Unlocking the Advantages of xESD for Electronic Components Carriers Fabrication

Results

Figure 2 shows the fabricated semiconductor component carriers evaluated between a Competitor and xESD, as indicated. The parts surpassed the resolution capabilities of the FFF hardware, as anticipated. The 1 mm pockets and channels were clearly defined and appeared to be functional upon visual examination. It is worth noting that the surface finish was noticeably different – the Competitor part had rougher surface quality, while the part fabricated on Nexa3D’s XiP desktop printer with xESD had a smooth, nearly glassy surface finish.

Figure 2: Photos of semiconductor components carrier fabricated using Competitor and xESD/XiP.

In order to ensure that the feature sizes and static dissipative performance meet the requirements of the Customer’s application, the next step involved conducting microscopy analysis and surface resistivity measurements. Figure 3 shows microscopy images of the fabricated components. When comparing the Competitor parts to the desired specifications, it was observed that there was a roughly 7% reduction in channel width and a 10% decrease in pocket size. The part fabricated using xESD exhibited a less than 1% increase in channel width and about a 3% increase in pocket size. The reduced pocket sizes in the Competitor parts rendered them unusable. In contrast, the slight increase in size observed in the part fabricated using xESD did not compromise the performance of the component. Fabricating high resolution parts is essential for the Customer due to the ongoing downsizing of semiconductor components, resulting in an increasing need for improved precision in their manufacturing processes.

Figure 3: Microscopy images of channels (top) and pockets (bottom) display significant deviation from CAD model in Competitor parts compared to xESD.

The static dissipative properties were evaluated according to the ANSI ESD S11.13 – Standard Test Method for the Protection of Electrostatic Discharge Susceptible Items – Two-Point Resistance Measurement. Measurements were taken at 10 locations on the part’s surface. Three separate specimens were tested for each resin and the values were reported in ranges. The measurement map for both the Competitor and xESD is shown in Figure 4. The Competitor part had resistance ranging from 107 to 1011 Ω, with multiple instances where an “Open Loop” reading was observed. An “Open Loop” or OL reading indicates that the tested component lacks continuity and possesses infinite resistance. Infinite resistance implies the absence of an electric current flowing through the component. In contrast, parts fabricated with xESD displayed highly precise surface resistance measurements, ranging from 106 to 108 Ω. The resistivity at any specific location on the component either varied by one order of magnitude or remained constant at 107 Ω.

Figure 4: ESD measurements map showing the range of resistance values collected from each location. The Competitor part failed to deliver acceptable levels of ESD protection. The xESD part displayed nano-uniform ESD performance throughout the component.

The observed variations in the static dissipative performance can be attributed to the noticeable disparities in the surface quality of the components and quality of the CNTs dispersion in a resin.

As noted, the Competitor components exhibited visibly rougher surface finish in contrast to the smooth surfaces of xESD parts. Microscopy images (see Figure 5) further illustrate this discrepancy. The Competitor part displayed an exceedingly rough surface finish with noticeable pitting occurring in multiple locations. When the electrodes of the resistance probe came into contact with the surface of this component, the presence of roughness restricted the effective connection between materials to only a portion of the available area. As a result, current flowed solely through the true contact areas, while the roughness introduced contact resistance. This contact resistance explained the significant differences observed in the surface resistance measurements obtained from the Competitor part when compared to uniform measurements of xESD components.

Figure 5: Microscopy images of the part surface for the Competitor and xESD, as indicated. The Competitor part has extremely rough surface finish compared to xESD. Surface roughness plays a crucial role in discrepancies of the static dissipative readings collected from Competitor parts.

Dispersion quality served as another factor contributing to the discrepancy in ESD readings. To illustrate this point, optical microscopy images of Competitor and xESD resins are presented in Figure 6. The images clearly indicate that Competitor resin contained a higher concentration of CNTs compared to xESD. The crucial distinction between the two was the inferior dispersion quality observed in the Competitor resin, where a significant number of CNT bundles coexisted alongside regions lacking CNTs.

In contrast, microscopy of xESD demonstrates a well-distributed and uniform dispersion of CNTs without the formation of CNT bundles or areas devoid of CNTs due to integration of xESD’s proprietary discrete, dispersed, and functionalized CNTs (D’Func) into the resin.

Figure 6: Optical microscopy images of the Competitor and xESD resins, as indicated. The dispersion quality of the Competitor resin is inferior to the quality of xESD, which contributes to discrepancy in the ESD readings.

Achieving high-quality dispersion is imperative to ensure homogeneous distribution of conductive additives within the polymer matrix. This distribution enables formation of conductive bridges, consisting of overlapping electronic structures, which facilitate electron transfer. The presence of regions without CNTs and highly concentrated areas adversely affects the uniform distribution of the conductive filler in the manufactured component, resulting in sections with inconsistent conductivity.