JP2003130776A - Method of measuring degree of cure of resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which the degree of cure of a resin can be judged accurately. SOLUTION: After the copper surface 16 of a copper-clad plate 15 is roughened, a CLE varnish is applied to the roughened surface 16 and preliminarily cured. After the varnish is preliminarily cured, the weight of the copper-clad plate 18 coated with the CLE varnish is measured. Then the preliminarily cured PLE varnish is worn away under a prescribed condition by using a rotary abrasion tester (made by Toyo Seiki Co., Ltd.). Successively, the weight difference (abrasion wear) of the copper-clad plate 18 before and after the varnish is worn away is calculated by measuring the weight of the copper-clad plate 18 after the varnish is worn away. Then the degree of cure of the CLE varnish is judged based on the calculated abrasion wear by utilizing the correlation between the abrasion wear and degree of cure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the degree of cure of resin or the like filled in through holes or the like formed in a printed wiring board. More specifically, the present invention relates to a resin curing degree measuring method capable of accurately determining a resin curing degree.

[0002]

2. Description of the Related Art In printed wiring boards and the like, through holes and the like are filled with a resin (thermosetting resin) in order to ensure flatness. However, for example, when the through hole is filled with resin, the filled portion becomes convex (see FIG. 1). If the upper layer is laminated in this state, the flatness of the upper layer cannot be ensured. Therefore, the convex portion of the resin is polished with a belt sander or the like to ensure the flatness.

Here, when the resin is polished under the same polishing conditions, the softer the resin is (not cured), the larger the polishing amount is, and the harder the resin is (hardened), the smaller the polishing amount is. That is, it is considered that there is a correlation between the amount of resin polished and the degree of curing thereof. Therefore, in order to accurately and flatly polish the pre-cured resin after filling the through holes and the like, it is important to know the degree of curing of the pre-cured resin before polishing. Therefore, conventionally, it is performed to visually judge the degree of curing of the resin from the color change or sag of the resin, determine the degree of curing of the resin by touching the finger, or determine the degree of curing by the pencil hardness method. ing.

[0004]

However, the conventional method has a problem that it is difficult to accurately determine the degree of cure of the resin. That is, since the determination of the degree of curing of the resin is finally performed by visual inspection or finger touch (human sense), it is highly possible that the determination result will be different if the determiner is different. Therefore, the degree of cure varies and cannot be accurately determined. If the degree of cure of the filled resin cannot be accurately determined, polishing of the convex portion of the resin is often performed in a state where the polishing conditions are not suitable. For this reason, when the filled resin is polished, there is a problem that polishing failure tends to occur such as excessive polishing or conversely insufficient polishing.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for measuring the degree of cure of a resin which can accurately determine the degree of cure of the resin.

[0006]

The method for measuring the degree of cure of a resin according to the present invention, which has been made to solve the above-mentioned problems, comprises:
Applying resin on a substrate, pre-curing the resin, measuring the weight of the substrate in that state, then abrading the resin in the pre-cured state under specified conditions, and measuring the weight of the substrate after the abrasion is completed. According to the above, the weight difference of the substrate before and after the abrasion is calculated, and the curing degree of the resin is determined based on the calculated weight difference.

In this measuring method, first, resin is applied onto the substrate. Then, the resin applied on the substrate is pre-cured in a heated state for a predetermined time, and the weight at that time is measured. Then, the precured resin is abraded under predetermined conditions.

[0008] Here, the resin may be abraded by bringing the wear wheel into contact with the pre-cured resin under a predetermined load and rotating the substrate by rotating the substrate a predetermined number of times in that state. Specifically, the resin may be worn using a wear tester. Then, the predetermined load and the predetermined number of rotations may be set to values that can be set by the testing machine.

