from a mold, shorten the key ring time of the resin molded body, and shorten the overall resin molding cycle time. The purpose of this is to provide a mold for sealing molding.Also, the surface of this type of mold is usually plated with HAλB, Cr, but the surface of the mold after molding is The reality is that it is not possible to reliably prevent residual resin from adhering to the thermosetting resin ( For example, it is thought that this is caused by so-called hydrogen bonds with hydrogen atoms in epoxy resin.Therefore, the present invention provides an electroless nickel plating layer that does not oxidize in the atmosphere on the mold surface. The object of the present invention is to provide a method capable of improving the releasability of a resin molded body from a mold surface and improving the adhesion between the mold material surface and an electroless nickel plating layer. [Means for Solving the Problems] The method of forming an electroless nickel plating layer on a mold surface according to the present invention, which addresses the above-mentioned conventional problems, has the following features: In the method of configuring an electroless nickel plating layer on a mold surface, a plating layer containing an element having a high spread coefficient with respect to both the material surface of the mold and the electroless nickel plating layer is provided between the material surface of the mold and the electroless nickel plating layer. In addition, as the plating layer interposed between the above-mentioned two, C
It is characterized by the use of U plating. Further, the present invention is characterized in that electrolytic nickel plating is used as the plating layer interposed between the above-mentioned two. Further, the plating layer interposed between the above-described two is 0. lμ
It is characterized by being constructed in the form of a thin film with a thickness of 5 μm to 5 μm. Moreover, as a plating layer interposed between the above-mentioned two, H
It is characterized by using ARDCr plating. Further, another method according to the present invention has the following features. That is, the method of forming an electroless nickel plating layer on a mold surface is characterized by interposing a nitride layer between both the material surface of the mold and the electroless nickel plating layer. Furthermore, the mold for resin sealing molding of electronic components according to the present invention includes:
It has the following features. That is, it is a mold for resin-sealing electronic components having an electroless nickel plating layer on the mold surface, and there is a layer between the material surface of the mold and the electroless nickel plating layer. In contrast, it is characterized in that it is constructed by interposing a plating layer containing an element with a high diffusion coefficient. The present invention also provides a mold for resin-sealing electronic components having an electroless nickel plating layer on the mold surface, wherein a nitride layer is interposed between the material surface of the mold and the electroless nickel plating layer. It is characterized by being configured with the following features. [Function] According to the present invention, the releasability of the resin molded article from the mold surface can be significantly improved. That is, by applying an electroless nickel plating layer to the mold surface, it is possible to reliably prevent adhesion between the mold surface and the thermosetting resin due to hydrogen bonding. The mold releasability of the resin molded article can be greatly improved, and therefore, it is possible to efficiently and reliably prevent residual resin from adhering to the mold surface. Furthermore, the curing time for accelerating the hardening of the resin material can be shortened from the conventional approximately 70 seconds to approximately 30 seconds. In other words, in addition to improving the mold releasability of the resin molded product, it is possible to efficiently and reliably release the resin molded product after the curing time (approximately 30 FM), which improves the overall This makes it possible to shorten the resin molding cycle time. Furthermore, in the present invention, since the adhesion between the mold material surface and the electroless nickel plating layer is improved, it is possible to reliably prevent the electroless nickel plating layer from peeling off from the mold material surface. It is. [Example] Hereinafter, the present invention will be explained based on the example diagrams shown in FIGS. 1 to 3. FIG. 1 shows an outline of a transfer resin sealing mold for sealing and molding electronic components with thermosetting resin material, and FIGS. 2 and 3 show , the main parts are shown enlarged. The mold includes a fixed upper mold 11, a movable lower mold 12 disposed opposite to the fixed upper mold 11, and P. A cavity (11l, 121) for resin sealing molding of the electronic component 13 placed opposite to the L side, and a feeding bot 15 for the resin material 14 placed on the lower mold 12 side,
A plunger 16 for pressurizing the resin material fitted in the bot 15, a passage 17 for transferring molten resin material that communicates the bot 15 with the upper mold cavity 111 side, and both upper and lower molds (11 and 12). A heating heater 18, etc., is provided at each of the two. In addition, the material surface of the mold (the contact surface with the molten resin material on the P.L surface of the mold), for example, the upper mold cull (17) corresponding to the bot 15 position and the upper mold cavity between the mold 1
Passage l7 for transferring molten resin material from the upper mold gate (172) communicating with 11 and both upper and lower cavities (11
■・l21)・An electroless nickel plating layer A is formed on the air vent 11■, which communicates the upper mold cavity 11■ with the outside. The following method is suitable for forming the electroless nickel plating layer A on these mold material surfaces. That is, as shown in FIG. 3, if a plating layer C containing an element having a high diffusion coefficient is interposed between the material surface B of the mold and the electroless nickel plating layer A, good. The plating layer interposed between the two may be, for example, C
U plating or electrolytic nickel plating may be used, and
The plating layer is preferably formed into a thin film with a thickness of 0.1 μm to 5 μm for the following reason. That is, ■The diffusion coefficient of Ni element to Fe element is 2.0cn
(/s, ■The diffusion coefficient of Ni element to Cu element is 2
．． 7 cnt/s, ■The diffusion coefficient of Cu element to Fe element is 25.0 cnt/s, so for example, first,
A plating layer C made of Cu element is applied to the material side B of the mold,
Next, an electroless nickel plating layer A made of Ni element may be applied to the plating layer C. When this method is used, the plating film is more efficiently diffused than when the electroless nickel plating layer A is applied directly to the mold material surface B, so that the Cu element is removed from the mold material surface B. By applying electroless nickel plating layer A through thin film plating layer C,
As a result, the electroless nickel plating layer A can be reliably adhered to the material surface B of the mold. Therefore, the electroless nickel plating layer A, which is firmly adhered to the mold material surface B, can be easily peeled off during resin molding, etc.
