This article describes one case of Hole plate board on the face of blistering analysis of the causes and the analysis offers a solution. Ultimately determine the cause Hole plate board surface causes blistering. 

Phenomenon: once after the replacement of PTH trough bath, double panel after plating by the full board plating thick copper plate surface after the foam was found, accompanied by nodulation. Irregular bubble Department, visual shape with the natural flow of a liquid similar traces left, and everywhere is a point to start foaming.

Analysis: Hole of the typical process is: Electroless copper (to oil - wash - coarsening - washing - Acid prepreg - - activation - washing - Reduction (1) - Restore (2) - PTH), total plate thickness of copper plating (water spray - Acid prepreg - - Full board electroplating - Washable - passive - Washable - air dry).

denied under the process of fault arising directly plating steps, because the plating process is simple, if this phenomenon, only then is the full board plating process, that the introduction of organic impurities in the bath. However, the sharing of graphics plating copper plating bath hardly had any problems, thus confirming the chemical produced in the copper section in Shenyang.

Shen copper in the chemical steps, we will focus on the reduction process with PTH. According to replace the bath before the treatment effect to the oil and activation are good, rough not too much of relationship with this phenomenon, but these do not replace the tank bath. According to the shape of foam that: This is caused by a still liquid, liquid preparation for PTH in strict accordance with the parameters of the implementation of suppliers, but also liquid is just preparation, and reducing agent in the introduction of impurities may lead to this phenomenon. Reducing agent composition is unclear, except that concentrate. After the restore is not washed, direct chemical PTH, which makes copper impurities into the slot Shen possible.

Solution: contact with the supplier, the supplier proposes to restore (2) to the distilled water washing. With recommendations, the situation has improved, but did not achieve the stability required for production. After more than a week of maintenance and adjustment of the solution reaches a steady state, after the chemical deposition of copper plate surface brightly-colored, dense layer of copper by the full board did not bubble produced after plating.

Summary: From the above situation, we think the analysis in turn, in which more than a week of time remaining on the parameters of vendor maintenance, replacement of only two to three days separated the first reduction (2) distilled water washing, to prevent the reduction (2) the reduction (1) the residue of the concentration from rising into the Er Shi. From this situation we believe that reducing the introduction of impurity analysis is wrong.

secondary analysis: Since the introduction of impurities may be negative, then why? In the control process to discover new reaction with the solution quickly, whether the activity of it bubbling? This concern to us, but because the solution has reached steady state, unable to find fault, the Bath of the replacement cycle is longer, for Tracing stopped bubbling.

activity of the relevant factors we have: Cu, NaOH, HCHO and other components of the content, temperature, complexing agent concentration, stabilizing agent for analysis. We can see from the following: 
1) The deposition rate increased as the Cu content increased, following the initial part of a positive correlation between almost. 
2) With the OH-, HCHO concentration and temperature increase, the deposition rate will rise. The main type of reaction can be confirmed: 2HCHO +2 Cu2 + +4 OH-→ Cu +2 HCHOO-+2 H2O + H2 ↑ (1) when [HCHO], [Cu2 +], [OH-] any of a rise in balance on the left, that reaction is accelerated. 
3) concentration exceeds the threshold, the slow deposition rate, there are data that increased side effects at this time. Few side effects noted: Cu2 + → Cu + (2) Cu + + Cu + → Cu ↓ + Cu2 + (3) (2), (3) type described in the alkali condition, Cu2 + may be reduced to Cu +, Cu + in alkali conditions, the formation of small particles easily disproportionation, irregularly distributed in the solution. 
4) reaction (1) type in H2 production. Therefore, starting from the response analysis: a new preparation of solution concentration we generally take the recommended upper limit and lower limit of the value, so the activity of strong solution.

assumed by the high levels of reduction (1) treatment, and then restored by low concentrations (2) processing, some residual board surface concentration of the solution has not been fully reduced, directly into the chemical tank PTH is highly Strong activity in the bath so that the rapid Cu deposition in the board, left the upper part of the catalyst concentration is strong, its response speed was faster, even too late to Cu, the deposition of dense and strong binding with the copper foil substrate. Reaction of H2 is too late to discharge, was the formation of air bubbles surrounded by copper deposition to the deposition of the copper foil substrate created separated from foaming. Tumor-like substances, there may be a byproduct of high-speed response to Cu particles attach to board, we know that Cu particles in spherical contact with the solution, does not seem to part of the area of contact with copper substrate.

result of the reaction area, the larger particles of copper, its much faster reaction speed, so that local self-catalytic chemical deposition faster. Based on the above understanding, we know that overactivity (ie, fast reaction) is the root causes blistering. Thus control the speed of response to a fundamental solution to bubble generation.

solution: replace the bath in the second, we note that the components of the control parameters and the changes to the supplier, is expressed as follows: Following the above changes, the operating temperature by cold start the control group were in the lower state. Replacement of bath deposited the first day of the board, bright color, coating density, hole of good quality, foaming ratio is only 0.8% (by block number of years) so, even in the presence of this phenomenon, bubble size, degree of light. Relative the previous volume, large area, gravity of the situation, the situation changed greatly. After two to three days of normal maintenance, blistering disappeared, so as to achieve stable production.

Summary: Following the above adjustments, the basic condition to achieve our expectations, but still blistering. From this adjustment is a test. Each group were not to achieve the best matching state. After appropriate adjustments are fully able to achieve the best.

suggestions: 
1) From a combination of factors to consider measures to slow the reaction rate can be more comprehensive. In the reduction of Cu, HCHO, NaOH concentration, while component, increase the complexing agent, stabilizer concentration, this will enable the group were to maintain a relatively high concentration, the concentration is too low to avoid the group were caused by black holes and other bad hole technology, but also maintain a relatively slow speed of response. That is to take a single approach is not desirable, that would lead to the solution in loss of balance. 
2) With the passage of time, component concentration should increase with. So, in the first few days, closely monitoring the concentration of critical components, appropriate adjustments based on sediment quality component concentration. When the stable state, should be provided to the supplier's parameter values. 
3) The concentration of reducing agent suitable lower. Must be pointed out: This is only for qualitative discussion, the concept for the amount of the actual situation should be different treatment. Therefore, the process reflected in the wording of this. During operation, make records, to identify general rules for the regular add, because some components of the growth and nonlinear. : Analysis of (Nanjing Electric Power Automation Equipment Factory 7 factory in Nanjing 210003)