After the resin is thus abraded, the weight of the substrate after abrasion is measured to calculate the weight difference between before and after abrasion of the substrate coated with the resin, that is, the amount of abrasion. Then, the degree of cure of the resin is determined based on the calculated weight difference. The degree of cure of the resin is known from the amount of wear (difference in weight) in this way because there is a correlation between the amount of wear of the resin and the degree of cure thereof (see FIG. 2). Here, the amount of wear of the resin is that when the resin is worn under constant wear conditions, and is measured by a measuring device. Then, the degree of cure of the resin is determined based on the amount of wear measured by the measuring device. That is, the degree of cure of the resin is determined without relying on the human sense. For this reason, according to the measuring method of the present invention, the degree of curing of the resin can be accurately determined with little variation among the measurers.

Further, in the method for measuring the degree of cure of a resin according to the present invention, it is preferable that the surface of the substrate is roughened, and then the resin is applied to the roughened surface and precured. This is to improve the adhesion between the substrate and the resin. That is, since the amount of wear can be accurately measured by preventing the resin from peeling off from the substrate during wear, the degree of cure can be more accurately determined.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The most preferred embodiment of the method for measuring the degree of cure of a resin according to the present invention will be described in detail below with reference to the drawings. In this embodiment, CLE
(Cross Linking Epoxy) When measuring the degree of cure of a varnish, the method of measuring the degree of cure according to the present invention is applied.

This CLE varnish is a thermosetting resin used for forming through holes formed in a printed wiring board or between wiring patterns, and includes CLE-A agent and C
It is composed of a LE-B agent. Where CLE-A
The agent is a mixture of silica filler and epoxy resin, and the CLE-B agent is a curing agent.

Such CLE varnish is manufactured by mixing an epoxy resin, a silica filler, and a curing agent. This manufacturing process includes a stirring process and a three-roll process. First, in the stirring step, by a planetary mixer, silica filler, epoxy resin,
And the defoamer is agitated and mixed. Next, in a three-roll process, the mixture is defoamed and the aggregated silica filler is dispersed. Thus, the CLE-A agent is manufactured.

Next, the curing agent mixing step will be described.
In this step, the CLE-B agent (curing agent) is mixed with the CLE-A agent obtained in the above mixing step. Thus, CL
E varnish is obtained.

Then, the CL manufactured as described above
The E varnish is filled in through holes and the like formed in the printed wiring board. Here, when the through hole is filled with CLE varnish, the surface of the CLE varnish becomes convex as shown in FIG. Also, when the CLE varnish is filled between the wiring patterns, the surface is not completely flat. Therefore, in order to completely flatten the surface of the CLE varnish, the CLE varnish is pre-cured and then polished using a belt sander. By this polishing, the upper layer can be laminated while the flatness of the CLE varnish is ensured. Then, the filled CLE varnish is completely cured by being heated in a state where the flatness is ensured.

By the way, as described above, it is considered that there is a correlation between the amount of wear of the CLE varnish (filling resin) and the degree of hardening thereof. Therefore, if this idea is correct, the degree of cure of the CLE varnish can be determined by measuring the amount of wear of the CLE varnish in the pre-cured state. Based on this idea, the curing temperature is 105 to 12 in increments of 5 ° C.
CL pre-cured at 5 ° C with different degrees of cure
The amount of wear of the E varnish was investigated using a rotary abrasion tester (manufactured by Toyo Seiki). The result is shown in FIG.

Here, a method of investigating the wear amount of the CLE varnish performed to obtain the results shown in FIG. 2 will be described.
First, as a substrate for applying the CLE varnish, a copper-clad plate 15 cut into a size of 10 × 10 cm as shown in FIG. 3 is prepared. Then, as shown in FIG. 4, the copper surface 16 of the copper-clad plate 15 is roughened by blackening treatment.
The roughening treatment of the copper surface (substrate surface) is not limited to the blackening treatment, and may be any treatment that can roughen the surface. The reason why the copper surface (substrate surface) is roughened in this way is to improve the adhesion of the CLE varnish. Next, as shown in FIG. 5, the CLE varnish 17 is uniformly applied to the roughened copper surface 16, and the CLE varnish 17 is pre-cured. The curing conditions at this time are that the curing temperature is the above-mentioned 5 conditions, and the curing time is 20 minutes. In this way, the copper-clad plate 18 with the CLE varnish for evaluating the degree of curing is obtained.

