Placement Accuracies Research Articles

91‐3: Placement Accuracy of MicroLEDs in the 5µm Size Range Being Laser Mass Transferred

MicroLED displays require device placement accuracies that meet the dimensional restrictions of the contact pads. We will report on accuracies achieved by a laser forward transfer (LIFT) system with dies in the 5μm size range over gap distances around 10‐20 times the thickness of the devices and discuss the implications thereof.

Comparison of accuracy and early outcomes in robotic total knee arthroplasty using NAVIO and ROSA

This study aimed to compare the cutting and component placement accuracies and early outcomes after total knee arthroplasty (TKA) between an image-free handheld robotic system (NAVIO) and a radiography-based robotic system (ROSA). This retrospective study included 88 patients (88 knees) who underwent TKA using the NAVIO (40 patients) or ROSA (48 patients) robotic systems. The accuracies of the robotic systems were compared. Clinical scores were evaluated using the Knee Society Score 2011 (KSS 2011) and the forgotten joint score (FJS)-12 at 1 year postoperatively. The femoral sagittal cutting error was smaller in the NAVIO group than in the ROSA group. The other cutting errors were not statistically different in both groups. Implantation errors did not differ between the groups. Regarding the clinical outcomes of the KSS 2011 subscales, the symptoms score was higher in knees operated using ROSA than in those using NAVIO. The other KSS 2011 subscales and the FJS-12 showed no differences between the two groups. In conclusion, the femoral sagittal cutting error was smaller in the NAVIO group than in the ROSA group, and the KSS 2011 symptom score subsection at one year was higher in the knees operated using ROSA than in those using NAVIO.

Fiber-Array-to-Chip Interconnections With Sub-Micron Placement Accuracy via Self-Aligning Chiplets

A self-aligning silicon chiplet approach is used on a silicon-on-insulator (SOI) substrate with ridge waveguides and grating couplers to enable interconnection with arrays of fibers. The approach is enabled by silicon micromachining and 3D printing, achieving highly scalable surface coupling of optical fibers to the gratings at repeatable sub-micron placement accuracies. The coupling efficiency relative to that of active fiber alignment at 1550 nm is 79%. Insertion points for 160 fibers across four chiplets are demonstrated. The design, fabrication and assembly processes together provide a potential technology for fiber-to-chip interconnects.

Comparative Retrospective Analysis of Accuracy of Robotic-Guided versus Fluoroscopy-Guided Percutaneous Pedicle Screw Placement in Adults with Degenerative Spine Disease

Background:Robotic-guidance for pedicle screws can reportedly increase placement accuracies and surgical efficiencies especially in percutaneous approaches.Objective:The study aimed to compare the accuracy of percutaneous pedicle screw placement and post-operative course of robotic-guidance versus fluoroscopy-guidance performed by a surgeon experienced in performing fluoroscopy-guided MIS spinal fusions.Study Design:This is a retrospective medical chart review of 2 cohorts of consecutive patients operated by the same surgeon.Methods:Medical records of adults suffering from degenerative spine disease treated by percutaneous spinal fusion surgeries with robotic-guidancevs. fluoroscopy-guidance were reviewed. Endpoints included pedicle screw placement accuracy (on post-operative CTs) and surgical complications and revisions.Results:Ninety-nine patients were reviewed in each arm which were similar in demographics and surgical indications. The robotic arm had 5.8 screws per case on average and 6.0 in the control arm (p=0.65). No significant differences were found in postoperative complication rates revision surgeries length of stay duration of surgery screw implantation times blood loss or results of Oswestry Disability Index questionnaires.Post-operative CTs were available for 52 patients (293 screws) in the robotic arm and 70 (421 screws) in the freehand controls. In the robotic arm 100% of screws were found accurately placed within the “safe zone”vs. 410 screws (97.4%) in the control arm (p=0.005). Of 11 breaching screws in the control arm one breached by 6mm but the patient did not suffer from any sequelae (12-month follow-up). The average follow up period was 9.2±4 months in the robotic-guided arm and 10.5±3 in the control arm. There were no significant differences in complications or revisions.Conclusion:A modest yet statistically significant increase in pedicle screw placement accuracy was observed with robotic-guidance compared to freehand. Larger prospective studies are needed to demonstrate differences in clinical outcomes.

Pedicle screw placement accuracy of bone-mounted miniature robot system.