Defects are prevented. When such defects (pinholes or microcracks) exist on the mold surface, the molten resin material infiltrates into the defects and hardens, resulting in the area being undercut when the resin molded product is released from the mold. It acts in the same way as cutting and becomes a cause of poor mold release. However, since the electroless Nigel plating layer A is firmly adhered to the material surface B of the mold, there is an advantage that, for example, there is no need for re-plating treatment for the purpose of repairing a defective part that has occurred on the mold surface. There is. Note that when the base material contains a large amount of Cr element or carbon, a phenomenon is observed in which carbides are formed and prevent the plating film from spreading. Therefore, from this point of view, it is preferable to select carbon tool steel or the like that does not contain a large amount of Cr element or carbon in the base material (mold material) itself. In addition, as a plating layer interposed between the above-mentioned two, I
LRoCr plating may also be used. In addition, an electroless nickel plating layer is applied to the above mold surface.
If this is prohibited, a nitride layer may be interposed between the material surface of the mold and the electroless nickel plating layer. That is, in this case, a synergistic effect can be expected, such as improving the adhesion between the two and increasing the hardness of the mold surface. Furthermore, the P. of the above mold. Required parts of the resin molding parts arranged on the contact surface with the molten resin material on the L surface, that is, the plunger 16, the bot 15, both the upper and lower cavities, and the extractor turbine (201) fitted in the cull part Also,
The above-mentioned electroless nickel plating NA is applied in the same manner to each mold P. The electroless nickel plating layer A is spread across the entire surface of the L surface. Note that the mold for resin-sealing electronic components having the electroless nickel plating layer A formed on the mold surface can be used in the same way as conventional molds. First, both types shown in Figure 1 <11
- When the mold is opened in step 12>, the lead frame 19 with the electronic component 13 mounted thereon is placed in the P. of the lower mold 12. At the same time, the resin material 14 is supplied into the bot 15 by fitting it into the predetermined position of the setting groove 122 formed on the L surface. Next, the lower mold 12 is moved upward to clamp both molds (11 and 12) (see FIG. 5), and the resin material 14 in the pot 15 is pressurized by the plunger 16. At this time, the resin material 14 is heated and melted by the heater 18 and pressurized by the plunger 16, so that the bot l
5 through the transfer passage 17 to the upper and lower parts. Cavity (1
11/12! 〉 will be injected and filled. Therefore, after the required curing time, both the molds (1 and 2) are opened again, and the cured resin in the cavities (11 and 12+) and the passage 17 is removed from the upper and lower ejector mechanisms.
By simultaneously releasing the molds at 0 and 20, the electronic components 13 in both cavities (11l and 12, The following table of experimental results shows the results and judgments regarding the mold releasability of the resin moldings obtained when resin molding was carried out under the following resin molding conditions. Note that the x mark in the experimental results table indicates that the resin molded product had poor or insufficient mold releasability, and that voids or missing portions were observed to occur due to residual adhesion of the resin during mold release. The same ○ mark indicates that the mold releasability is good and the above-mentioned adverse effects are not observed.In addition, the Δ mark in the overall judgment in the test result table indicates that it is not acceptable, and the same ◎ The mark indicates OK.

[Resin molding conditions] 【Consider】

1. ．． HARoCr (octa-dochrome), and
Products that have been surface treated with Tic (titanium carbide) have many holes and microcracks on the surface. The surface treated according to the present invention (electroless nickel plating) does not have these limitations, and the treated surface forms an extremely smooth surface. 2. If the molten resin material penetrates into the via holes or microcracks and hardens, those areas will act like an undercut when the resin molded product is released from the mold. Therefore, this is thought to be a cause of poor mold release, but in the case of the surface treatment according to the present invention, such an undercut effect does not occur.