C pre-cured under each curing condition
A hole for attaching to a rotary abrasion tester (manufactured by Toyo Seiki) is opened in the center of the copper varnished copper plate 18 (FIG. 6), and the weight at that time is measured. After measuring the weight, the CLE varnished copper-clad plate 18 is set on a rotary abrasion tester (manufactured by Toyo Seiki) (see FIG. 7). Then, CL cured under each curing condition by this rotary abrasion tester (manufactured by Toyo Seiki)
E Varnish abrasion test is performed.

Here, a rotary abrasion tester (manufactured by Toyo Seiki) will be briefly described with reference to FIG. Rotary abrasion tester (made by Toyo Seiki)
Is generally used for the wear test of flat materials. This rotary abrasion tester (manufactured by Toyo Seiki Co., Ltd.) is a rotary table 2 to which two wear wheels 21 and 21 having a grindstone 20 attached to the outer peripheral surface thereof and a motor M are connected.
2 and a suction hose 23 connected to a suction device (not shown) for sucking abrasion powder. And wear wheels 21, 21
Multiple loads can be applied to the. The rotation speed of the rotary table 22 is 72 rpm (6
0 Hz).

Then, the inspection material (CLE varnished copper-clad plate 18) is set on the rotary table 22, and the wear wheel 21,
The load condition applied to 21 and the number of rotations of the inspection material are set by a counter. In the present embodiment, the wear wheel 2
The load condition applied to Nos. 1 and 21 is set to 9.8 N, and the counter is set to "500 (rotation)". When the rotary abrasion tester (manufactured by Toyo Seiki Co., Ltd.) is operated after setting the various conditions, the operation is stopped after rotating the inspection material by the set number of counters. At this time, the inspection material is rotated while being in contact with the wear wheels 21 and 21, so that the contact portion is worn. Then, the degree of wear of the inspection material can be evaluated by the weight, thickness, and reduction of gloss of the contact surface of the inspection material with the wear wheels 21, 21.

Using such a rotary abrasion tester (manufactured by Toyo Seiki), a 10 cm square copper-clad plate 1
The wear amount of the CLE varnish applied on 5 and pre-cured is
The results shown in FIG. 2 were obtained by investigating by the method described above.
In addition, in FIG. 2, the N number under each curing temperature condition is
N = 3. From FIG. 2, C increases as the curing temperature increases.
It can be seen that the wear amount of the LE varnish is reduced. Here, generally, if the curing time is the same, the higher the curing temperature is, the higher the curing degree is, and the lower the curing temperature is, the lower the curing degree is. From this, it can be said that the result of FIG. 2 shows that there is a correlation between the wear amount and the curing degree. Therefore, CLE
By calculating the amount of varnish wear, the degree of cure can be accurately determined. Therefore, by this method CL
E Calculate the amount of varnish wear and CL based on the amount of wear.
The degree of cure of the E varnish was determined. Then, when the polishing conditions in the polishing step after filling the CLE varnish were set based on the result of the determination, the surface of the CLE varnish was precisely and flatly polished without causing polishing defects. That is, C
The degree of cure of the LE varnish was accurately determined.

