Matthias Schmeide

Integration of High Dose Boron Implants—Modification of Device Parametrics through Implant Temperature Control

In the present study, we have extended a previously reported 250 nm logic p‐S/D implant (7 keV B 4.5×1015 cm−2) process matching exercise [5] to include wafer temperature, and demonstrate that matching can be obtained by increasing the temperature of the wafer during implant. We found that the high dose rate delivered by the single wafer implanter caused the formation of a clear amorphous layer, which upon subsequent annealing altered the diffusion, activation, and clustering properties of the boron. Furthermore, increasing the temperature of the wafer during the implant was sufficient to suppress amorphization, allowing profiles and device parameters to become matched. Figure 5 shows a representative set of curves indicating the cluster phenomena observed for the lower temperature, high flux single wafer implanter, and the influence of wafer temperature on the profiles. The results indicate the strong primary effect of dose rate in determining final electrical properties of devices, and successful implem...

Characterization of Boron Contamination in Fluorine Implantation using Boron Trifluoride as a Source Material

Fluorine implantation process purity was considered on different types of high current implanters. It was found that implanters equipped with an indirectly heated cathode ion source show an enhanced deep boron contamination compared to a high current implanter using a cold RF‐driven multicusp ion source when boron trifluoride is used for fluorine implantations. This contamination is directly related to the source technology and thus, should be considered potentially for any implanter design using hot cathode/hot filament ion source, independently of the manufacturer.The boron contamination results from the generation of double charged boron ions in the arc chamber and the subsequent charge exchange reaction to single charged boron ions taking place between the arc chamber and the extraction electrode. The generation of the double charged boron ions depends mostly on the source parameters, whereas the pressure in the region between the arc chamber and the extraction electrode is mostly responsible for the ...

Integration of an Axcelis Optima HD Single Wafer High Current Implanter for p‐ and n‐S/D Implants in an Existing Batch Implanter Production Line

This paper is focused on the integration and qualification of an Axcelis Optima HD single wafer high current spot beam implanter in an existing 200 mm production line with different types of Axcelis batch implanters for high current applications. Both the design of the beamline and the beam shape are comparable between single wafer and batch high current spot beam implanters. In contrast to the single wafer high current ribbon beam implanter, energy contamination is not a concern for the considered spot beam tool because the drift mode can be used down to energies in the 2 keV region. The most important difference between single wafer and batch high current implanters is the significantly higher dose rate and, therefore, the higher damage rate for the single wafer tool due to the different scanning architecture. The results of the integration of high dose implantations, mainly for p‐ and n‐S/D formation, for DRAM 110 nm without pre‐amorphization implantation (PAI), CMOS Logic from around 250 nm down to 90...

Characterization of the beam transmission improvements for p- and n-LDD implantations on a single wafer high current spot beam implanter

This paper focuses on the characterization of the biased beam guide option installed in the 200 mm Axcelis Optima HDx single wafer high current spot beam implanter and its use for energy contamination free, drift mode p-LDD and n-LDD implantations. Biased beam guide mode allows reduction of space charge potential and corresponding transmission loss from beam blow up, resulting in horizontally and vertically smaller ion beams. Smaller, highly focused beams have several advantages, such as improved beam transmission, higher dose rate, and require reduced overscan area. Higher beam transmission and higher beam current combined with reduced overscan are two factors that directly affect throughput and productivity. We demonstrate these improvements for several important logic processes. A characterization of the effects of beam guide bias voltage for a 90 nm CMOS logic is reported in detail. The p-LDD and n-LDD implantations investigated were BF2+, As+, and As2+ in the energy range between 3 keV and 5 keV, bot...

Characterization of Charging Control of a Single Wafer High Current Spot Beam Implanter

This paper focuses on the characterization of charging control of an Axcelis Optima HD single wafer high current spot beam implanter using MOS capacitors with attached antennas of different size and shape. Resist patterns are implemented on Infineon Technologies own charging control wafers to investigate the influence of photo resist on charging damage. Compared to batch high current implanters the design of the beamline and the beam shape are comparable to single wafer high current spot beam implanters, however due to the different scanning architecture the dose rate of the single wafer high current spot beam implanters is significantly higher compared to the batch tools. Therefore, the risk of charging damage will be higher. The charging damage was studied as a function of the energy, the beam current and the most important plasma flood gun parameters. The results have shown that for very high antenna ratios the charging damage for single wafer implanters, even spot or ribbon beam implanters, is higher than for high current batch implanters.

Detection and Reduction of the Yield Impact of Particle Induced Structure Defects at Batch Ion Implanters

This paper focuses on the introduction and qualification of the in situ particle monitor so called High Yield Technology (HYT) sensor on an Axcelis NV‐GSD/E 200mm high current batch implanter to detect particles in real time during the implantation process. The particles on the wafer surface were measured with Surfscan and their composition was determined by means of Energy Dispersive X‐ray (EDX) analysis. A good correlation between the HYT particle counts and surface particles on dummy wafers as well as defect densities measured on wafers structured with photo resist was found. Moreover, there is a well defined linear correlation of the HYT particle counts to the yield loss. To reduce the level of particle contamination, preventive maintenance procedures were optimized and the hardware in the beam line was modified. In order to minimize structural damage from high velocity particles, the disk drive was upgraded from a belt drive to a direct drive which offers the possibility to decrease the spin speed, t...

Defectivity Reduction and Control In Ion Implant Systems Through Hardware and Process Optimization

Defect monitoring becomes increasingly important for smaller device structures. Previous publications have shown the damage of particles impacting device structures. The fast movement of the wafers in batch ion implant systems, or a fast moving particle in any implanter, can generate damage on patterned wafers. Defects generated are visible after the implant on an in‐line defect inspection tool as well. Yield loss can be observed at final test if poly‐silicon lines or photo resist patterns become permanently damaged. Reducing the speed of the wafers reduces the force of the particle‐wafer interaction, changing the defect type and severity. Adjusted maintenance procedures are shown to reduce the particle levels of an Axcelis HC3 implanter and lower defectivity levels. Reduced spin speed and specific hardware modifications in the source and beam line areas will be discussed. The influence of these changes on defect density and type is shown. The use of an HYT in‐situ particle monitor helps to detect the occ...