This article describes factors affecting the accuracy of transpedicle screw placements performed with the Renaissance robot-guided system and reviews the relevant literature. Between January 2013 and January 2015, Renaissance robot-guided spinal surgery was performed in 125 patients at Kaohsiung Medical University Hospital in Kaohsiung, Taiwan. The surgeries included 662 transpedicle screw implants and 49 Kirschner wire (K-wire) reimplants performed by intraoperative repositioning. The lead author evaluated the accuracy of all K-wire insertions and classified their accuracy into 3 categories relative to the preoperative plan for transpedicle screw placement. For cases in which screws required repositioning after the registration step, factors affecting pedicle screw placement were determined according to the consensus of 3 experienced spinal surgeons. According to the scheme developed by Kuo et al (PLoS One 2016;11:e0153235), the K-wire placement accuracies before and after repositioning were respectively classified as follows: 76.1% and 77.6% in type I; 12.2% and 17.7% in type IIa; 4.3% and 4.5% in type IIb; 6.4% and 0% in type IIIa; and 1% and 1% in type IIIb. The percentage of screws requiring repositioning due to drilling error was 85.7% (42/49). Comparisons of preoperative and postoperative function showed significantly improved accuracy. This study showed that inaccurate pedicle screw placement mainly results from errors in preoperative planning, mounting, registration, drilling, and robot assembly. Pedicle screw placement using a bone-mounted miniature robot system requires meticulous preoperative planning to minimize these errors.

A Decade of High Accuracy Die Attach Equipment and Process Developments (Addressing Photonics Device Packaging Challenges)

Fueled by the Internet and nowadays unlimited connectivity expectations, the assembly of optoelectronic packages became a key element to enable the explosive growth in the communication field around the entire globe. The primary challenge in the field of advanced optoelectronics and photonic device packaging (e.g. laser diodes, VCSEL's, optical benches, lenses etc.) is to accurately align the different optical components in reference to each other for optimal optical device performance. This growing need for high precision die attach (<= 0.5um @ 3 sigma) systems and solutions at the shortest possible cycle times has been studied and implemented by AMICRA Microtechnologies. AMICRA's state of the art high accuracy automated assembly system solutions have been successfully used for over a decade in both a laboratory setup and a high volume manufacturing environment. From handling a large variety of substrate materials, thin and fragile chips with odd aspect ratios, lenses and other components, the flexible and dynamic vision alignment concept and the bonding process controls required to achieve high overall component placement accuracies has been AMCIRA's industry focus since the company's inception. While significant progress has been made to provide solutions for all communications and photonics applications there are currently still some challenges out there to be overcome, challenges that can also change on an application by application basis. Besides the technical challenges the cost effectiveness or cost per bond for those applications is a very critical overall success factor as well. This paper will elaborate on manufacturability concerns and equipment automation challenges associated with the key parameters of a Photonics applications high accuracy die attach process which, amongst others, not only require highly sophisticated vision alignment algorithms but also thermal transfer processes either using an eutectic process or a laser soldering technique. Given the ever shrinking packaging form factors, all of AMICRA's research and developments in the Photonics field have also been successfully introduced and applied in more traditional semiconductor applications which have an increasing need for high accuracy die attach.

Engineering and quantum control of single spins in semiconductors

Abstract

A new stent for miniscrew implant placement

In recent years mini implants have added new horizons in clinical orthodontics. However, the success of miniscrew implant is mostly dependent on the placement accuracies in horizontal and vertical direction. To fulfill this goal the article introduces a new innovation – the TNA (Tarulatha, Nitin, Amit) stent. This particular stent with multiple loops in both horizontal and vertical arm will guide the clinician in choosing the right location with the abundant bone for the secure and safe implant placement. Vertical arm is of help in deciding the height of the implant placement in cases such as deep bite where the implant needs to be placed high. Other striking feature is of the occlusal guide arm for deciding the X-ray direction. Multiple use of this stent which can be constructed chair side makes it unique in the crowd of implant guiding stents.

Accuracy and Safety Assessment of Pedicle Screw Placement Using the Rapid Prototyping Technique in Severe Congenital Scoliosis

The application of rapid prototyping (RP) technique for improving accuracy of pedicle screw placement in congenital scoliosis is described in this study. To compare the accuracy and safety of pedicle screw placement in congenital scoliosis using the RP technique versus the conventional fluoroscopy. Maldeveloped vertebral components in congenital scoliosis leads to prolonged operation time and higher rate of screw misplacement. RP technique can enhance preoperative and perioperative planning. No data are available on the accuracy of pedicle screw fixation using the RP technique. Sixty-two consecutive patients with hemivertebra had undergone posterior-only hemivertebra resection. Pedicle screws were implanted either by the conventional intraoperative fluoroscopy technique (C-arm group; n=28) or the RP technique (RP group; n=34). Accuracy of pedicle screw placement was compared by postoperative computed tomographic scan. Seventy of 677 inserted screws were found to be misplaced, showing an overall accuracy of 89.7% (90.8% in the thoracic spine and 87.4% in the lumbar spine). In the C-arm group, 86.1% (167 of 194) and 82.0% (82 of 100) of screws were accurately placed in the thoracic and lumbar spine, respectively. While in the RP group, the respective screw placement accuracies were 94.4% (238 of 252) and 91.6% (120 of 131). In the C-arm and the RP groups, 94.8% (279 of 294) and 97.9% (375 of 383) of the screws were within the safety zone, respectively. Compared with the fluoroscopy method, the RP-assisted technique showed a shorter operation time and higher scoliosis correction rate. No neurovascular-related complication was observed with this technique during the study. The application of RP technique in congenital scoliosis can reduce the operation time, the risk of screw misplacement and its consequent complications. The use of RP technique in congenital scoliosis is safe and efficacious.