As described in detail above, according to the method for measuring the degree of cure of the CLE varnish according to the present embodiment, first, the copper surface 16 of the copper-clad plate 15 is roughened, and then the CLE varnish is applied to the CLE varnish. Is pre-cured, and the weight of the CLE varnished copper-clad plate 18 in that state is measured. Next, the pre-cured CLE varnish is abraded under a predetermined condition using a rotary abrasion tester (manufactured by Toyo Seiki). Subsequently, the weight of the CLE varnished copper-clad plate 18 after the wear is measured to calculate the weight difference between the CLE varnished copper-clad plate 18 before and after the wear, that is, the wear amount. Then, by utilizing the fact that there is a correlation between the amount of wear and the degree of hardening, C based on the calculated amount of wear
Determine the degree of cure of the LE varnish. In this way, the determination of the degree of cure of the CLE varnish is made without depending on the human sense. Therefore, since there is little variation depending on the measurer, CL
The degree of hardening of the E varnish can be accurately determined.

The present embodiment is merely an example and does not limit the present invention. Therefore, the present invention naturally has various improvements within a range not departing from its gist,
Deformation is possible. For example, in the above embodiment, CL
Although the measurement of the curing degree of the E varnish (thermosetting resin) has been described, the measuring method of the present invention is not limited to the thermosetting resin and is also applied to the evaluation of the curing degree of other curable resins (such as an ultraviolet curable resin). can do. Further, as shown in FIG. 8, the number of rotations of the CLE varnished copper-clad plate 18 and the CLE
It can be said that there is a proportional relationship with the amount of varnish wear. Therefore,
If you want to perform a hardness measurement test in a short time, set the counter setting value of the rotary abrasion tester (manufactured by Toyo Seiki) to "500" or less, and use the amount of wear at that time to obtain a wear equivalent to 500 rotations. It is also possible to estimate the amount and determine the degree of cure. However, in this case, the accuracy of determining the degree of cure may be slightly reduced.

[0024]

As is apparent from the above description, according to the present invention, there is provided a resin curing degree measuring method capable of accurately determining the curing degree of a resin.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which a through hole is filled with CLE varnish.

FIG. 2 is a diagram showing the relationship between the pre-curing temperature of CLE varnish and the amount of wear.

FIG. 3 is a plan view showing a copper-clad plate as a substrate.

FIG. 4 is a cross-sectional view showing a copper-clad plate after blackening treatment.

FIG. 5 is a cross-sectional view showing a CLE varnished copper-clad plate.

FIG. 6 is a plan view showing a CLE varnished copper-clad plate that has been processed for setting on a rotary abrasion tester (manufactured by Toyo Seiki).

FIG. 7 is a diagram showing a schematic configuration of a rotary abrasion tester (manufactured by Toyo Seiki).

FIG. 8 is a diagram showing a relationship between the number of rotations of a substrate by a rotary abrasion tester (manufactured by Toyo Seiki) and the wear amount of CLE varnish.

[Explanation of symbols]

15 Copper plate 17 CLE Varnish 18 CLE Varnished Copper Plate 20 whetstone 21 worn wheels 22 turntable 23 Suction hose

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhiko Takada             11 Ichibashi-nohonmachi, Higashiyama-ku, Kyoto-shi, Kyoto             Inside Nnopco Corporation (72) Inventor Naga Yasuhara             11 Ichibashi-nohonmachi, Higashiyama-ku, Kyoto-shi, Kyoto             Inside Nnopco Corporation

Claims (3)

[Claims] 1. A resin is applied onto a substrate, the resin is pre-cured, the weight of the substrate in that state is measured, and then the resin in the pre-cured state is abraded under predetermined conditions, and the substrate after the abrasion is finished. By measuring the weight,
A method for measuring the degree of cure of a resin, which comprises calculating a weight difference of a substrate before and after abrasion and determining a degree of cure of the resin based on the calculated weight difference. 2. The method for measuring the degree of cure of a resin according to claim 1, wherein a wear wheel is brought into contact with the resin in a pre-cured state with a predetermined load,
In this state, the resin is worn by rotating the wear wheel by rotating the substrate a predetermined number of times, thereby measuring the degree of cure of the resin. 3. The method for measuring the degree of cure of a resin according to claim 1, wherein the surface of the substrate is roughened, and then the resin is applied on the roughened surface to be pre-cured. A method for measuring the degree of cure of a resin.