Extremely good mold release action and effect on resin molded products can be obtained. 3 In the case of the surface treatment according to the present invention, no adhesion effect due to hydrogen bonding occurs between the electroless nickel plating layer on the mold surface and the thermosetting resin, so the curing time can be reduced by 30 minutes.
Even when set to sec, there is no residual resin adhering to the mold surface after resin molding. In addition, since an efficient mold release action can be obtained, there is no need to use a dedicated ejector mechanism.
The resin molded body can be released from the mold. 4. In the case of the surface treatment according to the present invention, the adhesion of the electroless nickel plating layer to the surface of the mold material is ensured, so it is possible to reliably prevent the electroless nickel plating layer from peeling off from the mold surface. Note that the present invention is not limited to the configurations of the above embodiments, and other methods and ellipses may be arbitrarily selected and adopted without departing from the spirit of the present invention. be. [Effects of the Invention] According to the present invention, the electroless nickel plating layer can be efficiently and reliably adhered to the material surface of the mold. Furthermore, since the mold material surface and the electroless nickel plating layer can be brought into close contact with each other, it is possible to reliably prevent the electroless nickel plating layer from peeling off from the mold material surface. Furthermore, according to the present invention, the releasability of the resin molded article from the mold surface can be improved, so that it is possible to efficiently and reliably prevent residual adhesion of the resin to the mold surface, and This has the effect of shortening the curing time for accelerating the hardening of the resin material, thereby shortening the overall resin molding cycle time. In addition, this improvement in the releasability of resin molded products can reliably eliminate the residual adhesion of resin to the mold for resin sealing molding and the aforementioned adverse effects on resin molding due to this. This product has excellent practical effects and can greatly contribute to the field of molding technology for this type of product, where high quality and high reliability are strongly required.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway longitudinal sectional front view showing the main parts of a mold for resin sealing or shaping according to the present invention, and shows the mold in an open state. FIGS. 2 and 3 are enlarged vertical cross-sectional views of the main parts of the mold for resin sealing according to the present invention. FIG. 4 is a partially cutaway longitudinal sectional front view of an example of a mold for sealing and molding electronic components with a transfer resin, showing the mold in an open state. FIG. 5 is a partially cutaway longitudinal sectional front view showing the mold in a clamped state corresponding to FIG. 4. FIG. [Explanation of symbols] A...Electroless nickel plating layer...Fixed upper mold...Cavity...Air vent...Movable lower mold...Cavity...Set part...Electronic parts ... Resin material ... Pot ... Blunger ... Transfer passage ... Cal ... Gate ... Heater ... Lead frame ... Ejector mechanism ... Eject turbine Fig. 2

Claims (8)

[Claims] (1) In a method of configuring an electroless nickel plating layer on a mold surface, a plating layer containing an element having a high diffusion coefficient with respect to both the material surface of the mold and the electroless nickel plating layer is provided between the material surface of the mold and the electroless nickel plating layer. A method for configuring an electroless nickel plating layer on a mold surface, characterized by interposing a layer of electroless nickel on a mold surface. (2) The method according to claim (1), characterized in that Cu plating is used as the plating layer interposed between the mold material surface and the electroless nickel plating layer. (3) The method according to claim (1), characterized in that electrolytic nickel plating is used as the plating layer interposed between the mold material surface and the electroless nickel plating layer. (4) Claim (2) or (3) characterized in that the plating layer interposed between the mold material surface and the electroless nickel plating layer is formed into a thin film of 0.1 μ to 5 μ.
The method described in. (5) The method according to claim (1), characterized in that HARD Cr plating is used as the plating layer interposed between the mold material surface and the electroless nickel plating layer. (6) A method for forming an electroless nickel plating layer on a mold surface, characterized in that a nitride layer is interposed between both the material surface of the mold and the electroless nickel plating layer. Method of constructing electrolytic nickel plating layer. (7) A mold for resin-sealing electronic components having an electroless nickel plating layer formed on the mold surface, wherein the material surface of the mold and the electroless nickel plating layer have a gap between the two. 1. A mold for resin-sealing electronic components, characterized in that the mold is constructed by interposing a plating layer containing an element with a high diffusion coefficient. (8) A mold for resin-sealing electronic components having an electroless nickel plating layer on the mold surface, with a nitride layer interposed between the material surface of the mold and the electroless nickel plating layer. A mold for resin-sealing molding of electronic components, characterized in that the mold is configured by: