GridPix R&D

TimePix3 GridPix Detectors

TimePix3 GridPix Detectors

Timepix GridPix Detectors

Timepix GridPix Detectors

Before wafer scale production

ChipID	Board type	Thickness SiRN (µm)	Drift length (mm)	Setup	Remarks
	DARWIN Relaxd	8	60	Gas gain setup	globtop drop on chip (top right)
G05-W0016	DARWIN Relaxd	8	(none)	Gas gain setup	spare
G04-W0057	DARWIN Relaxd	8	soon 60	Gas gain setup	new GridPix for Xe measurements
	NEXT	8	10	EDIT school
	NEXT	8	(none)	EDIT school (intended)	FBK DAC broken after discharge
	NEXT	8	1	Gossip test beam setup	IZM prototype
	NEXT	8	1	Gossip test beam setup	IZM prototype
	NEXT	8	1	Gossip test beam setup	IZM prototype
D02-W0019	NEXT	8	16	Proton therapy	slightly distorted field cage
	NEXT	8	16	EDIT school	originally prepared for Klaus Desch

IZM-2 batch

Put here the experience with the IZM-2 GridPix batch at Nikhef and important conclusions.

Topic	Log/Pictures	Author	Posted
Study SiRN protection layer; pinholes	SiRN layer	Martin Fransen	26-3-2012
Test SRN/Medipix deposition	Test of SRN deposition on MPX wafer	Yevgen Bilevych	11-6-2012
Test SRN/Medipix deposition (II)	New photos of SRN deposition on MPX wafer	Yevgen Bilevych	14-6-2012

IZM-3 batch W0056-TPX

Put here the experience with the IZM-3 Gridpix batch at Nikhef and important conclusions.

Topic	Log/Pictures	Author	Posted
Wafer defects and SU-8 profile of the wafer	Wafer defects map, SU-8 profile	Yevgen Bilevych	26-09-2012
Pics gridpixes from Bonn	Pics A, Pics B	Wilco Koppert	03-09-2012
H10 (Laser Setup)	occupancy plot	Wilco Koppert	04-09-2012
E10 (Gossip 1)	info	Wilco Koppert	21-09-2012
F10 (Gossip 2)	occupancy plot	Wilco Koppert	21-09-2012
J06 (Gossip 3)	occupancy plot, hint?	Wilco Koppert	25-09-201
J08 (Gossip 4)	info	Wilco Koppert	25-09-2012
B06	info
C06	info
D10	info
F04	info
I06	info
J02	info
K04	info
K06	info
M06	info
Testbeam dead chips report	Brief Report
Overview Testbeam Data	Overview
IFAE dead gridpix report	report_brokenGridPix

For the whole batch the wafer ID is W0056-TPX and the SiRN thickness is 8 µm. The list items are in order of the GelPack from top left to bottom right.

ChipID	Board type	Drift length (mm)	Setup	Remarks
B06
C06
D06	DARWIN PCB-A	soon 60	Gain measurement setup	digital test and THL Equ. OK
D10
E10	ReNext	1	Testbeam setup	Gossip 1
F04
F10	ReNext	1	Testbeam setup	Gossip 2
H10	ReNext	16	Laser setup	long term test at 620 (later 650) V grid voltage
I06
J02
J04
J06	ReNext	1	Testbeam setup	Gossip 3
J08	ReNext	1	Testbeam setup	Gossip 4
K04
K06
M06

Measuring the height of the amplification gap

Here at Nikhef Fred Hartjes usually uses an optical microscope: focusing on the grid surface and separately on a pixel inside a hole results in a difference of ocular units, 1 unit corresponding to 1.25 micron. Fred, Harry vd Graaf and Wilco Koppert were measuring the gap on several of the IZM-3 chips using this method. They found values of 62 up to 95 micron. Those results would indicate an inaccuracy in the production both in absolute as well as in the spread of achieved heights.

This is why we asked Yevgen Bilevych of what values he found:

1. There is an SU-8 thickness map automatically generated after the spin coating (thus before the baking), see the SU-8 profile. Although not quite clear why the thickness distribution has this shape (maxima lying at roughly half the radius) it lies in a well-defined region between 56 and 64 micron. According to Yevgen this thickness should even reduce a bit during the final softbaking step. Note the position of the "notch" in the display and the chip coordinates.
2. In this microscope picture you see a direct measurement of the pillar height of chip H03 (of pillars after stripping the grid) with the help of an optical microscope. The chip H03 lies in the region of higher thickness of 63 to 64 micron in the SU-8 map.

Concluding, two independent measurements indicate a thickness of 65 micron maximum and one estimating a gap height considerably higher which leads us to believe that there may be systematic errors in the (microscopic) focussing method.

-- RolfS - 2012-10-17