Three‐dimensional ultrasound image‐guided robotic system for accurate microwave coagulation of malignant liver tumours

The further application of conventional ultrasound (US) image-guided microwave (MW) ablation of liver cancer is often limited by two-dimensional (2D) imaging, inaccurate needle placement and the resulting skill requirement. The three-dimensional (3D) image-guided robotic-assisted system provides an appealing alternative option, enabling the physician to perform consistent, accurate therapy with improved treatment effectiveness. Our robotic system is constructed by integrating an imaging module, a needle-driven robot, a MW thermal field simulation module, and surgical navigation software in a practical and user-friendly manner. The robot executes precise needle placement based on the 3D model reconstructed from freehand-tracked 2D B-scans. A qualitative slice guidance method for fine registration is introduced to reduce the placement error caused by target motion. By incorporating the 3D MW specific absorption rate (SAR) model into the heat transfer equation, the MW thermal field simulation module determines the MW power level and the coagulation time for improved ablation therapy. Two types of wrists are developed for the robot: a 'remote centre of motion' (RCM) wrist and a non-RCM wrist, which is preferred in real applications. The needle placement accuracies were < 3 mm for both wrists in the mechanical phantom experiment. The target accuracy for the robot with the RCM wrist was improved to 1.6 +/- 1.0 mm when real-time 2D US feedback was used in the artificial-tissue phantom experiment. By using the slice guidance method, the robot with the non-RCM wrist achieved accuracy of 1.8 +/- 0.9 mm in the ex vivo experiment; even target motion was introduced. In the thermal field experiment, a 5.6% relative mean error was observed between the experimental coagulated neurosis volume and the simulation result. The proposed robotic system holds promise to enhance the clinical performance of percutaneous MW ablation of malignant liver tumours.

X-Ray Mask Fabrication Using New Membrane Process Techniques

A membrane process, in which the resist and the absorber are patterned after backetching, was developed to produce highly accurate X-ray masks. Two new techniques allow us to use the same equipment as that currently used in our wafer process. One is a one-point holder for electron beam writers that clamps, without causing any deformation, a small area of the wafer from both sides with just one pair of projections. The reproducibility of the pattern positioning obtainable with the new holder is below 36 nm (3σ) in both x and y directions. The other technique is an etching method that uses a heat sink to prevent temperature increases in the membrane during absorber etching. With the heat sink, there is no difference between the etch rate of the absorber film on the thinned membrane and that on the Si wafer. A comparison between the pattern placement accuracies of X-ray masks produced by the above membrane process and by the conventional wafer process confirms that highly accurate X-ray masks can be fabricated by the membrane process when there is extensive absorber coverage.

無変形真空チャックの開発

A new soft-handed vacuum chuck has been developed to allow the precise measurement of the placement accuracies of X-ray masks and wafers, which are deformed by stresses in processes. As their thicknesses are thin, it is difficult to clamp them without deformation. The chuck has three vacuum pinpads that prevent lateral movement and enable a vacuum seal. This set-up enables a lateral clamping force that can bear an acceleration of 0.3 g and clamping without deformation. Deflections of a 3-inch silicon wafer and an X-ray mask substrate with a 30-mm-square window calculated with the finite element method were minimized at the support radius of 24 mm and 29 mm. Using this chuck with a NIKON 3 I laser interferometry coordinate-measuring machine, we can measure the placement accuracies of an X-ray mask and a reticle with good repeatability at less than 20 nm (3σ).

Forest cut-over mapping from SPOT satellite data

Abstract Cut-over area and boundary placement accuracies from analogue SPOT Panchromatic (PLA) and Multispectral (MLA) Linear Array images were determined for forest cut-overs typical of the Canadian Prairies. Cut-overs were mapped using a Procom-2 to optically project images on to a photogrammetrically-produced planimetric base map. Overall area accuracies for the SPOT PLA and MLA images were 90-7 per cent, and 89-6 per cent, respectively. The influence of increasing accuracy with increasing cut-over size must be considered, however, when interpreting these figures. Proportional regression models were fit to improve the estimates of cut-over areas. On average, boundary placement errors were 24 m for the SPOT PLA, and 26 m for the SPOT MLA. These errors were influenced by the 25 times enlargement factor encountered in the optical projection, and the scale of the base map itself. The base map scale of 1:20 000 was a limiting factor in this study as both plotting errors and pen line widths contributed to ex...